Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: MNG on December 28, 2010, 06:22:00 pm
-
Hi,
I am looking to get either the Alpa Max or the Arca Swiss Rm3di for architecture with a Leaf Aptus II 12.
After shimming the mount on the Alpa Max with your digital back does anyone know which system is more accurate with regards to lens focusing? I'm thinking of a 23mm HR, 32mm HR and a 47mm XL to begin with.
Thanks
Michael
-
On a classical helicoid focus mount (Alpa) the focus ring makes (almost) one turn to focus from near distance to infinity.
On the Rm3D the focus ring makes 3 turns from near distance to infinity.
In other words: the resolution of the Rm3D's focusing mechanism is much higher.
http://www.snap-rent.de/Detail/Arca_Swiss_Rm3D_3.jpg
Alpa just introduced new focus rings (optional accessory).
Here's the scale for the 47XL and you can see the scaling quite good:
http://www.alpa.ch/docroot/tmp/940x550_stamp/articles/2010/photokina-news/news_pics/500200010_DSC4693s.jpg
I would say the scaling is fine enough for most purposes, however by design the focusing precision of the Rm3D is much higher (three time higher, so to say)
-
Just a minor correction to the above posting by tho_mas. I have the RM3D camera, and it has five turns from near focus to infinity.
As tho_mas points out, the Arca-Swiss R-line of cameras currently have the highest focusing precision capability of any technical camera.
-
They are both great systems, but as far as I know there is no way one can shim the Arca Swiss Rm3di. I think this is the weak link with the Arca and a deal breaker. The focusing on the Arca does not make up for shimming. Focusing maximally is not a substitute if the sensor is off-plane. After shimming my digital backs (both a 45+ and then a 65+) with the Alpa adapter, I can tell you it makes quite a difference. You think you have the sharpest image possible until you shim the adapter for the digital back. So unless you have a perfectly positioned sensor on your digital back - which is most likely not the case - shimming is absolutely essential in getting the maximum sharpness from your lenses.
-
They are both great systems, but as far as I know there is no way one can shim the Arca Swiss Rm3di. I think this is the weak link with the Arca and a deal breaker. The focusing on the Arca does not make up for shimming.
On the Rm3D you don't have to shim the back - you just offest the default distance tables.
The focus ring on the Rm3D doesn't show distance indications in meters or feet… it shows numeric values that translate to a respective distance (Arca provides tables for each lens). These indications are linear (as opposed to the logarithmic indications on classical lenses).
So you just have to find out the offset of your sensor's spacing. Once you know the offset you can use it for all your lenses.
-
Does anyone know a good place to buy a Arca Swiss Rm3d?
And what is the complete price without lenses?
Henrik
-
Hoi,
Europe
http://www.arca-shop.de/index.php
gr
-
On the Rm3D you don't have to shim the back - you just offest the default distance tables.
Btw, just to play devils advocate, what do you do if you've left the distance tables back at the house when you picked up the bag at 0'dark thirty? :P
In all seriousness, what DO you do?
-
Btw, just to play devils advocate, what do you do if you've left the distance tables back at the house when you picked up the bag at 0'dark thirty? :P
In all seriousness, what DO you do?
If you have a good dealer then they make sure you have a copy on your iPhone :-).
If you leave without your iPhone and without your table (which I would leave in the case with the body/lens) - then yes - you're pretty screwed. You could shoot at infinity and focus-bracket like crazy for anything closer, but otherwise you could not selectively focus on a certain distance.
The eModule - if/when it ships to end-users will be a holy grail of focusing. Everyone focuses on the ability to measure a distance using the eModule which I find (at best) moderately helpful. Where everyone should be excited is the real-time and ultra accurate read out of your current focus distance, and front/back focus depth (including ultra easy hyperfocal) which is actually fine tuned for your digital back's sensor (rather than the generic DOF indicators on any other system which are generic-for-film numbers).
That really excites me. It's actually much better than any other focusing option (for tripod based diligent photography). A quick flick of the wrist and you can set your focus for perfect hyperfocal distance every time and know immediately what distance in the foreground will still be tack sharp. This would also allow you to do VERY precise DOF stacking. Of course they have to ship it in significant quantities before it's anything (to me) other than a great idea/promise. Once/if it ships you can expect videos/explanations galore from Capture Integration.
Doug Peterson (e-mail Me) (doug@captureintegration.com)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter (http://"http://www.captureintegration.com/our-company/newsletters/") | RSS Feed (http://"http://www.captureintegration.com/2008/08/11/rss-feeds/")
Buy Capture One 6 at 10% off (http://"http://www.captureintegration.com/phase-one/buy-capture-one/")
-
Re: The focus on the RM3d/RM3di.
The focus, as several people have stated, is much finer than the Alpa can provide. The over ring accessory now available, does give a finer scale to the Alpa but you are still dealing with the limitations of the standard helical provided by the lens manufacturers, so not much help. As David said, a simple test at the beginning of use, can determine the amount of compensation for an individual back and camera combination. This won't change unless the back is changed. I also, for my customers have worked out maximum DOF numbers on a new camera w/lens delivery. This is sort of a hyper focal/aperture combination for each lens. ie: on my 72mm Digitar if I set 6 on the aperture ring I get 27' to infinity with no tilt and with 1/2 tilt I set 3 and get 9' to infinity. These are easy to save as Dave said above and can be useful if cards are lost, etc. I also work out 2 or three closer settings as well. It is the most precise currently available.
Any questions email me.
I love my RM!
:)
-
@DougPeterson: Is it possible to be reasonably certain of where the new Arca focusing module is targetting? Would the depth of focus reading provided by the module make it accurate beyond say 100 feet?
As an aside, no mention has been made here of the iPhone holder now available for the Alpa. With the "Viewfinder Pro" or similar app I suspect that the iPhone would make a super viewfinder and an effective lens-selection tool. Its high-res screen and user-settable "etch marks" allow viewing outside the frame, which should be a good aid for quick composition (within the iPhone camera's viewing range). It may be far superior to the zoom-able finder on the Rm2d/Rm3d which is a bit tricky to set accurately IMHO.
David
-
To all those (including the dealers who sell Arca) who think you can focus your way out of a misaligned sensor: you can not. If the sensor is misaligned - skewed - there is no way you can make up for it through focusing - no matter how "finely" you focus. On my digital back 45+, I had to cut the shim in half to make up for the misalignment.
The emodule as it is conceived is VERY limited. You don't know what you're focusing- especially at 100 feet! I could/would never rely on the emodule.
edit: Unless you have shimmed a digital back or unless you've seen someone shim a digital back and see the before and after, you have no appreciation for the importance of shimming and what a difference it makes. You think you have a sharp image until you see the shimmed version.
-
The emodule as it is conceived is VERY limited. You don't know what you're focusing- especially at 100 feet! I could/would never rely on the emodule.
@DougPeterson: Is it possible to be reasonably certain of where the new Arca focusing module is targetting? Would the depth of focus reading provided by the module make it accurate beyond say 100 feet?
I stated very clearly "Everyone focuses on the ability to measure a distance using the eModule which I find (at best) moderately helpful. Where everyone should be excited is the real-time and ultra accurate read out of your current focus distance, and [depth of field] [...]"
I would NOT buy the eModule in order to measure subject distance. As you said there is little to know way to be sure what subject it is measuring unless the subject is very large, flat, and parallel to the film plane. A leica distometer or a high-end point and shoot which can tell you the distance it is focused at would be much better for establishing subject distance.
I WOULD buy the eModule because it gives you a very accurate real-time read out of the distance at which the camera is currently focused. This includes a (specific to your digital back) reading of the depth of field. So you can look at the eModule and tell that the lens is e.g. focused at exactly 33 meters and at f/11 depth of field extends from 20 meters to infinity. That to me is revolutionary. Other systems have DOF markings on the focus mount but they are 1) designed for film DOF not for your digital back so you have to come up with a fudge factor and 2) they are not very precise since there may only markings at e.g. 10 ft, 30 ft and infinity.
This means you can skip the paper conversion chart and viewfinder rotatable-DOF-indicator and just have the numbers told to you strait-and-easy. It makes the system a lot more elegant in my opinion.
To all those (including the dealers who sell Arca) who think you can focus your way out of a misaligned sensor: you can not. If the sensor is misaligned - skewed - there is no way you can make up for it through focusing - no matter how "finely" you focus. On my digital back 45+, I had to cut the shim in half to make up for the misalignment.
If I found my 45+ was off in a skew (rather than absolute fore-aft position) I would rather send it to Phase for reseating/alignment than start half-shimming a body). Assuming it was under warranty and I had a good dealer relationship that is. But if you would rather buy an Alpa shim kit or a generic shim kit and tape/adhere it to the adapter plate you can accomplish the same thing with an Arca Swiss.
Doug Peterson (e-mail Me) (doug@captureintegration.com)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter (http://"http://www.captureintegration.com/our-company/newsletters/") | RSS Feed (http://"http://www.captureintegration.com/2008/08/11/rss-feeds/")
Buy Capture One 6 at 10% off (http://"http://www.captureintegration.com/phase-one/buy-capture-one/")
-
Hi tho_mas,
how do you find out the offset for your lens and apply this to the camera if there is only the focus ring with the pre-set numbers?
I dont see how the distance only when transferred to the Rm3d focus ring would be accurate if your digital back was out of its plane of focus? Is there a separate dial to allow for the lens offset?
With the Alpa style cameras where the digital back only moves up and down left and right, so I cant see how you can adjust the plane of focus without shimming the back?
Michael
-
To all those (including the dealers who sell Arca) who think you can focus your way out of a misaligned sensor: you can not. If the sensor is misaligned - skewed - there is no way you can make up for it through focusing - no matter how "finely" you focus. On my digital back 45+, I had to cut the shim in half to make up for the misalignment.
that's infact cool with the Apla shimming... that you also can compensate perpendicular misanlignement.
So you can...
- shim the entire back to achieve perfect focus at infinity
- shim the corners of the back to achieve a perfect perpendicular alignement
... but what would you do when the sensor is rotated?
At some point I think you simply should send the digiback back to the maker so that they service it, no?
The emodule as it is conceived is VERY limited. You don't know what you're focusing- especially at 100 feet! I could/would never rely on the emodule.
I'd suggest to re-read Doug's post carefully. As a measurment device it's actually not so great... but as a "display" that is electronically coupled with the lens and therefore providing reference data it's really very useful.
edit: Unless you have shimmed a digital back or unless you've seen someone shim a digital back and see the before and after, you have no appreciation for the importance of shimming and what a difference it makes. You think you have a sharp image until you see the shimmed version.
well, on other systems you can also simply adjust the focus ring on the lens to achieve accurate focus at infinity. Of course you have to see if the grounglass is still usable for focusing... if you use it for focusing at all...
-
I WOULD buy the eModule because it gives you a very accurate real-time read out of the distance at which the camera is currently focused. This includes a (specific to your digital back) reading of the depth of field. So you can look at the eModule and tell that the lens is e.g. focused at exactly 33 meters and at f/11 depth of field extends from 20 meters to infinity. That to me is revolutionary. Other systems have DOF markings on the focus mount but they are 1) designed for film DOF not for your digital back so you have to come up with a fudge factor and 2) they are not very precise since there may only markings at e.g. 10 ft, 30 ft and infinity.
Thank you for the clarity, Doug. I've been wondering whether my decision NOT to buy an emodule for the Rm2d was correct or not...
David
-
how do you find out the offset for your lens and apply this to the camera if there is only the focus ring with the pre-set numbers?
I think David or someone using the Rm3D should elaborate further but basically it's like this:
Let's say your focus point is at 10 meters (measured with a laser distometer). According to the Arca table you should set the respective lens to the numeric value 20 (fictitious example here) to focus at 10 meters. In the actual capture you will see if the focus is spot on or if there is back or front focus. Let's say you have back focus. So you turn the focus ring back until the motif in question at 10 meters is in focus. Read the respective numeric value on the focus ring which is now... for instance... 17. So the offset is -3 and you can use that offset all the time - as mentioned above the scale is linear, so the offset is consistent for all distances (and all lenses, basically). You can store that offset even in the E-Module so that its read-out takes the offset into account.
-
I think David or someone using the Rm3D should elaborate further but basically it's like this:
Let's say your focus point is at 10 meters (measured with a laser distometer). According to the Arca table you should set the respective lens to the numeric value 20 (fictitious example here) to focus at 10 meters. In the actual capture you will see if the focus is spot on or if there is back or front focus. Let's say you have back focus. So you turn the focus ring back until the motif in question at 10 meters is in focus. Read the respective numeric value on the focus ring which is now... for instance... 17. So the offset is -3 and you can use that offset all the time - as mentioned above the scale is linear, so the offset is consistent for all distances (and all lenses, basically). You can store that offset even in the E-Module so that its read-out takes the offset into account.
Spot on, Thomas! That focus ring has fantastic precision, and should prove effective even for future 150mp backs. I have a P65+. I calculated the "shim-offset" by taking a shot of a power line for example that was two miles away with the ring set to 0, then repeated the shot with the ring set to 1, 2, and 3 respectively. The sharpest shot proved to be at 2, but the focus travel is so precise that there was very little difference between the four. So little difference that I didn't bother continuing the calibration with the dial at 1.9 and 2.1 which would certainly have been possible. I'm now just adding 2 to the suggested ring settings for all of my shots.
David
-
that's infact cool with the Apla shimming... that you also can compensate perpendicular misanlignement.
So you can...
- shim the entire back to achieve perfect focus at infinity
- shim the corners of the back to achieve a perfect perpendicular alignement
... but what would you do when the sensor is rotated?
At some point I think you simply should send the digiback back to the maker so that they service it, no?
Once you shim the adapter to the back it doesn't matter about rotation because the Alpa adapter is square and you simply rotate it 90 degrees & refit for portait/landscape. With my P40+ I actually find that there's some disagreement between what the back thinks is level via the electronic horizon vs what my Alpa body & Arca Cube levels indicate. I simply trust the back's indication as it seems to reflect accurately the rotational skew the best. (This is a pet peeve of mine because none of my camera's flash mount/electronic indicator/heads seems to be 100% in agreement on level horizon indications!).
I'd suggest to re-read Doug's post carefully. As a measurment device it's actually not so great... but as a "display" that is electronically coupled with the lens and therefore providing reference data it's really very useful.
That does sound useful. I've had to go through the calibration process of determining the practical DoF for my lenses at f/8 - f/11 for hyperfocal/zone setting. There's a pretty decent tutorial for this by the folks at Optechs Digital that is equally applicable to any camera system, not just Alpa, over at: http://www.optechsdigital.com/Alpa_and_Hyperfocal.html (http://www.optechsdigital.com/Alpa_and_Hyperfocal.html)
Having an accurate indication of the focus distance & DoF range, visible easily from behind the camera vs peering over the top/down at the lens certainly seems a useful feature to me. Ditto for accurately being able to set up a focus stack set too. Thumbs up to Arca for that - albeit not for free :-)
well, on other systems you can also simply adjust the focus ring on the lens to achieve accurate focus at infinity. Of course you have to see if the grounglass is still usable for focusing... if you use it for focusing at all...
That's a tricky one. With the Alpa at least you have to assume that the shimmed back and GG are in agreement. With a 4x loupe I admit that I couldn't really check that out myself to the level of accuracy required to prove it. With the Arca I would assume that you've also got to take it on faith that the lens compensation for the back applies equally to the GG or that it's too small to notice when focusing off the GG I assume.
As an aside, no mention has been made here of the iPhone holder now available for the Alpa. With the "Viewfinder Pro" or similar app I suspect that the iPhone would make a super viewfinder and an effective lens-selection tool. Its high-res screen and user-settable "etch marks" allow viewing outside the frame, which should be a good aid for quick composition (within the iPhone camera's viewing range). It may be far superior to the zoom-able finder on the Rm2d/Rm3d which is a bit tricky to set accurately IMHO.
David
I'm waiting for the iPhone holder to ship - I've been told that it's being delayed by Alpa at the moment which is frustrating because I do use Viewfinder Pro for framing myself for particularly the reason you cite, ie. lens pre-visualization & framing. You can zoom and take a sample screen capture too. The other good thing is that you don't need to buy new masks as you add lenses either which I can almost use as a justification for the cost since custom masks (with multiple focal lengths) cost $200+ each time, although obviously some foresight would help you buy a mask for your anticipated lenses vs what you actually have today I guess.
With respect to the Alpa vs Arca question & trade offs, it certainly seems like it's a Lexus vs Mercedes type of comparison - i.e. both are stellar systems with slightly different advantages. I like the Alpa simplicity and setup accuracy myself but then again the Arca does offer a better tilt/swing system for all lenses. The shim vs lens calibration offset probably works itself out pretty quickly with whichever you choose and you get used to it. I haven't tried the new accurate focus indicators for the Alpa yet although for me it's not been an issue for me personally but that's probably because of my shooting subjects such as landscapes etc.
-
... but what would you do when the sensor is rotated?
Once you shim the adapter to the back it doesn't matter about rotation because the Alpa adapter is square and you simply rotate it 90 degrees & refit for portait/landscape.
I was refering to a rotated sensor. So a sensor out of level by 0.1° or 0.2° or so. There is no way to adjust this axis on the Alpa (or any other camera).
well, on other systems you can also simply adjust the focus ring on the lens to achieve accurate focus at infinity. Of course you have to see if the grounglass is still usable for focusing... if you use it for focusing at all...
That's a tricky one. With the Alpa at least you have to assume that the shimmed back and GG are in agreement. With a 4x loupe I admit that I couldn't really check that out myself to the level of accuracy required to prove it. With the Arca I would assume that you've also got to take it on faith that the lens compensation for the back applies equally to the GG or that it's too small to notice when focusing off the GG I assume.
You are right. It certainly can be tricky. I've adjusted my lenses (i.e. the focus rings) to achieve perfect focus at infinity (focus is also accurate at the 10m and 5m indication... never checked closer distances). My groundglass is still usable for focusing... but if it would not, I'd shim it :-)
However I use the groundglass only for focusing close distances... for mid and wide distances I use a laser disto. Focusing a 47mm (43mm) lens at 16 meters distance or so is almost impossible on the groundglass as the magnification of the subject is too small (I use a 6x asph. loupe... but I feel a loupe with higher magnification only enlarges the grain... it's not really better suited for focusing. At least that's my personal experience).
I've taped additional indications on my lenses so that a laser disto really works good for me (at least as long as the damn laser disto works... in bright sunlight it can be tricky). This is why I am finding the new Alpa HP focusing rings extremely useful... and the Rm3D simply outstanding.
-
With respect to the Alpa vs Arca question & trade offs, it certainly seems like it's a Lexus vs Mercedes type of comparison - i.e. both are stellar systems with slightly different advantages. I like the Alpa simplicity and setup accuracy myself but then again the Arca does offer a better tilt/swing system for all lenses. The shim vs lens calibration offset probably works itself out pretty quickly with whichever you choose and you get used to it. I haven't tried the new accurate focus indicators for the Alpa yet although for me it's not been an issue for me personally but that's probably because of my shooting subjects such as landscapes etc.
Agreed, Graham. To quote Mark Dubovoy, we're nit-picking here.
The elegant engineering and design of the Arca may prove advantageous though -- at least in theory. Lenses with Arca mounts do not require the per-lens helical threads, which should make them less expensive...
David
-
I think David or someone using the Rm3D should elaborate further but basically it's like this:
Let's say your focus point is at 10 meters (measured with a laser distometer). According to the Arca table you should set the respective lens to the numeric value 20 (fictitious example here) to focus at 10 meters. In the actual capture you will see if the focus is spot on or if there is back or front focus. Let's say you have back focus. So you turn the focus ring back until the motif in question at 10 meters is in focus. Read the respective numeric value on the focus ring which is now... for instance... 17. So the offset is -3 and you can use that offset all the time - as mentioned above the scale is linear, so the offset is consistent for all distances (and all lenses, basically). You can store that offset even in the E-Module so that its read-out takes the offset into account.
Why as a PHOTOGRAPHER would we need to go through above indicated process as compared to simply reading and setting a distance on a helical focus ring??? :'(
With the Alpa at least you have to assume that the shimmed back and GG are in agreement. With a 4x loupe I admit that I couldn't really check that out myself to the level of accuracy required to prove it. With the Arca I would assume that you've also got to take it on faith that the lens compensation for the back applies equally to the GG or that it's too small to notice when focusing off the GG I assume.
If I understand correct of Alpa, their cameras, lenses and GG are calibrated/fabricated to absolute exact within tight tolerances. Thus what remains to calibrate is the shimming of the digital back, which does not necessarily adhere to same very tight tolerances as Alpa cameras, lenses and GG.
Assuming Arca provide same tight tolerances as Alpa on cameras, lenses and GG, thus by accounting for the focus error of digital back by applying compensation to focus tables, thus what we focus on GG would require us to after perfect focus on GG apply same compensation to lens after focus as we do to our lens tables…
Dang, I am an is engineer and photo is my advanced hobby. Thus not problem to calculate, but… the Arca focusing is simply too $#(*^(&^$#** complex!!!
Now, one more issue; per my understanding focus of a tech camera is similar to a film 617, thus I will assume that one frequent focus based on hyper focal distance, or at least based on a zone (pretty much like pre-focus on a Leica)? Thus… assuming the back is perfect shimmed to a system with very tight tolerances (= depth of focus is perfect adjusted), then what why would it really matter if the focus ring have the very exact adjustments as Arca does? I do not get it. ??? ::)
Regards
Anders
-
Why as a PHOTOGRAPHER would we need to go through above indicated process as compared to simply reading and setting a distance on a helical focus ring??? :'(
you don't have to... But you can, if you want the high precision of Arca's focus mount.
As a PHOTOGRAPHER you can also buy the E-Module that shows you the distance in meters and feet and at the same time the DOF.
As a PHOTOGRAPHER you might also appreciate that you can read the E-Module when you are standing behind the camera...
you can even take it in your hands and read it when the camera is mounted above head level.
Now, as a PHOTOGRAPHER I'd say that's pretty cool.
-
The real reason for this variation is that the sensor manufacturers cannot tell you exactly how deeply embedded the pixels are chip to chip. So a camera manufacturer has to average and let you fine tune to your lenses. Thus we end up with shimming or a fudge factor. Even the higher end DSLR cameras have recognized this. They allow a user to calibrate the focus of the camera for each lens and save the result in the cameras memory. Canon has this in 7d and above for sure(Not sure on 60d or lower models) and Nikon on D300s and above you can for sure.
So even these cameras with fixed lens mounts need a tweak for their sensors.
Also as someone else cogently said, the easiest way to use the RM3d will be with the eModule by just watching the back of it. It will not only give you the distance focused, but actually 4 apertures
with the near/far distances for each combination. This will be further enhanced by the fine tuning mentioned for pixel pitch and circle of confusion choices. The hand held lasers can work, but in daylight are very hard to see at distance unless optical type, or if they are optical, they will not focus close if that is something you are trying. So when we get it, I believe the eModule will make the RM3di and RM2d the most accurate focusing cameras available at this time. :)
-
thus what we focus on GG would require us to after perfect focus on GG apply same compensation to lens after focus as we do to our lens tables…
I think this is where you are having difficulty understanding the Rm3d. There is no focusing on GG with the Arca. You can compose with GG (or not), but focusing is done with distance measurement with (or without) the E-module.
Now, one more issue; per my understanding focus of a tech camera is similar to a film 617, thus I will assume that one frequent focus based on hyper focal distance, or at least based on a zone (pretty much like pre-focus on a Leica)? Thus… assuming the back is perfect shimmed to a system with very tight tolerances (= depth of focus is perfect adjusted), then what why would it really matter if the focus ring have the very exact adjustments as Arca does? I do not get it. ??? ::)
Hyperfocal distance may be meaningful for cameras that do not have any front tilt or swing, which is not the case with the RM3d.
-
I think this is where you are having difficulty understanding the Rm3d. There is no focusing on GG with the Arca. You can compose with GG (or not), but focusing is done with distance measurement with (or without) the E-module.
Hyperfocal distance may be meaningful for cameras that do not have any front tilt or swing, which is not the case with the RM3d.
Hm.
Alpa:
Shim adjustment of back, together with all other components lends to perfect zone focus and hyperfocal distance focus. Also to viewing and perfect focus using GG. Alpa helical focus sufficient for these.
Using laser distometer one can also set the focus point rather exact using the helical focus.
Correct?
Arca:
No shim adjustment, apply fudge factors, assumes sensor is perfect parallel to camera system (including to shift, rise, lenses and GG).
GG for viewing only (unless perhaps apply same fudge factor as applied to lens focus, at a refocus post GG focus).
Focus tables require a lookup for more or less each shot.
E-module will give accurate the focus and DOF that lens is current set to, but the ultrasound is not at all times reliable. Also add cost and reliability issue.
Above correct?
Very high accuracy helical focus, but is this in reality at all useful compared to Alpa except when photographing tethered?
At tilt/swing how would one accurate determine focus without shooting tethered?
Please do not get me wrong, indeed I find the RM3D and especially RM2D interesting. Not to highjack this threat, but how would Cambo RS compare?
How about the sliding mechanisms of Arca and Cambo, are they as precise (in sliding plane) as are Alpa’s roller bearings?
Thanks!
-
Before i shimmed the 45+ I was satisfied with its focus. A friend showed me a before and after and I was amazed at the difference. When I shimmed my back it was off by a very slight fraction. Adding the half shim (plus a full shim) made all the difference in the world. Why should I have returned the back to the dealer? Because it wasn't seated in a fore-aft position but in a skew? Ridiculous! If the sensor is not seated optimally it doesn't matter whether it's fore-aft or skew. No digital back is perfect: calibration errors, dead pixels, misaligned sensors. For calibration errors and such, the digital back gets sent back. For sensor alignment, it's better to compensate with a shim because the next db you get could have the same issue. My db is great now. When I got my 65+, the first thing I did was reshim my adapter plate. Eeezy-peezy. Do it once and then forget about it until you get a new db.
The Arca has a lot of nice bells and whistles that appeal to a photographer. For me the bottom line is the quality and sharpness of my images. If the sensor is not seated optimally - and this is more than likely the case - then I would want a way to compensate for this, because not doing so would mean that no matter what lens I use and no matter how finely I focus, the final image will not be optimally sharp.
If I found my 45+ was off in a skew (rather than absolute fore-aft position) I would rather send it to Phase for reseating/alignment than start half-shimming a body). Assuming it was under warranty and I had a good dealer relationship that is. But if you would rather buy an Alpa shim kit or a generic shim kit and tape/adhere it to the adapter plate you can accomplish the same thing with an Arca Swiss.
Doug Peterson (e-mail Me) (doug@captureintegration.com)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter (http://"http://www.captureintegration.com/our-company/newsletters/") | RSS Feed (http://"http://www.captureintegration.com/2008/08/11/rss-feeds/")
Buy Capture One 6 at 10% off (http://"http://www.captureintegration.com/phase-one/buy-capture-one/")
-
Hm.
Alpa:
Shim adjustment of back, together with all other components lends to perfect zone focus and hyperfocal distance focus. Also to viewing and perfect focus using GG. Alpa helical focus sufficient for these.
Using laser distometer one can also set the focus point rather exact using the helical focus.
Correct?
"perfect" focus using only GG is not possible. It is a hard fact to swallow for most photographers, and until you actually prove it to yourself you will most likely remain in a state of denial. On the other hand, some photographers may have less concern for critical focus than others and do not really care whether they are able to capture 50 lp/mm versus 60 lp/mm of resolution.
Arca-Swiss has chosen to design their R-line of cameras based on this fundamental limitation of GG focusing in order to provide photographers with a tool to improve their focusing precision. Whether or not you need this capability is an individual choice.
Arca:
No shim adjustment, apply fudge factors, assumes sensor is perfect parallel to camera system (including to shift, rise, lenses and GG).
GG for viewing only (unless perhaps apply same fudge factor as applied to lens focus, at a refocus post GG focus).
Focus tables require a lookup for more or less each shot.
E-module will give accurate the focus and DOF that lens is current set to, but the ultrasound is not at all times reliable. Also add cost and reliability issue.
Above correct?
There are no "fudge factors" involved. Input data is needed in the form of distance measurements. A "fudge factor" is something that implies guesswork of unknown origins. The ultrasound of the E-module is intended for interiors or relatively close distances (e.g., within 30 feet or so) and its precision is proportional to its range (max. error of 0.1%). For longer distances or more precision, a laser must be used (which can yield accuracy +/- 0.04 inches up to 650 ft.).
Very high accuracy helical focus, but is this in reality at all useful compared to Alpa except when photographing tethered?
At tilt/swing how would one accurate determine focus without shooting tethered?
Again, everything is based on the ability to measure distance. You can use brute force Scheimpflug algebra to do the math, or you can attempt to make focusing tables for yourself at fixed camera heights, near/far distances, f-stops, and tilt/shift angles.
Please do not get me wrong, indeed I find the RM3D and especially RM2D interesting. Not to highjack this threat, but how would Cambo RS compare?
How about the sliding mechanisms of Arca and Cambo, are they as precise (in sliding plane) as are Alpa’s roller bearings?
Thanks!
I do not find any visible error when moving the rear x-y sled of the RM3D. I cannot comment on the other cameras, as I have not tested them.
-
With all these different ways to focus correctly with thse cameras, will they ever be able to focus better than the modern af systems like Phase and Hasselblad? Or is it just the best of what you can get if you need tilt and shift?
Are these new Rodenstock and Schneider lenses better than mf-lenses?
-
Henrik,
One thing you can rely on is that technical cameras can't focus themselves and rely entirely on the skill of the photographer, whether it be via focusing on the GG, transcribing a laser distometer reading or ultrasonic reading to the lens or zone/hyperfocal focusing. I know that I can do a better job of focusing with my Alpa than my Phase One 645DF can manage although obviously it takes a lot longer to do it.
As regards the lenses, no competition. Rodenstock & Schneider digital lenses are pretty much unmatched by any current AF or MF medium format glass. I don't think that anyone would dispute that.
-
As regards the lenses, no competition. Rodenstock & Schneider digital lenses are pretty much unmatched by any current AF or MF medium format glass. I don't think that anyone would dispute that.
Technically, the new Leica S2 lenses are optically competitive with the Rodenstock and Schneider digital lenses, as they are diffraction limited designs with low distortion, APO corrected and make prodigious use of exotic and aspheric glass (and also floating lens elements for additional corrections, unlike the Rodenstock and Schneider lenses). However, these Leica S2 lenses have much smaller image circles and do not offer the photographer any perspective correction with them, and so are basically unusable for architectural work.
-
What about tilt for the two systems?
As I understand the Alpa can tilt 6 degrees with some special adapter?
Is that front or back tilt or front tilt?
What about the Arca? How is the tilt done and how much can it be tilted?
-
The Alpa has two tilt/swing adapters. One is 0-6 degrees, the other is 0-12 degrees. I believe that this can be used either in front or behind the camera body to tilt the lens or back. Since this introduces a 34mm spacer into the body/lens width it requires short barrel lenses. What this means in turn is that the minimum focal length that can be used with the T/S adapter is 80mm or longer.
-
The Alpa has two tilt/swing adapters. One is 0-6 degrees, the other is 0-12 degrees. This can be used either in front or behind the camera body to tilt the lens or back. Since this introduces a 34mm spacer into the body/lens width it requires short barrel lenses. What this means in turn is that the minimum focal length that can be used with the T/S adapter is 80mm or longer.
Thank you, Graham!
Does anyone know how wide lenses can be tilted with the Arca?
-
I have the Alpa but from what I know about the Arca the tilt function is built into the body itself and thus one advantage of that mechanism is that you aren't restricted when it comes to wide lenses with tilt. I'm sure an Arca owner will elaborate ... ;)
-
Very high accuracy helical focus, but is this in reality at all useful compared to Alpa except when photographing tethered?
IMO the high focusing precision of the Rm3D is useful in particular when shooting non-tethered.
I think the decision also depends a bit on the focal lengths (and subjects) you are shooting. With wide lenses and shooting mostly realtively wide distances at apertures of f8 - f16 you actually don't really need super high precission of the focus mechanism. It is "relatively" easy to handle wide angle lenses with a classical helicoid focus mount (Alpa, Cambo, arTec etc.). The longer the lenses the more you can benefit from the Arca focusing mechnism. The same goes for shooting at wider apertures (f5.6 or even f4 with some Digarons).
IMO ...
Please do not get me wrong, indeed I find the RM3D and especially RM2D interesting. Not to highjack this threat, but how would Cambo RS compare?
Rm2D vs. WRS: the (lateral) movements on the Rm2D are not geared. In this regard I'd clearly favor the WRS. The WRS also offers larger movements (25mm rise/15mm fall, +/-20mm lateral). Too, the WRS provides a number of little features that add to the usability (it's really a clever design accounting for the compactness).
How about the sliding mechanisms of Arca and Cambo, are they as precise (in sliding plane) as are Alpa’s roller bearings?
I know that Alpa highlights their roller bearings design... and it's certainly super precise and solid. I can only speak for the WRS... but I have not discovered any issues due to perpendicular misalignement of the rear standard... there is no "tilt" or "swing" or so on the rear standard after 2 years of use. If there is some, it's easy to adjust (at Cambo, not by yourself!).
There are differences in design, in the machining and materials of all these cameras. But I think they are all very accurate...
IMO the decisive point between the Alpa and the Arca is whether you need tilt/swing even for wide or moderate wide lenses (on the Alpa only available for longer lenses... up from 70mm or 80mm I think / the Cambo WRS provides tilt/swing lens panels for almost all focal lengths) and whether you need the higher focusing precision of the Rm3D. Other than that you can't wrong... IMO.
I'd also take into account system integration and accessories. The Rm3D also provides a sliding back and you can use the Rm3D body as a front standard on Arca's M-Line view cameras. IIRC Chr. Barrett once had a short writeup on this on his webblog.
-
here...
CB on the Rm3D: http://christopherbarrett.net/blog/?p=1350
… and the M-Line II: http://christopherbarrett.net/blog/?p=800
An addional note on WRS vs. Max: The most obvious difference is, well, the price. Then the compactness of the WRS.
Now, if the Max offers all the features you need (i.e. if you are fine without tilt/swing for shorter lenses and if you don't need a sliding back...) and if you don't care about the cost you certainly can't go wrong with the Max.
Can you go wrong with the WRS? I would say no, but there are some trade offs (sure, if you consider the price difference).
For instance...
- no back shimming (you have to adjust the infinity lock on the lenses and then have to see if you can still can use the groundglass for focussing; on my kit the GG works fine)
- Jeffrey Totaro (who used to use Cambo... though AFAIK the WDS, not the WRS ... and now the Max) once noted somewhere here on the forum that the coating of the Alpa bodies is better suited to reduce internal flare. I would say I have no issues with flare or contrast in conjunction with my 47XL (resp. the 43XL lately) on the WRS, but with the 70mm. Actually I thought it's just the lens that is prone to show flare so I always adjusted my compendium as tight as possible. However after reading Jeffery's comments I've inserted black velvet in the lens barrel (also on the camera interface). Haven't shot any meaningful subjects with the 70mm since then but I would say there is an improvement.
So bottom line... the WRS possibly requires some "tuning", but still is capable of delivering the desired IQ.
Of course, if you don't mind the price of the Alpa you get it all out of the box.
RE handling me personally I like the WRS better. I often mount the camera above head level and due to some features on the WRS it's really easy to operate the camera "blind".
-
Does anyone know how wide lenses can be tilted with the Arca?
The tilt is on the body itself. Any lens which mounts to the Arca can be tilted.
Doug Peterson (e-mail Me) (doug@captureintegration.com)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter (http://"http://www.captureintegration.com/our-company/newsletters/") | RSS Feed (http://"http://www.captureintegration.com/2008/08/11/rss-feeds/")
Buy Capture One 6 at 10% off (http://"http://www.captureintegration.com/phase-one/buy-capture-one/")
-
And how does these cameras compare to Sinar arTec?
Seems to be a lot like the Arca?
And Sinar have been using shimmingsets for many years ;)
But as far as I know not on the newest backs?
-
Moved here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
And how does these cameras compare to Sinar arTec?
Seems to be a lot like the Arca?
no. The arTec is the only camera that is designed around a sliding back. So the sliding back is not an attachable accessory... the rear standard of the actual camera is the sliding back.
Therefore the arTec provides rise/fall on the lens and lateral movements on the rear whereas the Arca provides 4way shift on the rear.
-
Moved here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
You can in fact shim the Cambo Wide RS, and quite easily at that - basically following the instructions for shimming the Alpa. What you need are a set of shims, such as those available here (http://www.luminous-landscape.com/forum/index.php?topic=49894.20;topicseen) (which are the plastic type, easy to cut and with good enough dimensional stability under temperature change and pressure). You then simply remove the four screws highlighted, which are set in bushings that allow the bracket that the adapter plate sits in to move back and forward), and insert the shims as required. Two of the screws are hidden behind the small plates that hold the adapter plate on, so you need to remove these to access them. The screws used in the bushings are M2 x 5mm. A useful trick is to use a dab of thread locker (blue for instance - easily removed if needs be) to fix the bushings in place (flush to the plate they sit in), and then when you tighten the screws they won't move and it will be only the shims that determine the fore/aft position of the digital back. Plastic shimming is available as thin as 0.0005" = 0.0127mm. This is really thin, probably not much more than the WRS (or Alpa or Arca) would expand/contract on a really hot/cold day (respectively), but if you think it makes a difference no harm using it. The thicknesses I bought were: 0.0005" (~0.01mm), 0.001" (~0.02mm), 0.0015" (~0.03mm), 0.002" (~0.05mm), 0.04" (~0.1mm), 0.0075" (~0.2mm) and 0.12" (~0.3mm)
Note, before doing all this check that you need to - see the optechs video on their website first. The way the rear plate on my Cambo was set up was perfectly parallel (well done Cambo) - but it did need moving back a fraction to match the position of the sensor in my DB. In this respect, the way Cambo have designed the rear of the RS is very clever, the bracket that the adapter plate sits in is infinitely variable (in respect of front/back movement) by adjusting the height of the four bushings and locking them in place with the internal screws (which you could just do in order to shim your back, but as I said above, plastic [or metal] shims are less hassle since they keep the bracket square to the camera).
awesome - many thanks!!!
Could you please re-post the link to the shims... the link posted above refers to this thread... not to the said shims.
Man, this is really cool - thanks a lot again!
-
Moved here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
In the US: http://www.practishim.com/ (http://www.practishim.com/) is one place ($50 min order I think)
In the UK:
http://www.cromwell.co.uk/PCN9653710A (http://www.cromwell.co.uk/PCN9653710A)
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0681407 (http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0681407)
Would be nice if Cambo offered the shims - making a design to fit perfectly would be pretty easy (given that they have all the dimensions, I had to use a vernier calliper), and machining them would be a no brainer - in fact plenty of places on the net will machine them for you if you send a design.
great - thank you!
Yes, the cutting of those pieces is not easy as the edges twist when you cut them.
A precsion mechnic here told me those things are cutted using a laser (at least with metal shims) when I asked him to make shims for my Contax 645 screen.
Thanks again - you made my day!
-
Moved here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
super!
thanks again!
-
Moved here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
Have some other tips - will post them next week.
please do so - I am looking foward to it!
Maybe I can add one or two tips...
It's probably better to start a new thread as these "WRS tips + tricks" do not refer to the Max vs. Rm3D topic.
-
Good point - have moved everything here (http://www.luminous-landscape.com/forum/index.php?topic=49977.0).
-
I am saving up for the eventual purchase of an Arca rm3di, and at this time am attempting to absorb the extremely useful info posted here explaining how to make best use the camera's somewhat complex virtues. Thanks to everyone here for the explanations presented so far which I think I understand pretty well, but there is still one aspect that I am in the dark about. I do mostly landscape, and find myself using tilt whenever it can be of help, but from what I am understanding now, the rm3di's focusing devices cease to be applicable when tilt or swing is applied. This camera's design seems to be really brilliant overall, but what combination of approaches should be employed when a tilt or swing is indicated, and what can be done to account for the focus situation regarding three dimensional objects protruding slightly above a tilted focal plain? Can the rm3di's non visual focusing system be applied here as well?
-
The focus of an RM3di is still super accurate even with tilt or swing. When you get your camera you can work out a number for maximum depth of field for all your lenses.
For instance if you look on Schneider Optics site and go to the page for 72mm Apo-Digitar (copal) and look at the 'sample' tab. The landscape was made by me. I set up and leveled the camera. Then having predetermined for this lens the max depth for DOF and quality, sharpness etc., I dialed in focus '3' and 1.5 mks tilt along with 5 rise. As you could see the picture is sharp from foreground to infinity.(F11)
This is a quite easy procedure you can work out for each lens and once you have done it won't change unless your back changes and then it might not change either. I set up many customers for them if they have trouble or give them my numbers for where to start and they just tweak them to match their back.
Rod
-
Since there is a lot said here about Alpa, I wish to jump in and make some remarks:
I couldn't agree more with "fuzzyfoto": unless you have seen it with your eyes, done step by step with the shims, you won't believe it. You may believe that you have got it all out from your x MPx sensor and from your best lens, but no, there is (much) more to get out of it by shimming your own back correctly.
It takes 15 min, but then you are done and sure to be set at infinity the most precisely possible. It is, IMO, the most simple way to achieve the precise focus. But don't believe my sole words, test it out by yourself.
And yes, any back has some misalignment and has to be shimmed, sometimes (often) in both directions.
Best regards
Thierry
edit: Unless you have shimmed a digital back or unless you've seen someone shim a digital back and see the before and after, you have no appreciation for the importance of shimming and what a difference it makes. You think you have a sharp image until you see the shimmed version.
-
Dear Rod,
That's not the case: the Alpa HPF ring is not only of a big help, but does in fact allow for perfect focus, there where you need it, on any point of the HPF ring scale. I have in fact tried it out a couple of weeks ago, and it's not limited like one can read it here and there.
Best regards
Thierry
The focus, as several people have stated, is much finer than the Alpa can provide. The over ring accessory now available, does give a finer scale to the Alpa but you are still dealing with the limitations of the standard helical provided by the lens manufacturers, so not much help.
-
Thierry,
Not to argue, but as the helical focus does not rotate even 360 degrees it cannot possibly offer the fine focus adjustment of an Arca-Swiss. With the 5 turns of an Arca-Swiss focus mechanism it is a much finer pitch and allows for much finer adjustments.
The Alpa over ring was an improvement but is still limited by the helical used by the lens manufacturers since the 1970's.
Having said that that I am sure the Alpa does OK within those limits. And it will focus fairly accurately with the lens stopped down a bit. It will however not focus as close as an Arca-Swiss R camera nor as accurately and consistently when lens is wide open. I have played with a 12 max and it is a nice camera. Not quite as accurate as an ARCA but better, in my opinion than the rest of the competition. The RM3di can also use up to a 6x9 format without adapting the front and has body incorporated tilt.
Both are nicely finished cameras and can take excellent pictures...
Congratulations on your new position. Glad to have a knowledgeable person on board.
-
Rod,
Thanks for your words
No problem, we simply exchange information here, with respect but on an open basis. I simply have to disagree, when I know how I am precise by using it practically, not in theory. It doesn't need to rotate 360 degrees to get precise focus, try it out. It doesn't need to rotate 360 degrees to get precise focus, that's just a theoretical view to believe so, when otherwise the camera is so well designed and built and the back shimmed correctly.
Then, the focus-mechanism of Arca may be able to move 5 turns (mechanically speaking), but one forgets to say that this is not the case with all lenses. With some lenses (I would have to find out which ones) one has only a very limited rotation available.
I would anyway suggest anyone to try the focusing on both cameras out, side by side, in field-conditions, as I have done it.
Best to you too, Rod
Thierry
Not to argue, but as the helical focus does not rotate even 360 degrees it cannot possibly offer the fine focus adjustment of an Arca-Swiss. With the 5 turns of an Arca-Swiss focus mechanism it is a much finer pitch and allows for much finer adjustments.
Congratulations on your new position. Glad to have a knowledgeable person on board.
-
I simply have to disagree, when I know how I am precise by using it practically, not in theory. It doesn't need to rotate 360 degrees to get precise focus, try it out. It doesn't need to rotate 360 degrees to get precise focus, that's just a theoretical view to believe so, when otherwise the camera is so well designed and built and the back shimmed correctly.
Thierry, I'm with Rod on this one. The Alpa rings are a great method but to argue its as accurate as the Arca system is just plain wrong. The Arca R camera have by far the most accurate focus with any lens regardless of how many turns (5, 4, 3, 2 or 1) because of how finely geared the mechanism is. If using a wide aperture, I would think even after using a distometer to establish subject distance, a user could be slightly off applying these setting to the Alpa ring due to its limited helical range. A small error could possibly place the focus out enough to notice on the final capture.
-
Each camera has its advantages and disadvantages. I am a happy owner of both cameras. Both, I think a great tool. I know from experience that each of these cameras can be very precise. That Arca has a large ring from the standpoint of mechanics should mean that it is more precise, but I am convinced that Alpa is not worse in this respect - simple design can be misleading. Just skill. Once I could not adjust quickly focus on the 503CW, it seemed impossible. But after a few days, it was child's play. The choice of equipment is a personal issue. I love both systems:) Maybe because they are well done which is unfortunately rare these days...
-
I can understand because one cameras focus ring turns more revolutions you could assume it is more "precise". I'll agree technically it is certainly true, but in practicality for most (the exception might be a lot of very close up work where you are probably doing focus stacks anyway) the Alpa with the new rings is very precise - more than adequate. Personally it would drive me nuts to turn the lens that much to get it focus. As a landscape shooter, knowing that infinity is nailed is more important so I prefer shimming over an offset. But I think either system offers amazing stuff, and the real issue facing most tech camera shooters as the pixels get smaller is the lens design and resulting issues with wide angle lens. At this point, unless there is something wrong with my back, my Schneider 35XL is not usable on my Alpa with IQ180 back - even LCC doesn't compensate for the falloff and color shift. I'm better off shooting my DF with the PhaseOne 28.
Do the Arca lenses all turn past infinity in case the sensor plane requires that, or are the adaptors designed so that most of the time infinity needs to be fine tuned a little inside the infinity mark? Just sort of curious how that works.
I assume the offset is very consistent, so you only have to remember "one" number? How difficult is it to actually apply that, something easily done in the head or do you always have to refer to some guide or calculator? I feel like I'm in molasses when working with these cameras anyway, curious if this is a "no brainer" or if it slows you down a little more. (Please don't get defensive on this one, just asking because I admit working with any tech camera is a different world than SLR)
-
HI I own the Arca Rl3D and use it for landscape,I love it and is a little bigger,but you have more movements and there will be
a sliding back for this camera soon,and you will be able to do with a p65 in there shots vertical with the right lens a 30x60 image.The rodenstock 55 fits the bill and a very sharp lens,and any lens with 125 mm image circle can do the 30x60 image.Also for the shiming of the camera,you do not shim the camera but you can do it by the numbers,and I might add that you can do this for every lens and not just
one lens as on other cameras. Also every lens that Arca mounts in there cones is shimmed and tested by shooting test shots.Also the sliding
back will be of 4x5 format so you will be able to see the whole image circle at one time,as whats around your format box,and
will also have crop marks for other pano sizes with the 30x60 max size and you can make about 11 differant image sizes from the 2x4 format.
I'am sure there will other camera backs with crop marks for them also.
-
I feel the need to jump in and clarify a few things since there seems to be some misunderstandings on how the Arca works.
First, the focus helical on the Arca is part of the body and is therefore "generic" to all lenses. To get from infinity to really close, you may need all 4 revolutions with a longer lens. However with a shorter lens like a 40, you get from 0.5M to infinity with about one turn. The knob for that "turn" is about 4" in diameter and has 34 main graduations around the ring, with 5 divider hash points marked off between each whole number. You can easily interpolate to between each hash mark for basically 10 graduations between each whole number, or 340 distinct positions for one full revolution.
That may be a more fine set of gradations than most folks want, but I can tell you that with a 40mm lens over the IQ180 back, you can easily "see" the exact focus plane move pretty significantly in the image between one whole number mark.
Moreover -- and this may be the most salient point -- the Arca has tilts. When you impart tilt, even very minor adjustments to focus distance can have a magnified effect on the relative position and effect of that now tilted focus plane.
Thus, for a camera with tilts, having very precise, fine focus control is a clear benefit. With a camera that does not tilt, it is possibly less necessary -- meaning close enough often is. So while the existing arrangement for the Alpa without tilts may be more than adequate, the extra resolution on the focus knob of the Arca is welcome, especially if you impart tilts.
Finally, the amount of "time" it takes to do one complete revolution on teh Arca is trivial -- we're talking a fraction of a second.
Hope that helps clarify,
-
Thanks Jack. I've never really tried using tilts much for focus, but always assumed once you start tilting things, distance scales sort of go out the window. Maybe I'm wrong and the trick is being able to know exactly where to measure when figuring out your focus plane.
As far as precision, maybe some clarification on the Alpa as well. I only have the HPF rings for my 70mm. When shooting with the 47 or 35 I'm either focus stacking, using a limited version of hyperfocal distance (basically I shoot each lens at f/11 and f/16 and figure out where infinity fails to satisfy me and set it there), or I know there isn't anything close enough to worry about it. So I haven't put the HPF rings on the wides (yet anyway).
On the 70mm, the focus ring turns over 3/4's of a revolution and does make the ring much larger although prob more like 3". The HPF ring divides that into 50 increments, and there are 5 sub increments. It's actually quite easy to set the lens "between" each subincrement about the thickness of the line so the line covers the space between the two. However, the precision at close range is rather impressive, 10 of the 50 cover only 2.65 feet up to 3.31 feet, so 50 minor steps to go 9 inches. The next 10 get you to 4.4 feet, and overall 40 of the 50 major steps, or 200 of the 250 minor steps covers the range from 2.65 feet 16.6 feet - so thats 200 steps to cover about 167 inches. Of course, one challenge that makes them less useful than what I understand about the arca is the fact they are non linear, so each substep doesn't represent "x" inches. This means you have to sort of look at the two major steps, do some math in your head, and figure out what each substep represents in distance. Example, on the closest subset, each step represents 0.12" while at the 40th major step, each substep represents about 5.5" so even if you factor in using in between each sub-increment for distances between 14.3 to 16.6 feet your control is probably only around 2.5" per step. From there it scales and become pretty inaccurate so if you need precise focus at 192 feet, tough to do on the Alpa with the HPF rings ... so then your having to depend on whatever tools the back has for you.
They certainly are both great systems. I know alpa prides itself on precision, and won't do sliding backs. After calibrating mine and realizing .01mm spacing between the back and the body does make a difference I can see their point. Some method to account for that is critical, sounds like Arca's system works just fine. I certainly hope Phase realizes it the precision problem (certainly Joseph Holmes has documented it well). The DF really should have a focus calibration function much like dSLR's, to compensate for this as well as the difference between focus screen and sensor.
-
For anyone interested that may have missed it, I have published a video on the Arca-Swiss R system on my blog:
http://rodklukas.com/wp/arca-swiss/video-introduction-to-arca-swiss-r-cameras/
The first half is filmed in the studio - it takes you through the parts and accessories of the Rm3Di camera and how they function. The second part is making a photograph in the field. This will explain the system in some detail. Take a look, it may clear up your questions.
-
I feel the need to jump in and clarify a few things since there seems to be some misunderstandings on how the Arca works.
First, the focus helical on the Arca is part of the body and is therefore "generic" to all lenses. To get from infinity to really close, you may need all 4 revolutions with a longer lens. However with a shorter lens like a 40, you get from 0.5M to infinity with about one turn. The knob for that "turn" is about 4" in diameter and has 32 main graduations around the ring, with 5 divider hash points marked off between each whole number. You can easily interpolate to between each hash mark for basically 10 graduations between each whole number, or 320 distinct positions for one full revolution.
Thanks for pointing this out, Jack, this is a common error in Arca-Alpa discussions: You don't use 5 revolutions with each and every lens.
If you have a lens with a small hub, you stay within one revolution, e.g., with the Schneider 28mm. The supplied distance table for the SK28 runs from 0.5m (on the helicoid: 23.2) to 25m (0.4), so this is less than a full revolution. If you look at the Arca-table for the SK43, you go from 0.5m (RED 26.7) to 25m (1.1), that is, you are close to two revolutions. If you look at the table for the Schneider 90mm, you use use up to five revolutions but if you focus somewhere between 3.4m and infinity, focusing takes place within one revolution. Put differently, the precision of the Arca way of focusing increases with a large focus hub BUT one must keep in mind that you have large movements in the close range and these get smaller if you approach infinity.
One more point: Whether focusing an Arca-lens (without the E-module) or focusing an Alpa-lens with a HPF ring using a Disto, you have to have the respective table at your hands. Take the SK 43mm: on the Alpa HPF you have an explicit mark for 7.29m and another one for 4.89m. The table will tell you that the small marks between correspond to 6.63m, 6.09m, 5.63m, 5.23m respectively. On the Arca table, looking at approximately the same range, the following distances and corresponding values are given: 7.5m (3.7), 7m (4.0), 6.5m (4.3), 6.0m (4.7), 5.5m (5.1), 4.8m (5.9).
It's worth having a look at the Alpa-HPF distance tables to get a more concrete idea of what you can do with HPF rings (which you don't get for all lenses).
(Apologies for my usage of meter instead of feet!)
Chris
-
@ Wayne
you aren't wrong, the distance scale goes out when tilting (or swinging). For a tilt of let's say 5 or 6 degrees to get your sharpness plane set almost "flat" (parallel) to the ground for a landscape shot (to get DoF without stopping down too much), the extension of the now DoF is not longer from front to back (far & near points), but one has to know that the DoF in this case extends perpendicularly to the plane of sharpness. In this case (with the plane lying "flat") up and down. When you are focusing in this tilted setup the sharpness goes up (sky) and down (ground). Therefore one can't use the distance scales any longer as such.
@ Chris & Wayne
thanks for explaining so precisely what I try to explain since yesterday and which has been wrongly presented in this thread since its beginning: the Alpa HPF is in fact, and despite some comments which may induce in error, as precise as the Arca helico focus ring, actually more precise when one looks at the tables from both cameras. And in the contrary to the Arca helico ring, it is less complicated and faster to use, IMO. I can only suggest anyone interested to know what are the facts and to try both systems side by side: take your time to make some real-life shots with both systems and come to your conclusions.
Have a look at the Alpa video on how to mount the HPF ring:
http://www.alpa.ch/en/products/lenses/alpa-hpf/alpa-hpf-alpaschneider.html
The Alpa HPF Ring exists for following lenses:
Rodenstock HR Digaron-S 5.6/23 mm = RDS 23
Rodenstock HR Digaron-S 5.6/28 mm = RDS 28
Rodenstock HR Digaron-W 4.0/32 mm = RDW 32
Rodenstock HR Digaron-S 4.0/35 mm = RDS 35
Rodenstock HR Digaron-W 4.0/40 mm = RDW 40
Rodenstock HR Digaron-W 4.0/50 mm = RDW 50
Rodenstock HR Digaron-S 4.0/60 mm = RDS 60
Rodenstock HR Digaron-W 5.6/70 mm = RDW 70
Rodenstock HR Digaron-W 5.6/90 mm = RDW 90
Rodenstock HR Digaron-S 4.0/100 mm = RDS 100
Rodenstock HR Digaron-S 5.6/180 mm = RDS 180
ALPA AAA Apo-ALPAR 4.5/35 mm = AAA 35
ALPA AAA Apo-ALPAR 4.5/45 mm = AAA 45
ALPA AAA Apo-ALPAR 4.5/55 mm = AAA 55
Schneider Apo-Digitar 5.6/35 mm XL = AAS 36
Schneider Super-Angulon 5.6/38 mm XL = SSA 38
Schneider Apo-Digitar 5.6/43 mm XL = AAH 43 / SAD 43
Schneider Apo-Digitar 5.6/47 mm XL = AAH 48 / SAD 47
Schneider Super-Angulon 5.6/47 mm XL = SSA 47
Schneider Super-Angulon 5.6/58 mm XL = SSA 58
Schneider Apo-Digitar 5.6/60 mm XL = AAH 60
Schneider Apo-Digitar 4.0/60 mm N = SAD 60
Schneider Apo-Digitar 5.6/72 mm N = SAD 72
Schneider Apo-Digitar 4.0/80 mm N = SAD 80
Schneider Super-Symmar 4.5/80 mm XL = SSS 80
Schneider Apo-Digitar 4.5/90 mm N = SAD 90
Schneider Apo-Digitar 5.6/100 mm N = SAD 100
Schneider ALPA Apo-Switar 5.6/36 mm = AAS 36
Schneider ALPA Apo-Helvetar 5.6/48 mm = AAH 48
Schneider ALPA Apo-Helvetar 5.6/60 mm = AAH 60
I've never really tried using tilts much for focus, but always assumed once you start tilting things, distance scales sort of go out the window. Maybe I'm wrong and the trick is being able to know exactly where to measure when figuring out your focus plane.
As far as precision, maybe some clarification on the Alpa as well. I only have the HPF rings for my 70mm. When shooting with the 47 or 35 I'm either focus stacking, using a limited version of hyperfocal distance (basically I shoot each lens at f/11 and f/16 and figure out where infinity fails to satisfy me and set it there), or I know there isn't anything close enough to worry about it. So I haven't put the HPF rings on the wides (yet anyway).
On the 70mm, the focus ring turns over 3/4's of a revolution and does make the ring much larger although prob more like 3". The HPF ring divides that into 50 increments, and there are 5 sub increments. It's actually quite easy to set the lens "between" each subincrement about the thickness of the line so the line covers the space between the two. However, the precision at close range is rather impressive, 10 of the 50 cover only 2.65 feet up to 3.31 feet, so 50 minor steps to go 9 inches. The next 10 get you to 4.4 feet, and overall 40 of the 50 major steps, or 200 of the 250 minor steps covers the range from 2.65 feet 16.6 feet - so thats 200 steps to cover about 167 inches. Of course, one challenge that makes them less useful than what I understand about the arca is the fact they are non linear, so each substep doesn't represent "x" inches. This means you have to sort of look at the two major steps, do some math in your head, and figure out what each substep represents in distance. Example, on the closest subset, each step represents 0.12" while at the 40th major step, each substep represents about 5.5" so even if you factor in using in between each sub-increment for distances between 14.3 to 16.6 feet your control is probably only around 2.5" per step. From there it scales and become pretty inaccurate so if you need precise focus at 192 feet, tough to do on the Alpa with the HPF rings ... so then your having to depend on whatever tools the back has for you.
Thanks for pointing this out, Jack, this is a common error in Arca-Alpa discussions: You don't use 5 revolutions with each and every lens.
If you have a lens with a small hub, you stay within one revolution, e.g., with the Schneider 28mm. The supplied distance table for the SK28 runs from 0.5m (on the helicoid: 23.2) to 25m (0.4), so this is less than a full revolution. If you look at the Arca-table for the SK43, you go from 0.5m (RED 26.7) to 25m (1.1), that is, you are close to two revolutions. If you look at the table for the Schneider 90mm, you use use up to five revolutions but if you focus somewhere between 3.4m and infinity, focusing takes place within one revolution. Put differently, the precision of the Arca way of focusing increases with a large focus hub BUT one must keep in mind that you have large movements in the close range and these get smaller if you approach infinity.
One more point: Whether focusing an Arca-lens (without the E-module) or focusing an Alpa-lens with a HPF ring using a Disto, you have to have the respective table at your hands. Take the SK 43mm: on the Alpa HPF you have an explicit mark for 7.29m and another one for 4.89m. The table will tell you that the small marks between correspond to 6.63m, 6.09m, 5.63m, 5.23m respectively. On the Arca table, looking at approximately the same range, the following distances and corresponding values are given: 7.5m (3.7), 7m (4.0), 6.5m (4.3), 6.0m (4.7), 5.5m (5.1), 4.8m (5.9).
It's worth having a look at the Alpa-HPF distance tables to get a more concrete idea of what you can do with HPF rings (which you don't get for all lenses).
Chris
-
It looks like others are seeing as well the difference .01mm makes when shimming precisely his back. You won't actually see it before you have 2 shots to compare, side by side, and will then always believe that your not-shimmed back is perfectly sharp where you want it to be. The point here being that this will become more and more important with the sensors' resolution going up: in clear, why buying a IQ 180 when you don't use it at its full capacity, buy a 22 or 33 MPx back and you will get approximatively the same IQ.
Thierry
I know alpa prides itself on precision, and won't do sliding backs. After calibrating mine and realizing .01mm spacing between the back and the body does make a difference I can see their point.
-
out of curiosity, does anyone know, for the alpa and the arca, how many of those "ticks" on the dial correspond to, say 0.01mm of actual lens movement? that number being the alpa shim tolerance.
and what about backlash, or is everyone approaching their target number from the same direction?
-
I have a rough estimate when shimming that 0.01mm = 1 minor tick mark. I've shimmed about half a dozen times, so not the most experience out there. I haven't noticed any backlash effect, but that would be interesting to check.
I too think Jack is spot-on. Technically the Arca can be more accurate and that might be a welcome feature when applying tilt. Of course having 50 turns would be more accurate still! Both of these systems are awesome. Like Wayne, once I realized focus stacking could be used instead of tilt for the majority of my situations, I felt the Alpa was a better fit for me.
If you want/need tilt on WA lenses, then the Arca is the only choice. But if not, then it comes down to how you like to work and personal preferences.
Dave
out of curiosity, does anyone know, for the alpa and the arca, how many of those "ticks" on the dial correspond to, say 0.01mm of actual lens movement? that number being the alpa shim tolerance.
and what about backlash, or is everyone approaching their target number from the same direction?
-
The Arca R focus helix is approximately 110mm in diameter, has 172 tick marks (numbered every 5 ticks, from 0 to 34), and moves the lens in or out 2.5mm per revolution -- i.e., 2500/360 = 6.94 microns/degree, or 2500/172 = 14.53 microns/tick mark. Lacking a vernier scale, about the best that could be achieved in terms of repeatability is 1/2 a tick mark, or 7.27 microns. Arca claims 10 micron repeatability for the Rm3di <http://www.rodklukas.com/resources/Arca-Swiss_NewProducts_2010.pdf>, which coincides with the minimum shim increment from Alpa.
The scale that Arca uses appears to be based on the circumference of the focusing mount: 110 x pi = 345.6, which, when truncated to an even integer, yields 172 ticks and a final diameter of 109.50mm.
Dave.
As you might have guessed, I've received my Rm3di and an SK 43XL, but am waiting for a viewfinder and a way to mount a back on the camera. So I'm reduced for the moment to admiring the engineering.
-
Well, looks like my previous post was way off. A quick look at the Alpa distance tables show 0.03333mm per degree for Rodenstock lenses and 0.02778mm for Schneiders. Each minor tick is 1 degree.
Dave
-
If you want/need tilt on WA lenses, then the Arca is the only choice...
Or the Cambo Wide DS/RS (with their T/S lenses), or the Linhof Techno (with every lens). Both offer simultaneous Tilt and Swing (unlike the latest Arca), and the movements on the Linhof are yaw free.
-
Or the Cambo Wide DS/RS (with their T/S lenses), or the Linhof Techno (with every lens). Both offer simultaneous Tilt and Swing (unlike the latest Arca), and the movements on the Linhof are yaw free.
How does the focusing precision of the Cambo and the Linhof compare to the Arca? Also, do you find the yaw-free behavior of the Linhof to give you more accurate focusing capability when using tilt and swing movements?
-
I have no doubt about the precision of the Arca rm3di focusing mechanism, but it would be very helpful for me to understand more about the most effective use of the camera. While the correct application of the helical, evf, drum, tables, (and maybe e module), along with possible calibration of the back, will quickly and accurately cover any base lacking the inclusion of tilt use; and some formulas are available to work well providing an effective generic form of tilt focusing using said devices and another set of tables, I still need to know more. I am coming from 4 by 5 ground glass focusing using the method posted by Q.T.Luong on the LFphoto.info site under "How to Focus the View Camera" (procedure 2). This method is very specific to each image, and takes into account the periodic importance of finding the exact degree of tilt best suited for each situation, or whether tilt provides any advantage. Even more significantly, it also covers the situation in which the near and/or far focusing points are above or below the tilted focusing plane. So it would seem that when using the rm3di without employing focus stacking, there would still be times when I would need to go visual, either by tethering (which I would prefer not to do with landscape) or using some approach to viewing the screen on the digital back. As the ground glass is of little use focusing digital backs, I'm wondering why they are included at all (except for roll film use). The ground glass is sometimes mentioned as being useful for composition, but these references must be meant to apply to film use or in the absence of the evf, which I would think would be a better device for accomplishing that purpose. These are my ponderings in which I'm sure I'm missing a good bit, so any response from those in the Arca camp will be greatly appreciated.
-
I currently use the RM3D. I find the Arca viewfinder to be indispensable in the field. It can be used off-camera to investigate different shooting angles, locations and focal lengths (including shifting) without having to setup the tripod. I find it to be extremely accurate in its framing.
However, composing on the 6x9 ground glass is very useful, even for digital use. Maybe it can be considered a luxury and not a necessity, but most photographers who try it do enjoy the larger image with which to make their final composition. The large 6x9 view with grid is especially more convenient when planning stitched shots. And in general, the viewing experience with the Arca reflex binocular is infinitely more enjoyable than trying to compose an upside-down image using a loupe as with most other technical cameras. Although, I do not exactly like the extra bulk of this binocular. As usual, there is no "free lunch" and this is the price you must pay for such capability. Supposedly, Arca will be introducing a more compact reflex monocular soon.
-
How does the focusing precision of the Cambo and the Linhof compare to the Arca? Also, do you find the yaw-free behavior of the Linhof to give you more accurate focusing capability when using tilt and swing movements?
The focussing action of the Cambo is comparable to the Alpa - i.e it utilises Schneider's standard helicals. It should be possible to use the Alpa HPF rings on the Cambo, although the bars will need to be removed and some machining of the mounts may be required. I still maintain that a simple sticker over the current distance scale, with markings from (say) 1 - 100 is all that's needed (plus a lookup table per lens a la Arca).
No bellows camera is as easy to focus as pancake camera with a helical, but with the release of the IQ backs this is rather a moot point, since focus mask/live view may be all that's needed to make focussing a breeze. That said, there are many photographers using the Techno who don't have a problem focussing - it may well be this whole issue is one of those things that gets blown up out of all proportion in the world of photography forums. Hell, if I'd just dropped $40k+ on an IQ180 I wouldn't like anyone telling me I don't have the most accurate focussing system in the world in front of it ;D
For wide angle lenses the yaw free movement isn't so important - but for longer lenses it's nice not to have to chase the image around the gg.
-
No bellows camera is as easy to focus as pancake camera with a helical, but with the release of the IQ backs this is rather a moot point, since focus mask/live view may be all that's needed to make focussing a breeze.
I haven't tried the new IQ backs but the sensor is a CCD and live view is likely to suck (though I would love to be proved wrong). In my experience Focus Mask is of marginal use (mostly not much cop and totally useless in difficult-to-focus low-contrast situations where you need it most).
This issue as a whole is absolutely not unnecessary fussing. If you shoot with a wide-angle lens you can't accurately hit correct focus without a great deal of care and all the technological assistance you can get. As is frequently pointed out, 35mm DSLRs are currently very good and the fairly small resolution gain from view cameras is easily wiped out by inaccurate focus.
-
I suppose that IF the live view will work with the new IQ backs in a good way, then everything else is of no importance. Make the composition through the viewfinder and then finetune both composition and precise focus via live view. However, should it not work as many seems to suspect, then I think that a "smallish" macbook air 11" could do the trick even in the field. If you use a lot of shift and tilt/swing, then this could be an alternative and always be spot on. I am hoping that the live view on the back will be workable though, that would be fantastic!
-
I suppose that IF the live view will work with the new IQ backs in a good way, then everything else is of no importance. Make the composition through the viewfinder and then finetune both composition and precise focus via live view. However, should it not work as many seems to suspect, then I think that a "smallish" macbook air 11" could do the trick even in the field. If you use a lot of shift and tilt/swing, then this could be an alternative and always be spot on. I am hoping that the live view on the back will be workable though, that would be fantastic!
I always thought live view was a limitation of the backs processing power. If live view is decent tethered seems getting decent functionality with the new backs could be possible?
-
I always thought live view was a limitation of the backs processing power. If live view is decent tethered seems getting decent functionality with the new backs could be possible?
Otherwise there would be no progress... you remember what was the quality of 6 years ago, and what is it now? I think almost anything is possible. Just can not have everything in a very short time.
-
I might just have to go with Alpa simply because of the awful Arca-Swiss communication. Arca-shop.de are a real nightmare to deal with : 3 weeks and still no response to my email with technical questions, despite a follow-up phone call and another email. Alpa has been really good so far in dealing with my questions, and that is quite reassuring.
I wish I could find, in Europe, a better Arca-Swiss representative than arca-shop.de so please, if anyone knows one, do let me know. For my needs the Arca Rm3d seems like the better product, but I refuse to deal with the ridiculous response times. When the time comes, later in the year, Alpa will probably get my business, simply based on good communication, rather than product preference (not that the Alpa Max or STC are bad products :)), on the contrary, they appear to be outstanding, yet ... ).
-
I wish I could find, in Europe, a better Arca-Swiss representative than arca-shop.de so please, if anyone knows one, do let me know.
Get in contact with Christoph Greiner:
http://www.greiner-photo.com/
He sells Arca as well as Alpa. And he knows what he is talking about ...
Chris
-
Get in contact with Christoph Greiner:
http://www.greiner-photo.com/
He sells Arca as well as Alpa. And he knows what he is talking about ...
Chris
Thank you.
-
I would try to talk to Walter Pfisterer from Arca-shop directly. I get most answers after a day or so and if I call I get them right away.
-
I might just have to go with Alpa simply because of the awful Arca-Swiss communication. Arca-shop.de are a real nightmare to deal with : 3 weeks and still no response to my email with technical questions, despite a follow-up phone call and another email. Alpa has been really good so far in dealing with my questions, and that is quite reassuring.
I wish I could find, in Europe, a better Arca-Swiss representative than arca-shop.de so please, if anyone knows one, do let me know. For my needs the Arca Rm3d seems like the better product, but I refuse to deal with the ridiculous response times. When the time comes, later in the year, Alpa will probably get my business, simply based on good communication, rather than product preference (not that the Alpa Max or STC are bad products :)), on the contrary, they appear to be outstanding, yet ... ).
I was just thinking the same thing. We placed an order for a Rm3di on May 16, and we were told that we would receive it within 2 - 4 weeks. Now, it is 8 weeks later and the camera is still not here. The lack of responsiveness from Arca-Swiss is indeed troublesome. We never had any problems like this when we were Sinar customers.
In fact, the Sinar arTec camera might be a better choice for professionals who need more responsive customer support. The Sinar arTec can tilt and swing in any direction with any of the Rodenstock wide angle lenses, which is a key feature for us.
-
I would try to talk to Walter Pfisterer from Arca-shop directly. I get most answers after a day or so and if I call I get them right away.
I did call - almost 2 weeks ago. They told me they would get back to me ... hopefully by the end of that week :) I never heard back from them, even though I did send an additional email asking them for any sort of feedback ... :(
-
Following my post here, Marc from customer support at Arca-Swiss (not arca-shop.de), took the time, today, to answer my questions in a quick and informative manner. I'm glad the Rm3di is still in the cards, for me :) .
-
In fact, the Sinar arTec camera might be a better choice for professionals who need more responsive customer support.
In the US? Sinar? Customer support? Unless something has changed recently you're thinking about the old days.
-
In the US? Sinar? Customer support? Unless something has changed recently you're thinking about the old days.
You may be right about this. So, I guess that leaves Cambo. Although, even Sinar should be able to beat an 8+???? week delivery time.
-
I agree with Chris, he knows what he is talking about.
Thierry
Get in contact with Christoph Greiner:
http://www.greiner-photo.com/
He sells Arca as well as Alpa. And he knows what he is talking about ...
Chris
-
While we are on the Arca-Swiss subject, Rod Klukas will be visiting us here at Digital Transitions in NYC this Friday, July 15.
We are planning to go out and do some shooting around the city, possibly at The Highline (http://thehighline.org) .
If any members would like to come along we will have a R3Mdi/IQ180 and variety of lenses.
Also we should have one or two people bringing their ALPA's/Cambo's coming along too.
Please let me know if your in the area and I can share the details with you.
Would be great to get to meet more NY members and allow you to handle the gear we are discussing.
Looking forward to it.
Lance
lns@digitaltransitions.com
-
Hi Lance,
What time will you be meeting? This would be a great opportunity for me to meet with Rod and see if the Arca-Swiss delivery pipeline can improve.
I am trying to understand why some orders for Rm3di bodies in the U.S. ordered after our own order have already been delivered some time ago. I have been trying to get in touch with Rod, but still waiting for a call back. Hopefully, I will not have to wait until Friday to discuss this.
Thanks,
David
-
Yes Rod will be here.
We are looking to meet up at out offices at 1:00. We are located at 35 west 35th St -4th floor. We will spend a few minutes getting acquainted then head out to The Highline. If you can not make it to the office but want to meet up call my cell 610 496 5586 and I'll let you know where we are.
Please bring your equipment if you would like. I just thought this would be a great way for those in the area to check out the new Arca and IQ , and shoot it in a nice environment. We will have a wide range of lenses.
I want this to be more of a 'meet-up' and not a 'shoot-out' .
It's also a great opportunity for the NY area members to get together and put some faces to the posts.
Please let me know via email if you plan on joining us lns@digitaltransitions.com.
Lance
Bring some cf cards to take away some files.
-
Is the Arca Swiss viewfinder for the RM3d cameras accurate enough to compose with, without having the back tethered or is it suitable as a rough guide only?
Also has anyone tested the Rodenstock HR Digaron W 32mm f4 against the Schneider Digitar 35mm f5.6 with a 80MP back? The other option I'm considering is the Schneider Super Digitar 28mm lens but I dont want to have send the lens back to the factory like another user had to with another camera system.
-
Is the Arca Swiss viewfinder for the RM3d cameras accurate enough to compose with, without having the back tethered or is it suitable as a rough guide only?
I find the viewfinder to be extremely accurate in the field for landscape and architectural work. At close range in the studio, say for product shots or repro work, you will most likely be better served with a view camera that has more movements and maybe also shooting tethered with a multishot back.
Also has anyone tested the Rodenstock HR Digaron W 32mm f4 against the Schneider Digitar 35mm f5.6 with a 80MP back? The other option I'm considering is the Schneider Super Digitar 28mm lens but I dont want to have send the lens back to the factory like another user had to with another camera system.
You might want to reconsider your options here, as the Schneider Digitar wides do not seem to fare as well with an 80MP back in regard to color cast issues. The Rodenstock 32 and Schneider 28 on the IQ180 is discussed here: http://forum.getdpi.com/forum/showthread.php?t=27729