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Author Topic: sensor size vs optics  (Read 9609 times)

sholt

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sensor size vs optics
« on: January 31, 2006, 07:35:22 pm »

Brand new to this forun and joined to ask this one question, as other forums I belong to point to luminous-landscape for this discussion.

Today, after testing my D2x, I have a huge knot in the pit of my stomach I have made a serious error in switching to Nikon digital.  I am a pro, have shooting 35mm for 30 years and am very sure of my "look".  As a landscsape shooter I use mostly wide lenses and don't even own anything over 200mm and live by what I see with wide lenses.

Last year as I decided to switch to digital, I tested cameras, I asked around, I read reviews, and then bought the d2x.  Amazing technical files but somehow I felt I was not "getting inside" my photos the same as with my film camera.  Today I put the film and digital camera side by side on a dual mount tripod and the sinking feeling set in.

I put my Nikon 24mm on the film camera and the Nikon 12-24dx on the digital. I zoomed in to about 16mm which fills up the d2x view finder to be equivalent to the 24mm fixed focus film lens.  The optics are different, the images are not the same, even though they cover exactly the same area. Its is wierd, but obvious - and I don't like the digital.

I know enough about optics to know what has happened.  I read a Forum question here discussing the new digital format which is no longer based on a 24x35 image area.  In order to fill up the smaller (than 24x35mm) Nikon sensor with that same area of coverage I need wider coverage.  I did not think through the ramifications of this and now find the relationship of objects to each other, especially with wide lenses, is significantly different and the "look" is different.  In a nutshell the "sweet spot" of the 16mm lens that makes it seem to cover a traditional 24 has more distortion than the equivalent 24 had to start with.  No way can it look the same.  Shoulda known . . .  

To most folks this is not that important and a new generation of photogs will get used to new optics.  My question really is about the Canon pro cameras.  I know they use 24x35 sensors which should mean no change in the optical "look".  Is this true ?  Has there been a discussion of this somewhere that is not about price comparison ?

For the moment I am shelving the d2x until I can rent and test the Canon for myself, but what has this group decided about the optics?

Saxon Holt
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AJSJones

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« Reply #1 on: January 31, 2006, 07:59:57 pm »

Quote
Brand new to this forun and joined to ask this one question, as other forums I belong to point to luminous-landscape for this discussion.

Today, after testing my D2x, I have a huge knot in the pit of my stomach I have made a serious error in switching to Nikon digital.  I am a pro, have shooting 35mm for 30 years and am very sure of my "look".  As a landscsape shooter I use mostly wide lenses and don't even own anything over 200mm and live by what I see with wide lenses.

Last year as I decided to switch to digital, I tested cameras, I asked around, I read reviews, and then bought the d2x.  Amazing technical files but somehow I felt I was not "getting inside" my photos the same as with my film camera.  Today I put the film and digital camera side by side on a dual mount tripod and the sinking feeling set in.

I put my Nikon 24mm on the film camera and the Nikon 12-24dx on the digital. I zoomed in to about 16mm which fills up the d2x view finder to be equivalent to the 24mm fixed focus film lens.  The optics are different, the images are not the same, even though they cover exactly the same area. Its is wierd, but obvious - and I don't like the digital.

I know enough about optics to know what has happened.  I read a Forum question here discussing the new digital format which is no longer based on a 24x35 image area.  In order to fill up the smaller (than 24x35mm) Nikon sensor with that same area of coverage I need wider coverage.  I did not think through the ramifications of this and now find the relationship of objects to each other, especially with wide lenses, is significantly different and the "look" is different.  In a nutshell the "sweet spot" of the 16mm lens that makes it seem to cover a traditional 24 has more distortion than the equivalent 24 had to start with.  No way can it look the same.  Shoulda known . . . 

To most folks this is not that important and a new generation of photogs will get used to new optics.  My question really is about the Canon pro cameras.  I know they use 24x35 sensors which should mean no change in the optical "look".  Is this true ?  Has there been a discussion of this somewhere that is not about price comparison ?

For the moment I am shelving the d2x until I can rent and test the Canon for myself, but what has this group decided about the optics?

Saxon Holt
[{POST_SNAPBACK}][/a]
Commiserations that the particular choice didn't work as well as you'd hoped.  The small format sensors have certainly exposed the weakness in wide-angle lenses (which need to be correspondingly wider than they were for 35mm) in general as being difficult to build well.  Canon's best wide-angle offerings are often criticized even more so than Nikon's and there is a thriving market for Zeiss, Contax, Zuiko etc especially among landscapers - and the support in the form of adapters).  I suspect what you are reacting to is the compromises Nikon had to make to create that zoom and the resulting distortion at 16 compared to a (probably very good) prime at 24 on the film camera.  The *relationships of objects to each other* should be unchanged if the camera position is unchanged (only camera position affects perspective). so it must be the distortion.
Zeiss will be making lenses for the Nikon mount, so there's hope that you could get a 16, eventually, that matches the quality of your 24 experience.  Does Nikon offer a 16 or 17 prime you could check out or read the reviews [a href=\"http://www.fredmiranda.com/reviews/showproduct.php?product=86&sort=7&cat=28&page=1]here[/url] to see how others reacted to moving to digital and this lens in particular.  It gets pretty high ratings, but your expectations may be higher than many who contributed reviews.
In addition, some (myself included) feel that 8 or even 12 MP isn't enough for a landscape print of much size (I use a 4x5 for landscape and digital for birding) because of the "poor" rendering of e.g. distant tree detail - obviously what poor means depends on the size of the print.

I wouldn't look to Canon for salvation in your situation, rather start doing the rounds of lens reviews and get ready to hear about variation between copies to complicate your research!

Good luck
Andy
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Mark D Segal

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sensor size vs optics
« Reply #2 on: January 31, 2006, 08:59:12 pm »

There is no "group decision" about this question here, because the members are numerous with widely ranging opinions about everything. As well, there are lenses and lenses, all with their varying quality and characteristics. To start with, for doing mainly wide-angle work a full frame (24x36mm) sensor is probably preferable because there are traditional wide angle lenses designed for that frame size producing uncropped wide-angle images. Smaller sensors automatically give you a narrower field of view for the same focal length lens. That points you to Canon - 1Ds, 1DsII, or 5D. The best you can do is find someone who will let you test one of these models with various wide-angle lenses and you will see for yourself what works best for you. I think it's really the most useful approach in your circumstances.
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Mark D Segal (formerly MarkDS)
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Piece

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« Reply #3 on: February 01, 2006, 02:44:54 pm »

or wait for a Nikon full frame....
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benInMA

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« Reply #4 on: February 01, 2006, 03:18:20 pm »

The problem will be solved when Nikon ships a Full Frame camera.

You'd probably be happier with one of Canon's 24x36 digital cameras, but as someone with a Nikon investment that is a tough thing to hear.

The smaller sensor can be more or less effectively used for different subject matter but it is lacking for certain areas.

If you were using the 24mm prime frequently before IMO that is one of the areas that is going to be exceedingly difficult to duplicate.   I have yet to see how you can approximate the same look of a wide to normal prime on the smaller sensor.  You can get the same field of view but you cannot get the same combination of field of view and depth of field.

In my case the thing that drove me nuts and eventually got me to buy a FF Canon was lack of a way of duplicating a 50mm prime.   It is easier to get close to the look of a 50mm prime on an APS-C sensor then it is to duplicate the look of a 24mm prime though.  

If I was in your place though I'd probably just try and use the D2x for a few years.. Nikon will eventually ship a FF camera, it is way too hard for me to believe they won't.

IMO 35mm became a dominant film format because it was just large enough to allow certain combinations of perspective & depth of field without being excessively large.   I think digital is eventually going to go the same way and 35mm will dominate, at least until we arrive at something ground breakingly different optically.  (Like the microlens camera where the digital data can be massaged by a computer to create any depth of field you want after the fact)
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Giedo

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« Reply #5 on: February 01, 2006, 04:35:38 pm »

Quote
I put my Nikon 24mm on the film camera and the Nikon 12-24dx on the digital. I zoomed in to about 16mm which fills up the d2x view finder to be equivalent to the 24mm fixed focus film lens. The optics are different, the images are not the same, even though they cover exactly the same area. Its is wierd, but obvious - and I don't like the digital.
Could you share your vision with us by posting both images side by side?
Should be interesting to see what it is you (and others) don't like in a direct comparison of the two. It is hard to imagine the difference between the 16mm digital and 24 mm film shot without seeing actual pictures.
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Giedo

benInMA

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« Reply #6 on: February 01, 2006, 05:06:20 pm »

I don't have a pair of perfect A-B pictures to share, largely because I haven't owned a crop & FF camera at the same time (they're all so expensive!), and this is tough because most of my pictures in this category would be personal, and not something I want to share on the internet.

This is nothing special but it's 28mm @ f/1.8 on 35mm.  I had a very hard time duplicating this kind of thing on a cropped sensor.   I suppose a 17mm f/1.0 lens would get the job done but that was never available to me.

For a better idea think environmental portraits and other similar subjects.   35mm - 50mm primes on a 35mm format have a pretty decent advantage for these kinds of subjects at typical working distances.  If we start seeing much faster prime lenses designed for cropped bodies this gap can be closed, but for *me* the slower zooms which are being used to fill the gap make it difficult.

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Mark D Segal

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« Reply #7 on: February 01, 2006, 05:12:45 pm »

Nothing is impossible - who knows one day Nikon may produce a DSLR with a 24x36mm sensor. At this time, however, it is pure speculation and there is no hint they are so inclined. If I am not mistaken, Nikon does not manufacture their own sensors, whereas Canon does. This means Nikon does not control sensor size, unless they were to tool-up, or commission someone else to design and manufacture a full frame version for them. This doesn't happen over-night.
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Mark D Segal (formerly MarkDS)
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Ray

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« Reply #8 on: February 01, 2006, 06:46:36 pm »

Quote
I put my Nikon 24mm on the film camera and the Nikon 12-24dx on the digital. I zoomed in to about 16mm which fills up the d2x view finder to be equivalent to the 24mm fixed focus film lens.  The optics are different, the images are not the same, even though they cover exactly the same area. Its is wierd, but obvious - and I don't like the digital.

[a href=\"index.php?act=findpost&pid=57218\"][{POST_SNAPBACK}][/a]

Saxon,
I'm surprised that as a pro who has been shooting 35mm for 30 years you find this effect weird. Perhaps you are referring to some effect other than DoF?

It's well established that larger formats require larger f/stops for equivalent DoF with the same field of view, and of course, the reverse is also true. Smaller formats require smaller f/stops for the same shallow DoF. This factor has long been recognised as a major failing of very small format P&S digicams which often have a maximum aperture of f/2.8 producing a DoF equivalent to 35mm at f8.

The D2X is simply a smaller format camera than 35mm and therefore requires the use of appropriately smaller f/stops at equivalent focal lengths.
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John Camp

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« Reply #9 on: February 01, 2006, 08:11:14 pm »

An f2.8 16mm lens shot wide open on a Nikon D2x at three feet has a depth of field ranging from 2.5 to 3.74 feet.

An f2.8 24mm lens shot wide open on a FF camera at three feet has a depth of field ranging from 2.7-3.37 feet.

That's two and two-fifths inches on the near end, and about 4 inches on the far end.

I, personally wouldn't throw the camera away, unless all I did was shots of in-focus eyes and out-of-focus ears.  

To see all the possible combinations, there's a depth-of-field calculator here:

http://www.nikonians.org/html/resources/gu...yperfocal2.html


JC
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Ray

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« Reply #10 on: February 01, 2006, 08:38:16 pm »

Quote
An f2.8 16mm lens shot wide open on a Nikon D2x at three feet has a depth of field ranging from 2.5 to 3.74 feet.

An f2.8 24mm lens shot wide open on a FF camera at three feet has a depth of field ranging from 2.7-3.37 feet.

That's two and two-fifths inches on the near end, and about 4 inches on the far end.

[a href=\"index.php?act=findpost&pid=57274\"][{POST_SNAPBACK}][/a]


John,
From such a close shooting distance as 3ft, 2 1/2 inches in front and 4" behind the focus point can make all the difference between both the nose and ears of the dog being equally sharp and not being equally sharp. A similar situation is going to apply if you use a 50mm lens on the D2X instead of an 85mm (or 75mm) for portraiture. You might have difficulty getting the person's ears sufficiently OOF, if that's the desired effect.
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benInMA

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« Reply #11 on: February 01, 2006, 09:15:20 pm »

You know it's not the actual depth of field per a calculator that I am concerned with... (And it can vary by how you plug your #s into the formulas to make the calculator app)

It's what the picture looks like.   Even at the same depth of field the out of focus areas seem to look very different between different formats AFAICT... as if the appearance of an object changes with a different function of the distance from the focal point.

And for those of us who are not locked into Nikon...    The rest of us are not going to pay $1200-1500 to get 17mm f/2.8 out of a zoom lens when we can put that money into the body and get better results out of a $200-300 prime.
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John Camp

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« Reply #12 on: February 01, 2006, 09:57:28 pm »

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John,
From such a close shooting distance as 3ft, 2 1/2 inches in front and 4" behind the focus point can make all the difference between both the nose and ears of the dog being equally sharp and not being equally sharp. A similar situation is going to apply if you use a 50mm lens on the D2X instead of an 85mm (or 75mm) for portraiture. You might have difficulty getting the person's ears sufficiently OOF, if that's the desired effect.
[a href=\"index.php?act=findpost&pid=57276\"][{POST_SNAPBACK}][/a]

I know. The point I was making is that cameras are made for all kinds of things, and unless you are a specialist in certain kinds of photography, the difference in depth of field between a FF and an APS-sized sensor is not going to be too significant, especially in the real world, where there are always work-arounds for minor issues like this. Like Photoshop.

But if I did a whole bunch of portait photography and my style was eyes-in, ears-out, then I would either not buy an APS-sized sensor, or I would spend a few hundred bucks on a good used Hassy or film RZ and *really* get the effect. I'm pretty sure you could get a used RZ with a portrait lens for less than a grand right now...

From my point of view, the 1.5 sensor has many more advantages than disadvantages; reliable testers suggest that it's as good (depending on your definition of good) as the Canon 1DSII. And it has, IMHO, strong arguments at the wide end as well as at the long end, and will continue to have, as long as Canon doesn't produce some digitar-style wide lenses. And at the long end, the arguments are so strong that they seem overwhelming. One of Michael's video journals shows him shooting in Yellowstone (I think) with a borrowed 600mm Canon that was about the size of a cannon. The equivalent lens, in reach and speed, on a Nikon, would weigh about half as much. I have a reasonably sharp f 4.5-5.6 80-400 VR zoom, which gives the equivalent of a FF 120-600, and it's only eight inches long. You can stick it in the pocket of a photo vest.

These discussions can be endless, and I repeat, I know that for some people, not having that inch or two of narrower depth of field could be a deal-breaker, but not for me; as I said, I wouldn't throw the camera away.  

JC
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Ray

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« Reply #13 on: February 01, 2006, 10:42:35 pm »

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These discussions can be endless, and I repeat, I know that for some people, not having that inch or two of narrower depth of field could be a deal-breaker, but not for me; as I said, I wouldn't throw the camera away.   

[a href=\"index.php?act=findpost&pid=57279\"][{POST_SNAPBACK}][/a]


I agree. You wouldn't throw it away. (You could be accused of littering if you did   ). But I understand Saxon has just switched to Nikon. For a pro or indeed any keen amateur, the cost of lenses far outweighs the cost of the camera body. When choosing a system, the types of lenses available for that system is perhaps the most important consideration of all. If you are a wildlife photographer, there's no question that a cropped format camera such as the D2X is an advantage. But equally, if you use mainly wide angle lenses then the D2X has some serious disadvantages. Saxon, where have you been during the past few years   ?
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Ray

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« Reply #14 on: February 01, 2006, 11:12:03 pm »

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It's what the picture looks like.   Even at the same depth of field the out of focus areas seem to look very different between different formats AFAICT... as if the appearance of an object changes with a different function of the distance from the focal point.


[a href=\"index.php?act=findpost&pid=57277\"][{POST_SNAPBACK}][/a]

Not sure what you are getting at here. At the same DoF, the out-of-focus areas should not look very different if you are shooting from the same distance with different (but equivalent) focal lengths in order to achieve the same field of view.

However, if you are shooting from different distances such that the main subject occupies the same area in the frame, then the longer focal length will produce a narrower or less expansive background.

As I understand it, the situation that Saxon is concerned about is the fact that any 16mm lens on the D2X will need to have a larger maximum aperture than the equivalent focal length of 24mm on FF 35mm format to achieve the same DoF. The reality is that 16mm lenses in general have significantly smaller maximum apertures so therefore there's a significant discrepancy in the maximum shallowness of DoF that can be achieved with the D2X at these wide angles.

Not only that, I suspect that a good 24mm prime will also simply be a better, sharper lens than a 12-24mm zoom at 16mm.
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benInMA

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« Reply #15 on: February 02, 2006, 09:37:05 am »

Right..

I actually shot a couple at 28mm and 17mm last night as an experiment, however the most open I can get at 17mm is f/4 so it doesn't really help all that much.  I was trying to see if there was any difference in the appearance of objects in the foreground/background but since I used the same zoom lens for both thost I didn't really see much, and I didn't control things very well anyway.

Bottom line is they have to start making very fast wide primes for the small sensors to close the gap.   At this point I could care less cause I bought a 5D but it seriously annoyed me when I had a 10D.

It is extremely rare for me to pull out a flash when I go indoors, I almost always put a prime on and just go right ahead and open it up.   For someone like me being told I should use an f/3.5-f/4.5 or constant f/4 zoom and use a flash or use ISO 1600 is a pretty crappy thing to hear, the pictures look very different from ISO 400 + a fast prime.
« Last Edit: February 02, 2006, 09:38:55 am by benInMA »
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Ray

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« Reply #16 on: February 02, 2006, 11:13:40 am »

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It is extremely rare for me to pull out a flash when I go indoors, I almost always put a prime on and just go right ahead and open it up.   For someone like me being told I should use an f/3.5-f/4.5 or constant f/4 zoom and use a flash or use ISO 1600 is a pretty crappy thing to hear, the pictures look very different from ISO 400 + a fast prime.
[a href=\"index.php?act=findpost&pid=57300\"][{POST_SNAPBACK}][/a]

Well, of course, that's true. But there's also a major consideration here which should be examined. Are you using a wide aperture just to take a shot without a flash or because you actually want a shallow DoF?

I wouldn't mind betting that many amateurs who wonder if they should buy an f1.2 or f1.4 lens primarily have in mind its usefulness in low light conditions rather than its creative possibilities for extremely shallow DoF.

When I recently got my 5D, I couldn't resist also getting the new 24-105 IS zoom. The combination of low noise at high ISO plus image stabilisation makes possible reasonably sharp images with good DoF in low light conditions. I've got a number of street shots at night taken at ISO 3200, f8 and as slow as 1/13th sec which are acceptably sharp and preferrable to other shots of the same scene taken at f4 and 1/60th.
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benInMA

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« Reply #17 on: February 02, 2006, 01:40:46 pm »

I would say I'm doing it for 3 reasons:

- Shoot in lower light
- Use less depth of field creatively
- Freeze motion

I shoot in Av or M 99% of the time and I almost never shoot without stopping to think what kind of DoF I should use.

Personally I'm not a fan of many of the shots that are getting posted from the 5D and other new uber-cams that use the super high ISO abilities.

e.x. if you're shooting a street scene a darker photo with less depth of field to me approximates and/or captures the mood and the way I picture the scene in my head.   Shooting ISO 3200 and turning night into day isn't the same.  Though it can work in B&W and I'm not sure exactly what your photos look like.

When I was shooting film the only time I ever used 1600 or 3200 was a few goofy B&W portrait shots where the room was pitch black and I used a penlight for illumination.  And a couple times using it just for the grain effect.

The best use of high speed film I'd seen was people who were masters of low light work, smoky B&W bar scenes, concerts, dark street scenes with perhaps a film noir effect.    Lots of the 5D stuff I've seen is using the crazy abilities of the camera, combining it with IS, and making a dark scene look like it was shot in mid-day sun.  Not my thing.  I'm glad the camera can shoot at those speeds but I am not going to go use it by default.
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sholt

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« Reply #18 on: February 02, 2006, 03:48:33 pm »

Thank you,member of this group.  Indeed, many of you know my concerns and indicate a full frame sensor is the ultimate solution.  I will just have to do tests.  I have a technical concern from reports that the FF sensor does not render light well at the edges.  Supposedly light coming in from oblique angles of traditional lenses do not produce cleanest photos.  Nikon's digitally optimized lenses arrange the light to hit the sensor perpendicular to the image plane.  But that does not help me if that image plane, by being smaller, can not give me my wide "look".

I am unable to answer several of the direct questions some of you have raised, but do understand, my concerns with my wide angle "look" in the small sensor debate is not about depth of field.  I understand optics reasonably well and know the 16mm lens which fills my d2x frame similarly to the FF 24mm can not have the same look.  Image putting that 16mm lens on a full frame camera:  objects are not rendered the same.

I have talked with several pros on the phone the last couple days, have used the lens distortion tool in CS2, have tried other wide lenses - and just ordered a bunch of Velvia 50 from New York.  I am starting a new book project next week and can not risk using the "new" digital format.  Some say "get used to it" and maybe I will.

More likely, I will sell the newly acquired d2x system and D lenses while they still have value and switch next year to a full frame system.  Several of you suggest Nikon will come out with one?  While I do own a bunch of F3 cameras and some fine old Nikon lenses, I also shoot with Leica R8 and those wonderful lenses.  The Leica digital back adapted to the R8 is even more expensive than Canon.  Even though all the gear is a cost of doing business,  I wonder where it all stops.  Maybe stick to film forever and buy a drum scanner is not too crazy.

In this business, I must have the best quality images or the competion will eat me up.  I know the pro digital camera files are now superior technically to film and want to switch in order to upgrade my work.  But I can not (yet) sacrifice my "look", as subtle a difference it may be.

If I have the chance I may upload the side-by-side tests I did.  My film test has returned from the lab but I may not have a chance to before I hit the road.  For those who want to know "where I have been" while all the digital debate has been in converation, my new website:  www.photobotanic.com may show I was stuck in a text mode during a film age.  Trying to stay fresh, old timers die hard.

Thanks again for the dialogue - Saxon Holt
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benInMA

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« Reply #19 on: February 02, 2006, 03:53:03 pm »

Hey Saxon - you have some beatiful stuff on your website!    
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