Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs and Large Sensor Photography => Topic started by: Brian Hirschfeld on February 02, 2013, 09:10:13 PM

Title: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 02, 2013, 09:10:13 PM
Some of you may have seen or may not have seen a picture on my website that I took a few years ago with a PhaseOne P65+ and a Hasselblad H2 / 300mm lens which is one of my favorite pictures (of my own)

http://brianhirschfeldphotography.com/wp-content/uploads/2011/07/Lizard-Merged-1-via-final-40x24-for-wildlife-competition-copy-half-size-1024x614.jpg

As I mentioned in a recent post the effective focal length of this shot was a little over 800mm with the cropping that the P65+ afforded me, and this created a very good picture for me.

Well, I am again going back to Costa Rica, and I want to do it "big" by which I mean having a long lens to get some more "good" (or at least I think so) wildlife shots out of my IQ180. I understand the weight and size constraints of working with a long lens like the 800mm f/6.7, and know that there are adapters available for the 645DF.

In terms of stabilization, I own a Gimbal head as well as a sturdy Gitzo 3 series CF tripod, would these be enough to use and stabilize this lens?

Does anyone have any experience using it on any digital platform? how is it wide open?

If anyone knows any of these things I would greatly appreciate the input or advice. Suggestions of other lenses are welcome but please don't say silly things like the 39lb 800mm f4 or the also gigantic 600mm f4 unless you believe that one of these would be better.

The 600mm seems a bit heavy on the stabilization side or at-least thats what I got from the LuLa article on it, which would be my chief concern with this lens...although with TC's being able to make it 800 and 1200 wouldn't be terrible.... all thoughts are welcome, I am looking to get one of these fast.

Also if you think the 645D or some other camera would be better suited to this lens please mention that as well. Thank you.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: FredBGG on February 03, 2013, 01:40:19 PM
I think that one thing you need to keep in mind when considering shooting with an 800mm lens
is what it's going to be like looking through it when you are hunting around for an image.
By that I mean what you will see as you point the lens around looking for the subject and composition.


Various things come into play.

Very shallow depth of field will make things apear like a complete blur until you focus so when you are hunting
for a composition especially in a dense environment like woods, shrubs etc it can get quite un nerving.

Add to that the camera shake as you move the lens around, even on a tripod and things get even more difficult.

This is where image stabalization and very fast AF make a massive difference in the "hunt and compose" experience
especially if wild life is involved.

I also think that manual focusing an f6.7 lens will be rather tricky. Using flip up sunglasses would help. Flip up the sunglasses only
when you look into the camera. Kurtis surf goggles are really good for this. They are very light and have a brilliant lens.
I use them and just bring my face towards the viewfinder and catch the goggles on the top of the finder lifting them off my eyes.
It's really nice because it makes your viewfinder apear really brighter because you eyes are "set" to the darker light of the goggles.

While it certainly is an interesting challenge shooting with a very long lens on an MF camera I think you are
going to have a tough time and that a 400mm on a high MP count 35mm DSLR would give you better overall results
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 03, 2013, 01:52:58 PM
A Pentax 645D with the Pentax 645 600mm (if you can find one) would work really well. Pentax also has a 400mm AF lens for the 645D. There are Teleconverters for both those lenses--same converter. The 300mm and 400mm lenses can be handheld, but not the 600mm---you will want a gimble head, although that is not a bad idea for the 400mm too. The 645D is really a modern camera and great for this type of work. ISO is really very good all the way to 1600. The exposure modes also give a nice choice including Auto ISO. The viewfinder is really nice and would recommend the gridded one. You can also get a 90 degree angle finder.

The down side is write speeds. It is slow in comparison to most modern cameras. But batteries are cheap and plentiful and work all day, even in sub-freezing conditions. The camera is weather sealed, but not the lenses in this case. The dual SD card slots can be setup like a RAID array.

I have a D800E and prefer the Pentax over that, both for images and handling. But the D800 would have more choice of optics for bird photography.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 03:23:01 PM
Thanks Fred for the tips, tho the goal of the exercise is MFDB at extreme-telephoto, if I was being totally serious I would be taking my D4 and D3s out with some rented super-telephotos or something.

Do the pentax TC's work with the AF on the Pentax 645D?

also is there any advantage in stabilization in the 800mm f/6.7 vs the 600mm f4 in terms of stabilization....

There is also the 400mm f4 but with the 2x TC it becomes F8 which is a little limiting...any thoughts on this?

It looks like its between the 800mm 6.7 and the 600 f4

I think it will be better to put it on the IQ180, because I think whatever distance advantage I get from a cropsensor like the 645D I could just get with the cropping that 80mp gives me....unless the 645D is going to offer better connectivity with the lens because of their proprietary adapter or something....

thanks,
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: paul_jones on February 03, 2013, 03:33:15 PM
i have the 600mm f4 adapted to my contax 645 with a p65+.
its a nice look with the blur, but its not very sharp- also has heaps of CA.
weighs a ton, and the focusing is very hard.

personally, i think , you wont get better pictures with a medium format camera for this kind of stuff. dslrs are the way to go.
sometimes improving your chances of getting a shot is more important than 20% better res.

paul
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 03:33:53 PM
Could you post or email me a sample please? [email protected]
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: henrikfoto on February 03, 2013, 05:13:50 PM
I have found that the best way to stabilize with long lenses is a good tripod with a very heavy
bag hanging under it. But just as important is a long heavy sandbag (sadle type) on top of the lens and camera.
That bag on the top makes a lot of differnce.

Of course mirror up and remote relaese.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 05:15:53 PM
Bag hanger, and sand bag are definitely doable for these applications. Thank you for the tips! I'm not looking for it to be able to be used spontaneously, I assume it will take a bit of set up. If I am not mistaken if my shutter speed is in the 500-1000+ range in good light I don't think it would be too much of an issue?
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 03, 2013, 06:34:27 PM
...unless the 645D is going to offer better connectivity with the lens because of their proprietary adapter or something....

Automatic aperture control and AF confirmation. The converters do not preserve AF, but aperture control. And you simply get better ISO than with a IQ180. I can't see stop-down metering and focus with an IQ180 being particularly fun, especially with moving targets at those focal lengths. You should go with a DSLR in that case.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 06:46:36 PM
DSLR wouldn't be any fun, thats to easy! ;)

gotcha on the AF, thanks
 
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 03, 2013, 06:51:25 PM
DSLR wouldn't be any fun, thats to easy! ;)

gotcha on the AF, thanks
 


I certainly can understand the idea of going big--Eliot Porter did bird photography with 4x5 early in his career. I would probably get the stuff and try it out on some birds before you leave. I noticed with many setups for this type of work, mirror dampening can take some time to work out. It has to do with the dynamics of the system.

I am looking forward to seeing what you get.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 08:10:06 PM
I'm just struggling to determine if its the 600mm f4 or the 800mm 6.7...the 600mm f4 is cheaper, and I think I read that they are really the same weight, and the web sample jpeg's I was sent of the 600mm f4 exceeded my expectations, besides I would prob be shooting it stopped down a little....is the 800mm 6.7 offering me any real advantages? if I get a 2x TC the 600mm is also still usable....

Whichever I get, I think I will get an adapter for the IQ180 and then rent a 645D and see what it gives me in testing before going then decide if it is worth renting a 645D for the actual trip. I think that is the most economical way since I have no real need to own a 645D in my life...
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: BernardLanguillier on February 03, 2013, 10:40:29 PM
Just noticed that the Pentax 800mm f6.7 weights 6.5 kg and has a minimal focusing distance of 8 m...

To be compared to the new Nikon 800mm f5.6 VR weighting 4,6 kg and focusing down to 5,9 m. It is also 4 inches shorter.

I guess we all like to have fun in different ways.  ;)

Cheers,
Bernard
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 03, 2013, 11:38:15 PM
@BernardLanguillier when reading through your original message, which I saw in the email ;) it did seem like an attractive option to rent a 800mm f/5.6 which I would assume would be out by then and then use it with either a rented D800(e) or my D4, but then at the end, I reminded myself that half of the goal is the fun and challenge of trying to get some good images with a super-telephoto on medium format digital....where is the fun of using the absolute best tools for the job (800/D4) when you have to use some creativity and skill to capture something with my slightly different equipment choice.

You did however highlight a point that is worth some consideration....the 800mm f/6.7's minimum focusing distance is 8m and it weighs in at 6.5kg like you say...the 600mm f4's minimum focus distance is 12m and it weighs 6kg .... this brings in to question whether the added (approximately) 1lb of weight is worth an added 4m (~13ft) of focusing....and then there is the cost of say 2,000 USD for the 600mm and 6,000 USD for the 800mm....

I would probably just sell whichever lens I ended up with after the trip, do we agree that the 800mm may be the better investment of the two in this context? not to mention adding fairly a significant minimum focus distance boost for a minimal weight gain?
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Lacunapratum on February 04, 2013, 01:27:45 AM
Hey folks,

Not that easy.  The 600mm lenses for FF digital are autofocus and because of their high speed and the camera body's high speed allow for fast shutter speeds, which makes it possible to get reasonably sharp images under typical wildlife photography conditions.  In addition, the mirror is significantly smaller than any MFD mirror. 

The 800mm for the Pentax is "only" 6.3 and the back looses substanially at 1600ASA.  This would all be o.k. for average lenses, but the 800mm/6.3 ED is quite a beast.  Most medium format digital cameras add a lot of mirror and shutter vibration, and while these are acceptable for average focal lengths, at 800mm you will feel the effect, unless you do your best to minimize vibration (e.g. two tripods, bright sunlight, perhaps even other shutter dampening strategies). 

Thus, those 600mm rigs for FF are likely the better equipment for wildlife photography, unless you are prepared to go to great lengths to reduce mirror and shutter vibration. 

One lens that may be considered in this context is the 1000mm mirror lens from Carl Zeiss Jena.  Obviously, the Mirotar will do as well.  These mirror lenses are fairly compact and center well on a heavy tripod.  They also have little chromatic abberations as they are mirror lenses.  You'll have to put up with those donut shaped diffraction rings and that depends on your liking. 

I have shot both the 600mm and the 800mm Pentax on MFD, and both are prone to vibration effects, even though both are wonderful lenses. 

Just my 2c. 

Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: henrikfoto on February 04, 2013, 02:15:29 AM
Brian!

If you want to try the sharpest of all, look for the Zeiss Mirotar 1000mm.
Very heavy, but there is nothing like it.

Henrik
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: BernardLanguillier on February 04, 2013, 03:37:31 AM
Brian!

If you want to try the sharpest of all, look for the Zeiss Mirotar 1000mm.
Very heavy, but there is nothing like it.

Well, for what it is worth, the MTF charts of the new Nikon 800 + teleconverter are much better.

Plus the mirotar is a bit heavy at... 16kg... and seems impossible to find anywhere...

Cheers,
Bernard
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 04, 2013, 08:45:41 AM
Brian!

If you want to try the sharpest of all, look for the Zeiss Mirotar 1000mm.
Very heavy, but there is nothing like it.

Henrik

I'd be concerned about the donuts....and the 38lb weight...lol I'd find a 800mm f4 for that weight! thanks for the suggestion though. I think I need to somehow find one of these (800mm 6.7 / 600mm f4) in the NYC/NJ/CT/MA area to try and see what its like to decide if it is worth it....
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: yaya on February 04, 2013, 10:57:22 AM
For ultimate fun you can look for one of the old APO-Nikkor barrel lenses, I think the longest "production" one was 1800mm....

There are some Nikkor and Fujinon 4x5 lenses of 600mm that weigh 1/10th of that Pentax, you'll need a camera with some looong bellows though ;)
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: henrikfoto on February 04, 2013, 11:08:48 AM
I'd be concerned about the donuts....and the 38lb weight...lol I'd find a 800mm f4 for that weight! thanks for the suggestion though. I think I need to somehow find one of these (800mm 6.7 / 600mm f4) in the NYC/NJ/CT/MA area to try and see what its like to decide if it is worth it....


There are no donuts unless you shoot directly against the light.
And the sharpness is like nothing else. Imagine 1000 mm f.5.6 on a 80mp sensor..
And it has full sharpness fully open.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 04, 2013, 11:24:15 AM
Doesn't seem to load anything
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Lacunapratum on February 04, 2013, 01:21:58 PM
I agree with henrikfoto that the distractive effects of the donut shaped background diffraction phenomena are often overestimated. 

MFD with long telephoto lenses is certainly possible, but much more involved than technical data may suggest.  As I was saying, the Mirotar or the Zeiss Jena are one good approach.  Both have comparable resolution.  Speed and design of these lenses are fairly favorable when compared to the alternatives. 

The 800mm/f4 Pentax 67 is not an alternative, as chromatic abberations are not acceptable for digital use.  FF would yield much better images. 

The 600mm and 800mm Pentax ED lenses are a viable alternative, but you'd have to make considerable effort to reduce vibration.  Feasible, but not easy.  You would need good light.  Moving animals at dusk or dawn are almost impossible.     

Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: tsjanik on February 04, 2013, 03:48:18 PM
If you haven't seen this Brian:

http://www.luminous-landscape.com/reviews/lenses/Pentax-800mm.shtml
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 04, 2013, 07:36:12 PM
Yes, thank you I have seen the LuLa articles on the 600mm f4 and the 800mm f6.7.......I think I will try my Mamiya 300mm f/2.8 APO with its 2x TC....I don't know why I wasn't considering that before, aside from vingetting, as we can see from my testing its pretty damn good on sharpness etc, and I wasn't experiencing any vibration issues in good light with the 645DF body. 600mm might be on the short end but then again I was considering the 600mm f4 and that isn't terribly faster to make it worth the financial and physical stress.

I should give the 300mm f/2.8 A real workout, and not just on a stuffed owl.

http://brianhirschfeldphotography.com/2012/08/21/mamiya-300mm-f2-8-apo-lens-review-with-sample-images-and-comparisons/
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Lacunapratum on February 04, 2013, 11:06:24 PM
Sounds like a good plan to me  :).
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: atlnq9 on February 05, 2013, 01:02:56 PM
I don't have experience with the Pentax M* 67 800mm 6.7; but I do have experience with the Pentax M* 67 400mm 4.0 and Pentax A* 645 600mm 5.6 on a Pentax 645D.  So some of this may be good information for you.

Not sure how much you know about Pentax lenses but you don't want the old 6x7 lenses that do not have a star designation.  This primarily only leaves the Pentax 67 M* 400mm (which I have) and the Pentax 67 M* 800mm.  Stay away from the 6x7 400mm 4.0, 6x7 600mm 4.0, and 6x7 800mm 4.0.  Aberrations and sharpness are not up to digital...  The 645 A* 600mm is an excellent performer but is not up to a 1.4x converter.  Ergonomics are fantastic on this lens.  The 67 M* 400mm 4.0 is a fantastic performer and is up to a 1.4x converter; however, the ergonomics are not as good.  This lens does not have the top handle and requires an adapter.  Still up in the air which is my favorite lens since the 400mm is the optically best performer but the 600m is the usability performer...

Now for the medium format vs dslr discussion.  Well before the d800 a dslr did not even cross my mind.  It came down to in most circumstances I got the same quality image as was coming out of 16-20mp dslr with my 40mp medium format; sharpness, focus, higher iso, motion, etc. resulted in an image that could only be printed to that size and not show image imperfections.  However, on that rare 20% occasion you yield an excellent image.  And thats what it was all about using the medium format.  However, now with the advent of the d800 the game has changed.  Sure, it is still a battle to pull the full resolution but there is more in your favor with the dslr and image stabilized auto focus lenses.  I would have a d800 now to make a decision if I wasn't living in Namibia...  But I am.  Now on the other hand I like the 6x7 and square format so a digital medium format is a good ratio to crop to that...

Anyways, on to the use of long lenses on medium format.  First I find I have to have a focus magnifier to obtain crisp focus.  Second a solid wooden tripod is best, just seems to work better than carbon or aluminum.  I also use the really right stuff parts for the long lens support with an additional clamp going to the mount on the camera.  Then a 4th leg like the manfroto lens support which goes from the camera down to the tripod to further stabilize.  Weight the whole thing down with bean bags...  Setup takes a lot of practice to get everything setup outside, nail focus and get everything locked down followed by mirror up...  Third you have to have decent light or bump the iso higher than you want as with that amount of resolution you need to be using fast shutter speeds.  I found a drop in polarizer was a life saver here because you could shoot a little later in the morning and a little early in the evening when the light was bright enough.  It helps keep you from loosing contrast...  But again takes light away...  Shooting from a vehicle was difficult, possible but difficult.  Shutter speed and movement inside the vehicle must be watched very closely.  Vehicle must be turned off as is common sense...

Now on a side topic less than 5% of my wildlife images are shot with the long lenses.  It just has to have a lot working in your favor to pull it off.  I rather have better luck with a 300mm and incorporate much more of the landscape.  It works well here as the landscape is amazing that we have animals in.  The long lenses are used for about 10% of landscapes (primarily the 400mm) as it is a unique perspective creating some nice abstracts...  However, that leaves to massive and expensive lenses used for less than 6% of my photography.  I can't help but think I would use the longer focal length perspective more with a d800 as more things are in your favor.

Anyways, I think that is some good information to help you.  Ask any questions you want, I have been using the system for two years now on everything from lions, elephants, antelopes, landscapes, etc.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 05, 2013, 03:43:14 PM
Thank you for your in=depth response, do you have any experience with the SMC pentax-FA* 645 300mm F4 ED [IF] or the SMC Pentax-FA 645 400mm F5.6 ED [IF] the 400mm seems attractive especially considering it has AF on a 645D, any thoughts on these?

Do I assume correctly that adding a TC to the 400mm on the 645D would loose AF?
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: atlnq9 on February 05, 2013, 03:56:07 PM
Thank you for your in=depth response, do you have any experience with the SMC pentax-FA* 645 300mm F4 ED [IF] or the SMC Pentax-FA 645 400mm F5.6 ED [IF] the 400mm seems attractive especially considering it has AF on a 645D, any thoughts on these?

Do I assume correctly that adding a TC to the 400mm on the 645D would loose AF?

The Pentax FA* or A* 300mm f4 is an absolutely fantastic lens.  This is my most used lens for wildlife.  Another option which I use quite a lot is the Pentax FA 300mm 5.6.  This lens is incredibly light and compact, handholds easily, doesn't require quite as fast a shutter speed due to the light weight...  If you can get it stopped down to f8 it compares exactly to the 4.0 EDIF lens yet allows for a slightly slower shutter speed...

No experience with the 645 FA 400mm as I was told it was less than a star lens and I have the 67 M* 400mm.  I have always wanted to try it though since it is AF and lighter than the 67 version.

Unfortunately Pentax never made a AF teleconverter for a medium format system.  I find the 645 1.4x teleconverter to be pretty subpar.  Does not perform exceptional on either the 300mm 4.0 or 600mm 5.6.  Could be my copy, but I have my doubts that Pentax ever focused much effort on it...  The 67 teleconverter is exceptional though, designed specifically to work on the 67 M* 400mm 4.0 but also works on the 67 M* 300mm 4.0.  Truly exceptional on the M* 400mm 4.0.  The 67 M* 800mm had a specially designed 1.4x with it that works on no other lens, I presume that is an exceptional combination.

Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 05, 2013, 03:59:15 PM
Thank you for the added details :)
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: atlnq9 on February 05, 2013, 04:08:28 PM
No problem!

BTW you rarely see any of the 645 or 67 long star lenses for sale.  Took me 8 months to find my 645 A* 600mm 5.6.  But there has been a 67 M* 800mm 6.7 on ebay for a long time now.  I have been eyeing it over and over.  But a big risk bringing it to the US or Africa from Poland sight unseen for 6k...  And even rarer to find is the drop in polarizer, if you want the drop in polarizer don't expect to find it for sale on it's own.  Wait for a lens that includes it or expect to buy a lens later including it then turn around and resell the lens...  Th 67 drop in polarizer fits both M* 400mm and 800mm lenses and is a bit more common.  I have only ever seen one drop in polarizer for the 645 A* 600mm 5.6...

http://www.ebay.com/itm/Pentax-M-67-800mm-F6-7-800-mm-ED-IF-Lens-SMC-M-Star-For-Pentax-67-/261000277796?pt=US_Vintage_Cameras&hash=item3cc4d42f24
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 05, 2013, 04:12:40 PM
The 645 600mm f5.6 looks like it would be the most attractive option. I saw the 800mm 6.7 on ebay and contacted the seller but the response I received to asking if it was the earlier 8 or the later 10 element version was "I DO NOT KNOW" like that in all caps. Not sure if that is very confidence inspiring in a seller.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Lacunapratum on February 05, 2013, 10:09:56 PM
The 400mm/5.6 EDIF is a stellar lens, at least as good as the 300mm/4 EDIF.  They both work with the 1.4x teleconverter and I found that converter to be quite good.  The 600mm/5.6 or the adapted 800mm/6.7 both are better than the 300mm and the 400mm with teleconverter though, and heavier I might add  :D
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: chrismuc on February 06, 2013, 02:31:50 AM
... I wait until Stefan's (Hartblei) Mamiya RX67 - Contax 645 helicoid adapter becomes available to try the Mam RX67 500f6 Apo (+ 1.4x extender)
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 06, 2013, 10:43:11 AM
The Pentax TC 1.4X has a very good reputation with the 300mm and 400mm lenses--it was actually designed for them.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: tsjanik on February 06, 2013, 12:29:15 PM
Thank you for your in=depth response, do you have any experience with the SMC pentax-FA* 645 300mm F4 ED [IF] or the SMC Pentax-FA 645 400mm F5.6 ED [IF] the 400mm seems attractive especially considering it has AF on a 645D, any thoughts on these?

Do I assume correctly that adding a TC to the 400mm on the 645D would loose AF?

Brian:

The 400 is excellent.  If you have access to Llyod Chamber's site you can read his review.  The lens is light, very sharp and easy to find.  I find the AF accurate and usable for wildlife on the 645D.
These are handheld BTW.
Tom

Some examples:
(http://www.getdpi.com/forum/members/tsjanik/albums/645d/3981-igp9599.jpg)

(http://farm8.staticflickr.com/7065/6823296352_cd50e37206_b.jpg) (http://www.flickr.com/photos/[email protected]/6823296352/)
1_IGP7118 (http://www.flickr.com/photos/[email protected]/6823296352/) by tsjanik47 (http://www.flickr.com/people/[email protected]/), on Flickr

(http://farm8.staticflickr.com/7025/6496578259_1ca5d0253f_b.jpg) (http://www.flickr.com/photos/[email protected]/6496578259/)
_IGP6448 (http://www.flickr.com/photos/[email protected]/6496578259/) by tsjanik47 (http://www.flickr.com/people/[email protected]/), on Flickr
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 06, 2013, 05:37:23 PM
Thanks, that makes it a mighty tempting second camera, maybe I'll rent one or just bring one along.

As for my solution, I had another good idea (after realizing I had a 600mm lens a la 300mm f/2.8 APO + 2xTC).

It came to me today, that since I have an 80mp back, I can crop 50% and it will still be a 40mp file. Now you may go well duh, but thats effectively doubling the focal length with a center crop. In my Lizard image (which I like so much) I used a 300mm lens alone on a P65+ and was able to do a significant crop, so halving an 80mp is no issue.

However this could be very hard to frame in the viewfinder. So I had the idea of getting a viewfinder mask made that only shows the center 50% of the viewfinder. Then I will buy the Mamiya 2x viewfinder magnifier (which i know vignettes but that isn't the issue since I'm using a small area). and when I look through the camera it will be as if i added a second 2x TC to my camera (or atleast I can visualize what it will be like if I do.) This may mean having a 645DF body that has the viewfinder mask in it and a second for regular pictures, but its much easier, and smarter since vibration isnt an issue with this rig instead of what you would need to get to a 1200mm focal length with any of these pentax lenses... 
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 06, 2013, 08:47:37 PM
Brian, if you crop 50% top and bottom, you have 20MP left with your IQ180. If you crop to 40MP, the 645D will still have a larger image area--44x33mm vs. 38x28mm for the IQ180 (the Pentax has bigger pixels, my friend (and a bigger viewfinder)).

I am unsure why you think a 1,200mm lens on a 645D to equal a 600mm lens on an IQ180. The 44x33mm format is only a 1.27 crop factor from a 6x4.5 frame. A 760mm lens on a 645D would be an equivalent.
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 06, 2013, 08:53:26 PM
The viewfinder mask will be for the IQ180, the 645D would just be for the 400mm lens
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: theguywitha645d on February 06, 2013, 08:58:28 PM
the 645D would just be for the 400mm lens

Welcome to the dark side, young Skywalker. ;>
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Lacunapratum on February 06, 2013, 09:03:58 PM
"but the response I received to asking if it was the earlier 8 or the later 10 element version was "I DO NOT KNOW" like that in all caps"

Most sellers unscrew their lenses when they receive such a question from an interested buyer, count the individual elements, and then glue the lens back together.   ;D 
Title: Re: Pentax 800mm f/6.7 on Digital (PhaseOne IQ180)
Post by: Brian Hirschfeld on February 06, 2013, 09:04:49 PM
"but the response I received to asking if it was the earlier 8 or the later 10 element version was "I DO NOT KNOW" like that in all caps"

Most sellers unscrew their lenses when they receive such a question from an interested buyer, count the individual elements, and then glue the lens back together.   ;D 

Well, it would be nice...