best 35mm shift option : Pentax 645 HD DFA VS Contax 35 PC distagon for GFX 50r?

[rdeloe]

Hi Rob,

thanks a lot for your detailed information. Very helpful - and the answers are what I hoped for too ;-)
I read that the newer edition of the lens was even better. And since I go for ultimate quality in the GFX system I will try that. I will try to contact Antonio.

Best -
Marc

Makes sense. Good luck. If you do get one, I'll be curious to know what you think. I use this focal length a lot, and if I hear some more reports that it's superb, I may have to break down and get one too!

 

[D&A]

Hi, as I mentioned and outlined in my post "above" (in this thread), the Pentax HD D-FA 35mm f3.5 is heads and shoulders above it predecessor, the FA 35mm f3.5 . These observations are based on multiple testing of many samples of each lens on initially the Pentax 645D and subsequently, the 645Z. I've relied on others observations, regarding how these lenses performed when shifted.

Dave (D&A)

 

[Owen]

I would like to revive this thread because I think about buying the Pentax 35mm lens for shift use on the GFX 100. Three questions:

1. Is this the latest version of the lens? HD PENTAX-D FA 645 35mm F3,5 AL [IF]

2. From the information I could find I was not sure if the aperture can be controlled manually when I use a dumb shift adapter. It has an aperture ring, but this ring has an "A"-position which often is an indication that the aperture is controlled electronically via the body. Can anybody confirm aperture can be controlled without a pentax body?

3. Can anyone provide a sample image with this lens when used with a serious amount of shift on a GFX body? GFX 100, or one of the 50MP bodies. Complete image or 100% crops. Whatever you have would be helpful.

Thanks -
Marc

Marc, PM me your email address and I'll send you RAW files taken with the A and GFX100, shifted on a Kipon adapter.

 

[Owen]

That Pentax 645 HD seems good... i will probably go this way !

by the way, will it make any difference to buy a P645/EOS adapter + Eos/GFX shift... over the Kipon P645/GFX shift ?
What's the best solution considering flare and movements ?

You can actually combine the Kipon P645-EOS shift adapter with their EOS-GFX shift adapter and have dual movements. So, shift up and then stitch left to right. The 35mm is very resistant to flare (I've owned the A and FA, both are great), but any shift adapter may improve with a little flocking.

 

[Owen]

Hi, as I mentioned and outlined in my post "above" (in this thread), the Pentax HD D-FA 35mm f3.5 is heads and shoulders above it predecessor, the FA 35mm f3.5 . These observations are based on multiple testing of many samples of each lens on initially the Pentax 645D and subsequently, the 645Z. I've relied on others observations, how these lenses performed when shifted.

Dave (D&A)

Dave, have you noticed any differences in that odd distortion profile when shifted, particularly along the long edge? It's because of that I'm using the Canon 24mm in crop mode on the GFX100 rather than the 35mm, and then the 32-64 whenever shift isn't required. For commercial interiors any distortion is clearly visible and makes the A/FA hard to work with.

 

[D&A]

Dave, have you noticed any differences in that odd distortion profile when shifted, particularly along the long edge? It's because of that I'm using the Canon 24mm in crop mode on the GFX100 rather than the 35mm, and then the 32-64 whenever shift isn't required. For commercial interiors any distortion is clearly visible and makes the A/FA hard to work with.

Hi Owen. Unfortunately I haven't had the opportunity to test any of the three Pentax medium format 645 lenses (the "A", FA or HD D-FA) in a "shift" scenario....if I understand your question correctly. I could surmise (based on my experience with shifting with lens and shift adaptor but unfortunately that was not with any of the three Pentax 35mm 645 lenses being discussed. I would guess the "FA" version might be most problematic at full shift. It's interesting to note that optical properties of field curvature and distortion generally seen with the "FA" version is very different than with the "A" version...whereby the former has excessive (almost extreme in my opinion especially when lens focused at infinity) field curvature as opposed to some quite mild mustache type waviness distortion in the "A" version. What effect both these observations will have on either the short or long side when either these lenses are fully shifted, can only be determined when actually tried.

If I was a person contemplating use of one of these lenses adapted for shift use on the Fuji, my order of preference in trying them would be the HD D-FA and then the "A" version...the latter which for the money is a exceptionally good lens except for a bit of weakness along the short side edges and the mild distortion as mentioned. I feel I haven't been of much help with regards to definitively saying anything about each lenses potential as a shift lens but I am extremely curious. As a side note, it's interesting how the "FA" and HD D-FA lenses appear almost if not identical in both appearance and optical arrangement yet remarkably difference in performance. The increase in contrast is noticeable and is probably due to a change in coatings and the dramatic performance boost in almost eliminating its extremely field curvature, I put down to what info I have gleaned....that the aspherical element was re-computated as a primary change. It truly resulted in a remarkable change in performance.

It's interesting to note, that Pentax through the years never really touted unique optical parameters of their lenses as some other 35mm companies often did. A number of their high performing 35mm lenses contained aspherical elements in the days before they were commonly used in 35mm format lenses, yet Pentax never said a word in advertising. That conservative approach stayed with them almost until the time they were acquired by Ricoh, so it's no surprised that little is mentioned about the differences between the older "FA" version and current HD D-FA and yet the differences are quite dramatic, especially when files are examined or utilized at full resolution.

Dave (D&A)

 

[rdeloe]

Dave, have you noticed any differences in that odd distortion profile when shifted, particularly along the long edge? It's because of that I'm using the Canon 24mm in crop mode on the GFX100 rather than the 35mm, and then the 32-64 whenever shift isn't required. For commercial interiors any distortion is clearly visible and makes the A/FA hard to work with.

I use the SMC Pentax-A 645 35mm f/3.5 as a shift lens.

Unshifted, there's barrel distortion, which tidies up cleanly in Lightroom. I should really build a custom profile, but haven't done so. In the meantime, the FA profile works well for both vignetting and distortion (likely because I mostly shoot things that don't display the distortion).

The distortion shape changes to what looks like pincushion in the top 1/3rd when you make a 10mm plus vertical shift in portrait mode (in other words, a rise). However, what really happening is you're seeing one side of the mustache. Thus, the barrel distortion you see unshifted is the middle part of the mustache shape. On a sensor that covered the entire image circle as it was meant to be used, you'd see the full mustache form, which you don't see unshifted using a 33mm x 44mm sensor.

With a 5mm rise in portrait orientation, the problem I described for the 10mm plus shift is present, but to a much lesser extent. Except for the most demanding cases, the built-in tools provided by Lightroom clean things up nicely.

Needless to say, the shifted distortion form visible at 10mm and larger shifts is not easily correctable. If you're shooting landscapes or other scenes where you don't have regular, straight shapes aligned with the edge of the frame, it's not really a problem. But for architectural or interior work, I could see it being problematic.

 

[marc aurel]

I use the SMC Pentax-A 645 35mm f/3.5 as a shift lens.

Unshifted, there's barrel distortion, which tidies up cleanly in Lightroom. I should really build a custom profile, but haven't done so. In the meantime, the FA profile works well for both vignetting and distortion (likely because I mostly shoot things that don't display the distortion).

The distortion shape changes to what looks like pincushion in the top 1/3rd when you make a 10mm plus vertical shift in portrait mode (in other words, a rise). However, what really happening is you're seeing one side of the mustache. Thus, the barrel distortion you see unshifted is the middle part of the mustache shape. On a sensor that covered the entire image circle as it was meant to be used, you'd see the full mustache form, which you don't see unshifted using a 33mm x 44mm sensor.

With a 5mm rise in portrait orientation, the problem I described for the 10mm plus shift is present, but to a much lesser extent. Except for the most demanding cases, the built-in tools provided by Lightroom clean things up nicely.

Needless to say, the shifted distortion form visible at 10mm and larger shifts is not easily correctable. If you're shooting landscapes or other scenes where you don't have regular, straight shapes aligned with the edge of the frame, it's not really a problem. But for architectural or interior work, I could see it being problematic.

Good information. Thank you for that. Would have been great if the lens had barrel distortion all over. Moustache distortion ;-(
Unfortunately no program I know has profiles for Pentax 645 lenses. Neither Capture One nor the Alpa plugin for photoshop. But if you shoot architecture for custumors then an uncorrected image is a no go. So what to do if you want to use that lens?

The only way I can think of to correct the moustache distortion on this lens with more than a few millimeters of shift would be:
- open in Photoshop
- expand canvas to a size that covers the whole image circle of the lens (using the maximum shift you want to use)
- move your image in the expanded canvas until the optical centre of the lens is in the middle (you can create actions in PS to do those tasks)
- save to lightroom
- then you need a custom made profile for the Pentax lens with your expanded canvas to apply it to that image in LR. Then crop back to the original image size.
- this profile can be made using adobe lens profile creator.
- but for that you need at least nine images of a test target with different amounts of shift in different direction.
- every image must be expanded to the canvas size that covers the whole image circle of the lens
- very time consuming process

So would the sharpness of the lens in comparison to other options be worth all that work? I am not sure. The shifted Contax 645 35mm lens can easily be corrected with provided profiles in C1 and the Alpa plugin. This is an advantage of the Contax. Its disadvantage is that you can only use it with fixed aperture if you want to shift.

As was mentioned by others: cropping the TS-E 24mm is an option too. Would be interesting to see a comparison between these 3 options.

Best - Marc

 

[rdeloe]

Good information. Thank you for that. Would have been great if the lens had barrel distortion all over. Moustache distortion ;-(
Unfortunately no program I know has profiles for Pentax 645 lenses. Neither Capture One nor the Alpa plugin for photoshop. But if you shoot architecture for custumors then an uncorrected image is a no go. So what to do if you want to use that lens?

The only way I can think of to correct the moustache distortion on this lens with more than a few millimeters of shift would be:
- open in Photoshop
- expand canvas to a size that covers the whole image circle of the lens (using the maximum shift you want to use)
- move your image in the expanded canvas until the optical centre of the lens is in the middle (you can create actions in PS to do those tasks)
- save to lightroom
- then you need a custom made profile for the Pentax lens with your expanded canvas to apply it to that image in LR. Then crop back to the original image size.
- this profile can be made using adobe lens profile creator.
- but for that you need at least nine images of a test target with different amounts of shift in different direction.
- every image must be expanded to the canvas size that covers the whole image circle of the lens
- very time consuming process

So would the sharpness of the lens in comparison to other options be worth all that work? I am not sure. The shifted Contax 645 35mm lens can easily be corrected with provided profiles in C1 and the Alpa plugin. This is an advantage of the Contax. Its disadvantage is that you can only use it with fixed aperture if you want to shift.

As was mentioned by others: cropping the TS-E 24mm is an option too. Would be interesting to see a comparison between these 3 options.

Best - Marc

You left me behind with the step, "open in Photoshop" Seriously, that sounds like a lot of work. Were I shooting architecture and interiors for clients, I'd be looking for a better lens.

I should emphasize, I do not know if the optical adjustments made to the HD version corrected the mustache distortion problem. If I knew someone who had one it would be easy to check on my setup. Alas, I don't.

Good luck, Rob

 

[marc aurel]

You left me behind with the step, "open in Photoshop" Seriously, that sounds like a lot of work. Were I shooting architecture and interiors for clients, I'd be looking for a better lens.

I should emphasize, I do not know if the optical adjustments made to the HD version corrected the mustache distortion problem. If I knew someone who had one it would be easy to check on my setup. Alas, I don't.

Good luck, Rob

yes, I did that once. Was not worth it.
So I now know that the Pentax wont be for me.

 

[Owen]

You left me behind with the step, "open in Photoshop" Seriously, that sounds like a lot of work. Were I shooting architecture and interiors for clients, I'd be looking for a better lens.

I should emphasize, I do not know if the optical adjustments made to the HD version corrected the mustache distortion problem. If I knew someone who had one it would be easy to check on my setup. Alas, I don't.

Good luck, Rob

This is the flaw with the lens, there's too much distortion when shifted to use it for commercial architecture and interiors but as Fuji haven't produced their own we're stuck with it.

In Capture One you can use the Contax 645 35mm profile and get decent results, and using the 'Movement' tab you can type in shift correction. It's certainly much better with shift in landscape orientation rather than portrait. Also, the slight field curvature in the FA lens is quite useful for interiors where depth of field is a main priority.

 

[D&A]

This is the flaw with the lens, there's too much distortion when shifted to use it for commercial architecture and interiors but as Fuji haven't produced their own we're stuck with it.

In Capture One you can use the Contax 645 35mm profile and get decent results, and using the 'Movement' tab you can type in shift correction. It's certainly much better with shift in landscape orientation rather than portrait. Also, the slight field curvature in the FA lens is quite useful for interiors where depth of field is a main priority.

In my experience, the field curvature seen in the FA lens is proportional to camera to subject distance. At close range its relative small. At mid distance its noticeable but at near infinity for landscapes, it's extremely large. So much so, that at infinity and regardless of the f-stop (assuming the lens/camera adjustment shows no front or back focus), its nearly impossible to get edges side of the frame "sharp". Between myself and another forum member, we tried dozens of samples. One partial work around was to set the lens to backfocus at infinity to the point where the center of the frame still retained an acceptable degree of sharpness, but pushed the focus of the sides and edges of the frame "rearward", so that the sides and edges had at least a relative degree of being somewhat in-focus but even at that, softness at higher magnification was clearly evident.

Therefore how acceptable this field curvature is depends of camera to subject distance with the FA lens and of course subject matter.

Dave (D&A)

 

[rdeloe]

In my experience, the field curvature seen in the FA lens is proportional to camera to subject distance. At close range its relative small. At mid distance its noticeable but at near infinity for landscapes, it's extremely large. So much so, that at infinity and regardless of the f-stop (assuming the lens/camera adjustment shows no front or back focus), its nearly impossible to get edges side of the frame "sharp". Between myself and another forum member, we tried dozens of samples. One partial work around was to set the lens to backfocus at infinity to the point where the center of the frame still retained an acceptable degree of sharpness, but pushed the focus of the sides and edges of the frame "rearward", so that the sides and edges had at least a relative degree of being somewhat in-focus but even at that, softness at higher magnification was clearly evident.

Therefore how acceptable this field curvature is depends of camera to subject distance with the FA lens and of course subject matter.

Dave (D&A)

In my side-by-side comparison of an FA and an A at infinity, I saw the same phenomenon you're describing Dave. That's why I kept the A. I'm sure I'd feel differently about it were I shooting primarily architecture, but for what I do it's a very fine optic that serves me well.

 

[Ed Hurst]

I strongly suspect that the Pentax DFA would be the answer to this - it does seem to have corrected most of the problems in the earlier versions. But I don't have one to test, sadly. I do know one or two people who do though...

 

[wallpaperviking]

Am also in this market, I currently have the Canon 24mm TS-E II, Pentax 645 35mm A and the Hasselblad 50mm FLE.

Just saw this on Ebay when searching for the price of a Contax 645 35mm.


https://www.ebay.com.au/itm/264680715261?ul_noapp=true

and

https://www.facebook.com/kimca1977/


I contacted the guy and asked about the aperture, considering it is controlled electronically and this was his reply....

"Hello,

Thanks for your interest.

We have modified the iris to allow manual operation.

Question always welcome.

Best regards,
Kim"


Also asked about whether it would be cheaper without modifying to PL mount and this was his reply

" Maintaining the mount does not affect the cost of the operation.

This is because all parts of the lens have to be replaced by changing the aperture manually and rebuilding the housing. "

I also asked about whether it can be changed to an Eos mount and he replied

" It can be changed.

Since the mount side has been modified by PL work, it can be changed without problems. "





Very steep price but I can imagine how much work goes into it. Cannot quite remember what the Cambo conversion for the Actus is but I think it was over $1000 US and that is potentially less work..

https://www.cambousa.com/distagon-35-retrofit-for-cambo-actus


I wonder if any extra vignetting is introduced by this mod, when using it for the purpose of a "Shift" lens?

 

[Cambo]

Am also in this market, I currently have the Canon 24mm TS-E II, Pentax 645 35mm A and the Hasselblad 50mm FLE.

Just saw this on Ebay when searching for the price of a Contax 645 35mm.


https://www.ebay.com.au/itm/264680715261?ul_noapp=true

and

https://www.facebook.com/kimca1977/


I contacted the guy and asked about the aperture, considering it is controlled electronically and this was his reply....

"Hello,

Thanks for your interest.

We have modified the iris to allow manual operation.

Question always welcome.

Best regards,
Kim"


Also asked about whether it would be cheaper without modifying to PL mount and this was his reply

" Maintaining the mount does not affect the cost of the operation.

This is because all parts of the lens have to be replaced by changing the aperture manually and rebuilding the housing. "

I also asked about whether it can be changed to an Eos mount and he replied

" It can be changed.

Since the mount side has been modified by PL work, it can be changed without problems. "





Very steep price but I can imagine how much work goes into it. Cannot quite remember what the Cambo conversion for the Actus is but I think it was over $1000 US and that is potentially less work..

https://www.cambousa.com/distagon-35-retrofit-for-cambo-actus


I wonder if any extra vignetting is introduced by this mod, when using it for the purpose of a "Shift" lens?

A PL mount or the way we do it, both ways require a mechanical aperture but have different purposes. We prefer to get rid of the mount, as it gives better use of the lens' image circle. For cinema use that's obviously not an issue.

 

[wallpaperviking]

I have always been a fan of Peter Bialobrzeski's work and saw recently that he was shooting on a Fuji GFX 50R and stated he is using a Kipon Shift adapter and a Zeiss 45mm.

Minsk Diary — Peter Bialobrzeski Peter Bialobrzeski is one of the most renowned artist working with photography in documentary style. He is known for his explorations of Urban Spaces worldwide.

www.bialobrzeski.net

That can only be the combo of the Contax 645 45mm, with the aperture preset to a more usable landscape aperture I guess? Like f11 or f13 or thereabouts?

Or is there something I am missing?