My Phase One DF body doesn't like my adapted lenses . . . .

[Focusrite]

Hello, I thought share my ongoing experience with the rather bizarre behaviour of one of my Phase One DF bodies when using two of my adapted lenses at certain shutter speeds.

I noticed that some of my photos had pretty extreme purple fringing while using my Pentax A 35mm lens a couple of months ago, but over the last few weeks I have realized just how bad it is.

Basically, between the shutter speeds of about 1/10s and 1/100s the images range from having smeared high-contrast edges with "purple fringing" in the 20+ pixel range at the 1/10s end, to having an image that is completely tinted purple at 1/60s and 1/80s, where the problem is at its worst. I played around with it yesterday, and I am still not sure exactly what is causing it or why.

To be clear, this only happens when I am using the combination of Leaf Aptus II12, one of my DF bodies, and adapted lenses. This mostly includes my Samyang 24mm and Pentax 35mm lenses at those shutter speeds, but it was also very evident with another adapted lens I'm testing at even higher shutter speeds ( up to 1/400s - testing is still ongoing with that one ). My Mamiya lenses at the same shutter speeds are fine, no issue. Using my Aptus II 7 back on that DF body with those lenses at those shutter speeds do not show the same problem. Using the same lenses with the Aptus II 12 on my second DF body with the adapted lenses do not show the same problem. The batteries used for both the digital back and DF body were swapped between the setup and remained the same, good charge on both and a genuine ( but old ) Leaf battery for the digital back. I am at a bit of a loss as to what is going on; whether the DF body is somehow glitching out in communicating with the Aptus II 12 ( or vice versa ), the digital back is freaking out for whatever reason, or there is another issue there somewhere.

I even dug out my Sony RX100 and recorded the shutter actuating at 1/60s exposure time at 960fps. Even at that speed ( and very noisy video ) you only have a few frames where you can see the shutter actuating ( it's very fast! ), and nothing really seems out of the ordinary.

It bothers me, but it's not a major deal-breaker in any real sense. That body has been relegated to being my back-up now, and it's possible to work around those shutter speeds if I need to. It's just a bit of a shame to have its usefulness severely restricted, and it would be nice to know what's going on.

Photos show the issue at its worst. White balance is set basically permanently at Daylight on the digital back. No adjustments have been made in post, but from experience simply adjusting the Green/Magenta slider will not clear it up completely - the colour does become more normal, but very washed out. I did notice some banding in the sky on one of the purple images after trying to adjust it. Issue clears up completely at 1/125s. Mamiya 35mm is fine at the same shutter speeds.

 

[buildbot]

Maybe the lens contacts are being shorted out and it’s causing weirdness?? If you can somehow tape or otherwise cover the contacts does it still happen?

 

[Focusrite]

Thanks for the response.

Interesting idea, but I sat down to have a look at the cameras to see if it would be plausible and I don't know if that could have anything to do with it. One lens doesn't make any contact with the camera pins, the other should clear it, and the third lens I was free-lensing so it wasn't making any contact with the camera body at all. I might have another go, but it seems unlikely at this point.

I tried a few different batteries to make sure the digital back battery wasn't wigging out, but that didn't seem to make a difference ( unless all of my batteries are kaput, I'll have to try playing around with that a bit more ).

Just to add to the mix, I've spent the midday hours playing around further, and found that it's affecting both camera bodies in some way; it was just a lot more subtle on the other body. I now think it's the digital back, and it seems to have lost all patience with my adapted lenses and is getting worse quickly. It also seems to be a much broader range of shutter speeds that are now affecting it, with faster shutter speeds being much worse than the slower ones. Shots at 1/400s look awful, and on the other DF body there is a distinct colour cast at the top of the frame with some banding through it.

I tried to adjust the colour cast on one of the purple photos, and the banding becomes very obvious. 1/125s still seems to be a bit of an oasis on both bodies with minimal cast issues, but I don't know why. I'm still at a loss as to what is going on; but I guess I'll have to stick with the standard lenses for now, which cuts down on my system's usefulness, as well as rendering my efforts to adapt the lenses useless thus far.

I'll have to play around with it a bit more.

The worst of the first body, no adjustments in post:


Adjusting the White Balance in post on a purple photo from the first DF body, with obvious banding:


A photo from the second DF body, with obvious colour cast at the top of the frame with some banding:

 

[anwarp]

How long are you waiting between exposures? It could be that the sensor has not been reset properly between exposures.

 

[MartinN]

Weird, weird ! I simply can’t beleive that could be caused by adapted lenses. Something with that back and camera combination is really screwed.

 

[anwarp]

What about testing against a white wall with no lens? White wall or purple?

 

[sixby45]

Hmm that is quite a weird event, I use adapted lenses on my DF+ often, and while sometimes I get some fringing around hard highlight edges, or mild smearing its usually from the lenses themselves, and nothing on this level of full banding and color changes. The only experience I've had like this was with an H series digital back, which had the IR filter changed, and after the change everything was a slightly orange color - but that seems different than this. Definitely interested in learning more about how this continues on.

Good luck!

-Rich

 

[Focusrite]

How long are you waiting between exposures? It could be that the sensor has not been reset properly between exposures.

I usually wait until the orange light on the back stops blinking and it beeps. I would expect that is sufficient? The body doesn't let me actuate the shutter until the back is ready.

Weird, weird ! I simply can’t beleive that could be caused by adapted lenses. Something with that back and camera combination is really screwed.

Here's hoping it's a random glitch from a combination of things. I spent yesterday evening and this morning doing some shooting with my Mamiya lenses with no issue.

What about testing against a white wall with no lens? White wall or purple?

That is an excellent suggestion. I'll play around with that idea this afternoon ( hopefully, if I get some time ). I'll post results if I do.

Hmm that is quite a weird event, I use adapted lenses on my DF+ often, and while sometimes I get some fringing around hard highlight edges, or mild smearing its usually from the lenses themselves, and nothing on this level of full banding and color changes. The only experience I've had like this was with an H series digital back, which had the IR filter changed, and after the change everything was a slightly orange color - but that seems different than this. Definitely interested in learning more about how this continues on.

I'm actually curious about trying an older Mamiya lens on it, one that maybe doesn't have any internal chips or circuitry ( if they exist ), and whether the body/back needs confirmation from the lens for some reason. I'm still mystefied as to why it's happened; when I first used adapted lenses everything was fine.

 

[anwarp]

I'm actually curious about trying an older Mamiya lens on it, one that maybe doesn't have any internal chips or circuitry ( if they exist ), and whether the body/back needs confirmation from the lens for some reason. I'm still mystefied as to why it's happened; when I first used adapted lenses everything was fine.

The fully mechanical mamiya lenses work fine on the DF. The fact that you see the issue on both bodies, although differently, would suggest it’s not a problem with the body.

Another thought: Are you using the same adaptor for the adapted lenses?

I Had an issue with a mamiya rz that would trigger the flash randomly when mounted on a specific quick release plate. It turned out that a cable connecting the hot shoe to the lens was partly trapped under the bottom plate. With the pressure at the right point, the vibration of the mirror flipping would short it to the body and cause the flash to fire.

 

[Focusrite]

I ran some more tests yesterday, and safe to say I'm even more perplexed than I was earlier. I'm now not convinced that it's the digital back(s) alone.

What about testing against a white wall with no lens? White wall or purple?

It's purple. I did take the shot outside, as there wasn't enough light inside the house, so I took some shots of the garage door from outside. Still taken in the shade, at 1/400s. The purple hue is nowhere near as aggresive as when you are using a lens, but it's still there. No banding that I can see. I did take a shot at 1/160s, which was nearly completely clear of the hue, but that does sit in line with its behaviour with adapted lenses, where it does get better with lower shutter speeds. I might have to play around with that a bit more.

Aptus 12, 1/400s:


Aptus 7, 1/400s:

Are you using the same adaptor for the adapted lenses?

No, the adapters are custom for both lenses. The Pentax 35mm has a machined single-piece adapter out of aluminium, while the Samyang has an aluminium tube with a chrome-plated steel bayonet taken off a Mamiya extension tube.

And now for the plot twist: I retested the lenses on my different digital backs, and the issue is there on all of them. Not nearly as pronounced as with the Aptus 12, but the purple hue is still there as is the banding problem. I've now also tried different batteries in the body in case variances in voltage was causing it, as well as different batteries for the digital backs. Same story: adapted lenses take purple photos with banding and smeared details, Mamiya lenses don't, and now I'm at even more of a loss as to what the issue is. I did wonder if it was an issue with a lack of flocking or light-absorbing coating on the lens adapters, and perhaps that is scattering/reflecting light in weird ways. I understand the Aptus 12 has quite aggressive micro-lenses and hates wide technical lenses for this reason, but this still doesn't explain why I didn't see this issue when I first started using the adapted lenses. Maybe the DF bodies are slowing dying in an odd way, but I'm really just grasping at straws now.

Aptus 7 with Pentax 35mm then Mamiya. Banding is present, and you can even see where the seam between the sensor chips are:



Just to reiterate, this isn't stopping me from using the gear, just the adapted stuff. I got out and had a grand time yesterday, but I did miss having my wide angle. I will probably make some further tests, but I'm running out of lens/back/body/battery combinations to try! Suggestions are still welcome.