Colour cast on edge of Mamiya 645 AFDII ZD images

[michael_lewis11]

Hello, I am new to the Mamiya 645 afd II system with the ZD back but all of my

images have a greenish colour cast on the left hand side. The effect is subtle

but still very annoying. It covers maybe 1/8th of the frame. I had my original

back replaced because of this problem but the new back seems to have the same

problem. Anyone else out there experience something similar or any ideas as to

what might be the cause? I am starting to think a light leak of some kind but

really I don't know. Thanks a lot in advance for any suggestions.<div></div>

[Ed_Ingold]

It looks like vignetting, or possibly something related to the angle of incidence toward the edges of the sensor. It looks more grey than green to me, using a calibrated display. Small-format DSLRs have micro-lens arrays to counter the incidence effect. AFIK, MF sensors don't use these arrays - at least my CFV does not.

[michael_lewis11]

Is that something that can be fixed/calibrated or is that just a trait of the system do you think?<div></div>

[Ed_Ingold]

There are tools for correcting vignetting in Photoshop and other programs.

 

It is highly misleading to apply "auto levels" to such a low contrast image. It's like trying on swimsuits under fluorescent lights ;-) Seriously, Photoshop sets the white and black points very close together based on the image, which in turn exaggerates the contrast in between along with any defects.

[michael_lewis11]

I understand the black and white will totally go to extremes and produce an ugly image but that greenish colour on the left side shouldn't be there, right? It should just be a very black and white image. I am getting a consistent greenish colour on the left side of all of my photos and I can't understand why. I am less concerned with the vignetting and more concerned about the colour cast. Thanks again for your input, it really is helpful.

[Ed_Ingold]

The color shifts are artifacts of magnifying the limited contrast range to an extreme value. You see similar results when scanning blank film. Most of us should not model swimsuits in front of a mirror, either :-)

[michael_lewis11]

The problem is, I see a noticeable green tint on the edge of all of my photos, even without adjusting the contrast. I previously owned a 5D and I never had this problem. It seems to be a trait of the ZD system, this being my second ZD Back and the problem persisting. I can look at the RAW files from my 5D side by side with the Mamiya ZD files and easily spot the green tint on the Mamiya files only. Nobody, including Mamiya, seems to be able to explain it. What I really want to do is try a Phase One back and see if the problem persists.

[bill_caulfeild_browne]

I have the P45+ on the same camera but with no problem - with any lens. What lens are you

using?

Bill

[andersloof]

Hi,

 

Your problem is one I have not heard or read of during my ZD ownership. I posted of another problem at http://luminous-landscape.com/forum/index.php?showtopic=22698&hl=. You may check your ZD back for that one also. Further I recommend any potential ZD buyers to read careful what I written there. As of yet I do not know that newer ZDs have been corrected/improved. I received no correction from Mamiya and sold my ZD at loss.

 

The greenish colour cast clearly looks like a problem your agent should correct, or if lucky replace/refund.

 

Regards

Anders

[michael_lewis11]

I have the 35mm lens, the 120mm, and the 80mm. It shows up on all of them. I am in the process now of exchanging/upgrading to a Phase One P20+ Back. In some ways it feels like a step down but in many ways a step up. I just don't think those ZD backs are very good.

[michael_lewis11]

For anyone reading this who is considering buying into this system, let me just say that I have since replaced the ZD Back with a Phase One P20+ (16MP instead of 22MP) and I could not be happier. The images are simply better on the Phase One. I've been able to enlarge them up to 40 inches by 40 inches (the largest I've tried) and they look amazing. It also completely outperforms in low light and long exposures. Also, the ZD was slow and would always lock-up mid shooting and I would have to turn the camera off and start everything up again - very annoying and a little embarrassing when shooting in studio with models and crew around. Anyway, the Phase One is a dream. Everything you could want when spending that kind of money. Like driving a real sports car instead of a fancy looking kit car. That's my two cents.