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Need help with my gear (Phase One + ZD Back)

MaxKißler

New member
Take a look at the light bulb in the last picture. The purple area which I believe to be a reflection is in the light's emergent angle.

This image might explain what I mean:

View attachment 37984

@Terry
In Europe you have to abandon your return privileges in order to buy a used item.
 

Terry

New member
Wow so in Europe if you buy something on eBay that isn't working as stated in the auction there is no recourse.
 

MaxKißler

New member
Well, if you're using Paypal you're on the safe side even if something is defect. In my case, those 60 days of security are over and I haven't noticed the issue before.

Even if you don't pay via Paypal you can still sue people if a discription was wrong...
 

Sarnia

New member
Max,

I've just bought a ZD back (double buffer model) which I'm waiting to receive. When I get it I'll take some shots like yours and see what I get.

I have the Mamiya 28mm D lens so I'm quite excited to see what results I get on a MFDB as on 120 film it is outstanding.
 

jotloob

Subscriber Member
Take a look at the light bulb in the last picture. The purple area which I believe to be a reflection is in the light's emergent angle.

This image might explain what I mean:

View attachment 37984

@Terry
In Europe you have to abandon your return privileges in order to buy a used item.

Max

In my opinion , the light rays you show in your image are wrong . An object you see on the top will be projected to the bottom of the film or sensor .

Looking at the image with the light source (post #61) i find the magenta "reflection" is a very precise "reflection" and no flare .
That arises the suspicion , your issue could also be caused by your lens and not by the back .

Do you have the chance to try an other lens of the same focal length ? ? ?
 

MaxKißler

New member
@Jürgen:
Oh crap, you're right on both things. I guess I haven't looked thru a lens for some time now. And by saying "lens flare" I actually meant that reflection from the back element of the lens, back towards the sensor. As you said, I also don't think it has something to do with the back, rather with the coating of the lens.

Sorry my bad (I'm not too familiar with those terms yet)...

@Sarnia:
Thanks that would be great. Though I suspect that your output will differ from what I get as the coating of your lens might be much better. I would really appreciate it if you could do this test with an older Mamiya AF lens.

---

I should have made it like this:

View attachment 37999
 
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MaxKißler

New member
Are these purple blobs always displaced below (above looking at the sensor face) the bright area?
If so, I will go out on a limb and guess that this may be an a/d converter power supply recovery issue or system noise on vRef. I would assume a bad capacitor or disconnected capacitor or similiar issue.
In any case it suggests a hardware failure.
-bob
What makes you think that? I'm just curious...
These purple blobs are always on the opposite site of the light's source. Since I did several shots of that light bulb I can assure you they happen to be anywhere.
 

Bob

Administrator
Staff member
What makes you think that? I'm just curious...
These purple blobs are always on the opposite site of the light's source. Since I did several shots of that light bulb I can assure you they happen to be anywhere.
If they are always displaced to the same side, then I know of a few failure modes that might cause the problem,
If the displacement is radial about the lens axis, then it is more likely a rear element or light baffle reflection.
You might see if it appears the same with a different lens with more or less rear element curvature.
I was impressed by the sharpness and the size of the secondary image. that implies a reflection from a concave surface I think. A plano reflection would be significantly out of focus I would imagine.
-bob
 

Anders_HK

Member
What software are you using and have you investigated the firmware version in the back?
Max,

Prior to experimental research and speculating... bearing in mind that this is a recorded problem noted by many at the time of the earlier ZDs (both back and camera);

Best bet to reduce the issue is likely:

1. Ensure you have latest upgraded firmware.
2. Use latest Capture One.

As I stated prior, earlier ZDs had problem with internal processing and hardware design, from what I learnt from confidential source in industry. Thus they were "designed" with the shortcoming or fault built in, a.k.a. the purple problem (note not purple blotches, it is purple "artifacts"). Above 1 and 2 may have "tuned down" that fault, albeit that has not yet been confirmed per what I know. It could even be with later ZDs with dual buffers they did something minor in back to tune down the problem, noone except Mamiya Digital and perhaps Phase One would know...

Regards
Anders
 

Sarnia

New member
I also have a 35mm AF lens so I'll try that too.

I might be over a week before my ZDb is delivered.
 

MaxKißler

New member
Hi guys,

yesterday I tried a 75-150mm D lens in direct comparison with my old 45mm. I had the same purple reflections in the underexposed parts, BUT they were significiantly less intense (half of what the 45mm produced).

Sarnia, since you are going to get a ZD Back I can highly recommend you to expose for shadows.
Shadows shouldn't be more than 2,5 f-stops underexposed or it's likely to get these purple areas in contra-light shots. At least in my case. Maybe your ZDdb has a less reflecting IR-Cut filter...


Anyway, I guess I just have to live with it and preferably expose for shadows.
Thank you all for your help and ideas!

Regards
Max
 

Jan Brittenson

Senior Subscriber Member
The IR filter is user replaceable, so if you can find a dealer you could try a different filter and see if it works better. If so it might be worth buying one. Though I have to say I'd never expect to push shadows 2.5 stops - that's just massively underexposed in my book.
 

MaxKißler

New member
I don't think another filter would be any different and their availability over here is rather limited. At least no dealer seems to have one in stock.

As I said, I did this whole test only to see what the back is capable of and what it refuses to do... So I totally agree with you that 2 f-stops is way too underexposed.

However, when I got my first camera I often read it'd be better to expose for the highlights in order to preserve as much details as possible. I still had this in mind when I got the ZD Back. Unfortunately, this doesn't count for this one...
 

MaxKißler

New member
Does anybody know whether Phase One's Digi Clean is safe to use on an exposed CCD? Since the filter of the ZD Back is removable and the CCD itself more likely to catch dust particles I am wondering whether I would damage it by the attempt to clean it. Any ideas?
 

Valentin

New member
Does anybody know whether Phase One's Digi Clean is safe to use on an exposed CCD? Since the filter of the ZD Back is removable and the CCD itself more likely to catch dust particles I am wondering whether I would damage it by the attempt to clean it. Any ideas?
My advice would be to contact Phase One directly and ask them.
 

Anders_HK

Member
Does anybody know whether Phase One's Digi Clean is safe to use on an exposed CCD? Since the filter of the ZD Back is removable and the CCD itself more likely to catch dust particles I am wondering whether I would damage it by the attempt to clean it. Any ideas?
I doubt the CCD on ZD is exposed. There must be a protecting glass on it so can clean safe. However, if in doubt ask Mamiya agent.

Rgds
Anders
 

itsskin

New member
Well, I have old ZD back and use it with RZ67 ProIID. I did the tests with shooting into the window and push it up later in post. And yes, I have the purple problem. Here it is:


But if I have to push more then one stop - I consider the picture ruined and bad exposed. It just need to be deleted. Or converted to BW.

And I tried to find some real world backlit examples. They were proper exposed and the strange thing is that even after I push them - there is zero problems.







 
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