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Author Topic: Mamiya ZD  (Read 14840 times)
BJL
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« Reply #20 on: April 10, 2006, 05:23:45 PM »
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Hello Dennis,
are you sure the ZD capture is in 16 bit?
Cheers,
Willem.
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Firstly, Dennis says that the Aptus 22 is 16-bit, not the Mamiza ZD.

Secondly, it does not matter anyway: no sensor is anywhere close to "16-bit capture". Kodak's best dynamic range is about 4000:1, or 12 bits linear; Dalsa sensors give from 4000:1 to 8000:1 depending on operating conditions, which is still at most 12 to 13 bits. Probably at the lower end unless the sensor is in a cooled laboratory set-up, not a portable camera.

Beware marketing obfuscation about the bit-depth of output files: they could put in 24-bit A/D converters and produce 24-bit depth per color output, but it would not improve image quality over 12 or maybe 13 bit depth RAW files.
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mcfoto
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« Reply #21 on: April 10, 2006, 06:21:18 PM »
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Hi

The Aptus is 16 bit and the Mamiya is 12 bit ( 14 Analogue ).
Thanks Denis



quote=rethmeier,Apr 10 2006, 04:38 PM]
Hello Dennis,
are you sure the ZD capture is in 16 bit?
Cheers,
Willem.
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[/quote]
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Denis Montalbetti
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ivan muller
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« Reply #22 on: April 11, 2006, 03:21:27 AM »
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Also, for noise considerations, you should look at color prints unless you only work in B&W: to me, by far the most objectionable consequence of noise is the "confetti" of color noise.

OK this is what I have found so far. At 200 iso size 16x21inch colour print made with R1800(cropped section on A4) and premium glossy, waist lenght portrait, with mixed light, umbrella flash & fluorescent/daylight and 80mm afd lens, image looked superb with very fine film like noise/grain. Very sharp. I wouldnt hesitate to use the zd at 200iso
Iso 400 at same size and same image - not so good. Printed to size 13x17inch, not great but much better. B&w far more acceptable and filmlike
Made another col print at size 18x25inch of a sunny outdoor scene at 100iso, with no visible noise and very sharp and detailed (150mm afd lens)
All images on raw, opened in photoshop with focal blade sharpening, light to medium.
Regards Ivan
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rethmeier
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« Reply #23 on: April 11, 2006, 05:34:12 PM »
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Dennis,
my apologies!
I misread your earlier post about the 16 bit!
Cheers,
Willem.
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Willem Rethmeier
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Sydney Australia
BJL
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« Reply #24 on: April 11, 2006, 06:50:49 PM »
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At 200 iso size 16x21inch colour print ... image looked superb with very fine film like noise/grain. Very sharp. I wouldnt hesitate to use the zd at 200iso
Iso 400 at same size and same image - not so good. Printed to size 13x17inch, not great but much better. B&w far more acceptable and filmlike
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Thanks! These results sound better than I have heard elsewhere; I wonder if it is the usual mitigation of noise effects by printing compared to evaluation under the "digital loupe" of high magnification on-screen viewing?
And the final comparison of B&W to color fits my experience with color vs monochrome noise.
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BJL
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« Reply #25 on: April 11, 2006, 07:28:27 PM »
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The Aptus is 16 bit and the Mamiya is 12 bit ( 14 Analogue ).
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Thanks for the details: it turns out that the ZD uses a 14-bit A/D convertor but then stores only 12 bits per color channel. So it seems that Mamiya has paid the cost of an A/D convertor with more than enough range to handle the sensor's DR and then discards the two lest significant bits. The only options I see are
1) they are idiots, sacrificing dynamic range when it would cost nothing to keep the extra bits f A/D output in RAW output, or
2) they know that those last two bits are useless due to sensor noise.
Option (2) is the only serious one. Maybe the extra two bits allows for some margin of error in pre-amplification of the analog signal, so that the full DR of the sensor still fits into the 14-bit window of the A/D convertor even if the pre-amplified signal is somewhat stronger or weaker than ideal.
« Last Edit: April 11, 2006, 07:28:52 PM by BJL » Logged
ivan muller
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« Reply #26 on: April 13, 2006, 04:38:37 AM »
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I am going to have some fun with this camera!!!!.

Hi Dennis

I never got to test the ZD at long exposures. Will appreciate your feedback on long exposure/noise isues. Friend of mine has the Kodak 14mp camera and its useless for long exposures. I do ots of interiors etc with tunnsten lights and would definately use exposure times up to 30secs often. If it sound good I am definately ordering one!

Regards
Ivan (Jhb. RSA)
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mcfoto
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« Reply #27 on: April 13, 2006, 06:48:18 PM »
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Quote from: ivan muller,Apr 13 2006, 04:38 AM
I am going to have some fun with this camera!!!!.

Hi Dennis

I never got to test the ZD at long exposures. Will appreciate your feedback on long exposure/noise isues. Friend of mine has the Kodak 14mp camera and its useless for long exposures. I do ots of interiors etc with tunnsten lights and would definately use exposure times up to 30secs often. If it sound good I am definately ordering one!

Hi
I used the Zd for a job the other day. I shot at iso 50 flash fill outdoors with the 55-110 zoom.
I loved the results the quality is amazing. I had my Canon 5D as a backup and did not use it. My coments are ok screen quality ( contrasty ) and when shooting RAW you have to wait to get the card out of the camera after you fill the card. We never reached the buffer and we were shooting a portrait! We shot hand held with a Norman 200C unit at 200 ws. Exposre was 125X @ f12  iso 50. The balance of the camera is like a 35 DSLR. I find it easy to navagate the camera. The software is easy to use and we processed 57 raw (MEF) in 24 min with our G5 2.3 Dual/ 3 gig ram. I have use it at iso 400 indoors handheld and it is noisy, the Canon 5D is better at iso 400. I am not surprised and I will try the ZD at long exposures. Most likely there will be firmware updates with this camera in the future.
Thanks Denis  
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Denis Montalbetti
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meierruedi
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« Reply #28 on: April 18, 2006, 12:50:29 AM »
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"I never got to test the ZD at long exposures"

Well we did and it's a complete desaster!
We did a 30sec @ iso400 exposure. What we got back looked more like Seurat having fun than a photograph: big even very big colour "clusters" hanging around. Not usuable at all.....
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ivan muller
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« Reply #29 on: April 18, 2006, 01:32:55 AM »
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Well we did and it's a complete desaster!
We did a 30sec @ iso400 exposure. What we got back looked more like Seurat having fun than a photograph: big even very big colour "clusters" hanging around. Not usuable at all.....

Having tested the ZD at 400iso myself it would have been expected. Did you test it at the optimum iso ie 50 & 100?  At 30 sec's or more it would have to be on a tripod and then it wouldnt  matter how slow the iso was. Would appreciate your input!
Thanks
Ivan
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meierruedi
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« Reply #30 on: April 18, 2006, 11:36:58 AM »
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Well no we didn't. As we work mainly in the portrait and reportage section we were not very interested in ISO50.
(Would have been 4 minutes. Even the expensive backs had problems not long ago doing this ....)
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BJL
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« Reply #31 on: April 18, 2006, 04:58:04 PM »
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Well no we didn't. As we work mainly in the portrait and reportage section we were not very interested in ISO50.
(Would have been 4 minutes. Even the expensive backs had problems not long ago doing this ....)
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Did you do dark frame subtraction to remove fixed pattern noise? That is probably essential with these long exposures.

By the way, if your shutter speeds needs rule out low ISO, I wonder why you are looking at MF at all, beyond the small resolution gap of 22MP over 16.5MP.  By almost any measure other than pixel count, ISO 400 with a 36x48mm MF sensor is unlikely to have any advantage over using ISO 200 (and one stop lower for equal shutter speed) in 24x36mm format.

In particular, the dynamic range advantage of MF sensors is all about using their great highlight headroom to outweigh their disadvantage of a higher noise floor, which means giving them more light than a smaller sensor can handle without blowing highlights. That is, using minimum ISO speed or close to it. Since the larger Full Frame CCD photo-sites of MF sensors have a higher noise floor (more electrons of dark noise) than Canon or Sony DSLR sensors, and must also be used at higher f-stops and so need higher ISO to get the some shutter speed, MF sensors probably give less DR than good smaller format DSLR's when compared at equal shutter speed.
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meierruedi
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« Reply #32 on: April 19, 2006, 12:36:32 AM »
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"By the way, if your shutter speeds needs rule out low ISO, I wonder why you are looking at MF at all, beyond the small resolution gap of 22MP over 16.5MP.  By almost any measure other than pixel count, ISO 400 with a 36x48mm MF sensor is unlikely to have any advantage over using ISO 200 (and one stop lower for equal shutter speed) in 24x36mm format."

Keep wondering....
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ivan muller
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« Reply #33 on: April 20, 2006, 10:37:10 AM »
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Like you say they are all good cameras and backs. I am sure everyone of them in the hands of a good photographer will produce superb photographs! Did you manage to get an idea what the zd,s long exposure performance (at iso 50,100) was like on your easter weekend?
Thanks Ivan
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