DP2M: Shadow Issue(s) with SPP?
/forum/topic/1178410/0



dalegaspi
Registered: Dec 07, 2004
Total Posts: 417
Country: United States

Hi fellow DP2M owners:

I've recently acquired a DP2 Merrill and I have encountered a really huge issue which seems to be rarely discussed: shadow transition issue (well, actually, shadows in general...but i'd like to be more specific here to start with) when using RAW and converting using SPP.

I have DP2M firmware 1.03 and using the SPP 5.4.1 (both are latest as of this writing).

I have these two photos: one converted in SPP using "Convert to JPEG..." and the other by converting to 16-bit TIFF then converting it to JPEG in PS CS 5.5

Note that the AWB is Auto and Color mode is Neutral.

If you haven't noticed, the shadow transition for the Convert to JPEG is smooth, while the one converted to TIFF is blotchy greens/reds, abrupt shadow transition and has posterization (i think).

It's driving me nuts! below is the RAW file as well...I would like to attribute this as an SPP bug since that darn thing is (ironically) an EPIC fail when it comes to color management...

I tried so many combinations: using sRGB only (because apparantly at one point only sRGB workflow is supported in SPP), 8-bit TIFF, JPEG, and then 16-bit TIFF (trying all color space combinations) to no avail.

Or maybe I have a lemon.

Any insight is appreciated.

this is probably discussing what I'm seeing, but it's missing the image so I'm not so sure.

Convert from 16-bit TIFF
Convert to JPEG
RAW file



rscheffler
Registered: Aug 23, 2005
Total Posts: 4614
Country: Canada

I see posterization in both conversions, but the 'Convert to JPEG' file is noisier/grainier in the shadows and seems to mask some of the posterization by implying better gradation. Close comparison seems to reveal that colour posterization is still evident in the jpeg.

At first I had trouble seeing any issue until I increased the brightness of my display to maximum, which might also be a factor in 'accurate' viewing of the image. And I wonder if the problem might be exacerbated by your display?

Is this posterization a problem in your end use of the images, or only when inspecting at the pixel level? My guess is in print, it will not be readily noticeable.

Personally I prefer the conversion from tiff as it seems to have better colour information deeper into the shadows and greater sharpness/detail in the mid tones.



dalegaspi
Registered: Dec 07, 2004
Total Posts: 417
Country: United States

OK in a thread referenced in that forum thread, it's referred to in SD1 (which has the same sensor as DP2M) as the "rolloff" bug and it can be (somewhat) mitigated in PS with Hue Adjustments: Yellow -15, Reds +5...but it's not a silver bullet since it's a global correction, anything with yellows in the photo surely gets royally screwed.

Attached is the adjusted photo...somewhat better...but I dunno...could be placebo at this point .

Adjusted Hues -15 Y +5 R



dalegaspi
Registered: Dec 07, 2004
Total Posts: 417
Country: United States

rscheffler wrote:
I see posterization in both conversions, but the 'Convert to JPEG' file is noisier/grainier in the shadows and seems to mask some of the posterization by implying better gradation. Close comparison seems to reveal that colour posterization is still evident in the jpeg.

At first I had trouble seeing any issue until I increased the brightness of my display to maximum, which might also be a factor in 'accurate' viewing of the image. And I wonder if the problem might be exacerbated by your display?

Is this posterization a problem in your end use of the images, or only when inspecting at the pixel level? My guess is in print, it will not be readily noticeable.

Personally I prefer the conversion from tiff as it seems to have better colour information deeper into the shadows and greater sharpness/detail in the mid tones.


thanks for the response, Ron...it's quite visible in normal viewing, and it's quite apparent even in print, unfortunately. and note that I have a calibrated monitor (latest i1 display, iMac 27" 2011 model)



rscheffler
Registered: Aug 23, 2005
Total Posts: 4614
Country: Canada

I just see a change in hue relationships and not so much a change in posterization. Do you have the iMac set to maximum brightness?

Coincidentally, I just opened the window blinds in my room. Reevaluating the images again, I have more difficulty seeing the problem, even with the display at maximum brightness, so a number of variables may have an influence on how perceptible the issue is in 'normal' viewing. But, I guess if you can see it in your normal viewing conditions, then it's a problem.



Johnny B Goode
Registered: Jan 15, 2012
Total Posts: 434
Country: United States

my god that camera is sharp. Did you know he has hair on his forehead? I'm on my crappy laptop and all I see is an amazing image that benefits from good work flow. By the time I save up for this camera there'll hopefully be a better raw converter out there. (or a new model).



dalegaspi
Registered: Dec 07, 2004
Total Posts: 417
Country: United States

Johnny B Goode wrote:
my god that camera is sharp. Did you know he has hair on his forehead? I'm on my crappy laptop and all I see is an amazing image that benefits from good work flow. By the time I save up for this camera there'll hopefully be a better raw converter out there. (or a new model).


It is very sharp, and this is wide open (f2.8). Not only it's sharp, there is virtually no CA even wide open (puts some Leica/Zeiss lenses to shame!).

And you're right, this is a camera that has lots of potential with the right RAW processor. However, SPP is not even close, and worse...it does some things pretty badly.

- it's color management is still screwed up on the Mac, even with the latest version.
- i *think* it's bumping up the structure/acuity by default, which is why there's huge boost in microcontrast. To me, that's cheating.
- it's applying its own curves on the raw file even before you start doing something with it. This is very annoying and this is probably why the shadow gradation is horrendous and there is also substantial shadow clipping.

That said, there is no doubt in my mind that Foveon's technology (or similar) is the future. Bayer filter makes less and less sense. Unfortunately, Sigma keeps screwing this up.