Green cast in RAW? (Samsung GX10)

eljustino · 06-11-2007, 03:53 PM

I've got a Samsung GX10 which hopefully is enough of a Pentax for us good people! I have a Pentax flashgun (works in Wireless with 1.2 firmware if anyone is wondering) and macro lens, and the twin lens kit (18-55, 50-200).

I shoot only RAW.

I find auto WB is just excellent, and I can usually get the white balance I want...

However, the presets (day, shade, cloud, tungsten) are all unusable in Adobe Camera Raw as there is a strong green cast. I also find it hard to get strong greens right (ie grass/lawn!) possibly because of an over-sensitivity to green...

Also, almost without exception the "tint" shade has to be pushed FAR to the right to get correct colours when converting from RAW.

Anyone else seen this? Tried another GX10 at the shop - same thing. Could be a batch, could be just the GX10, could be the way it is with the K10D - or might be because the presets in ACR are not right for the GX10 - but the Samsung software does it too (and the Samsung software seems diffferent to the Pentax offering)...

This does not happen in JPEG.

Any views?

stewart_photo · 06-11-2007, 05:14 PM

I have the K10D and haven't seen the green cast you describe. Of course, I haven't even tried any of the WB presets with RAW. No need to since WB imperfections can so easily be adjusted later on the computer.

stewart

*barondla* · 06-11-2007, 08:09 PM

Have the K10D and shot raw also. No problem with awb (except indoor incandescent). No problem with presets - as long as they match the situation. No idea what the problem is. Have you tried the bundled Samsung raw converter? This would tell if something is wrong with the camera.
Recently saw a thread on dpreview or fourthirdsphoto about new Olympus E410 or 510 that went very magenta in the whites with certain raw converters. Sounds kind of similar. Very strange stuff. Hope you get it figured out.

thanks
barondla

jeffkrol · 06-11-2007, 09:20 PM

Originally Posted by eljustino

I've got a Samsung GX10 which hopefully is enough of a Pentax for us good people! I have a Pentax flashgun (works in Wireless with 1.2 firmware if anyone is wondering) and macro lens, and the twin lens kit (18-55, 50-200).

I shoot only RAW.

I find auto WB is just excellent, and I can usually get the white balance I want...

However, the presets (day, shade, cloud, tungsten) are all unusable in Adobe Camera Raw as there is a strong green cast. I also find it hard to get strong greens right (ie grass/lawn!) possibly because of an over-sensitivity to green...

Also, almost without exception the "tint" shade has to be pushed FAR to the right to get correct colours when converting from RAW.

Anyone else seen this? Tried another GX10 at the shop - same thing. Could be a batch, could be just the GX10, could be the way it is with the K10D - or might be because the presets in ACR are not right for the GX10 - but the Samsung software does it too (and the Samsung software seems diffferent to the Pentax offering)...

This does not happen in JPEG.

Any views?

Odd... if it was just ACR, I'd assume a calibration/software problem. If it was all images I'd suspect a monitor problem. How about checking the "preset" tweak screens??? Set to a green tint? Image courtesy of :
DCRP Review: Samsung GX-10

plucky · 06-12-2007, 06:57 AM

I also have a Samsung GX-10 and the WB presets in Adobe Camera Raw (v3.7) do the same for me. I haven't tried it in another converter yet because I've found using the Auto WB or selecting a neutral area with the 'eye-dropper' tool gives me the results I want.

From memory I think this still happens if you convert the Samsung generated DNG to an Adode DNG using the DNG Converter but I'll check this tonight.

I think the problem is that when you select any of the ACR WB Presets the 'Tint' value does not change but I think it should. As you've found you can adjust the slider yourself to get the correct result.

In my humble opinion (which isn't worth much) this looks like a software problem not the camera.

blende8 · 06-12-2007, 08:31 AM

In ACR in the last tab there are for K10D RAWS two possible profiles, one ACR and one Pentax.
I have found that in rare cases there is a huge difference between selecting either of the two, one having a very green cast. Normally there is basically no difference.

eljustino · 06-12-2007, 04:31 PM

[quote=barondla;65898] Have you tried the bundled Samsung raw converter? This would tell if something is wrong with the camera.

I have tried the bundled converter, and its suspiciously similar to ACR but slower.

Same result - green cast on presets.

eljustino · 06-12-2007, 04:35 PM

Originally Posted by jeffkrol

Odd... if it was just ACR, I'd assume a calibration/software problem. If it was all images I'd suspect a monitor problem. How about checking the "preset" tweak screens??? Set to a green tint?

Good tip and had me excited for a moment there - but preset tweak screens are all zeroed/default - didn't even know that was there but checked them all.

My monitor is fine and I've just changed from Canon, which generally gave pretty faithful results using the preset WB options.

I hardly ever use WB presets, but on photos (macros of plants in particular) with no white reference, it's very hard to get colour right and presets are a useful basis to start with.

A grey card is one option but that's yet more crap to carry around!!!!

eljustino · 06-12-2007, 04:42 PM

Originally Posted by plucky

I also have a Samsung GX-10 and the WB presets in Adobe Camera Raw (v3.7) do the same for me. I haven't tried it in another converter yet because I've found using the Auto WB or selecting a neutral area with the 'eye-dropper' tool gives me the results I want.

In my humble opinion (which isn't worth much) this looks like a software problem not the camera.

Glad I'm not the only one and thanks for the feedback. The AWB is indeed excellent and it's much easier to get good colour from the "dropper" than it was on my Canon.

I've tried another camera at the shop (green cast) and also found a Polish web site with some sample DNG files. Guess what! If you download a DNG shot in daylight and view it in ACR using a preset... Green cast!!!

raw.fotosite.pl - RAW samples from Samsung GX-10

There's something weird about the site above - on my browser it tries to download the files with .tif filenames instead of .dng - if I rename them .dng they open in ACR as normal!!!

WHAT BOTHERS ME MOST...

- It sort of makes me nervous about my camera

- How can reviewers all over the world have missed this if it's a common issue? I reckon they're all lazy and don't check the presets - they just look at an AWB picture, make their pronouncements, and move on!!!

Any more GX10 owners out there?

Really enjoying this camera otherwise...

*GaryML* · 06-12-2007, 05:32 PM

It sounds like a software problem rather than a camera problem. Have you tried another RAW converter? Have you tried updating the version of ACR that you are using? Earlier versions of ACR would screw up the color balance of PEF (which was easy to manually correct) but I've had no problem with the newer versions (using Lightroom) and using the newest version of Pentax Photo Lab with either PEF or DNG files.

blende8 · 06-13-2007, 12:35 AM

What happens if you use the supplied software?

Entropy · 06-21-2007, 06:47 PM

Have you tried dcraw (or for a shiny GUI), ufraw?

davemdsn · 06-21-2007, 08:10 PM

I had the green tint problem with my K10 until ACR3.7. That fixed it quite nicely. Is the Samsung supported by your current version of ACR? Or other programs? Just a thought.