Greenish tone in certain JPEG photos

[bencychin]

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I have encountered a strange phenomenon on my m10:

 

When I set my m10 to AWB, it can trigger an overall greenish tone when shooting in dim light of florescent warm tone indoor.

 I can see this on LCD screen when I half press the shutter in LV mode, and photos taken will show the same greenish tone.

 

If I switch the WB setting from AWB to florescent warm, florescent white or even tungsten, the overall greenish tone will disappear.

 

See my file photos that I had send together with m10 to Leica service centre, Singapore on 5 June.

They could not find the fault, so my camera was hospitalised in Germany.

I just received it yesterday 27 July.

 

The repair diagnosis reported "The error has been fixed with update of the new firmware".

They updated my FW to the 2.4.5.0 whilst it was with Leica.

 

Leica did not change any parts.

Services rendered:

Firmware update/clean sensor/adjustment of all parts/cleaning.

 

So far, my fingers crossed, the problem is resolved.

 

Benedict

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[pgh]

That doesn't look good, but fluorescent lights cycle, and their color temperature actually changes constantly because of this. I wouldn't ever really shoot JPG in fluorescent lighting, even if you set a custom white balance and shoot a series of images you're likely to have to work on them in post, they will all have different colors because of this cycling of the lights. I've never seen one this off though. That said, AWB is more of an assistant than anything if you just shoot raw. 

[adan]

Glad Leica thinks your problem is solved. However, it helps to know how "AWB" works.

 

A very few cameras (the Leica SL being one) have dedicated external WB sensors - they pick up light from the actual scene, over a wide angle, to measure the color of the light.

 

Most cameras (including the M digitals) do not have an external WB sensor. The only way they can identify white balance is to look at the actual picture colors after exposure, find the brightest point in the picture, and "assume" that that is a white object. And adjust the white balance to make that area "white" (equal parts red, green, blue). It happens fast at computer speeds - a miilisecond or so as the data is being processed for writing to the SD card.

 

However, in a given picture, where the "brightest" thing may be beige wood, or a blue spotlight, or a pink skin highlight, the AWB algorithm will remove what it thinks is too much beige, blue, or pink - erroneously.

 

This is no big deal if one shoots .DNG, because so long as one avoids the Lightroom or Photoshop or C1 settings for white balance "As Shot" or "Auto," the camera's choice of WB is ignored.

 

But in jpegs, one is stuck with the camera's imperfect "guess" using AWB. Better to use a preset which ignores colors in the scene, or better yet (but time-consuming), actually create a custom in-camera WB by using the camera's manual WB setting and shooting a gray card to "set" the camera for the actual lighting color.

 

Below, an M10 picture. Top version, WB was set by me in Adobe Camera RAW (similar to LR); Middle WB "As Shot" - what a jpeg would have looked like; Bottom version, with Adobe's "Auto" setting picked. The "As Shot" and "Auto" versions are confused, and too blue, because the "brightest" things in the picture are the bright-yellow safety jackets on the gentlemen in the background - and those settings try to make those as neutral-gray as possible.

 

I never shoot jpeg, and I never use any kind of "AWB" - not in the camera, not in the processing.

 

"Automation" - any means of having your camera make your mistakes for you.

 

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Edited July 29, 2018 by adan