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Something wrong with M3 AWB

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PhotoKhan

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These are 3 consecutive photos series using AEB, with 1 stop bracketing, shot with the EF-M22mm f/2 STM, all in "Auto" white balance.

AV, ISO 100, RAW.

Nothing changes between shots, except for the shutter speed elected by the AE logic.

14 seconds elapsed between the first and 9th shot. Day light remained constant.

How can AWB elect the "correct" setting only for those last 3 shots?



















PK

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PhotoKhan said:
These are 3 consecutive photos series using AEB, with 1 stop bracketing, shot with the EF-M22mm f/2 STM, all in "Auto" white balance.

AV, ISO 100, RAW.

Nothing changes between shots, except for the shutter speed elected by the AE logic.

14 seconds elapsed between the first and 9th shot. Day light remained constant.

How can AWB elect the "correct" setting only for those last 3 shots?



















PK

--
“Loose praise may feed my ego but constructive criticism advances my skills”
************************************************************
-------------------------------------------------
http://www.humbertoborgesfotografia.com/
http://www.pbase.com/photokhan
(PBase Supporter)
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Click to expand...
The first two series seem to have the greenish cast that some people have been complaining about if the third series are more "correct" in your view. I agree it is is puzzling the third series are so different and I can't think why at the moment! It is the AEB fps that has been slowed down compared to M so it makes me wonder if this is connected. Perhaps you ought to do some experimentation with different settings to see if it is always repeatable, e.g. ALO, HTP on off, different metering modes?
 
Tocsa said:
The first two series seem to have the greenish cast that some people have been complaining about if the third series are more "correct" in your view. I agree it is is puzzling the third series are so different and I can't think why at the moment! It is the AEB fps that has been slowed down compared to M so it makes me wonder if this is connected. Perhaps you ought to do some experimentation with different settings to see if it is always repeatable, e.g. ALO, HTP on off, different metering modes?
Click to expand...
I don't use ALO or HTP.

Yesterday, I finally had the opportunity to take my M3 for a test drive.

I took 800+ photos, now streamlined to about 250 to work on.

What I am noticing is that, most of the times, AWB becomes extremely confused when leafy shades are involved and has no problem rendering the green cast as the correct WB balance. If "Shade" WB is selected, everything turns extremely Orange/Yellow (as it normally does, to variable extents, in any model).

Sampling something close to neutral in a scene seems to neutralize things.

(I too have no idea why Auto WB changed so much between those series in the OP).



[ATTACH alt=""As shot" In-Camera Auto WB "]media_3199518[/ATTACH]
"As shot" In-Camera Auto WB






Shade WB






Auto WB in LR6






As the pillar looked, in the scene (Custom WB from gray area)

PK



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I am a Portuguese airline captain, with a photographic eye into some earthly things in addition to our wondrous skies. If there's a moment in our lives that defines our future non-human affections, mine was at a very early age. In the early sixties, my parents just newlywed, our family...
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Try to get this problem to repeat using a tripod, and don't touch the camera at all. I can see the camera moved slightly between shots, that can affect what the AWB sees.
 
That is exactly why I sold my M3. It could be something wrong with one batch of first cameras. I don't know. Other users seem to be fine. AWB on my M3 was terrible. Almost every shot needed color correction. I "upgraded" M3 to M2 and I am happy again.

Even on your 3 last good shots there is a greenish tint on left and right sides. These greenish stripes were also present on my M3.

I am thinking to buy another M3 later. Maybe only first cameras were affected.
 
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o_23 said:
That is exactly why I sold my M3. It could be something wrong with one batch of first cameras. I don't know. Other users seem to be fine. AWB on my M3 was terrible. Almost every shot needed color correction. I "upgraded" M3 to M2 and I am happy again.

Even on your 3 last good shots there is a greenish tint on left and right sides. These greenish stripes were also present on my M3.

I am thinking to buy another M3 later. Maybe only first cameras were affected.
Click to expand...
Two totally separate issues.

Green vignetting is due to lens/sensor diffraction, it's found in lots of mirrorless cameras (also found in the moss on the side of his picture ;) ).

http://tashley1.zenfolio.com/blog/2...r-shift-calibration-aperture-series-ettr-more

http://blog.kasson.com/?p=3877

http://lavidaleica.com/content/using-cornerfix-correct-images

This is a physics issue. I've found Lightroom 6's demosiacing and lens correction fixes any color-cast issues I had previously with OOC/DPP images from my M3.

AWB is just in-camera software algorithm.

http://web.stanford.edu/~sujason/ColorBalancing/robustawb.html

Unless there is an actual bug in the algorithm they're using, it's unlikely this will be changed. Not sure why it behaves differently than the EOS M, but I've found it's more sensitive to the composition of a scene. Maybe it was intentional?
 
Last edited:
verum lens said:
o_23 said:
That is exactly why I sold my M3. It could be something wrong with one batch of first cameras. I don't know. Other users seem to be fine. AWB on my M3 was terrible. Almost every shot needed color correction. I "upgraded" M3 to M2 and I am happy again.

Even on your 3 last good shots there is a greenish tint on left and right sides. These greenish stripes were also present on my M3.

I am thinking to buy another M3 later. Maybe only first cameras were affected.
Click to expand...
Two totally separate issues.
Click to expand...
Yes.
verum lens said:
Green vignetting is due to lens/sensor diffraction, it's found in lots of mirrorless cameras (also found in the moss on the side of his picture ;) ).

http://tashley1.zenfolio.com/blog/2...r-shift-calibration-aperture-series-ettr-more

http://blog.kasson.com/?p=3877

http://lavidaleica.com/content/using-cornerfix-correct-images

This is a physics issue. I've found Lightroom 6's demosiacing and lens correction fixes any color-cast issues I had previously with OOC/DPP images from my M3.

AWB is just in-camera software algorithm.

http://web.stanford.edu/~sujason/ColorBalancing/robustawb.html

Unless there is an actual bug in the algorithm they're using, it's unlikely this will be changed. Not sure why it behaves differently than the EOS M, but I've found it's more sensitive to the composition of a scene. Maybe it was intentional?
Click to expand...
Could be. I still have hope that only a few first cameras were affected. I don't see much troubles from other M3 users pictures.
 
o_23 said:
verum lens said:
o_23 said:
That is exactly why I sold my M3. It could be something wrong with one batch of first cameras. I don't know. Other users seem to be fine. AWB on my M3 was terrible. Almost every shot needed color correction. I "upgraded" M3 to M2 and I am happy again.

Even on your 3 last good shots there is a greenish tint on left and right sides. These greenish stripes were also present on my M3.

I am thinking to buy another M3 later. Maybe only first cameras were affected.
Click to expand...
Two totally separate issues.
Click to expand...
Yes.
o_23 said:
Green vignetting is due to lens/sensor diffraction, it's found in lots of mirrorless cameras (also found in the moss on the side of his picture ;) ).

http://tashley1.zenfolio.com/blog/2...r-shift-calibration-aperture-series-ettr-more

http://blog.kasson.com/?p=3877

http://lavidaleica.com/content/using-cornerfix-correct-images

This is a physics issue. I've found Lightroom 6's demosiacing and lens correction fixes any color-cast issues I had previously with OOC/DPP images from my M3.

AWB is just in-camera software algorithm.

http://web.stanford.edu/~sujason/ColorBalancing/robustawb.html

Unless there is an actual bug in the algorithm they're using, it's unlikely this will be changed. Not sure why it behaves differently than the EOS M, but I've found it's more sensitive to the composition of a scene. Maybe it was intentional?
Click to expand...
Could be. I still have hope that only a few first cameras were affected. I don't see much troubles from other M3 users pictures.
Click to expand...
AWB is entirely done in software. For RAW images, AWB gives you a predicted WB, but you can change the WB without affecting any of the underlying pixel RGB values. The in-camera AWB algorithm operates on these pixel RGB values. Different algorithms will give different predicted WB.

Only with OOC jpegs is this "predicted WB" baked in, so you cannot adjust the WB without affecting the underlying pixel RGB values.

The only way the "first few cameras" could be affected, would be if somehow the sensor was physically miscapturing RGB values and the AWB algorithm was therefore producing poor results. Then if Canon changed the sensor in later cameras, the AWB algorithm would be receiving different RGB values.

Alteratively, the software may have a bug in the AWB algorithm, but if it was fixed it would affect all of the cameras.
 
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When you are shooting outside, there are many things that can trigger a WB shift. On the most basic level, the lighting can change because the sun goes behind a cloud creating a distinctly different lighting situation. Light being reflected into your scene can shift as objects in the vicinity of your subject move around. It is really impossible for us to explain these shifts because we were not on site when the shots occurred. Something changed outside of the frame. If you have any other shots of the vicinity, you might want to scan them for possible explanations.

My guess, a cloud drifted over the sun.

--
> Bill.
 
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UCSB said:
When you are shooting outside, there are many things that can trigger a WB shift. On the most basic level, the lighting can change because the sun goes behind a cloud creating a distinctly different lighting situation. Light being reflected into your scene can shift as objects in the vicinity of you subject move around. It is really impossible for us to explain these shifts because we were not on site when the shoot occurred. Something changed outside of the frame. If you have any other shots of the vicinity, you might want to scan them for possible explanations.

My guess, a cloud drifted over the sun.
Click to expand...
 
PhotoKhan said:
What I am noticing is that, most of the times, AWB becomes extremely confused when leafy shades are involved and has no problem rendering the green cast as the correct WB balance. If "Shade" WB is selected, everything turns extremely Orange/Yellow (as it normally does, to variable extents, in any model).
Click to expand...
A different camera with a different sensor, but also a Canon:

"Throughout my evening's shooting, I found that the Canon G7X tended to underexpose its images and leave cool / green color casts in its images."

Loading…

www.imaging-resource.com
 
Honestly, its raw so who cares?

I always play with the WB/color temp anyhow don't you?

AWB is Auto, not Perfect WB - PWB !! ;)

Are you using DPP HDR, it works pretty well and is simple too, my results are as good as LR v6.
 
I would tend to agree with the main complaint of poor quality AWB on the M3. I shoot RAW on everything, but it would be nice to be able to get solid JPEG's when needed immediately. Also since WB is often off, it gives you a poor starting point in your RAW conversions. I would rate the inferior WB performance the top area for Canon to address in a firmware upgrade. From my perspective, the WB is not just off, it is can be just plain ugly. To much green (grass, trees, etc.) seems to cause some ugly problems. Pretty weird given Canon's typically good performance. I haven't tested this body next to my 5DIII to get a baseline comparison ... so that might be worthwhile.

Outside of this one issue, the M3 is doing a fantastic job for me and I have been able to work around these WB issues in post. Just wish it was better.
 
JJ Rodin said:
Honestly, its raw so who cares?

I always play with the WB/color temp anyhow don't you?

AWB is Auto, not Perfect WB - PWB !! ;)
Click to expand...
1. I rarely succeeded in adjusting WB. It is much more than adjusting one slider with color temperature. I had to use calibrated gray card to set custom WB in camera first. It is OK in studio when lighting doesn't change. In real life you cannot set custom WB for every shot. As alternative you can use color picker tool in PP to adjust WB, but it is not as good as preset custom WB.

2. I am already spoiled by AWB in 5D3, 6D and M1. It is very very good. Often I do not need to adjust WB at all. I shot RAW + JPEG, but mostly I can use JPEGs without any adjustments. I am not talking about printing for wall, I am talking about 300 shots on weekend on camping trip for example. I don't have time or big desire for adjusting WB on 300 shots individually. I can just send 300 to friends right away without any PP. For me shooting is fun, adjusting WB 300 times is not.

Your case could be different though. I am just explaining my case.
 
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