I just ran a quick test with repeatable results. It seems that if MAWB is enabled, it DOES influence the ACR values for 'as-shot' WB

So use of MAWB does have an effect (albeit not the intended one) on my workflow. .....I'll avoid using it.

davek

I think that you are probably right.

I'll test whether the ACR 'as-shot' WB value is affected by MAWB v AWB though.

davek

I didn't


Nigel, I agree that the WB presets are Adobe's idea of how best to represent conditions such as 'Daylight'. 'Tungsten' etc., but the 'as-shot' value purports to be what the camera actually measured.

ACR represents WB as a Colour-Temp and a Tint.
The Colour-Temp is presumably just copied from the camera, but since I don't know how the camera records WB information {whether just a Colour-Temp or Colour-Temp plus other data), I don't know if ACR copies the Tint value from the camera or derives it from the image.


John, I agree that it appears straightforward for camera-produced JPGs. My quest is for understanding how it fits into my workflow (RAW files converted by non Pentax/Ricoh software).

This issue, for me, equates to about zero on the Richter scale of practical problems, but it's fun trying to understand it.

davek

My interest in this arises because I always shoot RAW images, and convert in ACR. Not knowing any of the details of how MAWB is implemented gives rise to a concern that using it could have an adverse effect on my conversions.

After reading a Ricoh Paper here , it seems that MAWB is concerned with WB in light and dark areas, so I shot images with two light sources and light/shadow areas, expecting to see that RDCU5 would give different results for the AWB and MAWB images.

I used two images, one with AWB and one with MAWB. For both images ACR just offered 'as-shot' Temps and Tints and the usual pre-sets. RDCU5 indicated correctly that one used AWB and the other MAWB but didn't seem to improve colours. It could well be that my conditions were not suitable for comparing AWB/MAWB. I will try a more rigorous test later this week and also check out-of-camera JPGs.

In the meantime, until I understand more about how MAWB is implemented and could affect my workflow, I'll avoid using MAWB.

davek

Hence my confusion...

PDCU (it is now RCDU in V5) identifies the fact that MAWB was used, but I couldn't see any colour difference between this MAWB-aware converter and ACR v8.20 which is presumably not MAWB-aware.

Colours were more realistic in both converters when normal AWB was used.

This should be true for out-of-camera JPGs ( I haven't tried it), but I can't reach definite conclusions about RAW images.

I have played around with this today, comparing AWB & MAWB. I shot some images in a room lit with natural light from a window and a fluorescent light that gave some (not very dark) shadows. I then converted them in both ACR and the supplied DCU5 using no PP.

I couldn't see any real difference in colour between the ACR and DCU5 versions and in both cases AWB gave me significantly better fidelity than MAWB.

I retired confused.....

dave k

Interesting read, thanks for the link.

I was wondering whether the information about these differing segments is somehow mashed into the RAW data, or whether it is passed in Exif Makernotes to the RAW converter.

If this second scenario is correct, it presumably means that only the 'Digital camera Utility' will understand how to use it, and software such as ACR and LR will ignore it, with unpredictable results.

I suppose so experimentation is in order..

dave k

Can anyone point me at a description/explanation of how the 'Multi Auto WB' feature on the K3 is implemented.

Thanks
dave k

K3 v K5.

The desk is level




dave k