Would like a tone curve for Ricoh GXR A12


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slapp0
Would like a tone curve for Ricoh GXR A12

I would like to a tone curve for Ricoh GXR A12 (for the M-mount module specifically).

(I did try to edit one and thought it was OK. But I am not so sure anymore - sometimes it burns out the skies :-)
And my own tone curve never loads automatically so I guess I made an error naming it)

Doug
Can you send me a Raw file or two?

I'll try to make one using DPReview's studio scene for the A12/50mm. It looks like this uses the same sensor as the M-Mount, although the filter stack is different (different microlenses, no low-pass filters in the M-Mount). I'm not sure what effect the anti-vignetting processing in the M-Mount will have.

It'd help if I had a Raw file or two from your configuration, perhaps also with access to the JPEG, to check against. The optimum would be a clean, well-lit and well-exposed photo of a GretagMacbeth ColorChecker or a Kodak Q-13 chart, but that's probably too much to hope for. :-)

slapp0
Hi Doug

Hi Doug

You are probably correct in that the A12 50mm and A12 M-mount need different tone curves. I never thought of that and maybe that was the reason for my skies to burn out.

Anyway I would appreciate a tone curve for the A12 50.

Regarding the A12 M-mount I will see what I can do. The Kodak Q-13 seems hard to find nowadays but I will see if I could find one this afternoon.

Otherwise I have a QPCard 202 with 7 gray patches (and 28 colored ones) and with known L*a*b values. Do you think you could work with that?

Doug
QPCard 202

Yes, I can probably do that. I'll have to dig out my calculations for L*a*b*, but they're around here somewhere.

slapp0
Doug, thank you very much

The Ricoh GXR works well with my A12 28mm lens. It is also very 'clean' compared with the tone curve I had made previously. It is good to see what a tone curve looks like when made by a pro.

The tone curve works ok with the M-mount module as well. The lens name for that module is set by the user so I don't think a specific filename makes sense - maybe it should be just like CameraDefault;Ricoh GXR M-mount.lzn and any users can just rename it to their specific names.

I will try to make one or two tone curves by myself now when I can see what your looks like. Thanks again for your help.