2 replies to this topic

[Fred Nirque]

Sometimes we search for things in what may appear to be logical places but the answer actually lies in a place overlooked, probably because it was just too darn obvious.

So.... I think it's safe at the moment to say that processing these files has a substandard answer in the mainstream commercial programs such as ACR, C1, SP etc. There is the different approach (with its own, lesser problems) available in DCraw as a command line program and a few GUI front ends for it with their own interpretations of command-line strings for the initial processing such as free programs like Photivo and LightZone or commercial versions such as Helicon Filter and OloNeo Photo Engine.

All have their own interfaces which range from simple to utterly complex and confusing, or weigh the program down with extraneous functions which have nothing to do with the actual task of processing raw files.

With my mind spinning from trying to learn all these different interfaces and functions while trying to get the best result possible for the much maligned X-Trans sensor, I sat down this morning with a "What if?" thought in my head, namely that if the best straight, unmodified demosaicing available at the moment is the inconvenient to use DCraw, then what about taking one or the DCraw-based GUI programs, have it do a basic, unadjusted raw conversion as a linear raw (choose that if available, or in LZ disable or remove the X camera "raw tone curve" by unlocking and disabling it), save that dark, flat & ugly image as a TIFF, then simply adjust that in Photoshop (or ACR, LR, Photoshop, whatever).

The rub of it - it works perfectly well. A basic RAW conversion of a well exposed file (nothing too blown or underexposed) dropped into Photoshop & hit with Auto Tone (in Ps if you're feeling lazy) yields a beautifully rendered 1-255 spread of tones. If your image is less than perfect, then a visit to ACR Curves will do it plus give you the additional controls that make that program so desirable and quick, but without Adobe's hideous attempt to turn the file into an oil painting.

For the moment, and despite the extra space required for Tiff files (though they can be saved as DNG in ACR to save a bit of space), this gives what I consider to be the best interpretation of the X-Trans raw available until Adobe, SP C1 etc get their collective acts together, and I can now leave this time-consuming chase and get back to using the camera without worrying about the end result. Doing things this way means that no extra $$ need be expended - LightZone does the job and it is free.

I've attached the two images I've been using in this torturous process thus far as unresized jpegs saved at 10 quality plus the same images processed in ACR. 100% is revealing, 200% shows graphically where Adobe went wrong, and while the artifacts of both methods don't provide too much of a problem in normal usage, the biggest problem I find with ACR is the way whatever it does to smooth things over kills the colour depth and gradation, and their "solution" of boosting saturation and contrast to compensate is pretty crude. This is the thing which does affect the images at normal usage size, and what I have the greatest problem with.

Anyway, FWIW here are the results, and I'm off the case now. I'm happy with these results and the speed and simplicity with which processing can be done.

Attached Files

•  _DSF3755_lznLinearRawTiff&ACR.zip   6.6MB   21 downloads
•  _DSF3755ACR.zip   6.11MB   15 downloads
•  _DSF4206ACR.zip   4.34MB   15 downloads
•  _DSF4206_lzn RAW TIFF+ACRcrp.zip   4.67MB   15 downloads

Edited by Fred Nirque, 27 January 2013 - 02:53 .

[Lars Hansen]

I'm still reading your posts intensively - and I'm still stuck on the fence with regard to this sensor. I'm not ready to go into this kind of work flow that requires several tools. My hope was that C1 had solved the conversion issues to an acceptable degree - they've improved in some areas but in other areas it seems that they've unearthed new issues like odd horizontal and vertical artifacts appearing in complex patterns and I also agree the overall impression can be a bit like "plastic" as you've described it. I like to shoot nature and landscapes but this sensor doesn't yet seem to well enough supported in C1 to be the right choice for that - if I do buy an X-Trans camera it will not be for that kind of work.

I highly appreciate your effort with sharing your knowledge and findings - thanks a lot!

[Fred Nirque]

Thanks, Lars. It's not all that much different to processing in LR, Bridge or C1 and then doing final work in Photoshop - just substituting LightZone for the processing and then straight to either Bridge and save the final from there or straight to Photoshop and save the final from there. As each raw file is processed the same linear way, it is easy enough to save the preset in LightZone and simply apply it to process a folder of raw files in the background to save to TIFF, which can then be brought into Bridge (or LR, etc) in the normal way as if they were raw files for adjustment.

As I do more files this way I'm finding that it's going to take some experience to pick what file will work in which outcome, and it's awfully hard to resist making modifications in LightZone first as the image generally looks terrible and dark. Blown highlights are the thing I'm still working on - not that they're ever really "blown" when shooting at 400% HDR, but as I'm having to work this technique out as I go and there are no manuals there's a fair bit of trial and error to get through.

All the hype about C1 really was ringing warning bells with me, and to be truthful I think it can be worse than ACR in some situations, the weird horizontal and vertical artifacts are similar to what I used to get in the early days of ACR with my D2x. I have uninstalled C1 demo anyway - I hated it.

Personally I'm more than happy with the DCraw conversion as done by LightZone (or OloNeo PhotoEngine, but I won't be buying the latter now), but then I like the film-grain look whereas others like the smooth plastic look. Each to his own. I'm photographing tomorrow and I'll take some examples which should press this technique to its extremities - there is not as much adjustment available to Tiff files in ACR as there is to raw files, the sliders seem less responsive, so getting things right in the camera first may prove to be more critical. Kind of like film days .