Different rendition of raw files taken with an external flash

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Different rendition of raw files taken with an external flash

Hello everybody!

I was quite excited to tryout LightZone since I've had problems with all of the other, more advanced, raw editors for linux namely Rawtherapee for being extremely unstable and Darktable for not supporting my camera making itself unuseful. I am using Fuji S5 pro whos SuperCCD doesn't appear to be every editor's cup of tea.

After I installed LightZone, to my extreme joy, it worked right away quite wonderfully!

But then came a big surprise... When I wanted to edit photos I took with a flashgun I got this week, for some reason in the edit mode, photos appear one third perfectly normal, and two thirds completely blown out. And, really, the only difference to the photos I used to tryout the program was the external flash. Even photos taken with my Fuji's on-camera flash were rendered normally. The above mentioned alternatives had many problems, but not something like this. In camera and in ufraw and rawstudio, and in rawtherapee (when it chooses to work) and even in darktable (although on the extremely green side) the photos are evenly exposed. The flashgun is the only difference I can think of, but I'm have absolutely no Idea what difference should it make to the file itself...

Could anyone shed some light on the subject?


Never heard of this problem,

Never heard of this problem, and lately a lot of the artwork shots I've done all used flash guns, sometimes 2, and off camera (night shots).  Never had this problem, and I use Sony, which has squirrelly flash to boot.

Sounds strange indeed.

So you have some images, taken with flash, that look OK in LZ an some that do not look OK?


They all look OK in other converters?


Can you adjust the exposure value to bring them back into an acceptable (or even just visible!) range?


What, if any, are the differences in camera settings between the Ok and the not OK images?


Would you be able to make available one good and one "bad" file for people to experiment with and compare settings?


This is not something I have ever heard of before.







From a quick search ...



This dpreview forum thread seems to suggest that there may be some challenges for the S5 flash system, built in or external (the external seems not to have been answered) . However how that relates to what you are seeing is not clear at all.


What do you see on the camera screen when you view the images that have the problem?





ETA: I assume I am correctly understanding that 1/3rd of the images are OK and 2/3rds of them are over exposed.  The alternative understanding would be that for EVERY image taken with the external flash 1/3 of the image is correctly exposed and 2/3 is over exposed but I can't see how such a situation would then give an image in ANY converter that might look OK. Such a problem would normally be realted to a flash speed synchronisation issue bit would be visible in all software systems one would expect.

Thank you for the replies!

Thank you for the replies!

I understand it might sound crazy, but that is what I'm dealing with here. I'm not claiming it has something to do with the external flash, but that is the only difference between the photos that are normal in both preview and edit mode, and these "corrupted" ones. I ruled out the corrupt file problem since the photos are normal in just about any other raw editor I have on my computer.

And no, the photos taken with the S5pro's built in flash are completely normal, so it should not a matter of sync, especially if there was such problem, those photos wouldn't have made it to my hard drive in the first place!

Anyway, to prove my sanity, I've uploaded screenshots of the same photo as seen by some of my raw programs. I've also included  what happens if you try to compensate for the exposure difference... And regarding lightzone, yes the photo looks the same exported as it looks in the editor.




UPDATE: I've taken some more shots without, with built-in, and external flash, it happens now with all the files... :/ But still opens older files perfectly though...

Looks like you have a double RAW Tone Curve applied

Above the the RAW adjustments you have 2 locked tools where normally I would expect only one.  That would be the RAW Tone Curve.


What is the RAW Exposure Bias tool?


I have seen situations where a double adjustment can creep in to the process  - there was an example just recently and it was to do with some internal naming issues. If both of the locked tools are indeed tone curves it would be interesting to know firstly where the extra one has come from and secondly  - how it seems to affect only part of the image. My first reaction would be to look for some kind of region in a tool but there is no indication of it in the screen grabs.


The investigative route would be to unlock the Exposure Bias tool ( I think) and then untick the activation box and see what that gives you. If it fixes the prolem that will also be the immediate (short term) solution while we fidn out where that tool has come from and why.


If not that ... then it will be back to some head scratching.


Try the unlock and de-active options and see what happens and let's take things from there.







CCD failure

look for a tiny purple line separating the good and the bad. When my ccd began to fail this was the first thing I noticed. A good section and a bad seperated by a thin purple line only visible when I viewed the photo 1:1.

 I hope I am wrong.

Fuji S5 Pro - Same here

Same problem here ... top third of photo exposed correctly, bottom two thirds way overexposed. This is with Raw Exposure Bias enabled. If unlock and disable RE Bias, then bottom two thirds are correct while top third is underexposed. Mac 10.8.5, LZ 4.1.0 beta 6. Other programs demosaic ok.



Thanks, Roman

What Is RAW Exposure Bias?

I have LZ  (V4 Beta6 mainly) running on a Windows system.


I have run a search on the system and cannot find any reference to RAW Exposure Bias.


It's not  something I ever recall seeing in LightZone. Should I assume it is some sort of RAW Tone Map?


The common factors reported (and also the missing commonality to my setup) is that bpth of you have S5 s and run in on Linux. Is that correct?


In which case it seems that whatever causes the strange problem seems likely to be specific to the S5 and/or to the Linux build available.


Maybe there is something in the source files that the developers could identify more quickly than searching and testing would?


It certainly looks strange though!






RAW Exposure Bias


I found that the "RAW Exposure Bias" is defined ONLY in "FUJIFILM FINEPIX S5PRO.lzt":


Also, there is some special treatment only for Fuji S3 and S5, though this may or may not be related to this bug :



I'm not sure why, but this code have already been there at least since v3.9 (the first open-sourced version). I'm gessing they were required for older dcraw those days, but are not needed anymore because of dcraw improvement.

I'll look into this bug in this weekend.


Masahiro from dev-team


My guess was right. I've already committed the fix for this bug. I'll release the fixed package in next beta (v4.1.0~beta7).



S5 Pro bug

Great stuff Masahiro .... thanks!

cannot find other maps than /

I have an external HDD connected. LZ does not show the contents in the browser list.

In Windows version ok, but not in linx version (Xubuntu 14.04)

What am I doing wrong?