[BrianR]

Final pictures had about 25% of space black ?.

Which 25%? This sounds like a syncing problem- what was your shutter speed, flash power and how are you triggering your strobes when this happened?

The red (pink) color went away - and I was able to change it to any WB in LR afterwards.

Maybe I'm misunderstanding, but are you saying there's no colour cast to the problem photo when you corrected the WB in LR?

[Katja]

Which 25%? This sounds like a syncing problem- what was your shutter speed, flash power and how are you triggering your strobes when this happened?

Shutter speed was 1/180; one strobe was set at 1/4 power and the other one was at 1/8 power . I use Trimester II 2.4G by Aputure.

I've attached one of those picture - it's actually more than 25%!

Maybe I'm misunderstanding, but are you saying there's no colour cast to the problem photo when you corrected the WB in LR?

Not at all. It look fine - see the attached picture (WB is adjusted to Auto).

[Katja]

The previous files were too small so, here you can see the mentioned images. The first image - partially black. The second image with adjusted WB in LR - Auto WB.

[Edgar_in_Indy]

I wouldn't worry too much about the black streak caused by the shutter, unless it becomes a regular thing. That has always happened with my K-30 when using strobes, but it's rare. Like maybe once every few hundred shots. I don't even really know whether the issue is caused by my camera, or by my strobes, or by my radio triggers.

[Digitalis]

I don't even really know whether the issue is caused by my camera, or by my strobes, or by my radio triggers.

Probably a combination of camera/Strobes. I have worked with flash triggers that ran into similar issues. They were a few milliseconds too slow compared to my Pocketwizards.

[Katja]

Probably a combination of camera/Strobes. I have worked with flash triggers that ran into similar issues. They were a few milliseconds too slow compared to my Pocketwizards.

My theory is that this was caused by the Flash Synch Speed (1/180) and my strobes were not able to keep up with it. When I switched to 'M' mode and dropped shutter to 1/60 it was all working just fine.Then I tried to take a picture at 1/160 (still in 'M' mode) and all was working just fine. I switched back to Flash Synch Speed and I had no problem.

[Digitalis]

My theory is that this was caused by the Flash Synch Speed (1/180) and my strobes were not able to keep up with it.

When working with flash I often set my camera to the X mode, I only use manual when I use HSS or when I'm mixing light sources and need to drag the shutter. The triggering and optical slave circuits on most well made studio strobes can react to rapidly changing lighting conditions in a fraction of a millisecond. I'm confident the transmitter was at fault here as I have used triggers that showed similar issues with Canon, Nikon cameras at their native 1/250th sync speed*. Many Canon and Nikon DSLRs have to be used at 1/125th with some strobe triggering systems - and in these situations the transmitter is almost always at fault.

*and things become even more problematic with Leica S and Phase one cameras as their leaf shutter lenses are capable of 1/000th ~ 1/1650th shutter sync speeds.

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Last edited by Digitalis; 01-19-2016 at 05:53 AM.

[BrianR]

My theory is that this was caused by the Flash Synch Speed (1/180) and my strobes were not able to keep up with it. When I switched to 'M' mode and dropped shutter to 1/60 it was all working just fine.Then I tried to take a picture at 1/160 (still in 'M' mode) and all was working just fine. I switched back to Flash Synch Speed and I had no problem.

Here is someone else who had problems with the sync speed of the trigmaster II and a wiring modification they did to correct it: https://www.pentaxforums.com/forums/125-flashes-lighting-studio/179742-aputur...ml#post2100417

This page has a diagram of what happens during "Normal Sync": Sync About It…or Thinking About Syncing | PixSylated | Syl Arena's Photography Blog on Light & Imagemaking

If the flash is started too late, the 2nd curtain starts to cover the frame before the flash is done firing and you get a black area like in your photo. A longer duration flash pulse can also run into 2nd curtain problems. The duration of the flash pulse will depend on the power settings, so you can end up problems at some shutter speeds and not others depending on your flash settings.

I would stick to a shutter speed of 1/160 or 1/125 and see if you have problems there, unless you manage sort out exactly what power settings cause trouble at 1/180. Also make sure your triggers always have fresh batteries.


None of your photos seem to have the EXIF intact, could you post the ones from the original post again with all the EXIF? Size of the image won't matter. We should rule out user error of an accidental mode change or button press.

[Katja]

The triggering and optical slave circuits on most well made studio strobes can react to rapidly changing lighting conditions in a fraction of a millisecond. I'm confident the transmitter was at fault here as I have used triggers that showed similar issues with Canon, Nikon cameras at their native 1/250th sync speed*. Many Canon and Nikon DSLRs have to be used at 1/125th with some strobe triggering systems - and in these situations the transmitter is almost always at fault.

Many thanks for for spending time on resolving this issue for me - I really appreciate your time and saving me money as today I was so close to purchasing k3 II ( I still might do this as I really would prefer to have two camera body than one).

If the trigger is the problem - is it also possible that it could contribute towards the pink color cast?

[Katja]

Here is someone else who had problems with the sync speed of the trigmaster II and a wiring modification they did to correct it: https://www.pentaxforums.com/forums/125-flashes-lighting-studio/179742-aputur...ml#post2100417

This page has a diagram of what happens during "Normal Sync": Sync About It…or Thinking About Syncing | PixSylated | Syl Arena's Photography Blog on Light & Imagemaking.

This makes sense - thank you for posting it here.

would stick to a shutter speed of 1/160 or 1/125 and see if you have problems there, unless you manage sort out exactly what power settings cause trouble at 1/180. Also make sure your triggers always have fresh batteries.

Yes, the slower speed seems to be working with those particular triggers.
Re batteries - a night before last, I forgot to turn the receiver of so, batteries could not be the freshest.

None of your photos seem to have the EXIF intact, could you post the ones from the original post again with all the EXIF? Size of the image won't matter. We should rule out user error of an accidental mode change or button press.

Attached for you is a print screen including all info about the original image. Thank you for trying to figure out what was causing the issue - I am certainly learning a lot about troubleshooting via these discussions.

[BrianR]

Attached for you is a print screen including all info about the original image. Thank you for trying to figure out what was causing the issue - I am certainly learning a lot about troubleshooting via these discussions.

There's way more information stored in the EXIF than this little snippet. It will include many of the cameras settings, like a few of the White Balance options. Lightroom won't display all of it, but if you are so inclined you can see it yourself with a tool like PhotoME or ExifTool. Whatever program you've used to resize for uploading has been stripping this information out (this is pretty normal as it shaves a few kB of the file for uploading).

In a pinch you can export out of Lightroom, but make sure in the export dialog under the "Metadata" heading, "Include" sub heading, select "All Metadata". This will keep it mostly intact for us to look at, but Ligthroom will still strip a few things out. The next 3 ways are more work but will give more complete exif information.

Another option is to upload the original raw file to something like Dropbox or GoogleDrive.

Another is to use the cameras built-in processing to develop the raw file directly into a jpeg small enough to upload here.

A funner option is to get ExifToolGui and use it to extract the exif from the original file and upload this as a text file. This way you can look at all the little bits yourself, but setting up this program is a little more work.


The point of looking at the exif is to see what the camera thought it was trying to do and ruling out the possibility that you (or it) had unknowingly changed a setting between shots. It might not reveal anything, but it there could also be a simple explanation on why it chose a whacked out white balance.

[Digitalis]

If the trigger is the problem - is it also possible that it could contribute towards the pink color cast?

No, The flash triggers couldn't cause an issue like this as thy have no interaction with the sensor or the image processing pipeline.

I was able to replicate the visual effect of issue you have been experiencing by deliberately by adding a considerable amount of red/magenta filtration. It is possible that your camera adjusted the white balance and Light room simply followed the cameras instructions. So this issue probably is just white balance glitch, rather than a sign of impending catastrophic failure. Good thing you were shooting raw.

[Culture]

5000K is a very common light temperature - equivalent to midday sun, flash and many high CRI light sources. I use this setting as I work in the studio with flash and many cameras from different makers( Leica,Pentax,Canon,Nikon,Hasselblad,) and I use a fixed WB value so my workflow is simpler, in post processing I correct WB if needed - but I always have the 5000K baseline to work from with colour corrections.

Sometimes, I will change the WB to 3200 or 7600K - I do work with mixed light sources on occasion, and I have colour profiles for both of those settings.

---------- Post added 01-19-16 at 12:21 PM ----------



I agree, it is utterly bizarre. I can think of a possible way for a flash to produce erroneous spectra through overheating and under-charging capacitors. But it would require all the flash units in the scene to suffer from the exact same fault in the same millisecond which is extremely unlikely. I has to be something going pear shaped with the camera.

OK. Thanks for the explanation. I have to look into this then.