[Katja]

I can't get my head around a sudden WB change (no WB change in camera) during shoot. I was taking studio portraits of my girlfriend and all was good for the first hour or so. Then my strobes stopped firing. I had thought, they could be overheated due to a hot day (33 degrees C in the room with a fan on. So, I decided to give my strobes break by switching them off for a few minutes. When I turned them back on - they fired on/off and WB (still set on WB flash) was out to synch (please see attached pictures).

The gear / setting used during the shoot:

Pentax k5 - ISO 200 - F/8 - 1/60 - WB flash
Pentax SMC-FA 50mm FA f/1.4
GODOX K-150A studio strobe x2 - one set at 1/2 power and one set at 1/4 power
Metz mecablitz 50 AF-1 (for hair light) - set at 1/8 power

Can anybody think of a reason why this could be? Many thanks guys.

Attached Images

   

[MadMathMind]

That poor woman in the first photo! She has been totally fried!

That one doesn't look a white balance issue because more redness should turn her top redder, not green. Looks like you got set to IR or some crazy setting. That or the color of light got all screwed up. Strobe malfunction? Just because they fired doesn't means something else didn't happen to them.

[Katja]

Thanks for your comments MadMathMind. FYI the top in the first pic was actually green and yes, I agree my model looks fried! Where do I find IR setting on my camera? However, it would not explained why I was able to shoot alright for the first hour .. how would the IR setting got in? I somehow think, it could relate to strobes as they stopped working for while and then, they worked on/off. I will test them again and see if they are working properly today.

[MadMathMind]

I shouldn't have said IR. That would make everything B&W. Plus, cameras don't have that setting unless you mod them.

Sometimes when I'm shooting, I fumble a WB or other filter setting by accident. Usually it happens when I need to switch something and forget to turn back to focus point selection. Then my face or hands touch something they're not supposed to. But if you're in a studio and set it on a tripod, then that seems unlikely.

I think it has to be something with your strobes. It's like you lost half your spectrum and the light has become bright, bright red. I've never seen anything like this before. It's like instead of emitting white light they're now emitting colored light.

[Edgar_in_Indy]

My K-30 will sometimes ignore my manual white balance setting when I'm using strobes, giving me a warmer tone all of a sudden, depending on what I'm photographing. It annoys me, but since I shoot in RAW it's not a big deal. I'm not sure if you're having a similar issue though.

Do you have a second camera you could try? That would tell you definitively if it's the camera or the strobe.

[Katja]

My K-30 will sometimes ignore my manual white balance setting when I'm using strobes, giving me a warmer tone all of a sudden, depending on what I'm photographing. It annoys me, but since I shoot in RAW it's not a big deal. I'm not sure if you're having a similar issue though.

Do you have a second camera you could try? That would tell you definitively if it's the camera or the strobe.

Edgar_in_Indy - thanks for sharing your thoughts. No, I don't have the 2nd camera body as early this year I managed to sell my old kD100. Now, I'm tossing a coin if I should get K3 II or wait for the full frame camera body (subject to the market price).

On the other note,I had recently another weird experience with my k5 and the same lens (Pentax 50mm f/1/4) using my Metz 50 AF-1 (this time, it was mounted on my camera). All worked perfectly and then suddenly my pictures were way too exposed ..?! I was suggested to take off the lens - put on a different lens - take a picture - put back on the 50mm. I did exactly that and everything started working properly. In this instance, I think it was the camera electronic.

However, I think the instance described above it's related to strobes as MadMathMind mentioned.

[Digitalis]

That or the color of light got all screwed up. Strobe malfunction?

I have never seen a strobe malfunction cause an effect like that.

I think it has to be something with your strobes. It's like you lost half your spectrum and the light has become bright, bright red. I've never seen anything like this before. It's like instead of emitting white light they're now emitting colored light.

Both of us know this kind of spectral suppression isn't possible. The gasses used in flash tubes emit a wide spectrum of light, something would have had to have disastrously gone wrong for that property to change. The only thing I can think of is the modelling lights interfering with the light output which would really foul with WB. I'd say there is something wrong with the camera, not the strobes: as the chances of all of them suffering the same malfunction at exactly the same millisecond is astronomically thin. When working in the studio I work with a fixed WB of 5000Kelvin, I get my students to do the same.

I somehow think, it could relate to strobes as they stopped working for while and then, they worked on/off.

That is because the flash bulbs were overheating, these aren't fan cooled strobes like most studios have. Godox typically specify how many flashes per hour the units can output before overheating

Were you using any light modifiers on your strobes? what Post processing software (if any) you are using, also any custom camera profiles you are working with?

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Last edited by Digitalis; 01-16-2016 at 08:21 PM.

[Katja]

The only thing I can think of is the modelling lights interfering with the light output which would really foul with WB. I'd say there is something wrong with the camera, not the strobes: as the chances of all of them suffering the same malfunction at exactly the same millisecond is astronomically thin. When working in the studio I work with a fixed WB of 5000Kelvin, I get my students to do the same.

That is because the flash bulbs were overheating, these aren't fan cooled strobes like most studios have. Godox typically specify how many flashes per hour the units can output before overheating

Were you using any light modifiers on your strobes? what Post processing software (if any) you are using, also any custom camera profiles you are working with?

I had modelling light on for a while and may have accidentally left it on when I took a few pics . Could this cause the problem?

Re modifiers - no, I wasn't using any modifiers.

Re software - I used LR 5 and I could see this effect immediately on my camera - before I imported those pics in LR.

My common sense is telling me that after 1.5 hour using strobes (it was very hot day over here) without any problems they started overheating - that's when the above effect took place. Could this be the case?

Re Godox's recommendation 'how many flashes per hour' - I've just checked manual and it says 'the flash should be cooled down for three minutes after 30 times continuously triggers at full power, otherwise the long times will lead to overheating.' - well, I didn't count after how many pictures I gave these strobes break and I didn't use them at full power neither. I just know that all together I took 90 pictures over 1.5 hour.

[Alex645]

In the first portrait, is her green top supposed to be red like the second image?

[Digitalis]

My common sense is telling me that after 1.5 hour using strobes (it was very hot day over here) without any problems they started overheating - that's when the above effect took place. Could this be the case?

I would say yes! that is definitely a factor. But exactly what is causing the colour aberration is profoundly mystifying. I know from experience that modelling lights, when left on continuously create a ton of heat. Some flash units use LEDs which emit lower amounts of heat: with Australian ambient temperatures creeping over 35 degrees, overheating hardware is very common. I am fortunate to work in air conditioned studios with high power fan cooled Elinchrom flash heads with very large light modifiers, but on location I work with battery operated flash systems that do not have active cooling, and overheating can be problematic.

In the first portrait, is her green top supposed to be red like the second image?

no, it was green. It is curious to note that her skin under that top is also affected by the drastic hue shift.

[Alex645]

Were these shot as jpegs? If so, I'm thinking the firmware glitched somehow and set a digital filter to extract cyan. It could have just been an anomaly, but I would reinstall the firmware for the K-5. If you were shooting RAW, then I'm still stumped.

[Katja]

In the first portrait, is her green top supposed to be red like the second image?

No in the first picture, she is wearing a green top.

---------- Post added 01-17-2016 at 06:54 PM ----------

know from experience that modelling lights, when left on continuously create a ton of heat. Some flash units use LEDs which emit lower amounts of heat: with Australian ambient temperatures creeping over 35 degrees, overheating hardware is very common.

My partner just old me that I took a few pictures with modelling light on - I did notice it was on and not for long as I know that I can leave it on for 5 mins.

I am fortunate to work in air conditioned studios with high power fan cooled Elinchrom flash heads with very large light modifiers, but on location I work with battery operated flash systems that do not have active cooling, and overheating can be problematic.

Spot on and yesterday, it was so hot that I kept asking my model to go and reapply make-up. I had a little fan on and it did't do much other than blow her hair little.

Thank you kindly for you comment.

---------- Post added 01-17-2016 at 06:58 PM ----------

Were these shot as jpegs? If so, I'm thinking the firmware glitched somehow and set a digital filter to extract cyan. It could have just been an anomaly, but I would reinstall the firmware for the K-5. If you were shooting RAW, then I'm still stumped.

No jpeg - I always shoot RAW.I've just checked the firmware and it's the latest version. However, your comment made me think it might be the firmware glitch as not so long ago, I had very weird experience with my k5 and Metz flash - in this instance all shooting went well and then a few shots were way too exposed (no changes in exposure or WB). to fix this, I had to remove lens - put a different lens on - put my Pentax 50mm back on and all worked just fine. Both occasions happened not long after I upgraded the firmware for k5.

How do I uninstall the firmware if I want to reinstall it?

There is another thought that just came to my mind and could have contribute to the above color disaster - a week ago, I was using my analog flash Metz 45 CT-4 with adaptor SCA 3000 C - to make it compatible wiht my k5. It took me a little while to get it working and this was due to not fully charged batteries in the flash unit. So, I replaced them wiht fully charged rechargeable batteries and it all worked as it should. Is there any chance that the firmware and my analog flash could have interfere?

[Digitalis]

My partner just old me that I took a few pictures with modelling light on - I did notice it was on and not for long as I know that I can leave it on for 5 mins.

The modelling light for most 250~150ws studio heads is commonly around 100-150W - coupled with the already high ambient temperature, that would be putting out a considerable amount of heat.

I've just checked the firmware and it's the latest version. How do I uninstall the firmware if I want to reinstall it?

You are already using the latest version there shouldn't be any issues with the camera, I would just leave it alone.

[Alex645]

No in the first picture, she is wearing a green top.

---------- Post added 01-17-2016 at 06:54 PM ----------



My partner just old me that I took a few pictures with modelling light on - I did notice it was on and not for long as I know that I can leave it on for 5 mins.



Spot on and yesterday, it was so hot that I kept asking my model to go and reapply make-up. I had a little fan on and it did't do much other than blow her hair little.

Thank you kindly for you comment.

---------- Post added 01-17-2016 at 06:58 PM ----------



No jpeg - I always shoot RAW.I've just checked the firmware and it's the latest version. However, your comment made me think it might be the firmware glitch as not so long ago, I had very weird experience with my k5 and Metz flash - in this instance all shooting went well and then a few shots were way too exposed (no changes in exposure or WB). to fix this, I had to remove lens - put a different lens on - put my Pentax 50mm back on and all worked just fine. Both occasions happened not long after I upgraded the firmware for k5.

How do I uninstall the firmware if I want to reinstall it?

There is another thought that just came to my mind and could have contribute to the above color disaster - a week ago, I was using my analog flash Metz 45 CT-4 with adaptor SCA 3000 C - to make it compatible wiht my k5. It took me a little while to get it working and this was due to not fully charged batteries in the flash unit. So, I replaced them wiht fully charged rechargeable batteries and it all worked as it should. Is there any chance that the firmware and my analog flash could have interfere?

I'm not 100% certain, but I'd think just as if you were updating it. Take a blank SD card, download the latest firmware onto that card, make sure your camera battery is relatively fresh, then go to the menu and update the firmware.

Does anyone know another way?

Data, including software/firmware, can get corrupted for all kinds of reasons. If you get this color issue all the time, then I'd point the finger at a hardware problem. But if it is more of an anomaly, my first move would be to reinstall firmware. I have to do this often for things like print drivers and neither Apple, Adobe, nor DNP can tell me who is at fault or why it occurs.

[Katja]

The modelling light for most 250~150ws studio heads is commonly around 100-150W - coupled with the already high ambient temperature, that would be putting out a considerable amount of heat.



You are already using the latest version there shouldn't be any issues with the camera, I would just leave it alone.

Thank you Digitalis for all your comment. It drives me mad when I can't figure out what is behind this unexpected glitch and as I said earlier, I am most inclined to believe it was due to the overheating of my strobes and I should take less time using them on a hot day like yesterday or get a couple of descent fans to keep everything cool during the shoot. Thanks again.

---------- Post added 01-17-2016 at 07:38 PM ----------

Data, including software/firmware, can get corrupted for all kinds of reasons. If you get this color issue all the time, then I'd point the finger at a hardware problem. But if it is more of an anomaly, my first move would be to reinstall firmware. I have to do this often for things like print drivers and neither Apple, Adobe, nor DNP can tell me who is at fault or why it occurs.

Thanks for the additional information Alex. I've got another couple of people coming to my studio on Tuesday - I'll give it a shot with the equipment I've got and also my new knowledge re the possible overheating of the strobes. If the issue continues I will re-install the firmware. Thank you again for all your comments.