Beginner Strange colour-cast

JayJay

JayJay

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Jon
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I know these are terrible pictures - focus is even in the wrong place. I had just been reading an article about auto ISO and I picked up my camera for a play then fired off a few shots from the sofa pointed at the cat hiding from me round the back of its scratch post.

Anyway, of the 15 shots I took about half of them looked orange. I didn't change any white balance settings, in fact the 2 images posted are consecutive shots from the same burst. They are straight out of camera. One normal colour, one orange.

Does anyone know what's happened?




 
No. Set to cloudy. Only light was from the window behind me.
 
Are you sure there was no internal lighting? WB fluctuations are pretty common on strip lights and some energy saver bulbs.

On a slightly different note, you have missed focus. For shots like this you want it on spot focus so you can focus on the cat as opposed to the camera just focussing on the thing closest to you (the scratching post).
 
Shot in raw.
Lightroom has both shots with a temp of 6000.
Both shots taken less than a second apart on the same shutter press. All settings the same.

There were definitely no artificial lights on in the room, but there was an open door to the left of the cat, I can't remember if there was a light on in the next room or not, but if there was, wouldn't it have made all the shots orange, not just half of them?
 
JayJay said:
Shot in raw.
Lightroom has both shots with a temp of 6000.
Both shots taken less than a second apart on the same shutter press. All settings the same.

There were definitely no artificial lights on in the room, but there was an open door to the left of the cat, I can't remember if there was a light on in the next room or not, but if there was, wouldn't it have made all the shots orange, not just half of them?
Click to expand...

What's the shutter speed? looks quite fast considering you've frozen the cat paw, in which case artificial light could well be the cause (you usually slow the shutter speed a to stop this effect).

Either that or the light from outside suddenly changed, as you have fixed the WB any change in colour temp will not be compensated for by the camera.
 
I was in aperture priority at f5.6. Camera chose 1/40th and ISO 6400.

Assuming there was a light in the next room, can it be some kind of strobing effect that is too fast for the naked eye but effects one shot but not the next?

Just to add, it was a burst of 3 shots. Went orange-normal-orange. The rest of the shots don't alternate perfectly, but they almost do.
 
The camera would have calculated an exposure for each picture. I have no idea what it was calculating against though.
 
This kind of apparently inexplicable effect is 99% flickering lights. It's often more marked than this, and can change down the frame as the shutter scans down during the exposure, but all lights vary. In our kitchen, the small fluorescent strip under-lights are quite interesting at fast shutter speeds, changing from green to magenta at either end, with a brightness drop as well, but too fast for the eye to see so it all looks normal. Some cameras like the Canon 7D2 use flicker-detection via the metering system to delay timing of the shutter release to sync with the flicker and minimise it. Flicker can be a right pain at indoor sporting events at fast shutter speeds.

Try shooting the suspect light - just the light itself, at fast shutter speeds like 1/500sec and higher. Longer shutter speeds will get rid of it, or you might try 1/50sec and 1/100sec that should sync with the flicker.
 
JayJay said:
Assuming there was a light in the next room, can it be some kind of strobing effect that is too fast for the naked eye but effects one shot but not the next?
Click to expand...
That's EXACTLY how fluorescent lights work. They strobe at 50Hz, and the colour changes throughout the cycle. It's too fast for our eyes so we see it as continuous white light. But if your shutter speed is faster than 1/50th the camera will see only part of a cycle, so both the intensity and colour of the light will be unpredictably variable from one shot to the next. If the shutter speed is a bit slower than 1/50th, as yours was, the exposure will pick up one-and-a-bit cycles of light, which won't be so dramatic but can still play havoc with the colour and exposure.

If there's any fluorescent light around, the only safe shutter speeds are 1/50th, 1/25th, 1/12th, or slower. (Slower shutter speeds are capturing multiple cycles of the light, so getting an exact number isn't so important.)
 
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Thanks for all the replies, I now understand what occurred. I've seen the colour cast in indoor images before, obviously. It was that some of the shots had it and some didn't that had me confused, but not anymore. Cheers all. :)
 
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