Tuesday, April 22, 2008

Strobist: Lighting 102: 3.3 - Balancing Flash/Ambient Indoors

Strobist: Lighting 102: 3.3 - Balancing Flash/Ambient Indoors

This was an interesting exercise for me as I had never understood the relation between the flash and the camera settings. This is mainly due to being an "Av Mode" addict. The most I had gone into controlling the flash was using the camera flash compensation, which I would dial down for fill in flash.

Learning that the light from a flash is only affected by the aperture and ambient light was affected by both aperture and speed made me scratch my head for a while to understand the concept. I couldn't quite understand (or maybe it was believe) that the flash was also not affected by speed.

But as I could see from the results after this set of exercises I was convinced and have been putting this fact into use for some other experiments I have been doing (see the last photo).

The set of images below were all black when no flash was added. All shots were taken at 1/250, through a shoot through umbrella about 3 feet away.

The light seen in the images 1/250 to 1/100 is mostly fall off from the umbrella. All the walls in my house are white and bounce light like crazy. This is taken with no Gel on it hence the mixture of orange light from the ambient and white light from the flash.



The next set of images is taken with a Lee Filter CTO -Full, which as you can see also stops down the light between 1-2 Stops. Whereas in the previous image light was seen from the flash fall out from 1/250 to 1/100 here they are almost pitch black, and light doesn't start to show up until 1/60 to 1/40.


The next set of images is taken with a Lee Filter CTO -Full, which as you can see also stops down the light between 1-2 Stops. I also added tracing paper onto the umbrella to remove the obvious signs of umbrella light. To compensate for the loss of light I increased the light power by 1 stop.

The image below I took a few days ago to prove the above theory to myself and combine it with an experiment I had wanted to test out taking a photo with a Tungsten White Balance and gelled with a Full CTO.

I set the camera to 1/250 and then measured the sky and stopped down two stops using the aperture. I then set the flash to around 1/4 and placed it around 3 feet from the person camera right.


This was taken at mid afternoon and I really liked the affect. As it's only my first time attempting this you need to forgive the quality. You can be sure I'll be messing around with this affect a lot more. You can see all the attempts from the shoot here.

Please feel free to leave comments or questions about this article and I will endeavor to answer them as soon as possible.

Previous lessons from Lighting102:

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