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Negative Flash Exposure Compensation yields no effect

Started Mar 12, 2018 | Questions thread
cmcm789 Regular Member • Posts: 293
Re: Negative Flash Exposure Compensation yields no effect

okarlo wrote:

I have been experimenting with the Flash Exposure Compensation (FEC) setting on my recently-purchased EOS M3, firmware 1.20, shooting a close-up of a black camera bag in Program mode using the pop-up flash. I am having a problem where setting a negative FEC (-1, -2) seems to have no effect on the flash power--images taken at FEC -2, -1, and 0 are indistinguishable, even though the INFO screen correctly shows the FEC setting with each image. But If I set a positive FEC (+1, +2), the flash is clearly firing at a higher power, and the effect is very obvious.

I also have a Canon Powershot S2IS and a Pentax K-x, and when I set a negative FEC on those cameras, darker images result, as expected.

Has anyone else experienced this? Thanks.

If you're shooting in Programme Mode I assume the camera is trying to balance the Aperture Shutter and ISO for an overall even exposure. if you lower the flash output it will just adjust something else to get the same result. However, this would not explain why it is obvious when you increase the flash output unless it is keeping the overall scene the same but your subject looks a bit brighter (other parts of the image darker).

Try experimenting using M mode and manually set the Shutter, Aperture and ISO (Don't use Auto ISO). This will tell you is the flash EC is working.

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