Question by Tim G: How should I be setting my DSLR (in manual) while using a flash gun in TTL mode?
I have my DSLR in manual and I’m also using a flash gun in TTL mode.
Should I first adjust the camera settings to correct exposure according to the camera meter, or should I under compensate with camera exposure knowing that the flash will brighten anything within range?
The reason I ask is that some photos that I set to be correctly exposed according to the camera meter were blown out once the flash went off.
Best answer:
Answer by Jens
If the photos were overexposed if you used flash in TTL mode while the light meter indicated a proper exposure, then something went wrong. The flash should have fired at minimal power output in that situation, or not at all.
I would recommend using matrix metering or center weighted metering in that situation, as this will be closest to the method that the TTL uses to determine the flash output. TTL, at least for Nikon, uses matrix metering in normal mode and some kind of center weighted metering in TTL-BL mode. If you used your camera e.g. in spot metering mode, then the light meter result of the normal exposure and the TTL reading might not have fit together.
But yeah, i generally use center weighted metering then and measure for the foreground subject that way. If i then set to underexpose by one stop, then the flash will contribute that missing stop worth of light on the foreground subject, i.e. there will be a 1:1 balance between ambient and flash light as one stop underexposure means that only half as much light i there as required, and the flash will contribute the other half then.
If i wish to change the ambient/flash ratio, then i simply change the underexposure, knowing that the flash will contribute the light needed to boost it to a proper exposure.
Another possible cause of your problem might be that the subject was only a small part of the photo. Since the TTL reading is taken from a large part of the image, it may have been fooled into accepting an overexposure in a part, combined with an underexposure in another part, as a proper exposure in total.
Know better? Leave your own answer in the comments!
