Manual or AV w/580 indoors?

[SDJNJ]

Someone told me that using a 580 speedlite outdoors, you should always use AV mode on your camera. Haven't tested that yet.

For indoors, I was told that you set your camera for manual. Like f/11, 1/125, ISO 100-200. Then, I was told the 580 will set the correct amount of light. Doing this, indoors, I found that it was completely underexposed, (not a lot of ambient light, but still some daylight coming in) and to get it properly exposed, I bumped it up to +3 exposure compensation on the 580. Does this all sound reasonable? I also tried a 45 degree angle with Sto-fen omni bounce. The ceilings weren't clean bright white. Then, went to straight on flash with omni bounce. Much harsher. Using the histogram proved helpful in setting the right amount of exposure compensation. But, walking around the room with different light coming in from different windows, it was always something different and the need always arose to use exposure compensation on the flash. Isn't the flash suppose to take care of all of this, with minor fine tuning in the exposure compensation?

First day using the 580. Any tips would really help.

[PacAce]

Someone told me that using a 580 speedlite outdoors, you should always use AV mode on your camera. Haven't tested that yet.
You don't have to use the Av mode when using a flash outdoors. P and M modes will work just fine, too, as will Tv.


For indoors, I was told that you set your camera for manual. Like f/11, 1/125, ISO 100-200. Then, I was told the 580 will set the correct amount of light. Doing this, indoors, I found that it was completely underexposed, (not a lot of ambient light, but still some daylight coming in) and to get it properly exposed, I bumped it up to +3 exposure compensation on the 580. Does this all sound reasonable? I also tried a 45 degree angle with Sto-fen omni bounce. The ceilings weren't clean bright white. Then, went to straight on flash with omni bounce. Much harsher. Using the histogram proved helpful in setting the right amount of exposure compensation. But, walking around the room with different light coming in from different windows, it was always something different and the need always arose to use exposure compensation on the flash. Isn't the flash suppose to take care of all of this, with minor fine tuning in the exposure compensation?

First day using the 580. Any tips would really help.
Were you using f/11 @ 1/125 with the flash? What lens (focal length) were you using and how far away was the subject?

The problem with flashes is that their maximum flash-to-subject distance varies depending on the aperture, ISO and, for flashes with zooming heads, the focal length of the lens used. For example, if you are using a 50mm lens, the GN of the 580EX at ISO 100 is 137.8. That means that if you set the aperture to 11, the maximum distance the flash will cover (head on) is 12.5 feet. If you angle the flash to bounce the light off of the ceiling, or you use a diffuser device, the maximum subject distance will be decreased even more, to 8 feet or less. This could explain why you are getting underexposed pictures.

Also, when you angle the flash head for bounce, the head zooms out to the 24mm position and that decreases the GN to 91.9. At f/11, that's only good up to a max distance of 8.4 feet. To increase your working distance, you'll need to increase the aperture and/or the ISO. Unfortunately, once you've reach the max ouput of the flash, no amount of FEC increase will make it put out more than that. So, to make sure you don't get underexposed pictures, you'll need to be aware of the maximum distance your subject can be from you. When bouncing the flash, the total distance includes the distance to the ceiling and back down to the subject.

[SDJNJ]

I was using the 28-135 lens, not sure focal length & I've deleted images, and was about 10' away. I understand the GN. However, when doing fast moving photography, how is it possible to figure GN on the fly? Just something you get used to or is there a quick formula. Thanks for your help! It's really appreciated!

[PacAce]

I was using the 28-135 lens, not sure focal length & I've deleted images, and was about 10' away. I understand the GN. However, when doing fast moving photography, how is it possible to figure GN on the fly? Just something you get used to or is there a quick formula. Thanks for your help! It's really appreciated!
You don't need to figure GN on the fly. GN will never change. What you need to figure out is what your maximum distance is that your flash can cover for your camera settings. But you don't really need to do any math to figure that out. Just set your flash to Manual and it'll tell you, for the ISO and aperture your camera is set to, what your max working flash-to-subject distance is. Once you have determined that, you can set the flash back to ETTL mode and start shooting away.

[SDJNJ]

Leo, thanks! You've been a great help!