Question about fill flash

[dblightsey]

On my Canon Xti how far away can I expect my flash to work as a fill ? Using a 50mm lens I have to be quite a few feet away from the subject , am I expecting too much,should I be looking for a speedlite now ? Just wondering I could go out and experiment, which I will but Im just wondering from those who've already been there.

Thanks

[Samanax]

On page 54 of the XTi/400D instruction manual there is a effective flash range chart you can use to help you determine how far your can be and still use the pop-up flash when used with the kit lens. If you have a 50mm lens with a maximum aperture of f/1.8 or f/1.4 then that distance will be farther.

Have you thought about getting an external hot shoe flash for your XTi? The Canon 580EX II is a great flash to use but on the pricey side. The 430EX II is a nice flash and will work well with your XTi...it's just not as powerful as the 580EX II and lacks a few features and functions...but it's still a good flash to have.

[teaking]

Yeah you are going to need your guide number which as the above poster said will be in your book. It will be something like GN 12 at ISO 100

So you will know its good at 12meters at ISO 100

To work out what guide number you need you times the F number by the distance eg. 2m x f2.8 = GN about 6

If after you work out the guide number you need and you havent got enough range you can increase your ISO which will increase the effective distance of the flash and GN eg. at ISO400 GN=12 becomes GN= 24 .... I think

[Benji]

K.I.S.S. Take the shot and look at it on the back of your camera. If it is flat lit decrease the power of the flash by 1/2 and try it again. If it is still too much, decrease it by 1/2 again.

I don't own an XTi so I suggest you check the manual to see how to decrease the power of the on board flash (or if it can be done at all!) If it can't be done "in camera" simply obstruct the flash tube with some of your finger. That is how I did the shot below. Low tech? Yup. Did it work? Yup.

Benji