Night Flash Problem

Hi Guys

I should know this but I would like you comments/advice/experi​ence.

Using 580EX on 40D outside at night.

Am I missing something? How do I get it to autofocus on animals/objects in the garden at night without switching to manual. Or - when I switch to manual - how do I focus on the subjects without some illumination? It seems it will autofocus OK if there is a small amount of illumination.

Many thanks

The AF Assist light on the 580EX will help you focus.

The camera must be in one-shot or AI Focus (not AI Servo) AF mode for it to work.

Hi Curtis

I think think the AF assist light only has a limited range? But I will recheck when the sun turns off.

Thanks

Hi Curtis / Others

I have had another go - Read the flash manual and camera book - it looks like all is working OK but the AF Assist light seems to have distance limitations and does not always have the effective range quoted in the manual - this is noticable when uneven surfaces such as trees and bushes absorb the AF Assist beam - never the less, a good exercise - if only in reading the two books in conjunction with one-another.

I also discovered C.Fn-8 Quick flash with continuous shooting. This seems rather useful - I think I might be using that fairly often.

Regards

Ray,

Generally, lenses with larger max. apertures will focus better in low light. An f/2.8 zoom will do better than an f/4 zoom, and a f/1.4 prime will do better yet.

Just something to keep in mind if you shoot in low light often.

Hi Curtis

Thanks for your comments - can only agree - I must look around for a f/2.8 zoom - I have been thinking a lot about the 70-200 f2.8L. I have the f4 non-IS version of it. It is the sharpest lens I have. I keep hanging on wondering if the 2.8 will shortly be upgraded to a Mk2.

Curtis, Was it your good self who was considering producing an informative article on the use of the ringflash? If so, please hurry up.

Sorry didn't reply earlier - been so busy I sometimes have to stop myself being distracted by photography or I only go out and start spending again.

Regards

Ray.Petri wrote in post #4282170
Curtis, Was it your good self who was considering producing an informative article on the use of the ringflash? If so, please hurry up.

'Twas not I. I've never used a ringflash.

I'm working on a prototype ringflash alternative, but I need to keep it hush-hush until I get the all-clear from my patent attorney.

OK. Thanks curtis. I have had a couple of ideas for a ringflash using bright LEDs but I reckon I'll have to shelve it for a while - someone else'll come out with it before I get off the mark I suppose.

Regards