Custom Function Flash Settings

[GenEOS]

I have been testing various setting with the flash and my D60. I have noticed there is a custom function that allows you to fire the IR beam on the flash but not fire the flash.

Under what circumstance would you need to do this?

When set to IR assist but not fire the flash, the AE lock button "*", will fire the flash without recording an image.
So, I tried pressing the shutter half way down and pointing the camera at a subjecty in the dark, in most cases the IR assist grabbed the focus but when it did not and I fired the flash with the AE lock "*" button, it then aquired the focus...

Just wondering what this buys me? Ok, so it will focus in the dark, but since I had the camera set to not fire the flash and only IR assist, then what?

Only thing I can think of is maybe for timed exposures in very dark situations or something like that?

Any other ideas, or is there someone here who actually knows the answer to this question?

[Roger_Cavanagh]

First of all, it's not an IR beam, otherwise you couldn't see it. It's just a red light pattern that helps focusing. In low light or poor contrast, this light may be less obtrusive and more effective than the the built-in white light.

It's helpful enough that Canon offer a stand-alone version - the ST-2. It fits in the hot shoe and just emits the red beam - not cheap either.

Regards,

[GenEOS]

OK, excuse the ignorance. but can you explain the logic (Dr. Spock) behind the custom function setting.

Because, if the lighting is so poor you need the help of the flashes light pattern thingy-ma-jig (technical term) to help out focusing, than you probably need the flash too. So why have the function turn off the flash firing and just lighting up the target with the red do-hicky (another technical term) ?

I know this requires getting inside the head of a Japanese Camera Engineer and his plan for this function, but I would like to know what that plan was...

Just funning a bit here, don't take it personal.

[Roger_Cavanagh]

Well, you realise that since I'm not a Japanese camera engineer, I'm only guessing. :)

It's definitely not true that the red AF assist beam would only help in situations where the flash was needed. Don't tell me you've never hand your D60 go hunting in perfectly good light. :)

You might want to use the 550 to trigger slave flashes, but not fire itself, and have the red beam help focus in low light.

Regards,

[JFricks]

There are many times when my lenses will hunt for focus and there is plenty of light to get off a good shot especially with a fast lens....using the IR but no flash function is a great way to assist with that focus. Try it, it works!

[GenEOS]

OK, I will try it.

[Recondo]

I just tried it, it really works.
Thx for the tip.