can you use a flashgun just to assist focus, but not flash?

Hey all,

Not the most knowledgeable on flashguns, or their workings, so there's every possiblity i've no idea what I'm talking about, but I was wondering:

That little 'ol redlight that is built into the front of the flash gun (I use Metz 48 AF-1), that is shone onto your subject as you compose your photograph.. I assume it's there to assist the camera with proper focusing?

Obviously you'll not have much use for a flashgun in an incredibly well lit area, so they've built that in to assist with darker times when the camera would otherwise focus-hunt?


If I'm right in saying that, can I ask, is there any way to use a flashgun on your camera to take photographs, but only use it to assist focus, and not actually fire the flash when you press the shutter button?


With the combo of a 20D and 50mm 1.8, I find my focus will hunt at gigs. The light is terrible and more often than not, I end up in manual mode, trying to get a somewhat accurate focus, and then burst shooting as I continue to refine my focus. I reckon with a flash gun's help, I could lock focus much more successfully, but i wouldn't want flash, as it'd take the atmosphere out of the image.


Anyone ever thought of this before and found out if it's do-able?

pixbyjohn

You could have the flash head turned backwards and maybe have a cover over the head. The focus assist would still work maybe satisfactory.

Fajitas!

I don't know what camera you're using, or what the functions on the flash are like, but yes, you should be able to turn off your flashgun firing and just use if for AF Assist - some cameras/flashes have this as a custom function, if you can dig it out in the manuals

The Snipe

Turn on AF, and Flash on, Aim so it focuses, Disable AF and turn off flash, shoot - when taking next set of shots, Repeat. Thats what I do, cause I normally check the shots anyway :P

Fajitas!

That's an incredibly complicated process, when you could most likely just turn off the flash firing, and keep your AF on, and not have to worry about flicking switches when you're shooting!

oshead

With the Canon 580EXII you can turn the flash off in the menu options of the camera, while the focus assist stills functions as normal.

Fajitas!

As far as I know, there's a custom function on all the Canon EX range too. It's some obscure combination of buttons, but I'm sure a quick Google will sort it out if anyone is stuck.

Pete67

Also Canon ST-E2 wireless flash controller has built in focus assist lights and is much lighter than a flashgun. It can also be used to control several off camera flashes (its main purpose).

ditpaintball

Or just use the flash light as it is dark? Bounce it off the roof or set it to manual and its lowest power?

tommyl2010

Just tried what Al said wit the canon 430 exii and it works excellent just go to menu>external speedlight control>flash function settings> and set fire flash to no! very handy

Googled about a bit, seems the Metz 48 AF-1 doesn't offer the option to turn off the flash.

Hecklar

If its a Nikon you can defo do it. just go to flash settings, commander mode and set the flash to "--" instead of TTL or M.

couldnt tell ya as far as other camera's go, maybe someone else will have a solution.