580 EX II (E-TTL II) Pre-Flash

I'm a newbie, so forgive me if this is a dumb question. I've already checked various threads and I can't seem to get the answer:

My husband just bought me a 580 EX II flash to go with my XT. I wasn't getting very good flash coverage from the pop-up. I was told to leave the flash in E-TTL mode until I developed my skills in flash photography. According to the manual, there is supposed to be a "pre-flash" to allow the lighing to be evaluated, and then the actual flash when the picture is taken.

My question is, how do I know if the pre-flash is working? I don't see two flashes. I see a red flash, but not a bright white pre-flash. I have tried the flash on both auto modes (P-Program, and also the green square). Is there supposed to be a true flash, or just the red flash that I see??

Thanks so much..

the pre flash comes so close right before the main flash that they look like one flash... you can see a pre flash when you do flash exposure lock... the red light that you see is the focus assist lamp...

That is not pre-flash , it is red beam measure distance from the flash to the object and bounce back .

Yes : Red beam from the flash .

If you look through your viewfinder and take a shot with the flash the flash you see through the viewfinder is the pre-flash; the metered flash you won't see because the mirror will be up.

Otherwise.. set your flash to second-curtain sync and set the exposure to a second or so; you'll see two flashes, one immediately before and one at the end of the exposure. The first is the preflash.

If you're getting nicely metered flash-lit shots you can be assured that the preflash is working correctly


The red flashes are the AF assist beams.

Jim G wrote in post #4480125
If you look through your viewfinder and take a shot with the flash the flash you see through the viewfinder is the pre-flash; the metered flash you won't see because the mirror will be up.

Otherwise.. set your flash to second-curtain sync and set the exposure to a second or so; you'll see two flashes, one immediately before and one at the end of the exposure. The first is the preflash.

If you're getting nicely metered flash-lit shots you can be assured that the preflash is working correctly

The red flashes are the AF assist beams.

How do I set the flash to "second-curtain sync"?

If you know your working distance steady (6-10 feet) in every shot and set your flash to Manual 1/4 or 1/2 power ...your photo will come out perfect everytime .

You have to learn to use in Manual ....don't trust ETTL .

Jim G wrote in post #4480125
If you look through your viewfinder and take a shot with the flash the flash you see through the viewfinder is the pre-flash; the metered flash you won't see because the mirror will be up.

If you're getting nicely metered flash-lit shots you can be assured that the preflash is working correctly

The red flashes are the AF assist beams.

Thanks Jim. ... I do see a flash through the viewfinder, and now that you have explained it, it makes total sense that the actual flash occurs while the mirror is up!!! Duhhhh! Also, my flash images are WAY better than they were with the pop-up flash. You've made me feel a lot better. - I thought the E-TTL wasn't working, but obviously it is. THANK YOU !!!

QX56 wrote in post #4480176
If you know your working distance steady (6-10 feet) in every shot and set your flash to Manual 1/4 or 1/2 power ...your photo will come out perfect everytime .

You have to learn to use in Manual ....don't trust ETTL .

I will try setting the flash to manual 1/4 or 1/2. Thanks for the suggestions. This flash has so many buttons, dials, custom functions, it is just overwhelming. I wanted my husband to bring it back because it seemed so much harder to use than the pop-up flash.

But I think I will like it after I try your suggestions and get used to it.
Thank you so much!!

QX56 wrote in post #4480176
If you know your working distance steady (6-10 feet) in every shot and set your flash to Manual 1/4 or 1/2 power ...your photo will come out perfect everytime .

You have to learn to use in Manual ....don't trust ETTL .

Unfortunately, it's not as simple as that. Not only is the flash lighting affected by the flash-to-subject distance and the flash output power but it also depends on the aperture used and the ISO setting. So, pictures taken using one aperture and ISO setting may come out perfectly but not necessarily when other combinations of aperture and ISO are used. So, for completeness, you should also specify the aperture and ISO you've been using to get those perfectly exposed pictures.

I haven't used an XT before. I'm assuming it has FEC. That's your flash exposure compensation. If it doesn't, it doesn't matter, the flash has it. If you are shooting indoors don't point the flash at your subject. The best thing about an external flash is bouncing it off of something like a nearby wall. I even point my flashes behind me sometimes. Two real quick things, if you subject has a lot of light colors in it, like white, add FEC, +1 or so. If you subject has a lot of dark colors, like black, subtract FEC, -1 or so. If you don't use it now, start using the histogram to verify exposures. Those simple things will take you a long ways with using ETTL flash.