digital rebel question(s)

[inky]

Two questions:

One review site says this:

I will say that I'm not a huge fan of using the flash as the AF-assist lamp -- sure, it works great, but it always takes a flash picture, which sometimes I don't want to do.


what exactly does this mean and do?

and can someone tell me, would the lenses i buy to use on the digital rebel work on the 10d or any of the canon 35mm film cameras?

someone told me that the lens that comes with the kit will NOT work with other canon cameras, but if i buy the body only and a lens separately, that will work okay with other cameras.

i'm totally confused.

[Michael Fanelli]

Two questions:

One review site says this:

I will say that I'm not a huge fan of using the flash as the AF-assist lamp -- sure, it works great, but it always takes a flash picture, which sometimes I don't want to do.
what exactly does this mean and do?

Most AF systems use contrast to determine focus. A focus assist lamp uses a beam of light (or infrared) to read distances. The flash uses a beam but only when it's turned on. When flash is not used, the camera's normal AF system is used.

...can someone tell me, would the lenses i buy to use on the digital rebel work on the 10d or any of the canon 35mm film cameras?

All EOS EF lenses can be used on Canon film or digital cameras. All third party lenses "for Canon" can be used on all Canon film and digital cameras. The very special EF-S lens that is the "kit lens" for the Digital Rebel can only be used on that single camera. The kit lens is actually very good for $100 but won't work on anything else.

[inky]

Most AF systems use contrast to determine focus. A focus assist lamp uses a beam of light (or infrared) to read distances. The flash uses a beam but only when it's turned on. When flash is not used, the camera's normal AF system is used.

i'm still confused. can you dumb it down a little for me? the reviewer was saying it took a flash picture even when he didn't want it to. is that correct?

[opus]

In certain automatic modes, it will try to use a flash even if you don't want it to. For instance, in the automatic Macro mode, it will pop the flash in low light situations. I don't think there's a way to turn it off in some of those automatic modes. But you can choose "never flash" mode if you still want an automatic mode, or you can go over to the manual side which, I BELIEVE, won't give you a flash unless you force the flash. (You're in complete control on the manual side.) There's a button to force a flash even when the camera doesn't think it's needed.

[wburychka]

i'm still confused. can you dumb it down a little for me? the reviewer was saying it took a flash picture even when he didn't want it to. is that correct?

The 300D needs light on its subject in order to focus. If the existing light is too low, the camera needs an assist--it needs more light on the subject, so to say. The way your DRebel does that is with a flutter of low level flashes from the built in flash--if it is popped up. Of course, if the flash is up, the camera assumes you want to take a flash picture, so when you press the button halfway, the flash flutters, the lens focuses, and then when the button is depressed the rest of the way, the flash fires and you take a picture.

The reviewer was saying there is no way to get the focus assist without also firing the flash for the picture, and he was correct. Some cameras use an LED to provide focus assist to the camera. Sony is probably the master of low light with its red matrix focus light. Most mid to upper price range external flash units include a red focus assist light as well, although the reviewer in question would doubtless have the same objection to them--you can't get the focus assist without taking a flash picture. Not easily, anyway. Theoretically, you could half-press to get the focus light and focus, then switch the lens to manual focus and switch off the flash and take the picture--assuming your subject is still there.

Canon also sells an infrared flash triggering device for Canon flash units used off the camera, and I believe that remote control unit includes the red focus aid just like the Canon flash units. Of course, that remote control costs more than some Canon flash units and so may not be economically feasible as a focus aid.

All cleared up? It gets easier, although when I started taking SLR pics, I had only shutter speed, aperture, and a focus ring--all manual with a viewfinder indicator of exposure. The microprism spot in the center of the Canon FT focus screen made focusing a breeze, though.

[nickamado@sbcglobal.net]

If you're using fully manual settings in low-light situations, and you want to use autofocus, you can

1: force the flash,
2: depress the shutter button halfway, let the flash flutter help the lens determine the focus and,
3:with your finger still holding the shutter button and locking focus, click the flash down and take a picture.

This way the flash helps you autofocus and the flash doesn't fire, because it never does in manual mode (unless you want it to.)

naturally, in such low-light situations you'll need a tripod and a long exposure time and, ideally, a static subject.