Hi, I have a rebel 2000 camera. I am not a well versed photographer and hence have some doubts. when i used the camera in Tv(shutter speed priority) mode and aim the camera(auto focus mode of the lens) and press the shutter release button half way down, then i see the exposure reading at 0 in a scale of -2 to +2. This will be the reading when the flash is not lit. so does that mean when the reading is at 0, i can still get correct exposure without the flash.

or how does using a flash affect the exposure.. or how will i know, what exposure do i need when i used the flash.

Thanks, vishwanath

-- Vishwanath Somashekar (dagarshali@yahoo.com), February 25, 2002

Answers

If the exposure scale reads 0, then the exposure itself (shutter speed and aperture) is correct--with or without flash. If it is not zero, you need to adjust aperture or shutter, else you will be under (-1, -2, etc.) or over (+1, +2, etc.) exposing.

For the most part, if you set a "reasonable" shutter speed, say anywhere from 60 in low light to 500 in bright light, the appropriate aperture will be available and the shot will be correctly exposed. If you use shutter priority (TV mode) like this, you are telling the camera to choose the narrowest possible aperture (at your given shutter speed).

For flash, it gets complicated, as different picture-taking modes affect the overall exposure differently. For best results, just put the camera in P mode when you use flash. The camera will choose aperture and shutter values and flash output to illuminate your subject and make it stand out from the backgroud.

Also, to learn about the relationships between shutter and aperture values, put the camera in P mode and focus on the subject. Now turn the little wheel with your right index finger. You will watch the shutter speed value get faster (higher numbers), while the aperture value gets wider (smaller numbers). Turn the dial the other way and the reverse happens. These two factor determine how much light hits the film--so they always work in relation to one another.

Good luck!

-- Preston Merchant (merchant@speakeasy.org), February 25, 2002.

Since your question is essentially about flash photography you may find my flash photography article to be of interest:

http:// teladesign.com/photo/eos-flash/

As a side note, perhaps next time you post you could put a more informative subject line. "About taking picture" says nothing about your actual question. A more specific subject line such as "How does flash use affect exposure?" will help people scan the list of subjects more easily.

-- NK Guy (tela@tela.bc.ca), February 25, 2002.

Hello Vishwanath,

Contrary to the premise in your question, the scale at the bottom does NOT indicate an exposure reading. Rather, it is the scale for your exposure compensation. It will always show "0" unless you adjust it to suit your scene.

On your EOS REBEL 2000, Tv is an automatic exposure mode. This means that the camera will attempt to choose a lens aperture that should give a correct exposure. If correct exposure is not possible, the aperture indicator will flash.

Flash is metered with a completely different sensor, and will automatically adjust the flash power so long as you shoot within the suggested shooting range.

If you are not sure of what to do, choose the Green "Full Auto" mode and concentrate on getting your subjects to fill most of the frame. Hope this helps.

-- Julian Loke (elan7e-owner@yahoogroups.com), February 25, 2002.

My confusion . . . what I said about the exposure scale would be true only if you were shooting in full manual mode. Right, Julian?

-- Preston Merchant (merchant@speakeasy.org), February 26, 2002.

Hello Preston

Yes, the metering display obtains in "M" mode on the camera (not the flash). I believe that the high end EOS bodies (EOS 3, EOS 1V, and EOS 1D) have a double-dot display which can show ambient metering with one dot, and flash metering with another dot.

-- Julian Loke (elan7e-owner@yahoogroups.com), February 26, 2002.