How to to bracketing on Aperture priority camera

khushi2004 · Mar 13, 2004

I am a beginner, i hv bought one camera it is canon AV1 which is aperture priority camera for my lesson. But now i hv got problem to bracket.
My requirement is to take picture in correct reading and then over and under expose inceresing and decresing 2 stops, but in my camera when ever i change my aperture speed it will change its shutter speed automaticly in view finder so it is making hard for me to bracketing.
Is there any ohter option so that i can do bracketing by this camera. Regards

oriecat · Mar 13, 2004

Isn't there a way to turn the aperture priority off, so that you can do it all manually?

markc · Mar 13, 2004

The AV1 doesn't have manual mode, just Av, Bulb, and 1/60.

You can bracket by changing the film speed setting. Set it for a higher ISO to underexpose, and a lower ISO to overexpose. I think that's the only way with that camera.

khushi2004 · Mar 13, 2004

Yha MArkc u r rite.
After reading manual instruction i came to know there is only 1 way to bracket is by changing its film speed.
I am curious to know know that i hv never tried this b4, by bracketing changing film speed does this produce the picture what i am looking for bracketing by 2 stops up and down.
Please suggest me how should i do by changing film speed?
I know if i am using 400 film i hv to do 300, 200 and 500 and 600.
But i am worried bout the product how it produce.
I hv to take some picture in sunlight by bracketing.
Please suggest me! so that i can produce what i looking for.
Regards

markc · Mar 13, 2004

I hate to be rude, but... I have a hard time reading chat shorthand. I'm a visual thinker, and it all looks like a jumble to me. I have to sit there and sound it out to make any kind of sense to it.

Anyway, I don't own the camera, so I can't be of help with how to change the speed. You will have to check the manual.

From here:

Q:Why do the speed numbers seem to increase in odd increments, e.g. 25, 40, 50, 64, 80, 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, and 1600?

A: While this appears strange, it really is very logical. Each step represents an increase in speed that is equivalent to 1/3rd of a camera exposure stop. A change of 1/3 of a stop in camera exposure is generally considered to be the smallest, noticeable change in exposure.

So if you are using 400 speed film, setting the camera to ISO 100 would be overexposing by two stops. Setting it to 1600 would be underexposing by two stops. Taking the same picture at each of these film settings would give you a 2-stop bracket of the image: one at ISO 100, one at ISO 400 (the real film speed), and one at ISO 1600.

drlynn · Mar 13, 2004

I also have an AV-1 and that is the only way to bracket.

To expand Markc's explanation, to change your exposure by 1 stop requires you to double or halve the light hitting the film. On a manual camera, you can do it 3 ways: shutter speed, f-stop or film speed.

On the AV-1, your only choice is the film speed dial. So, lowering your film speed by 1/2 would reduce by 1 stop. Halving again would take you down 2 stops total. So from ISO 400, 200 would be -1 stop and 100 would be -2 stops. In the other direction ISO 800 would be +1 stop and 1600 would be +2. The list of ISO speeds Mark gave you is a very good reference to keep handy. As he said, each step up or down the list is a change of 1/3 stop.

The film speed dial on the AV-1 has 2 dots between the 100,200,400 etc settings. These correspond to the list Mark gave you.

Good luck with your class.