AE/AF Lock, Lens changing, and other n00b questions

[NeoteriX]

I've got about half a year of digital photography experience shooting with my Canon S1 IS, an excellent beginners camera BTW, and have gotten very comfortable with it. I'm very excited to move up to the Rebel XT, but am having to relearn a couple of the ways I approach shots.

The S1 IS only has a single center focus box (that you can move around, but its inconvinient), so in order to compose my shots better, I would center on the subject and focus with the half press, and depending on how well the autoexposure was set, either use that halfshutterlocked AE or lock the focus (seperate buttons on the S1 for AE and AF), recompose, half shutter again to get a new AE and then shoot.

I'm trying to duplicate this process on the XT, and I'm not actually sure how to procedurally do this. (I've decided on using the center point AF versus the auto AF, but I'm slightly confused about the difference between one shot and ai af, especially when you've chosen the AF point) For one thing, although it says it on the manual, it seems that when I half shutter press, it does not lock on the AE -- I can half shutter press, move to a bright object and watch the exposure settings change in the HUD. I've also tried the various custom settings to varying degrees of success, but haven't quite found something as seemingly easily as the procedure I used with the S1.

Lastly, I'm kind of curious how you guys deal with lens switching. It's like a huge juggling act for me since I"m trying to remove lens caps and all that stuff, and I'm not sure which has priority in terms of keeping the dust out. Should I get the lens on immediately or the caps on or what?

TIA~

[D Thompson]

Lastly, I'm kind of curious how you guys deal with lens switching. It's like a huge juggling act for me since I"m trying to remove lens caps and all that stuff, and I'm not sure which has priority in terms of keeping the dust out. Should I get the lens on immediately or the caps on or what?

TIA~
I always keep the front lens cap on unless I'm shooting or will be shooting very shortly. You should have a spare rear cap in your bag. I take the lens off & put the spare rear cap on. Old lens is capped both ends. Remove rear cap and put lens on camera. Rear cap goes in bag for next switch. I also try to keep my 20D pointed down as much as possible in this process and my back to the wind.

BTW - I don't use any protective filter on my lenses anymore, so I have to be a little more anal about the front cap than I used to be :D

Hope this helps.

Dennis

[TheObiJuan]

I've got about half a year of digital photography experience shooting with my Canon S1 IS, an excellent beginners camera BTW, and have gotten very comfortable with it. I'm very excited to move up to the Rebel XT, but am having to relearn a couple of the ways I approach shots.

The S1 IS only has a single center focus box (that you can move around, but its inconvinient), so in order to compose my shots better, I would center on the subject and focus with the half press, and depending on how well the autoexposure was set, either use that halfshutterlocked AE or lock the focus (seperate buttons on the S1 for AE and AF), recompose, half shutter again to get a new AE and then shoot.

I'm trying to duplicate this process on the XT, and I'm not actually sure how to procedurally do this. (I've decided on using the center point AF versus the auto AF, but I'm slightly confused about the difference between one shot and ai af, especially when you've chosen the AF point) For one thing, although it says it on the manual, it seems that when I half shutter press, it does not lock on the AE -- I can half shutter press, move to a bright object and watch the exposure settings change in the HUD. I've also tried the various custom settings to varying degrees of success, but haven't quite found something as seemingly easily as the procedure I used with the S1.

Lastly, I'm kind of curious how you guys deal with lens switching. It's like a huge juggling act for me since I"m trying to remove lens caps and all that stuff, and I'm not sure which has priority in terms of keeping the dust out. Should I get the lens on immediately or the caps on or what?

TIA~

With the XT using the default settings, after you half press the shutter, use the * button to lock the exposure. I find this only works if you don't refocus using oneshot. If you have AI Servo, then its fine. I have custom function 4, I don't know what it corresponds to on the 350D anymore, where I have the * button focus, and the half pressed shutter act as AE lock. If I want to re meter it, then I just repress the button. As long as I push the * button, it focuses, in AI Servo. In one shot, I just re push it. If you don't push the shutter half way, the camera will automatically meter and keep changing it in anticipation of you wanting to snap away. This may drain battery power but I never noticed a difference.