50D custom functions?

I've just been looking through the custom functions on my 50D to see if there's a way of setting up a button to switch between AI servo and One-shot and some of the shutter button/AF-ON button options are confusing the hell out of me!

Apologies if it's a dumb question but can anyone explain what C.Fn IV-1 option 2 (Metering start/Metering + AF start) actually does?

If I've got the right order

that enables metering by half pressing the shutter and metering and AF on pressing back button.

From the Canon Learning Centre
Back-button AF activation. Shutter button no longer activates AF, but of course fires the shutter. Metering is continuously updated — if you shoot a sequence of pictures, the camera takes a fresh meter reading for each one. There’s no locking of exposure, unless you separately press the AE Lock button (this last item is not possible on some EOS models).

Complete description of all possible selections can be found here on page 3
http://www.learn.usa.c​anon.com …ckbutton_af_art​icle.shtml

The actions on the left side of the slash dictate what the shutter button does, and the actions on the right side of the flash dictate what the AF-ON button does.

(Metering start/Metering + AF start) = Camera begins metering and or adjusting shutter speed/aperture (depending on if you are in av or tv) In manual it will just meter. / camera will start metering and focus when AF-ON is pushed.

I found this link helpful for me to understand what each of the settings on CFn. IV are for on the 50D:
http://jefflynchdev.wo​rdpress.com …friday-back-button-focus/

Hope it helps you as well.

John

Thanks all... those links made it easier to understand than the manual!

AFAIK, only the 7D has a dedicated or assignable AI Servo/One Shot button.

Do you use the Quick Control Screen (toggle to it with the Info button)? With some practice you can change the setting pretty quickly using the QCS. Also, if you wish you can assign the Set button to call up the QCS while shooting. To do so set C.Fn IV-3, option 5 "Quick Control Screen". That way the QCS can be called up with either thumb. (Personally I have the Set button assigned to call up Image Review instead, so I can use either thumb to take a quick peek at the histogram or check composition, focus. This because I have automatic image review turned off and only spot check occasional images as I'm shooting. I find auto display of image review distracting and it uses up battery power quite a bit faster, reviewing every image.)

Alternativel, you might want to go read http://www.learn.usa.c​anon.com …ckbutton_af_art​icle.shtml and try using Back Button Focus.

Using Back Button Focusing with AI Servo, it's not really necessary to switch to One Shot all that often. You can simply lift your thumb off the button to stop focusing, so it's a lot like using One Shot. You might want to give this a try. It only takes a little practice to get in the habit of "thumb focusing". BBF - especially when using a single, manually selected AF point - puts you in control of the point of focus, rather than leaving it up to the camera.

Occasionally when focus is really critical, you still might want to switch to One Shot (the switch is done in the usual way, with the top button and main dial... but you continue using the button on the back of the camera to actuate focus).

If using a BG-E2 or E2N with 50, 40, 30 and 20D and using BBF, you might want to swap the function of the * button and the AE On button. This because the grip doesn't have an AF On button, but it does have a * button and doing this swap you will be able to focus with the camera and grip in either landscape or portrait orientation.

I use BBF most of the time and had my 50Ds and grips set up this way. C.Fn IV-1, option 2 "Metering start/Metering + AF Start" and C.Fn IV-2, option 1 "Enable".

Thanks for the reply amfoto... The main reason for wanting to switch between AI servo and one shot is for shooting equestrian events, I use BBF with AI servo for shooting the action but then if I want to get a shot of something static I can't lock focus and recompose in AI servo. The answer is simpler than I thought, I just need to set it so the shutter button doesnt auto focus!

Hopefully Ive explained that properly, it made sense in my head anyway!

binliner wrote in post #12793922
Thanks for the reply amfoto... The main reason for wanting to switch between AI servo and one shot is for shooting equestrian events, I use BBF with AI servo for shooting the action but then if I want to get a shot of something static I can't lock focus and recompose in AI servo. The answer is simpler than I thought, I just need to set it so the shutter button doesnt auto focus!

Hopefully Ive explained that properly, it made sense in my head anyway!

Yes, that's the way I do it. I actually hated back button focus at first because I kept forgetting. I ended up switching it back. After shooting with it for a little while and finally getting the hang of it, I decided to keep it that way.