silly question (camera won't AF)

[Rjohn518]

Hi all

I've been reading and learning a great deal on this wonderful forum for the last year or so. I've also spent a lot of money based on what I've read. I recently acquired a Canon 100-400 L lens and LOVE it so far. However, since it is much bigger and heavier than any other lens I have, I am finding it a bit difficult to zoom, stabilize and focus simultaneously. I usually use manual focus for what I usually shoot, namely landscape, macro, portrait and wildlife. Problem is, I've forgotten how to reset auto focus...:o I've looked at custom functions but don't see it there. The lens switch is set to auto focus, but it won't work. I have the same problem with other lenses, so I'm sure it's me, not the new lens. I have the center point selected, where I usually leave it.

I know this is a silly question. Can anyone give some guidance?

Thanks for your help

Bob

[Mogwyth]

Hate to be the one to say this but if you are switched to Auto focus and nothing is happening then there may be a fault with your camera. Have you tried cleaning the camera to lens contacts?

[Rjohn518]

Oh no! I never even thought of that. I've had the camera for just about a year and it has performed flawlessly for me. Never even thought that there might be a problem with the camera--it is usually me that needs refining. I have checked the contacts and they seem to be clean. I will do a search for the best way to clean them. Any other suggestions?

Bob

[CyberDyneSystems]

If switched to Aouto on the lens,. then the lens should AF either by half pressing the shutter release,. or by pressing the * button with your thumb... if you have CF 4 set to 1,.. (as you should ;) )

[Rjohn518]

Yep...that's where all my settings are, although I forgot the * button trick. Like I said, I almost always use manual focus so the possibility that the camera might be at fault didn't occur to me.
Darn--just when I was getting ready to test out the 100-400 lens. Well, once I figure out what the problem is, I'll re-post. Maybe I'll try posting some pics from the new lens, too.

[Marshall]

Clean the contacts with an ordinary eraser as used to erase pencil,making sure you blow away any residue afterwards.

[Rjohn518]

Thanks, Marshall--you saved me from having to search on how to clean the contacts. That's what I remembered. I did clean the contacts, but still have no auto-focus. I noticed that when I push the * button to focus, the focus square lights red, but not when I half-depress the shutter button. Isn't the focus square supposed to light up when either of those is pressed?
Meanwhile, it may be time for a visit to the (dreaded) owners manual, or even the Canon site...
Thanks for the ideas so far.:)

[CyberDyneSystems]

I noticed that when I push the * button to focus, the focus square lights red, but not when I half-depress the shutter button. Isn't the focus square supposed to light up when either of those is pressed?
Nope,. It's one or the other,. but not both.


Godd news is this may be the whole problem :) Ie: no problem at all. :)

Whith the 10D and most Canon SLR's you can set it to focus with either the shutter button or the rear * button. To change this setting you use custom function "4"

Your camera sounds like it is set to either CF 4-1 or CF 4-3... in both cases AF works with the * button.

For many of us this is the preferred method for AF.

Did you buy the camera used?
The previous owner may have left it set up as CF 4-1... I have done this exact same thing to two peopl in the past when I sold my 1D and 10D :lol:

Anyway,. try it out using the rear * button,. if you can't get used to it go back to shutter AF by switching custom function 4 to "0"

[Rjohn518]

Thanks to all for the suggestions! I think I finally got it figured out.
In the past I had custom function 4 set at 0, which is just what I preferred, and the camera focused automatically. However, I prefer manual focus for many things, so I changed it to CF 4-1. Interestingly, for the last week or so, AF wasn't working on either setting or either button. This morning, I changed CF 4 from 1 back to 0, and now all is working...go figure.
By the way, after the great suggestions here, I think I do like CF4-1 better--it lets me manual focus as I want without trying to override me, even if the lens is set to AF. But I can still AF with the * button if necessary. Does that sound right? I really like this setup.
Oh, and the Canon 100-400L IS USM is an awesome lens! Thanks to all who have so glowingly recommended it.

Bob

[ScottE]

You've got it. CF 4-1 or CF 4-3. Now set you AF type to AIServo. That way if you hit the * once you get one shot autofocus. If you hold the * button down you get continuous predictive autofocus. If you don't touch the * button you have manual focus. This gives you instant choice of how you want your camera to behave.

Scott