I'm not sure why I wouldn't use the shutter to focus. I like it. : )

The focus isn't hunting or I'd know the problem : P. It locks on quickly and locks on a little off : /

SMILEY FACES ~ !

You should listen to advice from some one that knows what he is talking about. Canon would not send a lens out the factory with 5-10cm of back focus, all lenses go through a rigorous testing ritual before leaving the factory, 1-2 mm maybe but nothing that severe. Try manual focus if you are struggling with af.


Quote from google source :
Easier to lock focus
If you are shooting something like a series of portraits of a person, and you want them composed off-center, back-button AF makes it super-easy to take as many pictures as you want. Focus on your subject by pressing the rear button (more on which button later in this article). Once in-focus, take your thumb off the rear button. Re-compose the shot to move your subject off-center. Shoot as many pictures as you like. With focus activation removed from the shutter button, you now can fire any time you like, and remove your index finger from the shutter button after a shot is taken. No matter what, the camera makes no effort to re-focus when you press the shutter button half-way down again.

Easier timing of shots
Similar to point number one above, but yet another benefit of pulling focus away from the shutter button is that critical timing becomes simpler to manage. For example, if you were shooting a speaker at a podium, he or she might periodically look up or make a gesture that would be an ideal instant to capture. If you’ve focused with back-button AF, your index finger is free to shoot at the decisive moment. There are no worries about holding your finger half-way down and waiting, waiting, waiting in that position for your subject to do something interesting.

Even with a very animated subject that may be moving around, you can have your camera’s focus set to AI Servo AF (to track any movement), and just keep your right thumb on the back button to keep focus active, while your index finger can be ready to shoot with no worries about also preserving focus.

Less risk of focus errors with moving subjects
For sports photographers and others taking action pictures, back-button AF lets you stop focus whenever something might interfere with the moving subject you’re tracking — without requiring you to stop shooting. In sports, for instance, it’s common for a referee or another player to come between the camera and an athlete being photographed. With back-button AF, it’s easy to momentarily pull your thumb off the rear button, and you can still keep shooting by pressing the shutter button fully. The camera instantly stops focusing when your thumb comes off the back button. Once the obstruction is out of your way, you can immediately pick-up your primary subject by pressing your thumb on the back button again.

Easier over-riding of AF with full-time manual focus
More than half of Canon’s lenses have a neat feature called full-time manual focus*. Even if the lens’s AF/MF switch is in the AF position, these lenses allow the shooter to instantly adjust focus manually by simply turning the focus ring on the lens. There’s no need to first move the switch to MF.

With back-button AF, this becomes a nearly foolproof feature. Use the autofocus whenever you like by pressing the rear button with your right thumb. Shoot whenever you like by pressing the shutter button. And if you want to touch-up focus, or totally over-ride what the AF is doing, just pull your thumb off the rear button and turn the ring. No matter how many pictures you shoot, pressing the shutter button will not cause the AF to try to kick-in and re-set the focus you just adjusted manually.

Easier macro and close-up focusing
Many times, you’ll find that it’s actually easier to get consistently sharp close-up pictures of small objects by pre-focusing, and then moving yourself forward or backward until you see the critical sharp focus appear in your viewfinder. Once again, with back-button AF active, you can use the AF to get within general range (press the rear button with your thumb, then take your thumb off the button), and move a little bit to get things critically sharp. Most important, you can then shoot freely, without AF trying to re-focus each time you touch the shutter button. Finally, touching-up focus with the full-time manual focus feature on certain Canon lenses is simple and quick, and the autofocus never fights you by trying to un-do what you just adjusted.

Christ, i didn't expect that dense of a response wezman. You're basically telling me if someone gives me advice to take it, even if it has nothing to do with my issue. Talk about ignorant. Af lock is absolutely unnecessary for a still well lit shot of a static subject. The reason I'm being so hostile is based on how smug you came off with that statement.

Like I said, I am having focus issues and I'm not a fucking retarded photographer. I know how to focus the camera. I only use Af lock when I have to.

Maybe I should rephrase: either my lens is inaccurate at focusing, or it has a backfocus problem. This is not user error. Where do I go from there.

This post was edited by Canadian_Man on Sep 6 2013 04:16pm

It has everything to do with the issue. I'm knocking off, one by one, common issues that people have with focusing. You've had a camera for one month, you might know how to press a few buttons because you've read x on that forum and watched y on youtube but experience can be also helpful in identifying problems, you just don't have it.

It sounds to me it is simply missing because you are doing something wrong, the light isn't quite right or your camera/lens combination just isn't that great at AF. Maybe if you would just post a picture of the problem images it would help greatly!

Try keeping those shitty responses/attitudes out of here, we are a friendly bunch

I had issues with focusing awhile ago with my 35mm 1.8 lens on my D5100, but I think my issue was the lighting, shutter, etc., but I've since corrected that by learning more. I never considered really messing with the ISO, and I'm not a fan of flash, but once I realized that was a big part of my issue, I was able to correct it.

I'm glad Wezman posted the info about AF lock. I never realized how well that could work. Should my manual have info on how to assign a button to AF lock? Would I be replacing the exposure lock with AF lock? If so, is it worth the trade-off?

AF lock and AF ON are great and a VERY useful tools. I'm a big fan, I couldn't imagine not using AF ON.

I'm not sure why Canadian Man dislikes it so much...

Shoot in manual and you don't need exposure lock. Set your meter to spot metering so it will detect what ever you point it. Set you button to AF lock, it should be in the custom settings. Also, your shutter button, change it to shutter only if it has that setting. I'm not overly familiar with the Nikon setup but I can't imagine it being too different from the Canon.

I'm going to PM you some questions I have, so this doesn't go off topic. =-]

It's essentially the same.

I realize all of this stuff (though it is good advice): I've already been implementing these things in my shooting.

I generally prefer aperture priority, even though I do come out with better shots in manual. That's why I generally don't use my AF lock button for AF lock.

Okay, then you need to show us the images so we can see what is happening. Just suck it up, no one is going to judge your girlfriend

Wasn't trying to be funny, i just hope you would take good advice, even if its not to do with the issues your having, no harm intended.