robrory Loc: Coatesville, PA

This is not a question about the use of back button focusing or how it is done. I currently have my 50D set up for it and use it. I also own a 5D and want to know if it is possible to do this on that box as well.

tsilva Loc: Arizona

Yes

robrory Loc: Coatesville, PA

Could someone direct me as to how to set this up?

tinplater Loc: Scottsdale, AZ

5 second google got this...
https://www.youtube.com/watch?v=B0c9PrYZe14

mwsilvers Loc: Central New Jersey

Wrong camera but her advice is probably the same. There is no AF-On button on the 5Dc so the * button will have to be used and custom functions need to be modified as indicated below.

04 SHUTTER BUTTON/AE LOCK BUTTON. Usually set to 0:AF/AE lock. Pushing the shutter button half way locks both autofocus and exposure. If I want to separate the two, I set this to 1:AE Lock/AF so the star (asterisk) button on the back of the camera locks focus on the subject, I recompose, and the shutter button locks exposure.

RichardTaylor Loc: Sydney, Australia

See page 156 of the instruction manual
It's under custom function 04
The wording is confusing.
(I have never used it on my 5D)

The Canon USA web site also has an article on it which may help.

Dds82

Yes correct.....but is this not same as setting cam to Manual focus?

amfoto1 Loc: San Jose, Calif. USA

I don't have a 5D classic but have used numerous other models that have the same controls and always use them with BBF.



This is correct (with some minor edits... underlined)...

HOWEVER, I really don't recommend using the option 1. setting most of the time. That will cause you to get AE Lock on every shot you take, as soon as you half-press the shutter release button. Though you might want AE Lock occasionally, it is usually not a good thing to use AE Lock all the time.

Instead I recommend you normally set C.Fn 4 to 3. AE/AF, No AE Lock. This gives BBF while also allowing the camera to change auto exposure settings even when the * button is being pressed to run auto focus and the shutter release is half-pressed (in other words AE "unlocked" ). This way you can still get a correct exposure when you track a moving subject from one light condition to another (if using the other setting and locking AE in the first light condition, the exposure in the second condition would be incorrect).

As a result of using this setting instead, on these older models without an AF On button, you don't have direct access to AE Lock function. However, when you want AE Lock, you always can go into the menu and change this custom function to option 1. But, what I usually do is simply switch the camera to M mode and set all the exposure parameters manually myself. That's faster, easier than changing the custom function and gives the same result as AE Lock.

In fact, even on later camera models with an AF On button (including 50D), I swap the function of the that button and the * button for a couple reasons. One is because I'm in the habit of using the * button from having done so for so many years on cameras without the AF On button. But the main reason is that the * button is larger, more prominent and closer to my thumb... and I AF every single shot (with BBF), while I only occasionally use the AE Lock function. (This also may be necessary if using the BG-E2/E2N battery grip on 40D or 50D, because the grip doesn't have an AF On button, since it's a carryover from models that didn't have that button: 20D and 30D.)



Not at all... AF still works, as always. However, now it's been reassigned to the * button on the rear of the camera, putting the photographer more in control of when and where the camera focuses... and when it doesn't, simply by lifting pressure off the button.

One of the big benefits of this is the ability to use AI Servo focus mode as your default setting... for both still and moving subjects. This way you can be ready for anything, not fiddling around changing focus modes if a subject starts or stops moving, for example. Without BBF you wouldn't want to use AI Servo all the time because there are situations when it will mess up your focus (such as when using Focus & Recompose technique). But with BBF set up all you need to do is lift pressure off the button to stop AF... and can still take your shot regardless of whether AF is running or not.

There are other benefits to using AI Servo as your default setting, now that you've set up BBF. For example, many modern zoom lenses are varifocal designs, that don't maintain focus when the focal length is changed. This design costs less to make and is generally less complex than parfocal zooms, that do maintain focus when zoomed. If using One Shot focus mode with a varifocal zoom, you need to remember to re-focus the lens every time you change the focal length (done by lifting your finger off the button, then reapplying it). If instead using AI Servo, the camera will instantly correct focus automatically, including when a varifocal zoom's focal length is changed.

It's a lot more complicated to describe all this than it is to actually do, after just a little practice.

PixelStan77 Loc: Vermont/Chicago

You all set up?

mwsilvers Loc: Central New Jersey

Not having a 5Dc myself, I copied that reference from another site where someone with a 5Dc was describing setting up BBF. Frankly, I didn't review the setting in detail. My bad. :-(

amfoto1 Loc: San Jose, Calif. USA

Not "bad" at all... In fact your answer is correct and that's probably how most people tend to set up BBF initially. I know I did. But after seeing a lot of exposure errors occur because it forces using AE Lock on every shot, I pretty quickly figured out what was wrong and started to use the 3. option of the C.Fn instead.

flyguy Loc: Las Cruces, New Mexico

It's exactly the same way that you set up your 50D.

sirlensalot Loc: Arizona

Only focus set up I use on mine. Google or youtube for your reward.

markngolf Loc: Bridgewater, NJ

It is on the Canon 5D M III. What 5D model do you own?
Mark

robrory Loc: Coatesville, PA

Canon 5D classic. Original.