Custom funtion 4 and metering

Okay, I apologise in advance for this post as it's been covered many times before (and I've read about it many times before), but I'm still confused about the use of * focussing in a concert type situation.

To this point I've always used shutter button half press for AF/AE, and I'd really like to try using the * button, but there are a few concepts that I still just don't get. FWIW at this point I primarily use center AF point, spot metering, single shot focus, manual mode. I guess my goal is to learn more about using Av mode (and CFn. 4) effectively and efficiently.

I'm assuming that what most people do is use CFn 4 = 3 (AE on shutter, AF on *). I also assume (since most of us deal with low light) that the center focus point is being used. What confuses me is using CFn 4 with a focus/recompose or pre-focus (center AF) style shooting. It makes sense to me if Evaluative metering is being used. For instance, the shot is focused with *, recomposed, AE (eval) set with half press, then the shutter is released. Then there are the other metering modes. If using the center AF point, and a center weighted metering mode (partial, spot, average), what is gained by being able to separately set exposure and focus (unless in manual mode where you don't necessarily need to meter every shot)? Is it just a matter of learning to use Eval metering and maybe EC?

I suppose I could have just stated a 'what do you do?' type question, but I'd really like to know the how and why. It is entirely possible that I'm just making the wrong assumptions.

bacchanal wrote in post #2737293
If using the center AF point, and a center weighted metering mode (partial, spot, average), what is gained by being able to separately set exposure and focus (unless in manual mode where you don't necessarily need to meter every shot)? Is it just a matter of learning to use Eval metering and maybe EC?

Independent of the metering mode, there are two benefits:
a) you can focus on one part of the image and meter light from another part. This is sometimes useful, and I actually use this in evaluative mode (I meter and lock exposure from a part of the scene where no spots are hitting directly the lens, then recompose and THEN focus - it probably results to exposure that is a bit off, but sometimes compromises need to be accepted, and RAW helps a bit also when correcting bad exposure).
b) using servo focus, you can control exactly when you want the AF to search for focus. This basically lets you to either track movement (predictive focusing) or single shot -type focusing (just let go of the button after focus is achieved). You don't have to switch focusing modes, unlike you would have to if the shutter button would always start AF and you'd want sometimes to focus and recompose, and on other occasions to use continuous focus.

kmb wrote in post #2737549
Independent of the metering mode, there are two benefits:
a) you can focus on one part of the image and meter light from another part. This is sometimes useful, and I actually use this in evaluative mode (I meter and lock exposure from a part of the scene where no spots are hitting directly the lens, then recompose and THEN focus - it probably results to exposure that is a bit off, but sometimes compromises need to be accepted, and RAW helps a bit also when correcting bad exposure).
b) using servo focus, you can control exactly when you want the AF to search for focus. This basically lets you to either track movement (predictive focusing) or single shot -type focusing (just let go of the button after focus is achieved). You don't have to switch focusing modes, unlike you would have to if the shutter button would always start AF and you'd want sometimes to focus and recompose, and on other occasions to use continuous focus.

Thanks, both of your points make a lot of sense. I think your second point is what I wasn't quite grasping. I'd seen you mention the servo thing before, and that was really confusing me. I think the key point I was missing there was to let go of the freakin' button.

I'm confused now. How should I set CFn 4 again? If I set it to SERVO focus, it starts focusing when I press rhe * button, stops focussing when I release the button, and then I go on and release the shutter?

The brutal contrast of stage lighting makes metering difficult. So it behooves us to take control of the metering as much as possible. But there are several ways to do it.

The method I have settled on is to use CW average metering and adjust EC (sometimes a lot) to account for different backgrounds. This takes some practice to do well. When your subject moves from in front of a light colored backdrop to in front of a black curtain, the metering will change dramatically and will need to be compensated accordingly. With this method I use C.Fn. 4-3 so that the metering doesn't lock until the shot is taken. Theatre lighting changes often and I want to be able to keep shooting while the light changes.

Some people use partial or spot metering on the subject. It's not fool-proof, but it involves less guesswork if you are close enough to get your metering circle where you want. Generally you'll want to use C.Fn. 4-1 with this method, so you can lock metering by half-pressing the shutter, recompose and shoot.

Of course, all this is independent of focusing (the whole reason to focus with the * button to begin with). If you're shooting moving people, you'll want to use AI Servo and hold down the * button until you take the shot. I generally use the center AF point for single subjects, possibly swich to one of the others for shooting a couple, and use all AF points for fast moving groups.

krazziecliff wrote in post #2737633
I'm confused now. How should I set CFn 4 again? If I set it to SERVO focus, it starts focusing when I press rhe * button, stops focussing when I release the button, and then I go on and release the shutter?

I'm pretty sure that's the idea, and you can independently set exposure before or after focussing by using the half-shutter press. I think I'm liking CFn 4 set to 1 with the AE lock on the shutter. I'll have to see how it goes in practice though.

Cool...I just tried it. I think it takes a little getting used to, but its fantastic. Specially helps when you set the AF point on the multicontroller. Thanks you guys. I think i'm gonna keep this as my permanent setting.

My € 0.02

Mine is set to CFn4-3.
I don't want AE lock, as lighting is changng constantly.
(If light is constant, I can use M)
My 1D is set to spot metering on the active AF point (the face) or evaluative metering when in Av, with AiServo AF. When in M, I'm using partial.

When I use OneShot AF and Evaluative metering,you'll need to be careful, because AE will be locked, for as long as the '*' button is depressed. A little programming error (IMO) on Canons part.

Also worth remembering is, that Evaluative metering is 'weighted' around the manually selected AF point. Even when using CFn4, and not touching the '*' button.

I would probably never use CF 4-3 in a concert situation.

I use CF 4-1 so I can lock exposure on the exact part of the subject I want, and focus elsewhere if need be.

If you don't want to meter before taking the shot, then don't half press the shutter before taking the shot, and you can in essence have your cake and eat it too.. anytime you don;t want the locked exposure, just get your finger up off the half press to re-meter.

This is especially useful if you do use spot meter or partial. (I personally prefer partial)
Get the spot on the face or whatever your metering off of, half press, then shoot when you want even if the spot is now on the background scenery.

I tried C fn. 4-3 last night, and I think I'm forever changed. It did take some getting used to though. I'm left handed and shoot with my left eye, so there isn't much room for my thumb to move freely on the right side of the camera...but that is kind of par for the course being a lefty.
I didn't realize how helpful it would be to simply set the focus and lift my thumb off the button. It makes shooting quick manual bursts of hard to time shots (like clapping etc) an actual possibilty. I still found myself shooting manual most of the evening, but I think I'm getting a little better with AV + EC, though I haven't had much time to look at the images in post.

I'm reluctant to change any of the fine settings of the camera, going into a dark evening of concert shooting...

I use CF4 and spot meter on faces. BUT I keep urging people to bracket! Even as I prepare to shift to RAW shooting I already expect to continue bracketing, although a little differently. If you really, truly want to capture a good exposure under such dynamic conditions then bracketing is essential. Now please forgive me for doing exactly what I get upset about the RAW bigots doing by interjecting my own virtually unrelated bigotry, sigh.

DwightMcCann wrote in post #2756340
I use CF4 and spot meter on faces. BUT I keep urging people to bracket! Even as I prepare to shift to RAW shooting I already expect to continue bracketing, although a little differently. If you really, truly want to capture a good exposure under such dynamic conditions then bracketing is essential.

I was actually thinking about you and that the fact that you've mentioned that you bracket your exposures, as I was going over my Otis Day shots. I had a few captures that I really liked except for the fact that there were some glaring blown highlights that weren't recoverable (unless I can figure a way to do nice skin grafts with PS ). Had I bracketed, I would have been fine for those shots. Downside would have been a shortage of memory. So I picked up another 4gb card today. I'll be trying the bracketing next shoot.

bmoguy wrote in post #2756372
I was actually thinking about you and that the fact that you've mentioned that you bracket your exposures, as I was going over my Otis Day shots. I had a few captures that I really liked except for the fact that there were some glaring blown highlights that weren't recoverable (unless I can figure a way to do nice skin grafts with PS ). Had I bracketed, I would have been fine for those shots. Downside would have been a shortage of memory. So I picked up another 4gb card today. I'll be trying the bracketing next shoot.

Be sure to let us know how that works for you ... I couldn't shoot without bracketing!

bmoguy wrote in post #2756372
I was actually thinking about you and that the fact that you've mentioned that you bracket your exposures, as I was going over my Otis Day shots. I had a few captures that I really liked except for the fact that there were some glaring blown highlights that weren't recoverable (unless I can figure a way to do nice skin grafts with PS ). Had I bracketed, I would have been fine for those shots. Downside would have been a shortage of memory. So I picked up another 4gb card today. I'll be trying the bracketing next shoot.

If you can set your 20D, than I can set my 30D to do the same...Let us know what your settings will be.

DwightMcCann wrote in post #2756649
Be sure to let us know how that works for you ... I couldn't shoot without bracketing!

I'm under the impression that the 30D doesn't offer bracketing...