Toronto Photography Meetup Group

What focus mode do you use and why? And when, if ever, do you change focus modes? I am just trying to get a consensus on what focus mode most people use and what their reasoning is behind their choice.

poses or standard shooting, where the subject is pretty situated within dof ranges, is afs...mostly used for darker situations as well
afc for relatively quick action to and fro where from experience i know standard afs won't cut it
manual where contrast is way out there (white or black peaking the scale) or neither of the others is serving me well

Manual and scale focus, because it's just faster and easier. And my cameras can't autofocus.

I use autofocus 99% of the the time.
On my Canon I use ONE SHOT mode for relatively static subjects and AI SERVO for moving subjects such as birds in flight.

ONE SHOT AF on static, very slow moving also, AI SERVO AF on fast moving subjects, Manual focus for macro or practice Oh, and I use center point for focusing, not multiple points

One point focus with separate focus button rather then have the focus interlaced with the shutter I usually use the centre and recompose except for portraits and closeups where I choose the focus point closest to the point of interest. Focus AI , ... one shot as needed.

best of both worlds: AI-SERVO with AF-ON button activated, half press on shutter button does not focus, only metering start.

Need to track a moving object? Keep AF-ON
Need one-shot mode? Remove thumb from AF-ON button.

Took a while to get used to. Now I love it.

+1 for me... my exact practice, especially on kids running around

That is a nice tip, I didn't think of that this way, just release focus lock button and always keep in AI servo mode, right? Going to give it a try. It doesn't confirm the focus all the time though, unlike One shot mode

I've thought about setting it up like this, but I'm so used to half shutter button focusing, I'm worried I'll forget and miss a good shot.. lol

Focus confirm works exactly as it does on AI-SERVO, i.e. after the initial AF-ON press, lens focusses, AF confirm lights. Keep AF-ON, track subject, AF confirm does not keep flashing, but focus follows subject.

If you need AF confirm in ONE SHOT- like mode, press AF-ON again. That's pretty similar to ONE SHOT mode, isn't it?



Yeah, I thought so too. But after about a week or two of shooting unimportant things, using the AF-ON button feels very natural. Nice to be able to have the focus and metering functions separated from one button.

Kinda, I noticed it's a little different with confirmation, but this way I think you get more control on the street for sure. Going to use it from now on and see if I can get used to it

I've used this technique before but couldn't get used to it - perhaps I didn't give it enough time. One thing for sure - my wife didn't like it - she would mutter expletives under her breath indicating that the camera wasn't focusing .. lol.

One of the reasons I brought up this topic was to see if anyone was using the AI Focus mode - I used to use this mode but found it utterly incompetent - it simply doesn't do what it's supposed to do .. at least not with any consistency.

What I really enjoy are lenses with the full time manual override feature. It's really useful to combine auto focusing and the control of overriding focus with manual adjustments when needed.

oh yes, full time manual is good. With the AF-ON button, even better, because now you can AF-ON to get focus near where you want it, leave your thumb off the AF-ON button, MF to perfection, press the shutter release, and not have the AF come on again to over-ride your focus setting. I know you can maintain half press and MF if you do not disable half press AF, but that seems like more trouble to me.

To be honest though, I can't remember the last time I MF'ed... Don't think the focus screen is good enough. Wish I had the split prism focussing screen, but then, AF is so fast, and good enough for me.

I switch focus mode's depending on what I am shooting. Generally though, if I am using AF, I have it set to AF-Single. I also use the dynamic focus mode on my D700/D90 occasionally. Again, it really depends on what I am shooting.

When I am doing landscape, I am almost always focusing manually.

The only time I'd switch to continuous focus if I'm tracking something that's continually moving.

Otherwise it's single focus, or manual focus with the autofocus programmed into the function button so I can trigger it if I need AF while in MF mode.

I tried this technique a few times but once I set the AF via the AF-ON button and do a manual focus change - when I press the shutter release button the camera then re-focuses. Perhaps a setting in my 40D needs to be changed.

yes.

set Custom Function IV/1
Shutter Button/AF-ON Button to
2: Metering start / Meter + AF start.

More info can be found here:
http://www.usa.canon.com/dlc/controller ... Mode=print

or google "back button AF" and get much more perspectives.

+1 on this. Great technique if you can get used to it.

I also use back button AF with AI Focus AF set. I don't change it for anything... lol I use MF when selective focusing is critical (macro, close up shots, too dark). MF is useful when I'm streetshooting at night. My AF lenses will start hunting and I trust my eyes/skill better than my camera's AF.

Hey Mike, thanks so much for this! I have played around with this for about five minutes and can see how it can add more control to numerous shooting situations. Thanks for pointing it out.

One drawback to this technique is that if you press and let go of the AF-On button and then you move a few centimeters back or forth, which I tend to do sometimes, the focus will be off when I take the picture. But in One Shot mode it won't allow you to take the picture unless it's in focus.

This techniques makes recomposing much easier but yes, if you move and change the distance between yourself and the subject, the focus will be off. Train yourself to keep pressing the AF button before you press the shutter button.

I tried what you describe above and the camera took the out of focus shot. I am in Av mode, One shot focus and Metering start/Meter + AF Start. I focused on subject A, recomposed to subject B, squeezed the shutter and it took the picture. Am I miising something here?

I have experienced that before where the camera has hesitated or not taken the shot and always wondered why it did this.

Sorry James, I wasn't being very clear. I wasn't talking about focusing, recomposing and taking the shot, which is a valid practice. I was talking about the difference between having the focus lock on the back focus button as opposed to the shutter button. In One Shot mode the focus lock on the shutter button will kick in when you half depress and the camera will not let you take the shot until it confirms focus.

With the focus lock assigned to the back focus button there is more risk of a distance change between camera and subject since the camera now doesn't care if anything is in focus and also you are introducing a two button procedure instead of one, which may cause a delay. Eric suggested keeping the back focus button depressed until you take the shot but this defeats the usefulness of separating these two functions.

It's not a big deal but something to be aware of.

In terms of the difference between One Shot and AI Servo in regards to the hesitation and/or camera not taking the shot try this test. In a 'hard to focus' situation like low light or constantly moving subject put the camera in One Shot mode and try to take the picture by fully depressing the shutter button - the camera will hesitate and not let you take the picture until it confirms focus lock. Then try the same scenario in AI Servo mode - the camera will try to focus but it will let you take the picture, in focus or not.

Cool - I tried putting the camera in one shot mode and it mimics the situation in the past when my camera was hesitating - good to know. My work around had always been to drop into manual focus mode but I have a 40D and the default focus screen on it is not very good for MF situations. My MF shots are rarely in focus whereas my AF shots are *sometimes* in focus Perhas this is another 'Operator Error' but even in controlled tests I find the AF works better for me.
My buddy has a 5D with a precision foces screen and what a difference it makes.
Thanks for everyones input on this thread - it certainly has opened up some more options on how to use my camera!

As far as I know the canon cameras use different algorithms for AF in ONE SHOT and AI SERVO. They (Canon) recommend to use ONE SHOT for static subjects.

If I remember correctly in AI-SERVO the camera uses the center AF point for initial focusing and then it uses a predictive algorithm to track the subject using the adjacent AF points.

There is a difference in the light metering as well:
- in ONE-SHOT mode the exposure is determined when the focus is achieved
- in AI-SERVO mode the exposure is determined when the picture is taken.

I too use the AF-ON button for focusing but mainly because I can manually override what the camera thinks is the best focus and not have this changed when I half press the shutter button.

"Ring of Fire"