How Do You Usually Focus?

[KrazyPete]

You guys have got me digging through PDFs of my camera manuals at work. Not cool!

 

[MarkBarbieri]

Jen, are you able to do that on your XTi?

It's Custom Function #4, setting 3 (or 1 if you also want it to do AE lock). I'm pretty sure that's true of all Canon DSLRs.

As for it's usefulness, here is what Canon says:

C.Fn 4-1 (or, 4-3), where the rear (*) button is used to activate the focusing system, is almost universally accepted by professional photographers as the best way to shoot sports. …

C.Fn 4-1 (or, 4-3), where the rear (*) button is used to activate the focusing system, is almost universally accepted by professional photographers as the best way to shoot sports. …

There are several advantages to working this way.
The photographer can capture focus on the subject well in advance of shooting the image without worrying about pre-metering or accidentally firing a shot.
The camera can stay in focus on a single subject for longer periods of time (e.g., waiting for a batter to swing) and when ready, the photographer can shoot with better camera responsiveness.
While pressing the AE Lock button in this mode, you have AI Servo tracking focus. Let go of the button and you are now locked at that distance (as if you were in One-Shot). And with Canon EF lenses that have Full-Time Manual focusing, including all USM lenses with distance scales, you now have manual focus… all three focusing options available without having to take your eye from the finder.

It's kind of like being able to switch between manual, AF one-shot mode, and AF continuous mode instantly.

I did use MF at the zoo while trying to get pictures through the mesh or bars

That's a good point. I often use manual when shooting through screens or dirty windows. I also use it when trying to shoot subjects partially obscured by brush or other items that confuse the AF. Sometimes that can be handled by switching AF points and sometimes it can't.

 

[DVC Jen]

Jen, are you able to do that on your XTi?

I very rarely use manual focus - as someone else mentioned, my eyes ain't what they used to be - but I did use MF at the zoo while trying to get pictures through the mesh or bars. It worked very well.

Like Mark said - yes I can. The XTi is the camera I started using it on. When I got the 30D I had forgotten that I had manually set the focus to a different button and it totally threw me off to focus with the shutter. I changed it on the 30D very quickly.

 

[DueyDooDah]

I have been using only the default modes for AF. Although I have finally "mastered" af/recompose/shoot, I am going to attempt your method. I like the idea of having a separate button to focus and another to meter and shoot. I never MF, as my eyes need replacing.

 

[photo_chick]

Mostly manual focus here. Of course lately since I notice my eye are going down hill I have been using the AF more and more so in a year or so I suspect my answer would be different.

 

[MICKEY88]

Mostly manual focus here. Of course lately since I notice my eye are going down hill I have been using the AF more and more so in a year or so I suspect my answer would be different.

must be nice to be young enough to have that option..

 

[MarkBarbieri]

I can still see the distance stuff, but my the near stuff is fading fast. I was just using a magnifying glass trying to read the "instructions" for a CPU heatsink.

 

[cryssi]

I usually let it pick the AF point. When shooting portrait shots, I often switch to the right-most AF point because, when I rotate the camera, it's in the upper part of the frame near the subject's eyes.

I use the AF. I am wondering, however, about this above. I find that when I shoot 2 people, they are blurry b/c the AF is focusing on a point between and behind the couple. Now if you move the AF point to focus on one person, is the other out of focus? I suppose I could just try it, but, you know, that takes effort...

 

[gruZ]

I use the AF. I am wondering, however, about this above. I find that when I shoot 2 people, they are blurry b/c the AF is focusing on a point between and behind the couple. Now if you move the AF point to focus on one person, is the other out of focus? I suppose I could just try it, but, you know, that takes effort...

It depends on what setting you are using (or your camera is choosing) for the aperture. "Smaller" numbers (such as f/1.8 or f/2.8) actually mean a larger opening in the lens to let the light through. This also means a shallower depth of field (DOF), and more than likely most things in front of or behind the focal point will be out of focus. "Larger" numbers (such as f/10 or f/11) mean a smaller opening, and a greater depth of field. Things in front of and behind the focal point will be in focus.

So, the answer to your question is if you are using the appropriate aperture setting, both subjects will be in focus.

Distance to the subject also comes into play - the less distance to the subject means a smaller depth of field all other things being equal.

Take a look at this site for a more technical explanation.

 

[cryssi]

It depends on what setting you are using (or your camera is choosing) for the aperture. "Smaller" numbers (such as f/1.8 or f/2.8) actually mean a larger opening in the lens to let the light through. This also means a shallower depth of field (DOF), and more than likely most things in front of or behind the focal point will be out of focus. "Larger" numbers (such as f/10 or f/11) mean a smaller opening, and a greater depth of field. Things in front of and behind the focal point will be in focus.

So, the answer to your question is if you are using the appropriate aperture setting, both subjects will be in focus.

Distance to the subject also comes into play - the less distance to the subject means a smaller depth of field all other things being equal.

Take a look at this site for a more technical explanation.

thanks for the link, I've bookmarked it for future reference! I had a sneaking suspicion it was user error...

 

[handicap18]

I use AF probably 98% of the time. I will use MF with my macro lens. The Tamron 90mm f/2.8 Macro is very simple to switch to MF and has a very large focus ring so it is easy to use.

As for the auto focus points, I switch them all the time. My D50 has 5 different points to focus on. Many times I'll use it in conjuction with the focus lock depending on the subject and the composition I want.

The back focus button I believe is a Canon thing, because I haven't heard about that on a Nikon. I know the D50 doesn't have it. I can switch the AF/AE lock button to work both or just one or the other. I have always kept it set to lock both. If I need a different exposure than what I want when I use the lock button, I'll switch to M and set the exposure myself

For the question re: taking a pic of 2 people and getting the focus off. I"ll usually focus on one person's eye's by switching the auto focus point. Sometimes I may have to lock the focus and recompose to get a better shot. If their faces are pretty much the same distance away from you then they'll both be in focus, but to be sure just use an f/stop that is 5.6 or smaller, probably better off with f/8 or f/11. Fill flash can always be used if necessary.

 

[MarkBarbieri]

The back focus button I believe is a Canon thing, because I haven't heard about that on a Nikon.

No, it was a Nikon shooter that first told me about it. I'm not sure about S/P/O.

 

[tinksdad]

My D200 does have the AF button as well as the AEL button on the back of the camera. I've used the AF back button underwater as the housing shutter release isn't as sensitive as my finger on the shutter without the housing.

It also employs a three tiered focus control; Single servo for that focus priority and will beep when focus has been achieved and locked. I use this most often. It also has a Continuous Servo for moving objects that continuously changes the focus to the subject and really never locks, but even a tiny change will cause the camera to refocus. There is also a Manual servo for manual. If I'm shooting macro shots then it's manual all the way. My older macro lens is kind of slow and the manual give me the option of where I want the focus which for those kind of shots I think is a better option.

I typically use the Single Area Autofocus, and Dynamic Area Autofocus. The camera also has a Group Area Autofocus but I haven't seen the need for that with what I shoot so far since I can control some of that through DoF.

 

[Groucho]

I manual focus when using manual focus lenses. Easy choice.

I do MF on some of my AF lenses occasionally. Motorsports are an obvious time. Fireworks are another.

I really wish my old screw-mount 400mm was AF - that thing takes forever to manual focus and it's tough getting the focus just right, even with the camera acknowledging focus.

I would MF a lot more if a had a proper split-prism or other MF-friendly viewfinder on my DSLR. I'd mount one in an instant but I'm concerned about exposure problems, which seem to be a common issue when adding such a thing to a DSLR.

 

[photo_chick]

must be nice to be young enough to have that option..

I used to be, as I keep looking at my images and the soft focus and I wonder when did I get old. If you saw my gray hair you would not think me so young.

 

[photo_chick]

Oh, and for the record the Rebel XT can also do the custom function with the * button as the focus. So could my old 35mm Rebel G.

 

[Groucho]

If we're going "for the record" my little $367-with-kit-lens *ist DL can do this as well, you can set the OK button to either focus normally or spot focus when in MF mode, or cancel AF if you're already in AF mode. I suspect most any DSLR can do this?

OK, back to the "when do you focus" discussion, already in progress. I've never tried setting it up this way, I think I'd probably prefer the half-shutter press.

 

[Gdad]

I usually use manual focus for anything macro- its usually easier for me to just shift 1/4 inch or so to or from the subject to get the dof exactly where I want it. Nothing irritates me more than my lens hunting focus all the way to infiniti while my subject is crawling/hopping/flying away.

 

[KrazyPete]

I'd like to give the back button focus method a shot but it looks like I have to give up my AE/AF lock button. by default, it locks both the focus and the exposure. I have 11 different options I can assign to that button and one of them is AF-ON.

AF-ON initiates autofocus and takes that functionality away from the shutter release button. It won't hurt anything to try it out but I was wondering what your opinions were. is AF-ON a better use for that button?

Thanks

 

[Shifletjl]

Just subscribing so I can find this later. Very informative. Thanks everyone!