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07-29-2009, 04:57 PM   #1
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AF. C or AF. S ??

Which do you use? Or does it depend on if you are shooting small children or older people who can actually stand in one spot for more than a mili second? I've been using AF.S......focusing on the eyes and then re composing...but, I took a couple pictures of my baby girl the other day and they are adorable except the focus is at a weird spot. So with a little person, should I be using AF.C ? Or doing something all together different?

Here is a picture to show you what I mean. I"m not even sure where the focus fell, or if the whole image is OOF...but something's off and I"m not sure if I should be doing something different.




Last edited by BethC; 07-29-2009 at 05:13 PM.
07-29-2009, 06:14 PM   #2
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Couple of things. First, I don't know what your shutter speed is. It's possible you could have a little bit of motion blur from child moving her head. If you are using center point and recomposing you do need to use A.F.S. unless you want the focus point to be in the center. Because A.F.C. will continue to focus wherever the focus point is, if that makes sense.

Personally, I like selecting my focus point. I only use A.F.C. if I am photographing action, and I always select the focus point in that mode.
07-29-2009, 06:50 PM   #3
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In theory, AF.C sounds like the best thing. The camera focuses continuously and you just snap when you are ready.

The good news:
You can snap whenever you want.
The bad news:
You can snap whenever you want.
The only problem with AF.C is that it allows exposures even when the camera has not attained focus.

Steve
07-31-2009, 05:51 PM   #4
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If I were taking this photo, I would use AF-S and select auto focus point, choosing the auto focus point closest to her eyes. If you practice with you auto focus point selection, you can get pretty fast with it. Then, the only other thing is to be certain that your shutter speed is fast enough to freeze any motion blur. Somewhere around 1/100 second should be plenty.

I think your focus point is somewhere on her right arm and that there is some motion blur as well. Still, an awfully cute picture of an awfully cute girl.

07-31-2009, 07:38 PM   #5
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Beth,

Cute girl! I agree with Rondec.

The issue you are having may be the DOF is too shallow for your aperture / distance from the subject; failed focus and or motion blur.

But to me it seems like the focus didn't work right if you said you tried to recompose.

I don't know which lens you used, but the manual lens wouldn't allow you to recompose.

What was the lens / camera you used in the shot?

Try a lower aperture like 6.3+ with flash to get more in focus while maintaing a shutter speed that would prevent slight blurs from movement.
07-31-2009, 08:01 PM   #6
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Awe, thanks....we actually think she's pretty cute too LOL

So sounds like AF.S is what would be best in the shots I mostly take.

I have a K10D and I used the kit lens on this picture. I have problems with my exposure if I lower my aperature, and then have to compensate with the SS and all....so I guess I should bump up my ISO then? shoot wider, then run neatimage to get rid of the noise? I have a flash for my camera but am really bad with it. I try to use just natural light.
07-31-2009, 10:38 PM   #7
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Technique gets harder with larger apertures and slower shutter speeds. But as it is with shooting people, and even more so with kids, you may have to just shoot away and come away with those few quintessential captures from the hundreds you take, simply because there are too many factors that can go wrong with a portrait shoot...
07-31-2009, 11:21 PM   #8
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I've got AF assigned to the OK button (on a K100D) in order to decouple it from the shutter button.

By choosing AF-C I can thus get an AF-S effect by pressing the OK button shortly or an AF-C effect by keeping it pressed.

The only (and big) problem has been pointed out by stevebrot: When using AF-C you can fire without having something in focus.

The camera should really give you all four options,
AF-S with shutter priority or focus priority, and
AF-C with shutter priority or focus priority.

Most often I'd like to have AF-C with focus priority but that option isn't available.

08-01-2009, 04:46 AM   #9
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My exif program reveals your camera settings as: K10D- shutter speed 1/180 sec., f4.5 which is wide open on 18-55, and you were at 45mm with ISO at 400. Pattern metering rather than center point and what I don't understand is you were using Manual mode???? Personally this is one of the times with the K10 that TVA mode comes in handy. Set both apature and shutter speed to desired settings (your choice) and let camera pick ISO. Off hand on this photo I would say the biggest problem is doff and focal point. jim
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