Tips for improving focus. ??

[AMOMENT]

I have a Nikon D3100 and often use either my 50mm 1.4 lens or my 55-300 f/4.8-5.6 My camera has 11 AF points but I have noticed that unless I use the central one (which has crosspoints) my focus is always blurry. Even if I raise my aperture to increase depth of field and my distance from the subject. (in some cases) For this reason I often shoot af-s , lock focus, and then recompose. I recently posted some pics in the People gallery and people said what I suspected, which is that my focus was off. I don't necessarly understand why. I am not shooting wide open, at least for now, to comopensate for my tendency to miss focus. I almost never shoot with a shutter speed slower than 1/200.

When I shoot moving children I still usually shoot af-s and just hope for a still moment and snap quickly. When I shoot af-c, I almost never get the shot because by the time my camera locks focus, the moment is over. I am shooting single point but I wonder if I should be shooting dynamic for moving kids. I suspect no because I generally want the child to be highlighted.


What else can I do to improve my focus? Since I am shooting with AF and obviousely not MF, it seems to me that these are all the adjustments I can make. I could use a tripod but this would be nearly impossible to do and use when shooting kids who are all over, constantly changing their positions and whereabouts. I'd be running around with a tripod and there would be no time for even adjusting to get down low or move up higher.

-I'm not shooting wide open

-I'm putting more distance between my subject and I when needed (but not too much so that the camera does not focus)

-I am not shooting at a shutter speed slower than 1/200 and MAYBE slightly below that. Most of the time it is faster.


If you need some examples I posted two shoots in the People Gallery. Thank you all

 

[jake337]

I have a Nikon D3100 and often use either my 50mm 1.4 lens or my 55-300 f/4.8-5.6 My camera has 11 AF points but I have noticed that unless I use the central one (which has crosspoints) my focus is always blurry. Even if I raise my aperture to increase depth of field and my distance from the subject. (in some cases) For this reason I often shoot af-s , lock focus, and then recompose. I recently posted some pics in the People gallery and people said what I suspected, which is that my focus was off. I don't necessarly understand why. I am not shooting wide open, at least for now, to comopensate for my tendency to miss focus. I almost never shoot with a shutter speed slower than 1/200.

When I shoot moving children I still usually shoot af-s and just hope for a still moment and snap quickly. When I shoot af-c, I almost never get the shot because by the time my camera locks focus, the moment is over. I am shooting single point but I wonder if I should be shooting dynamic for moving kids. I suspect no because I generally want the child to be highlighted.


What else can I do to improve my focus? Since I am shooting with AF and obviousely not MF, it seems to me that these are all the adjustments I can make. I could use a tripod but this would be nearly impossible to do and use when shooting kids who are all over, constantly changing their positions and whereabouts. I'd be running around with a tripod and there would be no time for even adjusting to get down low or move up higher.

-I'm not shooting wide open

-I'm putting more distance between my subject and I when needed (but not too much so that the camera does not focus)

-I am not shooting at a shutter speed slower than 1/200 and MAYBE slightly below that. Most of the time it is faster.


If you need some examples I posted two shoots in the People Gallery. Thank you all

When you focus and recompose you are shifting the focus plane no matter what aperture you use.

So you are saying when you choose any other focus point besides the center it does not focus properly? Have you tested this on a tripod on static subjects?

 

[Dao]

Just one quick question, do you shoot raw and sharpen the photo during post?

 

[tirediron]

Avoid focus and recompose. Depeding on the angle, and especially if you are close to the subjects, it can drastically alter your focus on the subjects. First, as mentioned, verify by use of static subjects and a tripod that your camera is focusing corretly (I'm 99.99999% sure that it is), and, assuming that to be the case, then get your kids, take 'em outside, Feed each of them ten large Slurpees, and let 'em go, and spend an hour practicing. Get used to selecting a particular focusing point, and nailing the focus. I use AF-S for all types of work from portraits to children, to motorsports. Did I mention? Practice!

 

[AMOMENT]

(Jake337) no I haven;t but I will do a focus test today and post.....

I would love not to have to recompose but it seems that whenever I use any other AF point other than the middle, despite my steps to increase DOF, it becomes blurry.

(Dao) I do shoot raw and sharpen but try not to overdue it.

(tirediron) THANKS! I feel like I practice like crazy and still drasntically miss focus. I do have a shaky hand for whatever reason. I've tried holding my breath or stabalizing the camera through different positions. I will do a focus test and post pics later...

 

[MTVision]

no I haven;t but I will do a focus test today and post.....

I would love not to have to recompose but it seems that whenever I use any other AF point other than the middle, despite my steps to increase DOF, it becomes blurry.

I would try a focus test with all your focus points as well. I rarely use the center point and I haven't had any issues. All focus points should be useable.


EDIT: in your other thread titled something child photography there is a picture of your daughter #4 in the post. It looks to be decently focused but your depth of field was pretty shallow and if you recomposed you could've really lost focus.

The zoom lens you have is going to give you a shallower DOF at f5.6 (depending on your distance) then the 50mm. From your exif of that photo it says you shot with a focal length of 125 and an aperture of f/5.6. For the distance to subject the exif says 67/20m which I think is like 11ft (if I'm reading it right).

With that focal length, aperture and distance you had .42 ft of depth of field (5 inches). Which is not a lot at all. With longer focal lengths to increase depth of field so you get better focus you are going to have to put more distance between you and the subject and/or use a smaller aperture.

 

[Derrel]

I would switch to using AF-C focusing for kids in motion. I think AF-C simply works better and is the "appropriate" mode for action shooting...it keeps the camera focusing all the time. You say you are "hoping for a still moment"...and yet, your focus is very frequently "off"....well...you need to shift the focusing switch to AF-C, so that the camera is CONSTANTLY able to re-focus, as the subject moves.

 

[SCraig]

I would switch to using AF-C focusing for kids in motion. I think AF-C simply works better and is the "appropriate" mode for action shooting...it keeps the camera focusing all the time. You say you are "hoping for a still moment"...and yet, your focus is very frequently "off"....well...you need to shift the focusing switch to AF-C, so that the camera is CONSTANTLY able to re-focus, as the subject moves.

What he said. If you can't get a focus lock on a moving kid something is wrong unless they are coming straight at you. I've gotten focus lock on motorcycles traveling close to 200mph on a race track, birds in flight, jet fighters in flight, drag cars at launch, all with no problems.

I seldom use anything but AF-C except for landscapes and I seldom use anything other than the center focus point (in 4 years of using cameras with the ability to change the focus point I can remember doing so once). I never, ever use 3D dynamic auto tracking or whatever it's called, the focus points dancing around all over the place drive me nuts.

If your subject is moving my guess is that you are inducing motion blur or not panning with the subject. If you aren't panning (properly!) with a moving subject you should be shooting much, much faster than 1/200 second.

 

[AMOMENT]

Thanks everyone! Here is my focus test. Grantid the exposures and everything is off but I just wanted to show you my focus. There are 4 images. I used my 50mm 1.8 lens and set up 10 feet away. My aperture was 7.1 and shutter 1/800 (I believe) The first one is with my center point, the second with the bottom, third with the top, and fourth with the upper left. (I didn't do all 11) Important to note that I originally did the focus test on a children's basketball hoop (about 4 feet from ground) and EVEN when stationed on a tripod, AF-S and using center point, my camera would not lock focus and allow me to take the photo when that center point was targeted at the whie backdrop of the hoop. My suspicions have always been that my camera latches onto a FP that has the mose contrast. (which would make sense) but I was still surprised. For instance, if I take a photo of a child with a bright headband on, even when AF is locked on their eye, the headbad will be sharper.


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[AMOMENT]

Thank you, Megan. I do believe you are right in that my DOF was too shallow. I think I really need to practice adjusting my DOF spontaneousely and being able to do so without recalculating on my DOF calculator. I often get an estimate of DOF I'm lookinf for before hand so I have a general idea where I want to position myself in relation to my subject.

I have the Adobe DNG converter and for the last two days it has not successfully converted anything. I had a folder with only 4 images that I was trying to convert and when it popped up it said there was like 146 in there. I have only one folder selected and have it set to save in the same folder. All settings are the same. I restarted my computer, ran spybot, and still same problem. Also, after attempt to convert and it says it was converted successfully (though it hasn't been) the whole rogram pops up again without me prompting. Have you run into any problems with this program? I know you have used it.....

 

[AMOMENT]

I would switch to using AF-C focusing for kids in motion. I think AF-C simply works better and is the "appropriate" mode for action shooting...it keeps the camera focusing all the time. You say you are "hoping for a still moment"...and yet, your focus is very frequently "off"....well...you need to shift the focusing switch to AF-C, so that the camera is CONSTANTLY able to re-focus, as the subject moves.

If I depress shutter halfway on my moving subject and then pan and try to shoot, it doesn't allow me to take the picture (on AF-C) ...it begins re-zooming/adjusting/focusing to the point where it is almost pointless and impossible to get much of anything "in the moment." Any suggestions? I'm sure I am doing something wrong but I don't know what..

 

[AMOMENT]

These next two photos are WRONG in every way but I simply used them and took them to test my other AF-points. These two were taken using the upper left point which I positioned on her right eye (if we were looking at her, left) and even though I was still and my subject was, and my DOF was sufficient, you can see how blurry it is. I then took a picture using the center point after this and got a much more in focus shot.

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[Josh66]

Avoid focus and recompose.

:thumbup:

Why Focus-Recompose Sucks

 

[SCraig]

... The first one is with my center point, the second with the bottom, third with the top, and fourth with the upper left.

It's doing what you are telling it to do. The first one is focused on the flower, the second on the rail of the fence under the chair, the third I can't really tell because it's in the trees somewhere, and the last one, upper left focus point, is focused on the house in the background.

 

[MTVision]

I think doing a focus test like the one in the link below will be a lot more accurate. It will help determine if your lens is back focusing/front focusing or if it's focusing properly.

This link brings you to the chart that you print out - or you could use a ruler
http://www.photo.net/learn/focustest/scale45.jpg


These are the directions

http://photo.net/learn/focustest/

I think this test will probably be a lot more accurate.