Nikon 55-200 Lense Image Focus

Pissupoosa · Dec 30, 2014

Hi ,
I am new to here, and I have year old Nikon 3100 with Kit lens. Recently I bought a Nikon 55-200 mm lens and I am facing a problem here.
The most of the images are not focused correctly. Even it looks correctly in viewfinder, and when I look the image in system they are focused some where.

For example in the attached image, I tried to focus the kids and it got focused on temple.
This happens Even in Auto/Manual Mode.

I use Center Weight Matrix mode. Can Some one help me to solve the problem.

480sparky · Dec 30, 2014

When you say you focused on the kids, exactly what did you do? (BTW: Metering modes do not affect focus)

If you pushed the shutter button halfway down when aiming the camera at them, then recomposed the image and pressed the shutter button again, of course the camera will refocus. You need to hold the shutter button halfway down during recomposing for the camera to 'hold' the focus.

KmH · Dec 30, 2014

Center-weighted, Matrix, and Spot are light metering modes you can use and a metering mode is used to control exposure, but not focus.

Auto focus modes are AF-S (single focus), AF-C (continuous focus), and AF-A (the camera selects either AF-S or AF-C.
In addition to the auto focus mode, you also have to choose an auto focus area mode.
Review the Focus section (pages 55 - 63) of the D3100 Reference Manual.
For metering modes see pages 79-82.

Next you need to be familiar with depth-of-field (DoF)
In the photo you posted the DoF was quite deep and the things furthest from the camera are in focus so the rear DoF limit was close to or at infinity.
The boys are blurry because they are in front of the near limit of the DoF in that range of distance between the camera and the DoF near limit that cannot be in focus.

Pissupoosa · Dec 30, 2014

I focused the kids only , and when I focused the location I saw the focus was on the kids not the temple. Can you tell guide the reason for the blur on this photo?View attachment 92120

And I am not facing this issue with Kit lens. I am not sure the issue is with the camera or with me.

480sparky · Dec 30, 2014

It could be the focus point(s) the camera is using to achieve focus. If it's not in the part of the scene you want in focus, it can make what you want to be in focus blurry.

Pissupoosa · Dec 30, 2014

480sparky said:
It could be the focus point(s) the camera is using to achieve focus. If it's not in the part of the scene you want in focus, it can make what you want to be in focus blurry.

How can avoid this problems?. Need to take a good photos, while viewing them from Livewview it looks good and when viewed from system the image becomes blurry with 55-200 lens.

480sparky · Dec 30, 2014

Learn to use the viewfinder. That will show you which focus points are being used. Also, read through the manual on how to use the various autofocus functions. There is no one-size-fits-all option.

wfooshee · Jan 2, 2015

Live view is NOT how to use the camera!!!!

Autofocus works completely differently in Live View, because the camera's main focus sensors are not even available, as they live in the upper part of the body in the pentaprism. That area is not used in Live View.

Autofocus is superior in every way when using the viewfinder. The viewfinder shows you where the image is being focused by illuminating little squares representing the focus sensor in use. If you want to force a certain section of the picture to be in focus you can use the cursor button to move that square around the picture until it's over the part you want focused.

In the situation of the image in the first post, AF mode should be AF-S, with a single point selected. Use the arrow button on the back to position that square over the subject, and shoot. Keep in mind that the kids are different distances from the camera, so you will probably only get one of them in focus unless you use a small aperture (high f-number.)

The image in your post appears to be focused in the distance, at the center of the frame.

If you'd rather leave the center sensor selected, you can do that, too. Make sure AF-S focus mode is selected. Move the camera to put your intended focus point in the center, press the shutter halfway, move the camera to re-frame the photograph without letting go of the shutter button, and when ready, press it fully. If you have it in AF-C or AF-A it will probably refocus even while holding the button in a half-press, as those modes will switch to continuous focusing, not locking your selected focus before you moved.