Camera not focusing correctly

laurenivy

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Hi all! Just wondering if this is a common problem or is there some setting I should know about that will calibrate this?!?

I have a Nikon D90 and a couple lenses, all of which seem really soft when wide open. If I get close to my subject the focus looks fine, but if I back up its very soft or the focus is sharp on the wrong part of the image. I'm using single point focus, and more times than not, I come out with a blurry image or a part in focus that is not where I put the point. (is this making sense??)

Is there anything I can do to fix this?
 
Do you have the same problem with different lenses?
I had this problem with my camera but I found out that the lens was defective...
 
Understanding Camera Autofocus

You're issue is likely related to a less than complete understanding of depth-of-field (DoF) and how a wide aperture can make the DoF very shallow.
Understanding Depth of Field in Photography
Understanding Camera Lenses

This is a common issue for inexperienced photographers using 'fast' prime lenses that can open wide, like f/1.8 or so.
You don't say which specific lenses you are using.

Fast prime lenses generally have to be stopped down 2 stops or so before they hit the start of their sharp focus sweet spot. focus sharpness begins falling off again when the lens aperture gets small, because of 'diffraction'.
Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks
Camera Lens Quality: MTF, Resolution & Contrast
 
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A lot of normally-priced lenses are somewhat low in contrast, and sometimes fairly high in chromatic aberration, when used wide-open. Lower-priced zoom lenses are often not all that great when shot wide-open. Even good, normally priced lenses are often somewhat 'soft' when shot wide-open. The softness can be in several forms, like lower resolving power; a sharp central image and somewhat not-so-sharp edge and corner performance; a very slight degree of veiling, or a soft,subtle loss of contrast compared to how the lens looks when shot stopped down 2 to 3 stops from wide-open; and sometimes pretty significant loss of light in the corners and into the edges (commonly called fall-off of vignetting in common terms).

it's kind of like driving with the throttle wide-open (WOT)...the fuel mileage sucks, the brakes take a beating when used, and when you hit things, parts go flying off the car, and minor mistakes become MAJOR boo-boos reallllly fast, with sparks, and maybe even fire, and crunching metal...

Shooting wide-open with many lenses means the lens performance is going to be a certain way; if EVERYTHING is not done just right, the results can be sub-standard at f/1.4, or f/1.8, or even f/2.8.
 
Even if I'm shooting at 2.8 on a 1.4 lens the in-focus part is usually behind where I put the focus point. I have an 85 1.8, a 35, and a 50 1.4, and this happens with all of them. Could it be something with the camera needing calibrated?? Is there a setting I can recalibrate with??
 
Even if I'm shooting at 2.8 on a 1.4 lens the in-focus part is usually behind where I put the focus point. I have an 85 1.8, a 35, and a 50 1.4, and this happens with all of them. Could it be something with the camera needing calibrated?? Is there a setting I can recalibrate with??

Have you done a tripod focusing test to rule out personal error? Are you shooting in single-servo mode? Are you pressing the shutter button immediately after focusing, or recomposing/taking any time? Do you have your fingers on the focus ring by accident at any point without noticing?
 
Even if I'm shooting at 2.8 on a 1.4 lens the in-focus part is usually behind where I put the focus point. I have an 85 1.8, a 35, and a 50 1.4, and this happens with all of them. Could it be something with the camera needing calibrated?? Is there a setting I can recalibrate with??

Don't be afraid to send the D90 to Nikon (or APS) the get the AF checked.

My D90 was good with all my glass until I got the 24mm f/2.8 D - total crap.
Upgraded to D700 and D7100 - many reasons, but a HUGE one was the AF fine tuning capability.
The 24mm f/2.8D was extremely sharp after AF tuning (was still crap before on the D7100 and D700).

Not telling you to upgrade. Just saying that if the cam body hasn't been checked out in a while, then the AF (and metering) may need some adjustment.
 
Most people on forums will tell you it is user error, which it might be, however, I really recommend doing a test in a controlled environment with a tripod and test chart (or batteries or stacked books). When I had my D90 with my Tamron 200-500 it wasn't back-focusing by a little it was missing by yards.. Sent it to Nikon, it came back and focus was perfect...
 
It's way more often user error than an equipment malfunction, particularly when using a wide open aperture and a wide angle to normal focal length.

But yes, it could be the camera needs an adjustment.
 
It's way more often user error than an equipment malfunction, particularly when using a wide open aperture and a wide angle to normal focal length.

But yes, it could be the camera needs an adjustment.

I agree 100%, that's why I recommended a controlled test :)
 
Ok. Thanks all. Yes, I'm using single servo. I just realized today that the central focal point does not have this problem at all when I use that. It's the outer ones. And yes, sometimes I am locking and recomposing, and they are usually blurry also when using those outer points. I used the center one all day today and had no issues at all. Hummm.... I should do a controlled test. Thanks everyone.
 
The center AF point is the only cross-type AF point the D90's Multi-CAM 1000 AF module has. Cross-type AF points can detect both vertical and horizontal edges.
The other 10 AF point either detect vertical edges, or horizontal edges, but not both.
 
So I guess shooting at a low aperture and recomposing with those outside points arent as forgiving as using the middle one? So there is more than likely nothing wrong with the camera....
 
Hi there "Laurenivy", just registered with this forum & have noticed your posts on the focusing issues you were having with your D90- I just wondered how you got on with solving the problem with all the relevant advice coming from the forum. I ask this as I have also noticed of late that I am having the same problem with getting sharpness in focusing.
 

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