[dofmaster]

I was looking at some photos I recently took and noticed that in some of the shots the face was out of focus when viewed at 100%. When I was checking the focus to see where the focus point was, it seemed that the centre and bottom half of the image appeared much sharper, which is odd because I would think that everything is roughly on a plane to the camera.

This applies to both the subject and the mortar lines in the bricks behind her. Can anyone else see this or am I imagining things? And what do you think the cause is - is the person really not on a plane to the camera? Or some other explanation?

They're shot with the DFA 24-70mm at 70mm, at f2.8, 1/800 and ISO 100. Autofocus mode would be either AFS + single point or manual focus.

'Original' files (unedited but exported from PS) here

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Last edited by dofmaster; 08-09-2018 at 08:23 AM.

[eccs19]

Shooting at 2.8 and 70mm, your DOF can be shallow. I've had shots where the shirt if sharp, but the face isn't and it's because of this. If I get the eye in focus, then sometimes even the tip of the nose is out of focus. The longer the focal length, the more noticeable this will become wide open.

[chrism888]

Agree with Eccs19, as the most likely cause

[Robot camera]

The lens height seems to have been about at the level of the second mortar course from the top of the brick stack. This means that you had to point the camera slightly down to frame the model; the plane of focus was slightly tilted. This might have something to do with it, but where in these images did you focus?

[twilhelm]

Looking at your crops, your lens may be back focused slightly. I would start by checking that first. With it back focused and the thin dof at 2.8, it would be quite noticeable.

[jatrax]

Unless you had the camera at her waist height you would be shooting slightly down. This would be true if you were standing with the camera at your eye. So the model or brick wall would not be perfectly in plane. With f/2.8 DOF would be very small and I would expect this effect.

Try shooting it again with the camera precisely level and at the height of the center of the image.

[mikeSF]

have model step aside and shoot that brick chimney or a suitable brick wall using a tripod to maintain precise focusing distance and be sure camera is perfectly level when shooting a perpendicular wall. This will be a better test for what may be happening with the lens if anything. Good luck!!

[ntrao]

Looks to me a little lens issue. When checking the pic at full resolution, I didn't find any problem with lower half of the brick wall behind her legs, it is perfectly sharp. Where as the upper part of brick wall, behind her head is completely off. To my knowledge, the entire plane should be sharp or off at whatever aperture, not just one half or the other.

[Tom S.]

Kind of funny given your user name....

[JohnX]

If the OP was standing when he took the shot, as he appears to be, could the plane of focus actually be parallel all the way up from the models toes to the top of her head? I suspect the camera was tilted down, however slightly.

As suggested, take another shot with the camera on a tripod at right angles to a brick wall, etc.

[repaap]

Mike said it best, to try it really out, that is the way. Just brick wall and camera absolutelly leveled. To me it looks like focus is little behind her. and if camera is tilted, the focus would be even more off at top, where head is. I'd keep on eye of this. On the other hand, if she would be leaning like that and you have camera pointing down and focus at eyes, she would be in focus from toes to head.

[pentaxfall]

I was looking at some photos I recently took and noticed that in some of the shots the face was out of focus when viewed at 100%.

I suggest doing a brick wall test. You can see what I mean Uneven sharpness in DFA 70-200mm - PentaxForums.com

FYI, when doing the test
-Use MF preferably Focus-peaking
-Remove lens filter
-Use tripod, along with MLU
-Level the camera(i use the leveling indicators given in K1 viewfinder)
-Keep camera parallel to wall. It is difficult make sure they are parallel. Repeat the test at 2-3 locations. This may eliminate human error.
-Keep F = 2.8

[Alex645]

have model step aside and shoot that brick chimney or a suitable brick wall using a tripod to maintain precise focusing distance and be sure camera is perfectly level when shooting a perpendicular wall.

Looks to me a little lens issue. To my knowledge, the entire plane should be sharp or off at whatever aperture, not just one half or the other.

Agreed you need to run a better test to go thru a process of elimination.

Are you using OVF AF or LiveView or MF?
If with a flat surface perpendicular to your lens you get the same problem at f/2.8 at that focal length regardless of focusing technique, then it's the lens that is de-centered.

Keep in mind that the center of your lens will be sharper than the corners and edges at large apertures and wide angle.

If the problem can't be replicated with a flat surface centered at lens level, then it was probably an AF fine tuning problem that can be corrected in the menu. Typically you'll get your best AF with Live View. If MF, zoom into the focal point of your shot (like her face), focus, and then without changing the focus, zoom out.

[dofmaster]

Unless you had the camera at her waist height you would be shooting slightly down. This would be true if you were standing with the camera at your eye. So the model or brick wall would not be perfectly in plane. With f/2.8 DOF would be very small and I would expect this effect.

Try shooting it again with the camera precisely level and at the height of the center of the image.

As someone else has said you can see that the camera height was about 2nd row of bricks down, so I was shooting down somewhat.

But then I would think that, given that the bottom half is in focus, then the plane of focus would be behind the model's head. But if you look at the photo from the side (both were taken about a minute apart with the same settings) you can see it's blurring all the way back, so the focus point must be in front of the model's head.

[jatrax]

As said above little can be discerned by photos like this. You might have been leaning, the model might be leaning, the plane of focus is not exactly square with the subject.


Use a tripod and a fixed, flat subject like a brick wall. Make sure the camera is perfectly level and perfectly in plane left to right. That is the only test that really shows if there is a problem. I do not trust any test that was taken hand held, there are too many variables.