Softness at a distance.

Might be a little strange to ask, one of my 50mm lenses (50 1.8 MARK 1) has a weird issue where when a subject is close, it focuses on them perfectly and you can see the detail in their skin (i.e. headshot). When you move to a full body shot, their face becomes overly smooth with very little detail in the face or subject, and aliasing around the edges of the subject (not chromatic aberration). Lens has never been dropped or damaged.

I've tried messing around with AF micro adjust extensively to no avail. AF micro adjust just reverses the effect--subjects at a distance are sharper, and subjects that are closer lose detail. The best way I can describe the issue is simply a lack of detail. If I took a picture of a brick, you wouldn't really see the detail in it as much as you'd be able to see the brick. It's not really blurry. Soft, but in a sharp way, if that makes sense.

I've tested this in the real world and have to compensate quite a bit for the issue at times. I make it work, but it's still of nuisance.

I'll post test shots soon.

Waiting for the image but you are naturally going to get less detail as the subject moves farther away simply because you'll have fewer pixels on the target.

gjl711 wrote in post #17242066
Waiting for the image but you are naturally going to get less detail as the subject moves farther away simply because you'll have fewer pixels on the target.

That's true. But I'm not talking 50 feet away. Not even 20. I'm talking like 5--enough to get a full body shot and still be able to get some detail out of the face. I'll post an image when I get home.

If you have a face and it fills the frame, you'll probably have the bulk of the cameras pixels defining the face and you'll see lots of detail. When moving to a full body shot, the same pixels are defining the whole body but if you look at just the face, it will be a fraction of the whole.

Take a close-up of the face. Then take a full-body shot and crop it to just the face. Take a note of the pixel dimensions of the cropped image. Now re-size the full-face shot to the same pixel dimensions.

The two should look similar.

If the OP states that adjusting the MFA reverses the problem, making more distant objects sharper but nearer objects less detailed, why are we still assuming that this is purely a pixels-on-target issue? Sounds to me like his lens/body combo focuses differently at different ranges.

I'd try splitting the MFA difference to see if that's workable. If not, I'd get a different lens.

In my experience, the auto focus tend to be off when:

- the focusing box barely covers the spot you are focusing on
- the focusing spot is soft (i.e. human skin, face, certain clothing item)
- the contrast behind the focusing spot is high

This happens for all my bodies using wide to mid focal length lenses. My tele lenses work fine in the above situations on the same camera bodies.