A Startling Revelation

[Brendo09]

I've been gathering a few lenses, and then taking photo's with them. Generally, I'm pretty disappointed with the image sharpness, as the focus on all of the lenses seems to be a little off.

I then found out about the Auto Focus Fine Tune, and over the last hour and a half have been fiddling around with al my lenses and some text on a 45 degree angle and some of the kids figurines set up at slightly different depths.

My conclusion is thus.

I've been far too far away from the subject for the lenses I have. That, and you need good light for tight focus. With ISO's over 800 my camera (d7200) struggles. If the subject doesn't take up a good deal of space in the view finder, I'm not going to get a sharp image.

I took a few of the kids outside in good light and the lenses I tried were sharp (not tack sharp, razor sharp, knife edge sharp etc). I was only a few metres from them, and they were still and co-operative.

I tried the 55-300 on some Twenty Eight parrots which were only 7-10 metres from me, and the images stunk. I was leaning on a wall to stabilise myself, the light was average, and the images were very soft.

So what's the outcome? For me, it's to take photo's within my distance means. Landscapes are one thing, but kids, pets, cakes, drawings etc all need to be within 4m.

Luckily learning is enjoyable... I just hope I learn more of the straight forward stuff early on.

[ameerat42]

So are you saying it's "now fixed "? - Or nt?

[Brendo09]

I'm saying that it wasn't the Auto Focus that was the problem 98% of the time.

[swifty]

I'm a little confused by your post but I hope some of the following info might help.
The AF fine tune feature on current Nikons can only have one setting per lens.
However, unfortunately some lenses require different AF fine tune amounts at different focus distances and for zoom lenses, there may be a difference at various focal lengths too.
This is one of the limitations of DSLR's PDAF implementation.

The general advice is to do your AF fine tuning at your most commonly used shooting distances, using the centre AF point. There's also another guideline that tells you to perform the test at X times the focal length of the lens. I can't remember the exact figure because I don't use this method and prefer to fine tune at my most commonly used subject distance for that lens.

You need to eliminate as many factors that could cause AF error as possible when dialling in your fine tune setting. Which means using a sturdy tripod, a good AF target and good illuminations. Even though you're on a tripod, good illumination ensures good shutter speeds to perform your tests. Mirror lock up, time delay, remote shutter etc. can further improve your results.

There are many methods for performing these tests but in general, what you should try to establish is what is the best your lens can do and this is probably best done by manual focusing in live view with the aperture wide open. After repeating this a few times to get the sharpest image you can, now switch to AF and perform a series at various fine tune settings, also with the lens aperture wide open. Do it systematically so you don't get confused with what settings you've tried.
What you want is an AF fine tune setting where the results are as close to your live view best result as possible.
Once you get repeatable results, now try your dialled-in lens on real world subjects off the tripod and see how it compares.
If you're getting substantially worse results in the real world but repeatable good results on a tripod with a well illuminated target, then the AF fine tune is not the problem.

[Brendo09]

Thanks Swiftly. I've read the original post back and your right, it sounds like I've been suffering from some blunt force trauma to the noggin.

Ultimately my post was meant to say that I'll get best result if I stay within the limits of my equipment. It's all well and good to be optimistic, but it can't outreach your limitations.

[swifty]

Thanks Swiftly. I've read the original post back and your right, it sounds like I've been suffering from some blunt force trauma to the noggin.

Ultimately my post was meant to say that I'll get best result if I stay within the limits of my equipment. It's all well and good to be optimistic, but it can't outreach your limitations.

Yep, definitely agree regarding staying within equipment limits for best results. Just that from your original post it appeared there were very large discrepancies even within what I'd consider the normal shooting window. What I forgot to highlight in my post above was that AF fine tune should affect small discrepancies and in the same direction ie. consistently back focusing or front focusing by a bit rather than big misses.
So quite possibly other factors are causing the poorer results. If you care to share, post some of the poor samples and the camera settings you took them with.