Nikon AF Fine Tune and Tokina 28-70 f2.8

Seems I am getting some back focus from my Tokina AT-X Pro 28-70 f2.8. I have download some test charts and ran some tests and the results are the same. Better focus above my focus point.

 

To try and compensate, I went into the AF Fine Tune on my D700. The camera recognizes that I am using a Tokina lens. I turn on the AF Fine Tune and do some test shots. I get the same results as if the AF Fine Tune is turned off. I adjust in the positive side and the negative side. I really do not see any difference.

 

I am wondering (out loud here) if the AF Fine Tune is just for Nikon lenses. I don't know. Just a SWAG. Am I out in left field thinking this? The default value is 0 while I make adjustments with, and save the other values.

 

Anyone have any thoughts on this? Thanks

AF fine tune should work for 3rd-party lenses as well. The one concern is that if that 3rd-party lens doesn't have a Nikon equivalent, e.g. a Sigma 40mm/f1.4, there may not be a spot in the Nikon lens DB to store the info, since Nikon doesn't have a 40mm f1.4. However, there is a Nikon 28-70mm/f2.8 AF-S, which I happen to have. Hopefully your D700 can work with that

The one concern is that if that 3rd-party lens doesn't have a Nikon equivalent, e.g. a Sigma 40mm/f1.4, there may not be a spot in the Nikon lens DB to store the info, since Nikon doesn't have a 40mm f1.4.

Doesn't seem how this works - Nikon doesn't have a 24-105 but my Sigma registers just fine. So does the Sigma 150 - again no equivalent in Nikon's line up.

IIRC, you can even have two of the same lenses fine-tuned with different parameters.

Edited March 28, 2019 by Dieter Schaefer

Doesn't seem how this works - Nikon doesn't have a 24-105 but my Sigma registers just fine. So does the Sigma 150 - again no equivalent in Nikon's line up.

Interesting, sounds like Nikon DSLRs store the AF fine tune info in a different way from what I read.

Thanks ShunCheung. I think I would have a better understanding if I knew what was happening. Is the compensation stored in the camera or in the lens' CPU?

 

And yes, the lens is registered twice in my camera. I just select which offset I want to use by selecting the save parameters.

Focus calibration is not stored in the lens the way you're doing it. There are lenses that can do just that but, unfortunately, your Tokina is not among them.

 

I wouldn't waste too much time on what you're trying to do, if I were you. You are very unlikely to achieve consistently accurate focus with your setup, no matter how long you fiddle those calibration settings. And if you do manage to somewhat "tame" your lens, it will "behave" only at one particular set of parameters, let's say, 70mm zoom setting, focused at infinity. If you change your zoom or focusing distance, the focus will be off in your pictures.

In-camera focus "fine-tuning" is next to useless in the real world. It only sorta works for prime lenses, at a single focus setting, let's say: infinity.

 

To get much more accurate and consistent focus you should acquire your focus in Live View. For maximum accuracy you should also open up the lens, while doing so. If you and your subject are not moving you should be able to flip back to OVF and proceed to taking the picture the "old-fashioned" way. For subjects that are relatively close to you, you will have to capture right there, in Live View but the focus will almost always be noticeably more accurate than what you would get otherwise.

 

Best part is that you can keep fine-tuning your AF, it don't bother Live View focus.

 

*If you haven't done so already, change your camera's settings so that the shutter release is not engaging the AF. I've been focusing with the AF-ON button since my first Nikon F5.

Edited March 28, 2019 by david_r._edan

*If you haven't done so already, change your camera's settings so that the shutter release is not engaging the AF. I've been focusing with the AF-ON button since my first Nikon F5.

 

Thanks for that info. I tried once before with AF Fine Tune but gave up on it. I just started again. But will probably give up again. You do make a fine point about zoom and focus issues. I will just keep shooting around f8 or so.

 

I am not following what your are saying in the quote above. Can you elaborate?

Thanks for that info. I tried once before with AF Fine Tune but gave up on it. I just started again. But will probably give up again. You do make a fine point about zoom and focus issues. I will just keep shooting around f8 or so.

 

I am not following what your are saying in the quote above. Can you elaborate?

 

When the camera is set to AF at half-press (shutter release) you will lose your (in most cases perfect) focus when trying to actually take the picture after you've switched back to OVF (optical view finder). I've been focusing with LV since my first DSLR that had that capability. I often do not take the actual picture in LV but rather flip back to OVF for framing and capture. And by "framing" I mean moving the camera around ever-so-slightly, with no zooming. This approach, obviously, works only for static objects that are some distance away and for it to work you need to make focus acquisition and image capture 2 independent functions. (There IS an AF-ON button on your D700 and it is there for this kind of scenarios).

 

The thing about "shooting around f8" is that when the focus misses it still goes somewhere. Just an example: You're shooting a closeup portrait of a person and you know that your lens always back-focuses a little. You stop down to F8 and focus on one of the subject's eyes. In the final picture the eyes are just a tad soft but they're sharp enough. The ears, however, look magnificent! They're in perfect focus, even sharper than the eyes. Awesome!

 

Bad focus is just BAD.

 

The problem with DSLRs (and film SLRs alike) is that by design, the camera acquires the focus in one place and captures the actual image at a different place. In Live View, focus acquisition occurs at the image plane. Mirrorless cameras, bridge cameras and every digital P&S camera from the last decade do not have the issue that you're currently dealing with.

The best "solution" so far has been to calibrate not the AF system in the camera but the actual lens, at several points of focal length and focus positions. For that you need a lens that has this capability built-in. My Tamron 24-70/2.8 G2 is like that. I can have separate AF "correction" parameters for 24, 35, 50 and 70 mm, at 3 different focus positions each. The calibration process itself is tedious work and I must say that even after having completed it, my focus is still off whenever I'm in between those fixed points. I shoot mostly with a D850 nowadays and I focus via LV whenever I can, regardless of the lens. Sure, the focus isn't always perfect but the odds are always in my favor this way. *For anything that moves very quickly LV isn't gonna do you much good.

 

Best of luck.

Edited March 28, 2019 by david_r._edan

Nikon AF fine tune stores the tune value for each lens inside the body, and I recall the D700 can store the data for 10 lenses.

 

When it comes to zooms, you can only fine tune at one focal length at one distance. I usually don’t bother.

ROFLMAO... Live View. I completely forgot about that feature. Sorry guys, my main gear is Canon. I wanted the Nikon so that I could be ambidextrous photography wise. I think I should spend a little more time with the D700. I just tried the focus via LV and the camera's zoom feature. Focus was snot on. Brilliant.

 

My faith in oxygen has been restored. LOL

 

Thanks tons for your help

Or try mirrorless. Probably won't need AF fine tune any more.