Went through this morning AF Fine Tuning some lenses on my D610 with FoCal. Here results are attached below. The difference the 24-70 had between 24mm and 70mm has me wondering if there is something wrong.
Interesting - that sounds fairly extreme. Try re-doing the calibration, and maybe try at 30mm and 60mm too. Also take test shots at the distances you'll be using the lens - it might have more variation at close focus than infinity.
If it's indeed wildly off through the range, I would see about a factory recalibration. But make sure it's actually causing your shots to be misfocused, because trying to get a lens realigned is not always a fun process.
I re-did the calibration under difference lighting conditions, but still got the same values ±1. FoCal barked at me when I tried to do the calibration at anything other than the extreme lengths, but I'll try to work around that and test at 30mm and 60mm next.
Is the lens calibration process really that much of a PITA? I was hoping to just to drop it off here at the Melville repair center and have them run through the process. Should be covered under warranty I would think.
Do you have a prime, or can you borrow one?
AF tuning is easier than on zooms w/only a single FL
to worry about. Master that procedure and then tackle
your zooms. It's really fast...no charts, no weird light.
Shoot me a PM and I'll walk ya thru it. FWIW my D600
and D800 are "off" the most of my 7 Nikon bodies but
I've yet to have to send anything in. (16 lenses)
If you have a nearby centre, then yeah, go for it. I'm not sure how long it takes, I was going off experience with shipping. If you can explain precisely why you need it calibrated and ensure that they actually do it, all the better. Give them a call and check.
trenchmonkey wrote:
Do you have a prime, or can you borrow one?
AF tuning is easier than on zooms w/only a single FL
to worry about. Master that procedure and then tackle
your zooms. It's really fast...no charts, no weird light.
Shoot me a PM and I'll walk ya thru it. FWIW my D600
and D800 are "off" the most of my 7 Nikon bodies but
I've yet to have to send anything in. (16 lenses)
I've been using the Reikan FoCal software and everything is automated except for changing focal lengths to test extreme ranges of the zoom. I just point the camera at the chart and the software goes to town and spits out a final value. I can borrow a prime this week and give it a go. My concern was that the process worked flawlessly for 2 other lenses.
I've never used the FoCal. I'm surprised your proposed AF tuning values are so different and change sign. Do you need to change the subject distance when you change the focal length? With a zero adjustment, are you getting out-of-focus shots?
You could try the moire method, which is free, and compare.
Cacciatore wrote:
Went through this morning AF Fine Tuning some lenses on my D610 with FoCal. Here results are attached below. The difference the 24-70 had between 24mm and 70mm has me wondering if there is something wrong.
some_film wrote:
I've never used the FoCal. I'm surprised your proposed AF tuning values are so different and change sign. Do you need to change the subject distance when you change the focal length? With a zero adjustment, are you getting out-of-focus shots?
You could try the moire method, which is free, and compare.
are you doing macro work with this lens? If not, don't bother with af fine tune. Most of the time it creates more problems than it solves. The DOF at normal shooting distances will cover any micro differences in focus. This af fine tune non-sense is just another form of silly measurebating IMO.
I've used FoCal extensively and have had similar issues with zooms. The software works extremely well for primes, but they do admit to AF fine tune problems with zooms.
You do need to change the distance to the cart when using extremes on a zoom lens. Make sure the target is evenly and well lit.
In the end, I opted to pick a most used focal length for each zoom and set the AF fine tune for that FL.
glowhunter wrote:
The DOF at normal shooting distances will cover any micro differences in focus. This af fine tune non-sense is just another form of silly measurebating IMO.
It really, really doesn't. A fast lens at wider apertures on a high res sensor shows even a tiny focus miss.
Everyone's quality standards are different though....
mitchel674 wrote:
I've used FoCal extensively and have had similar issues with zooms. The software works extremely well for primes, but they do admit to AF fine tune problems with zooms.
You do need to change the distance to the cart when using extremes on a zoom lens. Make sure the target is evenly and well lit.
In the end, I opted to pick a most used focal length for each zoom and set the AF fine tune for that FL.
Even then, I generally bias the adjustment to fit the "most likely" focal length. So with my 24-70, I tend to go with a value on the wider end, with my 70-200 generally on the longer.
If you don't know which you use most often, LR, Aperture and ExposurePlot will analyze your images.
My first question is, what prompted you to do this in the first place?
Im still just starting out but when i was even more of a newbie i read into the Fine tune stuff and then started to question my lenses and the focus of them. After doing a lot of messing around i thought maybe my D7200 need to be recalibrated. After messing with it some more i just decided that is was probably more user error than anything and moved on.
You however are using a software calibration tool so i guess that takes the human error out of it.
I recently aquired a D610 that had autofocus issues, it looked like the thing got dropped from a foot off the ground and took a tumble on a few rocks. Everything else worked great, although the focus point in the view finder vs what was showing on the image review (what the sensor was actually seeing) was different. The result of that was the Sensor needing to be shifted so i tore down the camera and did that.
The AF sensor was a bit more of a pain since you have some cylindrical allen screws in the mirror box, ontop of the AF Sensor itself appeared to have some allen key adjustments that are reachable when you remove the bottom of the camera. So between messing with both of those using a cardboard calibration tool i made, i was able to get it to a very exceptable range. And really the issue i had only became apparent at wide open on fast lenses since the DOF was considerably small. First thing i had to do was figure out where on the view finder it was actually focusing on, i did this buy placing the square at the edge of my calibration tool and had it about 2ft off the wall so i could go back and fourth between it and the wall and make adjustmens accordingly till it was back inside the focusing square in the view finder.
I think my situation was a little different then yours, but what i learned was that of all those adjustments all i was doing was adjusting basically the cross hairs of the focus, not actually calibrating anything as far as the actual AF Sensor itself and what it determines is in focus. If your camera for some reason has a bad sensor then it needs to go back, especially if its under warranty.
I am not surprised in the least by your results, as I experienced (and experience) something very similar.
24-70G needed different fine tunes at 24mm and 70mm, although variation was little enough not to bother me. It was a handpicked copy (out of 3); other 2 tried exhibited enough shift to be visible on the low res D3s when shooting AF vs Live View.
24-70E needs practically the same fine tuning through all the range. It was a fine picked copy (out of 4). I paid a price for this: two of the other copies I tested were much sharper (mine, honestly, sucks in the 40-55mm range, really needs ƒ4...), but it was clear that one fine tune at 24mm wrecked image at 50mm and 70mm, and vice versa.
Previous 70-200 VR II was super sharp, and very consistent from 80-200 with a positive value for fine tune needed. 70mm to 80 it needed a strong negative fine tune! I used it as a 85-200/2.8 and lived with that. Bad mistake selling it.
Current 70-200 VR II has a "wavy" variation in fine tune throughout the range, and is not nearly as sharp as the earlier sample (and positively ugly at 85-105/2.8). Again, tested others in the shop, some sharper, but wilder af-tune requirements.
Unfortunately, all this is old news. It was just less apparent on lower resolution bodies.
I think we truly need contrast based and aperture dependent autofocusing, to eliminate:
* different fine tunes for different focal lengths
* different fine tunes for different distances (Sigma addressed these 2 with their dock)
* focus shifts, especially on fast primes
I understand people shooting sports or wildlife, but for those shooting static, or non hectic subjects, that would be the ticket.
The situation as it is, on high resolution bodies, is quite depressing, although as usual, its impact varies as a fluid combination of personal needs/technical expertise/...sheer luck...
