When fine tuning focus on zoom lenses, is it better to use the widest setting on the lens, or the maximum zoom setting? (i.e. 80mm or 200mm) Or is it better to use the middle of the lens?
I am sure others will chime in but from what I have read it is best at the long end where depth of field is more shallow and smaller errors in focus will be noticed. Just my 2 cents.
I'm kind of new to photography but here's how I understand it for what it's worth.
Focal length: Find the setting at 80mm, then find the setting at 200mm. They will likely be a little different. Then you can take an average of them, and use that. I also shift mine toward the more used focal length so if you tend to be more on the 150-200mm end, I may skew my average a bit in that direction. So if 80mm was a -2 and 200mm was a -10, rather than choosing -6 as my setting for the lens if I shoot at the 200mm end more often I may make it a -8.
Aperture: Your widest aperture will make finding the focal midpoint much easier. The depth of field will be smaller so it will be easier to see were the focused area begins and ends.
I have been working on this AF Fine Tune question on the D7000 for quite some time since taking two courses on the D7000. After much reading and experimenting, I have come to the following conclusions:
1. For the 17-55, I set the AF Fine Tune for about 30mm. Really sharp shots.
2. For the Nikkor 70-200 f/2.8 and Sigma 150-500 "BigmOS", I set AF Fine Tune at 190mm and 480mm respectively because that focal length is what I got those lenses for! (Although I do admit that the 70-200 is set almost to 0 in AF Fine Tune and I use it for portraits sometimes. It is such a masterpiece of photographic glass...)
3. I have other settings when using teleconverters.
4. The method I used to determine what settings to use was to go through all the AF Fine Tune settings from -20 to +20 in 5point increments taking the same photo over and over at specific focal lengths. Sounds like a lot of work but it went fast once I got into it. Then I was able to look at the range of shots and pick the best settings.
I tried using a chart at 45degrees of incline but it seemed too artificial and I want my lenses to work in real situations like outdoor sessions.
In the outdoors context, using f/8 routinely is the optimal aperture for sharp photos.
At one point, I took my D7000 to Nikon Service and asked them to check the AF settings for me. They gave it back to me saying that there was little adjustment needed. This has made me realize that this camera takes such fine resolutions photos, that any motion blur, lens issues or bad technique will show up pretty immediately because when I do manage to get it all together, the D7000 takes significantly better photos than my D300.
Live View does seem to get sharper photos as others have noted. This is why a lot of D7000 owners suspect the mirror issue is the culprit for getting sharp shots.
ChrisCoy wrote:
When fine tuning focus on zoom lenses, is it better to use the widest setting on the lens, or the maximum zoom setting? (i.e. 80mm or 200mm) Or is it better to use the middle of the lens?
Try both ends and see if there is much difference. If it is minor, you may want to split the difference. Ours is calibrated at ~180 mm as that seemed to work well enough on the D7000.
hjanssen wrote:
Try to find out which focal length you use the most and make that the calibrated length.
This, everything else is just a compromise. FWIW in the last 2 years ~180,000 clicks on a total
of 6 D7K's used with 9 lenses....ZERO AF fine tune on any Lucky? I don't really think so. Took
the time to learn the camera like the back of my hand. BTW, 'monkey settings for a beer via PP
trenchmonkey wrote:
This, everything else is just a compromise. FWIW in the last 2 years ~180,000 clicks on a total
of 6 D7K's used with 9 lenses....ZERO AF fine tune on any Lucky? I don't really think so. Took
the time to learn the camera like the back of my hand. BTW, 'monkey settings for a beer via PP
We used 'em for spec. shootin' rodeo for 2 complete seasons of barrels/team roping/roughstock.
2 full time, 1 back-up each year....and sold when the season was over. Still keep one on hand for
BIF that I bought new this Spring, so make that 7
Same situation as Trench, thought I needed the focus adjustment at first because I could, but I haven't had to do any fine tune with any of my lenses. I have two personally and people tend to bring me theirs to set up, I think I've seen one that "needed" it. I think it was her technique though, some mom on the sidelines trying to snap some shots of her kid.
I have two personally and people tend to bring me theirs to set up Fully a third of my time at Bosque is done doing just that tho not limited to the D7K
trenchmonkey wrote:
This, everything else is just a compromise. FWIW in the last 2 years ~180,000 clicks on a total
of 6 D7K's used with 9 lenses....ZERO AF fine tune on any Lucky? I don't really think so. Took
the time to learn the camera like the back of my hand. BTW, 'monkey settings for a beer via PP
Well trust me... this Sigma is back focusing severely. It's the most pronounced in low light. I hate this friggin lens. Worst decision I ever made was trading my Nikon off for this one and the 80-200. HATE this Sigma lens. Its jumpy, it back focuses, and its just not as quick as my Nikon was. I can't wait until after the first of the year when I can buy another Nikon.
I haven't noticed as much of an issue with the 80-200, but what I have noticed may be (as previously stated) the issue of higher resolution and more pronounced camera shake. I use a single focus point. I've tried to use a multi-point focus as you suggested - like the 9 pt, but I can't get used to it. I don't like when I go to focus on something and it hits something just behind it, or just to the side of it, or on top of it - and I have to keep hitting my rear focus button trying to get it to focus on the right thing. I've always used a single focus point on my D90 and never had an issue, ever.
FWIW in the last 2 years ~180,000 clicks on a total
Lucky? I don't really think so. Took
Fully a third of my time at Bosque is done doing just that 
tho not limited to the D7K 