D7000 Focus Fine Tuning - Zoom Lens
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tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Just starting to fine focus my lens on the D7000, With the zoom lens, where (FL) do you fine focus. . . mid range or perhaps at the FL you use the most?



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

I believe it's recommended at maximum FL if you have to pick one, but you can also see what you get at 2 or 3 different FL's and then pick a compromise setting if you're willing to spend the time. Fortunately, zooms aren't all that fast so it's not as critical as with a nice fast prime!



tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Both my zooms are 2.8f.



trenchmonkey
Registered: Oct 22, 2004
Total Posts: 35302
Country: United States

Tom, I believe trying to fine tune a zoom...is an exercise in futility. Using a zoom as it's intended, you'll be "zooming"
Setting an arbitrary +/- at a specific FL defeats it's whole versatility. FWIW I have zero on 8 lenses (2 f2.8 zooms)
with my 2 D7K's and NO default values either. Never wanting for sharpness...I just shoot, and I score!



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

trench, maybe you got your own auto tuning aura but I personally do believe in fine tuning and if a zoom lens, throughout its zoom range, is consistently front or back focusing (but not both in one lens), then I think some tuning in the other direction will improve AF performance. It's boring, but on some lenses (like my 200 f2), it makes the difference for me between almost all keepers and almost all slight, very frustrating misses



trenchmonkey
Registered: Oct 22, 2004
Total Posts: 35302
Country: United States

I'll admit to setting -2 on one of my 200 f2's with an older D7K, but it was @ zero on the D3s/D3.
My 200-400 f4 was totally left alone, and keepers were pretty much automatic. We don't print @200%
so I may be missing something...maybe.



tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Here's where I am now with fine tuning:

AF-S 300 4D at -17
AF 80 - 200 2.8f (tuned at 200) -10
AF 20 - 35 2.8f (tuned midway inn the range) I can't say that I've found any difference.

I am most confident with the fine tuning of the 80-200 however I need to use this tuning with all of its range. It'll get a good workout Saturday.

In truth, I need to get more work out of these lens to evaluate these settings.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

I have a new D7000 on the way and intend to use an ai-ed 300 f/4 with it that will shoot soft on my D300s. I need a clue as to how to fine tune it because I think there is a slight front focus, although when I did the test with the coke can at every F-stop they were all real clear.. slightly sharper around F9-11 range.... so, perhaps the softness is me.. but even when I use a monopod I am routinely getting soft images. When I did the can test, I used a remote shutter release, so I think that helped too.

So, I'd like to know how to fine tune on the D7000 right away if possible if I need it.

Thanks
B



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

There are tons of tutorials and great explanations online, no special equipment or software is really needed, but the fine tuning is always done with the lens wide open. I do recommend a solid tripod and a release or self timer, but even handheld you'll get there if your shutter speed is high enough to prevent any blur.

Here's a nice calculator for suggested distances for lenses - see the distance tool tab.

http://michaeltapesdesign.com/lensalign.html

(edit) that link isn't working right for some reason, just copy and paste it in I guess.[



tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Why don't we give him a link to your favorite one??



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

^ I don't mean to plug any particular product, I just thought that distance calculator was nicely done. A product like this may get the job done a wee bit faster, but it won't do it any better than a cardboard box sitting on the lawn, as I've stated in other threads...



Gregstx
Registered: Dec 07, 2010
Total Posts: 595
Country: United States

I have had good luck with AF fine tune on zooms. I loved my 80-200 f2,8 push-pull on my film cameras. When I tried it on my shiny new D70, I was surprised and disappointed that it didn't look that good. Bummer. My favorite lens went into semi-retirement. When I graduated to my D200, it never looked sharp on that body either. When I tried it on a friends D300, I was disappointed again. When I got the D7K, I did an AF fine tune at full telephoto and eureka. Now the lens looks very sharp at all zoom ranges. I'm in love again.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Workerdrone, what does this distance calculator do for me? I'm just not sure what to do with the information it gives me.



tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Blutch, in my search I did find this:

http://camerafocustest.blogspot.com/



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

It's a pretty simple process - the goal is to eliminate fuzzy testing factors and poor test enviroments, find a CONSISTENT error in a camera body / lens combo, and use fine tune / microadjust to fix it.

1 - have an AF target of some kind (I previously had great sucess with a big piece of cardboard, folded in half so it would stand on its own, about 16x20 inches or so on the face, and I made a big 'bar code' on it with strips of black duct tape of varying width.)

2 - I stood this on the lawn (the grass will be very useful, just wait) in GOOD light - not too bright, not too dark

3 - I determined the test distance using that distance calculator that I linked to (or use the 50x focal length guideline, but really what you want to use is a very common distance that you would be using that lens at), and put the camera on a good tripod that distance from the target

4 - align camera to the same plane (sensor PARALLEL to cardboard) as the target, and put your focus point on the lower portion of the target, near where it is meeting the lawn but do not have any lawn inside the focus point, only target itself

5 - set lens aperture wide open, iso at base, single point focus (whatever focus point you want to test), and use self timer or cable release to shoot.

6 - take a few shots; before each, manually unfocus the lens and then use viewfinder AF (NOT live view) to focus on the target, then take a test shot. Unfocus, AF, shoot. Unfocus, AF, shoot

7 - review your test shots either in the LCD for gross adjustment or on the PC for fine detail. If your AF is working properly, the blades of grass in the same plane as the target should be in sharpest focus. If the camera is consistently focusing in front of the target, you have front focus (dial in + adjust). If in back, back focus (dial in - adjust). The blades of grass are just as good as the fancy computer generated test targets and focus rulers I think, they really show the plane of focus.

8 - dial in adjustment and repeat test until you can't make any further improvements, then move on to the next lens.


Typically it goes something like this for me - test/test/test - whoah - that's back focusing a lot. Dial in -15. test/test now it's front focusing a bit. Dial in -10. test/test/test still back focusing a bit. Dial in -11. test/test/test, Dial in -10 test/test/test Dial in -12 test/test/test, decide that -11 is the best of the 3, not so easy to tell anymore, but I'll leave it there. Stop testing, go out and shoot real world shots, enjoy my higher keeper rate.



tmak54952
Registered: May 16, 2009
Total Posts: 181
Country: United States

Great! Thanks! I even can understand that!



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

WD - Thank you for this basic explanation. I am having trouble visualizing the cardboard and it's justification to the front of the camera. Do you happen to have a test shot or two of this setup you could show us?

I typically use this 300mm f4 lens from a big distance away.. 80-90 feet. Should I go that far back to test it?

Thanks again!



workerdrone
Registered: Dec 29, 2010
Total Posts: 1160
Country: United States

The distance calc says for a crop camera with a 300 f4, 25 to 50 feet is good for tuning. You do want to generate shallow enough depth of field so you can clearly see the sweet spot of the focus plane.

I'm afraid I don't keep any test shots so I don't have photos to share - but just picture a sheet of cardboard folded in half, then let it make an A shape so it will stand up, with the fold up top and the two edges resting on the lawn. Like a signboard or an old pup tent. It makes two planes - one has the stripes of black duct tape to make the nice contrasty target for your AF. Place that one facing you, parallel to your sensor for the testing (or parallel to your camera LCD if that helps?) So your camera would be on the tripod tilted slightly down to make it parallel...



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Ok. I finally got a chance to do this today. I settled on +15 for the 300mm f4 and it seems much better.. on a tripod or monopod.

Then I shot some flowers and other things handheld and it appears I have some blur.. could there possibly be camera shake at 1/400th??

Thanks!



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

I should clarify.. I have some blur SOMETIMES. Other times they are dead on. Unfortunately, it is about 50/50.



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