70-200 fuzzy

Joined
Apr 5, 2005
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1,148
Location
Clarksville, IN
I am hoping someone can help but I fear not. I am going to Florida to shoot primarily Ospreys and my 70-200 that I was going to use as a best available backup to the 200-500 is no longer sharp. Comparing the 70-200 set at 200mm to the 200-500 set to 200 and taking the same shot at the same setting with tripod and NO VR, Shutter set at 1/4000 and 70-200 at 2.8 results in an image less sharp that even my non techy wife can see.
The camera was set for single point focus and frame rate of 1 with a ten second delay, No wind.
Looking through the viewfinder I would manually defocus and I could see the lens focus shift to what appeared focused as soon I a pushed the button.
I was expecting the 70-200 to be far superior to the 200-500. Seeing the difference I adjusted the fine focus value of the 70-200 to a value of -2. the 200-500 was sharpest at 0.0
Image 1 is a screen grab of three raw files,
002 is the 200-500 at f5.6
005 is the 70-200 at f/2.8
008 is the 70-200 at f/11

Image 2 is a screen grab of the NEF converted to JPG with only contrast and sharpening applied. The same settings were applied to all 3. As you can see by sharpened and going to f/11 on the 70 to 200 I can almost make it sharp but at the cost of 4 stops of light that I can't handle. this test was run at 100 yeards and again at 15 yards which is displayed. The results were very similar

looking at the internet it mentions a typical problem of the focus sticking at one extreme of travel. I do not believe that is a problem here but yes I have experienced it.

Any suggestions would be appreciated
.
Image 1
NEF Files from screen shot..jpg
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Image 2
contrast and sharpening.jpg
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Joined
Jan 2, 2009
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6,535
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Alaska
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Dan
It certainly looks like a focus tuning issue. The fact that it pulls in at a smaller aperture/wider DOF is a good clue. How did you land on -2 for focus adjustment. I've done a good bit of focus tuning on long lenses and judging by the degree OOF that your images appear an adjustment of 2 isn't going to touch it. When I start tuning a lens I shoot a series across the full range -20, -15, -10, etc to +20. Once I bracket the sharpest apparent setting I narrow the span and zero in with 2 point intervals. For example after the first set if -5 looked the sharpest I'd then take a series from -10 to zero at 2 point shifts.
 
Joined
Apr 5, 2005
Messages
1,148
Location
Clarksville, IN
your process of fine tuning is exactly the same as mine. .
bracket by shooting @ f2.8,
tests from -20 to +20 in increments of 5.
select the best in this case it was 0
then tests from -5 to +5 in increments of 2
select the best which was -2
then verify by shooting -3,-2,-1
Set camera to -2
then shot full range f2.8 to f22 in 1 stop increments.
 
Joined
Jan 22, 2019
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Jupiter, FL
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Andy
It looks like an AF tuning issue to me. Are you able to achieve sharp focus manually?

I suggest downloading and printing a focus target and trying AF tuning again indoors.
 
Joined
Jan 22, 2019
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Jupiter, FL
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Andy
although I never do it I am convinced AF fine tuning matters alot
I once borrowed a 70-200 VR1 from a friend while mine was out of commission. It appeared to be very soft when I first tried it. Then, I used Reikan FoCal to calibrate it on my D500 and found that it required a -20 AF fine tune adjustment. It was a little disconcerting to have to use the max adjustment value, but the lens worked flawlessly once that was set.
 
Joined
May 11, 2006
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CHARLOTTE
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Randy
I once borrowed a 70-200 VR1 from a friend while mine was out of commission. It appeared to be very soft when I first tried it. Then, I used Reikan FoCal to calibrate it on my D500 and found that it required a -20 AF fine tune adjustment. It was a little disconcerting to have to use the max adjustment value, but the lens worked flawlessly once that was set.
I should do that, so far I send them to Nikon
that's one of the things I love about my z6, perfect AF accuracy every time and no fine tuning
 
Joined
Jan 22, 2019
Messages
2,502
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Jupiter, FL
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Andy
one of the things I love about my z6, perfect AF accuracy every time and no fine tuning
So true. I tried tuning all my AF-S lenses on the Z6 with Reikan. Unsurprisingly, all came out zero. I could be mistaken, but I believe it is possible for a lens to require a significant adjustment on a mirrorless body - which indicates something is out of adjustment in the lens itself.
 
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