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Archive 2014 · Focus Issues D7000...Suggestions needed

Jim8EL
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p.1 #1 · p.1 #1 · Focus Issues D7000...Suggestions needed

So here's an issue that's been beat to death here but I'm stumped and need some advice from my FM friends. I haven't been completely happy with the focus consistency of my 300 F4 AFS on my D7000 for some time. Mostly I've passed it off to poor technique. But I decided once again to try to tweak the AF fine tune of this combo but the results are confusing to me.

Doing the standard ruler on a 45 to the camera test I tried to dial the lens in at first making minor adjustments. But seeing no positive results tried a test. I tested on a tripod aimed at a yardstick. I used the IR remote with mirror up to do the test. I then auto focused on the target with AF fine tune set to -20. I then change to a setting of 0 took a shot and then a setting of +20 being very careful not to re-focus or bump the rig. Hers the surprising part, all of the shots look identical. The big fine tune swings seem to do nothing to move the focus point forward or backward.

I'm thinking the body needs to go to APS for service. Your thoughts are appreciated.

Jim

Feb 27, 2014 at 07:03 PM

CanadaMark
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p.1 #2 · p.1 #2 · Focus Issues D7000...Suggestions needed

Can you show us some examples at AF fine tune zero with EXIF instact?

What are your shutter speeds like?

How are your real world shots? I wouldn't read much into the ruler shots.

The 300/4 does need a little better technique than other lenses, being heavy, no VR, and an average OEM collar. It shouldn't bee too hard though.

How does PDAF compare to CDAF? Take a shot using the center AF point, and then take the same shot in live view, of an easy to nail, flat target. That is a helpful test as well.

Feb 27, 2014 at 07:36 PM

trenchmonkey
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p.1 #3 · p.1 #3 · Focus Issues D7000...Suggestions needed

I used the IR remote with mirror up to do the test. I then auto focused on the target with AF fine tune set to -20. I then change to a setting of 0 took a shot and then a setting of +20 being very careful not to re-focus or bump the rig. Hers the surprising part, all of the shots look identical.

You NEED to reacquire focus every time. Rack to infinity or hand in front of lens in between shots.
You NEED to hit OK every change to save the adjustments. Might be the reason for "no difference"
You NEED to shoot at f4. If your other (shorter) lenses are good on the D7K...it's NOT the body.

Feb 27, 2014 at 07:50 PM

Jim8EL
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p.1 #4 · p.1 #4 · Focus Issues D7000...Suggestions needed

CanadaMark wrote:
Can you show us some examples at AF fine tune zero with EXIF instact?

What are your shutter speeds like?

How are your real world shots? I wouldn't read much into the ruler shots.

The 300/4 does need a little better technique than other lenses, being heavy, no VR, and an average OEM collar. It shouldn't bee too hard though.

How does PDAF compare to CDAF? Take a shot using the center AF point, and then take the same shot in live view, of an easy to nail, flat target. That is a helpful test as well.

Mark,

Shutter speeds for testing are low because I'm testing indoors (single digit temps and windy outdoors) but with tripod, remote trigger and mirror up I didn't think that would be an issue.

Real world shots are OK sometimes but seem to require more sharpening than I thought should be necessary.

PDAF and CDAF are very close.

Below is one I just shot. Corrected for WB only. No output sharpening. How do you think it looks. This looks better but that is part of what I've been going through. It's inconsistent.

On another note, as I focused I got a focus confirmation dot but the picture was clearly very much out of focus in the VF. I had to rack it out to infinity and re-try to get good focus. Anyway let me know what you think. Thanks.

Feb 27, 2014 at 09:43 PM

Jim8EL
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p.1 #5 · p.1 #5 · Focus Issues D7000...Suggestions needed

trenchmonkey wrote:
You NEED to reacquire focus every time. Rack to infinity or hand in front of lens in between shots.
You NEED to hit OK every change to save the adjustments. Might be the reason for "no difference"
You NEED to shoot at f4. If your other (shorter) lenses are good on the D7K...it's NOT the body.

Box of cereal on gravel drive or lawn from ~30' Look to side of box for sharpest gravel/blades. Adj.
accordingly. Should take max of 5 minutes. Rinse, repeat process with TC moving back a few steps.
Clean contacts (body AND lens with CRC or equivalent) Rocket blow AF...Show more →

Ah, thanks Will. I wasn't re-focusing between shots. I was hitting ok to save the setting though and shooting at f4. My other lenses aren't much to speak of. Mostly value (cheap) zooms. The shot in the above post is ok I think but not getting consistent results. Most of what I've shooting has been from a gimbal head and decent shutter speeds (1/1250 and up) so I don't think that's the issue.

Another thing I've noticed is that the lens chatters (very fast micro focus adjustments) in af-c. Even in bright light.

Feb 27, 2014 at 09:49 PM

CanadaMark
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p.1 #6 · p.1 #6 · Focus Issues D7000...Suggestions needed

Jim8EL wrote:
Mark,

Shutter speeds for testing are low because I'm testing indoors (single digit temps and windy outdoors) but with tripod, remote trigger and mirror up I didn't think that would be an issue.

Real world shots are OK sometimes but seem to require more sharpening than I thought should be necessary.

PDAF and CDAF are very close.

Below is one I just shot. Corrected for WB only. No output sharpening. How do you think it looks. This looks better but that is part of what I've been going through. It's inconsistent.

On another note, as I focused I got a focus confirmation dot...Show more →

Tripod & mirror up should be fine, I doubt camera shake is ruining your images (You could also pump up the ISO if you wanted to try faster shutter speeds indoors). If you're using the OEM collar though, it is known for not being very stable. Can you shoot through a window or something? It shouldn't affect IQ too much, but I would be curious what happens at 1/500 or 1/1000, just to rule that out. And fill the frame with something if you can, don't shoot a telephone pole in the far distance or something like that.

If PDAF and CDAF are very close, and acceptable with other lenses, that should rule out your camera body as the issue. Also if you aren't having any issues with other lenses.

That picture looks OK to me but I am not sure how to view it at full size. At that resolution, anything will look OK unless it's extremely soft. Do you have any larger samples? I know it might be difficult to embed in the forums, maybe a link elsewhere would do.

If the VF is blurry during focus confirm, first thing to check is the diopter. You may have accidentally moved it. Otherwise it would be unusual to get focus confirm and a very blurry VF.

You could try run through another AF fine tune, but keep in mind you are only tuning it at the exact distance where you do the fine tuning, and may be making all other distances worse. Often what happens is you make one distance 5% better, and other distances noticeably worse. Some people seem to have luck with global adjustments, but that has not been my experience at all. Nikon actually recommends you not to use AF fine tune in most circumstances, for that exact reason. Until there is a way to fine tune lenses at every focal length AND subject distance combined, and quickly, I would simply exchange the lens if it wasn't good at 0. I've never had to do that though. If you're needing +/- 20 and it's not razor sharp, and failing every other test, I'd exchange the lens.

That focus chatter is fairy normal, lots of lenses do that if they can't quite decide on focus. For example, if you were trying to focus on a 45 degree ruler, it would probably struggle a bit to guess exactly where you wanted to focus. I wouldn't worry about that too much. If you have a good, flat, AF target though, it should snap right on.

At the end of the day, you know best. I'm sure you have experience with other lenses, and have been satisfied with them. If you are bending over backwards to try get a 300/4 to take a sharp image, I'd wager the lens may be defective. It is razor sharp at F4.

Feb 27, 2014 at 11:10 PM

Gaylon Holmes
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p.1 #7 · p.1 #7 · Focus Issues D7000...Suggestions needed

When I re-focus between changes I like to use the focus ring. Turn it the same direction and same distance each time.

If the tripod collar is a concern stuff a rubber stopper or similar widget in the foot-to-lens space. This helps the poor design noticeably.

AF-C chatter is not unusual - its an f4 lens looking for contrast.

D7000 focus points are rather larger than the viewfinder display indicates. A large target helps. The cereal box is a good one and combined with a large rule placed appropriately makes things easier.

Feb 28, 2014 at 12:36 AM

chuhsi1
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p.1 #8 · p.1 #8 · Focus Issues D7000...Suggestions needed

is this with all lenses or just this one?

Feb 28, 2014 at 02:00 AM

Jim8EL
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p.1 #9 · p.1 #9 · Focus Issues D7000...Suggestions needed

CanadaMark wrote:
Tripod & mirror up should be fine, I doubt camera shake is ruining your images (You could also pump up the ISO if you wanted to try faster shutter speeds indoors). If you're using the OEM collar though, it is known for not being very stable. Can you shoot through a window or something? It shouldn't affect IQ too much, but I would be curious what happens at 1/500 or 1/1000, just to rule that out. And fill the frame with something if you can, don't shoot a telephone pole in the far distance or something like that.

If PDAF and CDAF are very close, and acceptable with other lenses, that should rule out your camera body as the issue. Also if you aren't having any issues with other lenses.

That picture looks OK to me but I am not sure how to view it at full size. At that resolution, anything will look OK unless it's extremely soft. Do you have any larger samples? I know it might be difficult to embed in the forums, maybe a link elsewhere would do.

If the VF is blurry during focus confirm, first thing to check is the diopter. You may have accidentally moved it. Otherwise it would be unusual to get focus confirm and a very blurry VF.

You could try run through another AF fine tune, but keep in mind you are only tuning it at the exact distance where you do the fine tuning, and may be making all other distances worse. Often what happens is you make one distance 5% better, and other distances noticeably worse. Some people seem to have luck with global adjustments, but that has not been my experience at all. Nikon actually recommends you not to use AF fine tune in most circumstances, for that exact reason. Until there is a way to fine tune lenses at every focal length AND subject distance combined, and quickly, I would simply exchange the lens if it wasn't good at 0. I've never had to do that though. If you're needing +/- 20 and it's not razor sharp, and failing every other test, I'd exchange the lens.

That focus chatter is fairy normal, lots of lenses do that if they can't quite decide on focus. For example, if you were trying to focus on a 45 degree ruler, it would probably struggle a bit to guess exactly where you wanted to focus. I wouldn't worry about that too much. If you have a good, flat, AF target though, it should snap right on.

At the end of the day, you know best. I'm sure you have experience with other lenses, and have been satisfied with them. If you are bending over backwards to try get a 300/4 to take a sharp image, I'd wager the lens may be defective. It is razor sharp at F4....Show more →

Mark,

Using RRS replacement collar. I'll try a shot outdoors in good light but won't get to it until Sunday...work, work, work.

If you would like to see the full size raw of jpg, pm your email and I'll send it to you. I may just send the lens and body in for a cla anyway just for piece of mind. Thanks for your help and interest.

Jim

Feb 28, 2014 at 03:09 PM

Jim8EL
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p.1 #10 · p.1 #10 · Focus Issues D7000...Suggestions needed

Gaylon Holmes wrote:
When I re-focus between changes I like to use the focus ring. Turn it the same direction and same distance each time.

If the tripod collar is a concern stuff a rubber stopper or similar widget in the foot-to-lens space. This helps the poor design noticeably.

AF-C chatter is not unusual - its an f4 lens looking for contrast.

D7000 focus points are rather larger than the viewfinder display indicates. A large target helps. The cereal box is a good one and combined with a large rule placed appropriately makes things easier.

Thanks Gaylon. I'll try the cereal box or similar this weekend.

Feb 28, 2014 at 03:10 PM

Jim8EL
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p.1 #11 · p.1 #11 · Focus Issues D7000...Suggestions needed

chuhsi1 wrote:
is this with all lenses or just this one?

My other lenses are consumer grade zooms so not very good glass to judge small focus errors. The 300 f4 AFS though is pretty much razor sharp. Not like the best of the best but not far below either. Just trying to get all I can from it. Thanks.

Feb 28, 2014 at 03:13 PM


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