D7000 back focus issue, tried AF tune for 80-200, still cannot...

[Kai2810]

Just came across some vids about Nikon AF Tuning, and had some issues focusing with my 80-200 on a recent Pulau Ubin trip organized by David, and so tried it out.

Really got problem...sian.

I setup my D7000 on a tripod and placed a 30cm ruler on the floor, and focused on the 5cm spot. Here's what I got.

AF-Tune set to 0 on the left, -20 on the right.

AF-Tune set to 0 on the left, -20 on the right, zoomed in even further.

Have a faint hint of difference, so I tried with my 18-105 kit lens. BIG difference.

I think the AF-Tune works ok for my kit lens, but it's still not effective for my 80-200.

Any advice? Send it to service centre for inspection?

Quite pissed I only found this out after 2 yrs of usage...

 

[LBL2009]

Check the focus point to see that it aims at the 5cm mark to be sure.

If 18-105 okay and 80-200 far off, maybe the problem is with the 80-200.

 

[daredevil123]

Can you please use a proper focus chart?

 

[Light Machinery]

Hello.

It is quite difficult to determine the results if the AF fine tune test jig isn't set up properly. Plus it will not yield the desired result that you may need.

1. You need a big, brightly lit & high contrast target for the center AF point to focus properly.

2. Set up your target plane to be parallel with your sensor plane.

3. Zoom to the lens to the max or to the distance that you typically shoot.

4. Set up your target about 20-50X of the lens focal length or to the distance indicated on the distance scale that you typically use.

5. Then shoot & determine it it is back or front focused.

5.1 Please visit the Nikon page about AF fine tune for more information.

Nikon Europe:
https://nikoneurope-en.custhelp.com.../51633/~/how-to-use-the-af-fine-tune-function

Lens align web page: http://michaeltapesdesign.com/lensalign.html

6. Once confirmed. Take your results, lens & camera to NSC & explain to them.

7. NSC will definitely will be able to remedy the situation by tweaking the lens.

May I ask if the effected lens is a AFS 80-200 or a AF 80-200 D?

 

[akuma]

are you Kai from Digitalrevtv?
have a read at this thread.
http://www.clubsnap.com/forums/cano...bration-there-need-share-your-experience.html

 

[Kai2810]

May I ask if the effected lens is a AFS 80-200 or a AF 80-200 D?

Hi Light Machinery, thanks for that link, I just redid the test, using self-timer to get my hands off the camera.

I'm using a AF 80-200D.

Here are the shots, focusing on the 14cm mark on the ruler which is placed next to the flat surface of the book cover.

18-105 AF0 vs AF-15 Not much difference

shots from the problematic AF 80-200D
AF0 vs AF-15

AF-15 vs AF-20

The sweet spot seems to be AF-15.

I clearly remember I did my first test shoot 2 years ago with my friend using a D90, shooting the esplanade with a wide angle lens. My friend's shots were significantly sharper than mine, tested with the same lens, tripod and remote trigger. Didn't think much about it back then...

May I know what do you guys think? Should I just have this setting for the 80-200D, or should I send in my D7000 to check?

 

[Kai2810]

are you Kai from Digitalrevtv?
have a read at this thread.
http://www.clubsnap.com/forums/cano...bration-there-need-share-your-experience.html

Hi hi,

nope I'm not!

 

[daredevil123]

Looks like AF-15 is the setting for your 80-200. But apart from looking at just the point of focus, need to really look at the entire depth of field as well. to see where it starts to get blur in the foreground as well as the background.

 

[Light Machinery]

Hi Kai2810. Glad to hear from you again. I see you have made some progress in isolating the problem.

The 18-105mm has a much smaller aperture (f/5.6 at 105mm) lens, thus it will have a much deeper depth of field and the AF fine tune adjustment will not have much effect on it.

Yes, looks like -15 setting is the sweet spot for the AFD 80-200mm f/2.8 and the images of the number 14 on the ruler is much sharper but I cant judge where is the depth of field from your cropped image. Also -20 is a bit too much and the image is not that sharp anymore.

I have looked at your set up. The ruler is quiet at a steep angle and it will be quite difficult to see the overall depth of field, especially where it starts to blur in the foreground and background as mentioned by "daredevil".

The ruler is usually recommended to be placed at an angle of 30 deg or 45 deg, this way you will be able to see the depth of field very clearly when the lens is shot wide open.

You may want to do a recheck with the ruler placed at a shallower angle.

But if on recheck with the ruler placed at shallower angle and the AF setting remains at -15 to give the best overall depth of field (i.e. the depth of filed behind and in front is about equally the same), I will leave it as it is as it in spec.

Personally I have some lenses that needs -20 AF fine tune and it still back focusses, these were the lenses that I took to NSC with the body and have them tweaked. Any lenses that have a well centered DOF after AF fine tune I will use it as it is.

Did you try shooting faces up close after tuning? Just compare the pictures of the same person and same pose with AF fine tune and without AF fine tune.

 

[kcchew]

For what it's worth, when I had the two-touch AF-D 80-200, there was horrendous backfocus at close distances (<3m) that could not be saved with AF finetune, similar to what TS is facing. Beyond that distance, focusing was spot on. In the end I replaced it with the AF-S version and don't have that problem anymore.

 

[Kai2810]

Hi Kai2810. Glad to hear from you again. I see you have made some progress in isolating the problem.

The ruler is usually recommended to be placed at an angle of 30 deg or 45 deg, this way you will be able to see the depth of field very clearly when the lens is shot wide open.

Thanks for pointing that out! Managed to squeeze out some time to reshoot, but somehow the shots this time are quite soft?? I shot a couple of times, including inserting a white piece of paper behind the ruler hoping to get a better focus, but no difference...

This 'softness' is another irritating problem I had when I was shooting at Chek Jawa, with the same AF 80-200D lens.

Here's my altered setup, with the ruler at a 30ish degree angle. I placed a piece of white paper behind the ruler for the following shots.

Lens: AF 80-200D

AF0 vs AF-10

AF0 vs AF-15

AF0 vs AF-20

 

[Kai2810]

Zoomed out, for DOF view.

I can't see much diff with the DOF here...anyone has any advise on this?

AF0 vs AF-10

AF0 vs AF-15

AF0 vs AF-20

 

[Light Machinery]

All right. Good progress again!

1) Look carefully at your pictures again. The DOF is about 5 inch to 7 inch on the ruler. Look carefully at the picture, from 5 inch it is clear right up to 7 inch.
2) With AF fine tune of -15, it is very easy to see that the focus has moved to the front. The focus is clear from 5.5 inch up to 7.5inch.
3) With AF fine tune of -20, again the focus has moved to the front again. The focus is clear from 6 inch up to 8 inch.

Again looking at the 3 sets of picture. Looks like -15 is about the best value as the focus straddles the 14cm mark, with 2cm in front is in focus and 3cm behind in focus. It looks very good indeed.



Look carefully at the attached picture below, this is how I typically adjust and place the depth of focus about the "0" and it can be seen the depth is about from -1 to 1. The transition is quite sharp.

[/url][/IMG]

Most lenses are soft wide open and gets sharp when used at a smaller aperture value. The 80-200 AFD is best used stopped down by 1 or 2 stop. It is as sharp as most lenses out there.

Kai, every lens and camera will have some manufacturing tolerances. Some times it is a bit of luck, lets say you have a body with back focus and happens to use a lens with front focus then they more or less cancels each other out. You can pick and pick lenses until you turn blue but remember that set of lenses will only match that body. If you replace the body then the cherry picked lenses may or may not match the new body.

I also shot with a D7000, it had back focus with some of my lenses, chiefly the 18-200 and 70-200 VRii. Both need a setting of about -15 and -18 to have it well centered. My D7000 just shot fine with these setting on the two lens.

Also if you use a heavy lens, always support the lens with your free hand and if possible never ever carry the camera with a strap and let the heavy lens hang from the camera, the lens mount on the camera may get wrapped by the heavy lens.

Now go out and take some pictures with it.

 

[Kai2810]

All right. Good progress again!
Most lenses are soft wide open and gets sharp when used at a smaller aperture value. The 80-200 AFD is best used stopped down by 1 or 2 stop. It is as sharp as most lenses out there.

*slaps head*

lol forgot about this...the shots posted yesterday were shot at F2.8, not wonder it was blurred. The shots posted on the 29th June were shot at F6.3.

Here are my shots at F8. Don't know why this time AF20 seems to be sharper. Distance from the book is the same as before, and with a white paper behind the ruler.

AF0 vs AF 15

AF15 vs AF20

Here are the DOF shots

AF0 vs AF 15

AF15 vs AF20

This time I can see the diff. The 17cm mark was sharp throughout, while the lower end shifted from the 15cm@AF0 -> 13cm @AF20.

With the 17cm mark being sharp throughout, does that mean it is not really focusing as it should and the DOF is still somewhat behind?

If the focus is corrected, it should be something like sharp from 16cm to 12cm?

 

[daredevil123]

BTW, when you tune focus, you should be tuning at the widest aperture. From your photos so far, -20 seems to the the correct setting.

BTW I noticed you are using the non-D version of the push pull... There are lots of reviews on this lens that the output is soft wide open actually. the AF-D version was very much improved in this respect.

 

[Kai2810]

BTW, when you tune focus, you should be tuning at the widest aperture. From your photos so far, -20 seems to the the correct setting.

BTW I noticed you are using the non-D version of the push pull... There are lots of reviews on this lens that the output is soft wide open actually. the AF-D version was very much improved in this respect.

There's a D after the 1:2.8 on the lens, should be it right?

 

[daredevil123]

There's a D after the 1:2.8 on the lens, should be it right?

Yes that is a AF-D push pull... This lens shouldn't be that soft wide open...

These are some sample pics from my 80-200 AF-D push pull...
Confessions of a Sensory Addict: The Little Cannon

I think there is something wrong with your lens. You might want to get it checked out.

 

[Light Machinery]

Looks like your depth of focus still isn't well centered, after looking at the enlarged pictures posted today. With -20, from the picture, the depth of focus is only 1cm in front of the 14cm and extends way pass 17cm at the back (the 17cm onwards is still sharp). If it is corrected the focus will be like you said, about 12 to 16cm well in focused and sharp.

Okay, take it down with the body to NSC. They will check what is the problem and will report back to you accordingly.

 

[Kai2810]

Yes that is a AF-D push pull... This lens shouldn't be that soft wide open...

These are some sample pics from my 80-200 AF-D push pull...
Confessions of a Sensory Addict: The Little Cannon

I think there is something wrong with your lens. You might want to get it checked out.

WAH...those shots you had are at F2.8?

Ok something's really wrong with mine.

Looks like your depth of focus still isn't well centered, after looking at the enlarged pictures posted today. With -20, from the picture, the depth of focus is only 1cm in front of the 14cm and extends way pass 17cm at the back (the 17cm onwards is still sharp). If it is corrected the focus will be like you said, about 12 to 16cm well in focused and sharp.

Okay, take it down with the body to NSC. They will check what is the problem and will report back to you accordingly.

Thanks for your help DareDevil, Light Machinery. :thumbsup:

Hopefully things will be fixed after sending in to NSC. What is the cost range I should expect?

 

[Light Machinery]

Hi Kai.

I can't give you a figure as I have never been billed for all the times I been down there for minor checks, lens and bodies cleaning and AF calibration.

Shhhhh!!!!!

Give them a call and ask if they will charge for AF calibration and explain to them that you have severe back focus with your D7000 and AFD 80-200mm lens.