Focus - lens and body possibly incompatible?

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Ken-D

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Ken Dickson
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Hi,
New member and first post.

Current kit includes Nikon D90 and D7000 bodies. D7000 is the one I normally pick up.

I recently bought a used Nikon 50mm 1.8 AF-S G. First prime lens I've had for DSLR. Picked the lens up today to try it for the first time on the D90 with excellent result. Put it on the D7000 and the focus was way off. My heart sank thinking it was the body at fault. Popped a Nikon 18-55mm 3.5-5.6 AF-S G VR on the D7000 and focus is perfect. The 18-55mm is also perfect on the D90. Then I thought I was just being dim not setting something properly on the D7000. About an hour later, testing both lenses on both bodies with different apertures, making sure all camera setting match, it seems the 50mm 1.8 just isn't focussing properly on the D7000, at least at the 1.5m(ish) distance I've been testing at. Something between the two is just not working correctly. I think the true focus is a bit behind the point the camera and lens are focusing at, but I've not pinned that down for sure. I have other lenses and another couple of bodies I could continue trying this with but It's not going to alter the position I'm finding now.

Has anyone experienced similar and are there any recommendations / suggestions to get the lens / body combination working well?

Thanks.
 
Yep agree with Steve , you need to micro adjust the lens to the camera .. it’s a ball aching job but they do make fine tuning guides available on e.bay and amazon . You will be amazed at the difference it makes once done . A basic crude way of doing it is to use 3 AA batteries in a line with each one a half inch behind the other aim at the centre one and see which is in focus that will tell you if your front or back focusing and adjust the camera accordingly, it will only effect the lens your doing not any others .i used to do it that way years ago till I got the proper gauge
Best look up a u tube on micro adjusting it might help
 
Thanks guys, really appreciate the help.
Does seem a bit of a faff but better than what was going through my mind to start.
This is the starting point for the two bodies, both set the same, both jpg's cropped at 100%. As you can see, it's not just a fine adjustment needed.
I'll run through this process with all my lenses tomorrow.

D90
_DSC2482A.JPG

D7000
_DSC1379A.JPG
 
The second shot seems to be from a bit closer - maybe you're closer than the Minimum Focussing Distance (just)? Try from around 2m rather than 1.5.
 
Nod said:
The second shot seems to be from a bit closer
Click to expand...
Only looks than way because of the D7000’s slightly higher resolution. They are full resolution crops from the image centre. I didn’t express it very well saying “cropped at 100%”. The RDS logo was the focus point. Those two images were at about 2m. Not that far off infinity for a 50mm 1.8.
 
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I still think it’s in need of micro adjusting ,try the three AA battery as I said ,line them up like this / and aim at the centre one to establish front or back focussing issues , what your not taking into account is age of equipment . .your test shot is oof across the whole focal plane which also points to to micro adjustment .. been down the same path far to many times in the past . If I’m wrong all you have lost is a bit of time and effort .
You don’t even have to use batteries drinks cans do the same job as long as there lined up diagonally and you focus on the centre one.
You have already said in your initial post you think it’s back focusing so all you have to do is establish it is then it’s @ easy cure on the D7000
 
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For a bit of history your D90 is a first generation dslr the D7000 is a third or fourth generation one . Canon and Nikon both realised that with the advent of these better higher powered sensors and AF modes that older lenses would show up manufacturing flaws I.e back and front focusing problems plus the influx of third party lenses so they built in to the menu system a means for the user to fine tune the camera/ lenses themselves. It’s there to use of the very many I have done for myself ,friends , forum members etc I have found there’s no common denominator some will be a + 5 and others need a - 20 but one things certain there’s no such thing as a non compatible set up
And here’s a easy check for you stick the lens on the D7000 and manually focus it if you still can’t get a sharp shot then there’s likely a loose element but if it’s working on the D90 thats unlikely
 
Ken-D said:
Those two images were at about 2m. Not that far off infinity for a 50mm 1.8.
Click to expand...
A 50mm at f/16 on a DX body *infinity is at 25ft (~8m); at f/1.8 it is 230ft (~70m). I'm surprised the camera actually considers that to be in focus and yet it doesn't have an issue with other lenses.

(*the hyperfocal distance)
 
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So, what I've done is mount the D7000 on a tripod, set it at single AF, centre focus point, matrix, ISO200, Aperture pri, F1.8, remote firing, subject about 2m. Also put a bounce flash on in TTL for better lighting consistency. Then ran through 20 shots + and 20 shots -, letting the camera settle for a few seconds between setting the fine tune menu and remote firing.

I was wrong about the actual focus point being behind what the camera was taking. Best image appears to be -5. The +-0 is from yesterday. Focus point was again the RDS logo.

Again, full resolution crop from centre of image.

Interested to know if you think this is fine or if I need to do more.

+-0
+-0 99%.JPG

-5
-5 99%.JPG

At some point I'll do other lenses but all the others are zoom, and if it means doing this for each of them at short, mid and long zoom, that's more than I can face right now.

Really appreciate the help on this guys.
 
if your happy with it now leave it .if the other lenses work o.k then no need to bother the adjustment only applies to that particular lens . glad you got there in the end
 
I had to use AF Fine Tune for all of the lenses I shoved on my D7000 if I remember correctly. All very different amounts though, with the 18-200 only needing one increment to get it there. I found mine hated my 35mm 1.8 DX lens (which was a lens I rather liked, and one that went very well on my D3000). Even with the full 20 increments I couldn't get it sharp consistently. A search online suggested that quite a few people found that lens didn't work well with the D7000, so it didn't take me much longer to part ex the body in against a D3S.
 
For AF tuning, if you have back button focus enabled and shutter button focus disabled this works. I do the following:

From a fixed position (a door frame works) autofocus using live view to a set point. Make sure the focus box goes green. Then switch to optical viewfinder and half press the shutter button to check the focus on the set point using the green dot. The lens focus won't move but the autofocus system will tell you if you are in focus. Adjust the fine tune until the green dot focuses ahead and behind the set point by the same amount.
 
Were you focussing the lens at its' widest aperture? I found my 50/1,4G and 85/1.8D truly sucked when I tried to use focus calibration. Sent them to Nikon who said they were ok, and still I was having to apply severe adjustment for the 85. The calibration operates at the widest aperture and when i used the software to find the optimum aperture I discovered both lenses improved dramatically at f2.3-2.5. Still, I sold the 85/1.8 and kept the 50/1.4. So, if you try testing the lenses at f4-11 I think your results would be much better.
 
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