Weird problem with a Nikon 28mm 1.8G

clarnibass

Senior Member
I bought a Nikon 28mm 1.8G lens after it seems fine at the store but after testing it more thoroughly at home I found a strange issue.

The lens focuses fine in LV. When using the viewfinder, if focusing from the infinity side it focuses fine and is as sharp as LV. If focusing from the macro side there is significant front focus. If focusing from the macro side, then once it "thinks" it is focused I refocus, then it's fine too. This is at f/1.8. It is completely consistent and repeatable.

The reason I'm posting this is... I noticed a dead zone in the focus ring. However, my 50mm 1.8G also has a dead zone but no focus issues at all. So I suspect the dead zone is just the way this lens is, but want to make sure from others who own the lens.

In addition, after a few minutes of testing my camera was suddenly paralyzed (turning on and off did nothing). I changed battery and it turned on but gave an error message. This has never happened with any lens, including third party. So I really suspect something is wrong with the lens.

I'll call the store anyway and see what they can do, but wanted to confirm the dead zone in the focus ring first (if others don't have it then a problem is very obvious).

Thanks
 

§am

Senior Member
If there's an issue with the lens, and it appears to be causing strange behaviour on your camera, then I'd take it back to the shop where you bought it from and get a replacement or at least have it looked at.
 

BackdoorArts

Senior Member
Dead zones are found on all AF lenses to some extent, your problem is not. I'd contact Nikon. What camera are you using? I have the lens and will try it on my D600 and D800 today if I get a chance.
 

clarnibass

Senior Member
Thanks.

Just to clarify, my 85mm 1.8G has such a tiny dead zone that it's essentially non-existent. Same for a relatively cheap Tamron lens I have. The 50mm in comparison is very obvious (but no issues) and the 28mm has a sligthly bigger dead zone than the 50mm (its focus ring also feels the flimsiest of all the three primes).

I use a D600.

I will definitely contact the store about this. I just found that with a bigger distance the problem is a lot more obvious.
 

clarnibass

Senior Member
I looked more into it.

First, it seems to need approx +8 FT. I guess I was lucky until now and never needed FT. This improves it, however, it doesn't fix the problem at all and it's obviously still there.

What I found out now is that (in AF-S mode, though I've tried AF-C too), if I focus from macro, it doesn't focus well. Then, if I press to focus again, it almost always fixes the focus. I can hear it and see it in the distance window too, moving a fraction to the correct focus. If I focus twice the focus is good. From the infinity side, it does this only rarely (which I guess is normal to happen occasionally), while it does it at least 90% or more of the times from the macro side. My 50mm and 85mm lenses don't do this except maybe a couple of times out of many dozens of tries.

In addition, for a few minutes earlier it didn't focus at all if I put it manually on the macro end. Moving it slightly to a farther distance fixed it. A few minutes later it was fine.

From these consistent and intermittent issues I'm sure there's a problem, which is too bad because other than that (and the need for FT) the lens is great and without the focus shift that some seem to have and I was worried about.

I'll ask for a replacement.
 
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