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I recently bought VIVITAR 100-300mm F5.6-6.7 macro zoom. I use it with Nikon D70S. Here is my problem. When distance between my D70S with VIVITAR and object of photography is 15meters and more, I can not focus on this object of photography. I am in manual mode and in manual focus. Focus is set on infinity - everything less than infinity is more, out of focus. I attach photo of roof, 31meters away from D70S (1/40s, f14, 300mm).

Do you know, what it is going on?

Thank you for answer. 1/40s, f14, 300mm

  • Just to be clear: when you say "focus is set at infinity", do you mean "focus on far objects is as sharp as I can get it" or do you mean "the ring is turned all the way"? – Please Read Profile Jan 11 at 17:27
  • I meant, focus ring is turned all the way. – Lukas Jan 11 at 17:34
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    Does this answer your question? Why am I allowed to turn my focusing ring beyond infinity? – Please Read Profile Jan 11 at 17:43
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    How do you know it's not in focus but just not sharp? – Please Read Profile Jan 11 at 18:03
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    Does this lens have a Nikon mount, or does it have some sort of adapter to mount it to a Nikon body? – scottbb Jan 11 at 23:01
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Answer is assuming that a) lens is not adapted, b) camera is in calibration, c) lens isn't so heavy that it warps the lens mount elastically.

This looks like the infinity stop on that lens is simply out of alignment.

Professional repair is likely uneconomical here.

You can attempt to fix that yourself. How to do that is lens dependent, and zoom lenses are absolutely not good starter lenses to learn that on, especially if a service manual is not available (see my comment on vivitar serial numbers).

Typical ways to align infinity on lenses are a) mechanical pegs that can be shifted after loosening a screw, or b) focus rings with an integral end stop that can be loosened and readjusted after loosening a screw, or c) shims that will need to be added or, in your case, much more likely removed. The trouble with zoom lenses is that there is not unlikely to be a combination of either a) or b), and multiple places with c) - all interdependent, and needing to be aligned in concert. Setting things to the wrong balance can compromise image quality in some cases.

Most of the users here that have some experience with lens repair would likely consider it a write-off without a service manual.

If the focus range is off because something got misaligned that is not even intended to define the focusing range, that is worse news.

Other options: Return, discard, use as a closeup/portrait only lens, pass on to someone willing to try and fix it, pass on to a mirrorless user who might in some cases be able to use it with a slightly short adapter (as many are).

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Many large zooms focus past infinity, you may need to focus back.

Secondly, this may not be a sharp lens at f14, try rolling back to f8.

Thirdly, 1/40 second is not going to help. Take a test show nearer 1/500-1/1000 of a second and report back.

  • I agree with this answer and would also like to add: One might find that this is the best possible performance for the lens at Infinity. For example, a notable zoom with a similar issue at infinity focus is the Nikon 200-400mm f/4. I own this lens and I don't use it at infinity; but it is still a great lens because of its performance at closer ranges. – meklarian Jan 14 at 18:06
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    @shashin I tried all focus ring positions. All the way from one side to another. Nevertheless, if object of photography is 15 meters and more from me, it is out of focus, no matter how I set focus ring. It seems like if I could turn it further (past infinity), I would reach focus. – Lukas Jan 14 at 21:01
  • @shashin Secondly, I tried it at f7.1 also, result was same. Thirdly, I tried it at 1/200, 1/400, etc., result was same. – Lukas Jan 14 at 21:08
  • Sorry to hear the issue @Lukas, looks like the lens does not mount accurately, or the elements have taken a knock and are out of alignment. Or, this is the actual performance of the lens. Are you able to test against another copy of the lens? (Unlikely, I know). That's the only way to be sure. – shashin Jan 14 at 21:48

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