Does my Nikon 50mm f/1.4 AI lens need a CLA?

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jayel

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My lens when I turn it all the way to the right should be focused well at infinity, but I have to turn it back about 2mm for it to be completely sharp. Is this normal, or do I need to get it repaired. Thanks
 

resummerfield

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That particular lens should be sharply focused at infinity when the focus ring hits the stop. However, it is not uncommon for a lens to be designed to focus beyond infinity, as your lens apparently does, to compensate for thermal expansion. If the lens operates properly in all other respects, I would not send it in for a CLA.
 

E. von Hoegh

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My lens when I turn it all the way to the right should be focused well at infinity, but I have to turn it back about 2mm for it to be completely sharp. Is this normal, or do I need to get it repaired. Thanks

Do you have other lenses which line up at infinity on that body? because it could be the body; a misaligned mirror, an improperly seated screen, or missing shims under the lensmount could all cause this. 2mm sounds like too much.
 

BMbikerider

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I think there will only be a problem if the lens did not go right to infinity, going past is not a problem.

Some Olympus lenses I used many years ago were sent to be adjusted because they did not focus right at infinity. I never knew the cause but after adjustment they worked perfectly.
 

E. von Hoegh

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I think there will only be a problem if the lens did not go right to infinity, going past is not a problem.
Some Olympus lenses I used many years ago were sent to be adjusted because they did not focus right at infinity. I never knew the cause but after adjustment they worked perfectly.

I've never seen or heard of a Nikkor (or any other lens) going that far past infinity.
 

BrianShaw

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What is past infinity? Please answer using engineering terms, not metaphorical psychobabble.
 

mmerig

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Many years ago I took apart a Nikkor 50mm 1.4 non-AI lens to clean it, and if my memory serves me well, there was a stop built-in to the lens so that the focus ring stopped at infinity. Perhaps the AI version is similar, and the stop is chipped or bent so that the focus ring goes too far.

The infinity stop on all of the manual focus ai or ais lenses I have is built in to the lens, so unless the rear element hits something as it recedes to the infinity position, there should not be an issue with the body. If the rear element hits something, the focus ring will not go far enough to reach the infinity setting, so this does not apply to you, as your lens goes too far.

By the way, my 300-mm 2.8 AIS ED goes about 7 mm past infinity and this is normal, to allow for thermal expansion (it is internal focus, and 7 mm is not that much compared to how far the focus ring turns for the full-focus range).
 

E. von Hoegh

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What is past infinity? Please answer using engineering terms, not metaphorical psychobabble.

When the index is set at infinity, the lens is "past" infinity (lens closer than it's infinity focus) and the index has to be set at a closer distance to bring an "infinite" (say the moon) object into focus. Sounds like the OPs lens needs to be set around 20 meters to focus at infinity.
 

BrianShaw

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When the index is set at infinity, the lens is "past" infinity (lens closer than it's infinity focus) and the index has to be set at a closer distance to bring an "infinite" (say the moon) object into focus. Sounds like the OPs lens needs to be set around 20 meters to focus at infinity.

Ahh. I got sidetracked I guess and was wondering how far (mm, inches, yards, kilometers) past infinity "past infinity" was.

Like you said earlier... I've never seen nor heard of a Nikkor that didn't stop at the infinity index mark. Something wrong with that lens probably. If the infinity index is offset, I wonder if the others are equally offset.
 

cjbecker

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That particular lens should be sharply focused at infinity when the focus ring hits the stop. However, it is not uncommon for a lens to be designed to focus beyond infinity, as your lens apparently does, to compensate for thermal expansion. If the lens operates properly in all other respects, I would not send it in for a CLA.

Mine does it also.
 

Steve Smith

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What is past infinity? Please answer using engineering terms, not metaphorical psychobabble.

If you consider the distance from film to lens when focused to infinity to be x, Increasing x focuses on things closer. Making x smaller than it's infinity value is effectively past infinity.

In the real world, this greater than infinity distance doesn't exist - but if it did, it would be in focus!!


Steve.
 

mdarnton

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I've been working on acquiring a full stable of MF Nikon lenses, sending them in for cleaning as necessary, and at one point several years ago one came back focusing past infinity. I called the repair shop (one of the most respected, most recommended Nikon repair facilities) and talked with the technician about it. He said that at a Nikon workshop they'd been told that some of the AF cameras won't pick up focus at infinity in manual focus mode and give the green light unless you focus past infinity and come back from there, and they'd been told to make the lenses go past to solve that issue.

I estimate focus a lot (the particular lens was a 28mm), so I sent the lens back, and he set it right, warning me that from now on I should tell them if I wanted to keep the lens as it had originally been made.

People on other boards start arguing with me about whether this is necessary or not (infinity should be pretty easy to find without the dot, shouldn't it?), so don't start in on me--I'm just repeating what the technician told me. I can believe it--some camera users are pretty dumb (for instance, I note that today on another forum someone's asking what the proper AF selection points woud be for landscapes, since his camera isn't giving him sharp landscapes).

Anyway, I wonder if your lens may have had a CLA in the last few years, and that might be what causes the problem.

The other cause would be if your camera's mirror needs adjustment. This tends to show up on wide angle lenses more than teles, as an infinity that's slightly off, one way or another, and seems to be a very common problem with older cameras. I've had this on two OM1s, a Hasselblad, and a couple of Nikons. You need to eliminate this possibility before you start in "fixing" lenses that aren't broken.
 

E. von Hoegh

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Ahh. I got sidetracked I guess and was wondering how far (mm, inches, yards, kilometers) past infinity "past infinity" was.

Like you said earlier... I've never seen nor heard of a Nikkor that didn't stop at the infinity index mark. Something wrong with that lens probably. If the infinity index is offset, I wonder if the others are equally offset.

Or if it's the OPs only lens and there's a problem with the camera body. No one else seems to have picked up on that, and the OP hasn't answered.
 

Xmas

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using the end stop on the focus ring for fitting or removing lens is not a wonderful idea
 

John Koehrer

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Ahh. I got sidetracked I guess and was wondering how far (mm, inches, yards, kilometers) past infinity "past infinity" was.

I believe the measurement you seek is "furlongs per fortnight".
 

Tom1956

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The OP spoke of Nikon, and I've had a fair amount of experience working on Hasselblads, which are supposedly divinely made. And from what I have been able to tell, "infinity" is all over the place on Hass'. I haven't been able to pin down any kind of "infinity" on any of them yet. So far, a well-adjusted Crown Graphic and Kalart has them all beat.
 
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My lens when I turn it all the way to the right should be focused well at infinity, but I have to turn it back about 2mm for it to be completely sharp. Is this normal, or do I need to get it repaired. Thanks

check if your other lenses work as you expect them to.It may not be the lens but the focus screen in your camera that needs an adjustment. this was the case with my Mamiya 6.anywaymy newAF50f/1.4 does focus at infinity at the infinity markAS ONE WOULD EXPECT.
 

Salem

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I had, and still have, this lens (50/1.4 ai) for so many years. A couple of years ago it started to stop short of infinity. I took it apart with the help of an online guide and moved it a little and now it's spot on. If I remember right the adjustment done by loosening a small screw and moving a brass disk that lives beneath the front element a little bit and checking until you get infinity right.
 

Xmas

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you need a plastic pill box lid which is just smaller than 52mm and a rubber kitchen glove cut glove to a doughnut to fit name ring unscrew name ring.

Normally there are three screws holding a brass ring secured with nail varnish ~ remove varnish with nail varnish remover cotton wool soaked in on end of match stick back of screws one turn then reset infinity on star or moon.

tighten screws they don't need to be tight dab with garish nail varnish replace name plate

you need to be sure it is the lens and not the body...

send to repair shop is better...
 
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