Stupid old 35mm f2 AI Nikkor can't focus infinity!

[bill t.]

OK, got this old AI 35mm f2.0 manual focus Nikkor that is a pretty good lens, but on my digital bodies careful focus testing shows it's just a little shy of being able to reach perfect infinity focus.

It needs 1 degree more turn for a super crisp infinity focus.  It hits the the infinity mark, but not the true infinity focus.  And yes, it really matters, all that "depth of focus" hocus pocus is nothing more than an urban legend, IMHO.  I make big prints and there is only perfect focus or slightly soft focus, and the latter isn't acceptable.  It has already compromised my lucky shot of the year.  

I wonder if anybody has managed to slip the focus adjustment on that lens a little bit this way or that?  Does it take more than a jeweler's screwdriver?

Would be nice if I could do it myself, otherwise it's $70 and 5 weeks of peak Summer shooting at the camera repair to "look into it."

[Rob C]

OK, got this old AI 35mm f2.0 manual focus Nikkor that is a pretty good lens, but on my digital bodies careful focus testing shows it's just a little shy of being able to reach perfect infinity focus.

It needs 1 degree more turn for a super crisp infinity focus.  It hits the the infinity mark, but not the true infinity focus.  And yes, it really matters, all that "depth of focus" hocus pocus is nothing more than an urban legend, IMHO.  I make big prints and there is only perfect focus or slightly soft focus, and the latter isn't acceptable.  It has already compromised my lucky shot of the year.  

I wonder if anybody has managed to slip the focus adjustment on that lens a little bit this way or that?  Does it take more than a jeweler's screwdriver?

Would be nice if I could do it myself, otherwise it's $70 and 5 weeks of peak Summer shooting at the camera repair to "look into it."

Are you sure it isn´t a problem with the camera body rather than the lens? Lots of instances of micro-adjustment seem to suggest that there is a huge problem with lens to sensor distances not matching lens to pentaprism screen distances.

Film, though it seldom lay perfectly flat in the gate, apparently gives better performance than rigid sensors that should lie perfectly flat in the right place. And therein lies the problem: is it in the right place, the sensor? As there´s no af to confuse things because of its secondary mirror, I can only imagine the first cause I suggested.

I have had two editions of the 2.8/35 and both were fantastic optics. I see no reason to think the f2 would be inferior, unless, perhaps, it suffered damage before you got it?

Rob C

[bill t.]

Are you sure it isn´t a problem with the camera body rather than the lens? Lots of instances of micro-adjustment seem to suggest that there is a huge problem with lens to sensor distances not matching lens to pentaprism screen distances.

Film, though it seldom lay perfectly flat in the gate, apparently gives better performance than rigid sensors that should lie perfectly flat in the right place. And therein lies the problem: is it in the right place, the sensor? As there´s no af to confuse things because of its secondary mirror, I can only imagine the first cause I suggested.

I have had two editons of the 2.8/35 and both were fantastic optics. I see no reason to think the f2 would be inferior, unless, perhaps, it suffered damage before you got it?
Rob C

Yes it's probably a camera body issue.  For my manually focused landscapes I focus using tape marks found through trial and error.  One mark is perfect inifinity focus.  The other mark is as close as I can focus (at f8) without infinity getting mushy, and it's pretty close to the infinity mark.  On my previous D2X both my 28mm and 35mm lenses have perfect infinity just short of the actual mark.  But on the D5000 and D3X for some inscrutable reason the new 28mm infinity position is now well short of the actual mark, whereas I can no longer reach infinity with the 35mm.  Weird.  Did Nikon change the flange->film specification for some reason?

Not wishing to fool with the bodies, I want to attack the 35mm lens as a fix, even though it doesn't deserve it.

The 35mm f2 is probably not as good as the f2.8, but it's the lens I got.  OTOH the 28mm f2.8 AIS is way better than I deserve.  And the 50mm f1.8 AIS...ooh la la!  Zooms are nothing but disappointing by comparison.

[Rob C]

And the 50mm f1.8 AIS...ooh la la!  Zooms are nothing but disappointing by comparison.

I agree completely: I have the latest 1.8/50 manual version and even close-ups at its limit are excellent; you might remember reading my horror story somewhere on this site about the new 2.8/24-70 Nikkor that I had for about a month; finally got it out of the way for a 2.8/180 a/f Nikkor which seems very crisp at pentaprism level, but I have yet to see anything from it in real pictures: I did a test of a rule inclined at 45 degrees and about 10 feet away - missed focus by about 1.5 cms (at the centre) which, on a heavy Gitzo and manual focus is pretty poor, considering that on the screen it shows the difference in the mm lines so clearly. This was tested at 2.8 only. I did the test using the two wider sides of the screen as test areas too; there it seemed to miss focus by about 2+ cms, suggesting a curved field... in all three focus experiments, actual focus was closer than it should be.

With all that money (to me) sloshing around on two lenes, I am waiting until my nerve settles before doing some real-life work with the 180mm. Perhaps I just hope to mask the truth from myself? Never, ever, found such problems with film in F, F2, F3 or F4, FM, FM2n. There is something not right with digital manufacturing, dress it up they will.

Rob C