Is there something wrong?

nealjpage · Mar 24, 2008

Here's a stupid question, but I've got to know: Can lenses, as they get older, lose their focusing ability? Case in point is my daily shooter, a Nikon FE with a Nikor 50mm f/1.4. While looking through the viewfinder, everything looks in focus. When I process my film, I come to learn that the focus is off. A few examples:

This was shot a moderate aperture, around f/5.6 (I think..my notebook's in the car and I'm too lazy to get it) on Adox ART 25. Focus was on infinity. or there abouts. Clear and in-focus in the viewfinder.

Similar situation. Adox 25, f/5.6ish, focus on infinity.

What gives?:scratch:

Sw1tchFX · Mar 24, 2008

seems more like an error on the cameras part where the ground glass is.

Battou · Mar 24, 2008

I often find with my Canon FD 50mm 1.4 and EF focusing screen that infinity is always crystal clear in the fiew finder, how ever the split circle sais it is wrong and out of focus. I do what the center circle tells me is right and not the rest of the screen.

Try backing off from infinity just a touch, You may be surpassing it.

Garbz · Mar 24, 2008

In which case the camera needs to be recalibrated. For the record both switch and I have Nikon FEs too. And none of my equipment has had any problem ageing.

I can only assume a knock or something has moved the mirror or the focusing screen so the distance from the mirror to the film plane is no longer the same as the distance to the focusing screen causing your discrepancy between the viewfinder focus and your actual focus.

KevinDks · Mar 24, 2008

Perhaps I'm missing something, but at f/5.6 and with the focus on infinity, your depth of field extends from 48' 6" to infinity. Those sheds look like they are closer than 48'.

Kevin

compur · Mar 24, 2008

Why is focus on infinity?

nealjpage · Mar 24, 2008

Well, it was near infinity. That's when things looked focused. Maybe I need new glasses. :lol:

Alpha · Mar 24, 2008

Glass can lose focus. Take it to a shop and have them fix it.

compur · Mar 24, 2008

If you are judging focus only by viewing the overall image in the viewfinder,
then any eyesight issue will affect your focus.

I would check the lens by placing the camera on a tripod and focusing (using
the focusing screen's focusing aid) on a particular object at various distances.

It's unusual that a 50mm f/1.4 Nikkor would have a focus problem if the lens
appears in reasonably good condition and the focus adjustment moves
smoothly with no evidence of mechanical problem. I've owned dozens of
Nikkors and bought and sold many more and never had focus problems with
any that had good appearance and smooth operation.

And, since you are using a very slow film, I suspect that a slow shutter speed
may be adding to the problem as well.

christopher walrath · Mar 24, 2008

nealjpage said:
Well, it was near infinity. That's when things looked focused. Maybe I need new glasses.

About every two or three years my images get soft and that's when I know it's time for another visit to Lenscrafters.

Garbz · Mar 25, 2008

Alpha said:
Glass can lose focus. Take it to a shop and have them fix it.

+

christopher walrath said:
About every two or three years my images get soft and that's when I know it's time for another visit to Lenscrafters.

Doesn't explain why the image looked fine in the viewfinder. Especially if he's correcting the image by adjusting the focus point. 3 years... Are they made of water? :lol:

KevinDks said:
Perhaps I'm missing something, but at f/5.6 and with the focus on infinity, your depth of field extends from 48' 6" to infinity. Those sheds look like they are closer than 48'.

Yes but in the viewfinder it would be at f/1.4 unless the viewfinder is stopped down. In which case if the focusing aids say it's in focus then it's not the lens. Anyway a remotely competent camera repair man can determine this for you.

Battou · Mar 25, 2008

Garbz said:
christopher walrath said:

About every two or three years my images get soft and that's when I know it's time for another visit to Lenscrafters.

Click to expand...

Doesn't explain why the image looked fine in the viewfinder. Especially if he's correcting the image by adjusting the focus point. 3 years... Are they made of water?