Problem with Focus while Zooming?

S

SE7

Well-known member
Hey... I was wondering if I could have some help figuring out what is wrong with my camera/lens. It's the Krasnogorsk K-3 16mm film camera with the standard Meteor zoom lens. The problem is:

Whenever I focus on something and then zoom in on it, it blurs INSANELY. Even zooming in the slightest amount will result in an out-of-focus shot.

I forgot exactly what the back focus was, and maybe this is the problem? I have no clue... Do you guys know what the problem is and how to fix it?

I would greatly appreciate any help. Thanks a lot.
Worley
 
Hello SE7,

If I'm reading your post right I think your setting your focus backwards. You need to focus on your subject at the longest focal length and then it should hold focus as you zoom to the wide angle. That is if all other parameters in the lens and camera are correct.

Chuck
 
Thanks for the tip, but when I zoom in, I move the focus ring from the farthest left and slowly to the farthest right, and it still never gets in focus. This even happens when I zoom in a little tiny bit and try to adjust the focus... still blurry.

So any advice would be awesome! Thanks

Worley
 
SE7,
Sounds like more than a bakfocus issue. If you place the focus chart 6-8 feet away, zoom in and focus , then slowly zoom out and lose focus toward the wide end: that's a classic backfocus problem. From your description, it sounds like your lens may have taken a hit hard enough to cause actual misalignment of one or more lens elements.
Don't know where you're located, but you might to have it professionally repaired and collimated.
Hope this helps,
Ken
the Screen Skins guy
 
Thanks for the bad news. (haha) But this is what happens:

I focus on something, zoom in, it becomes out of focus, so I begin adjusting the focus... the closer I get to infinity, the more focussed it becomes. But once I hit infinity (zoomed in), it still is not completely 100% focussed. This only happens zoomed in.

So I can get close to it being in focus, but never completely when zoomed in.

Thanks.
 
SE7 said:
Thanks for the bad news. (haha) But this is what happens:

I focus on something, zoom in, it becomes out of focus, so I begin adjusting the focus... the closer I get to infinity, the more focussed it becomes. But once I hit infinity (zoomed in), it still is not completely 100% focussed. This only happens zoomed in.

So I can get close to it being in focus, but never completely when zoomed in.

Thanks.
Click to expand...

Is the object you're trying to zoom all the way into real close or real far?
 
I not getting the vibe it's a lens problem. Sound to me like the object you're trying to focus on is inside the minimal zoom range, or something like that.

you said:

"Whenever I focus on something and then zoom in on it, it blurs INSANELY. Even zooming in the slightest amount will result in an out-of-focus shot. "




Right, its going to do that. That's because that's not how you set focus. Your doing it backwards. Are you sure you're just not standing too close to the object?
 
Last edited:
Hey your absolutely right! Thanks for the help. The subject was too close... silly me. Crazy how a simple little problem can get by and totally change everything!!

Another thing I noticed is that my viewfinder is very dark. I don't know if this is normal on the K-3 but your eyes have to really adjust to be able to see into it. Has any else noticed this or have any advice for this problem?

Thanks.
 
SE7 said:
Another thing I noticed is that my viewfinder is very dark. I don't know if this is normal on the K-3 but your eyes have to really adjust to be able to see into it. Has any else noticed this or have any advice for this problem?
.
Click to expand...


This is normal. Not much you can do. Just open up your iris all the way and set your focus, then close it back down. You DOF and or focus can change a little when you do this, so keep your eye out for that.
 
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