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05-11-2010, 05:13 PM   #1
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Vivitar Series 1 105mm macro infinity focus problem

I have a Vivitar Series 1 105mm 1:1 macro lens that I purchased. Upon receiving the lens I discovered it won't focus at infinity. As a macro lens it is a great lens. However, the lens can't be used as a short telephoto lens because it won't focus at infinity or beyond 25 feet and over.

Based on the Vivitar serial number, I determined that this version is manufactured by Kiron for Vivitar. I followed Lowell's thread on adjusting Kiron lens https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/89824-adjustme...on-lenses.html

Here are the steps I took to correct my issue.

Disclaimer: I have never repaired nor worked on lenses prior to this lens. I am simply left with no choice but to thinker with the lens and Lowell's thread gave me the confidence that there will be members out there who are kind to show you the way. So proceed at your own risk.

Below is the image of the Vivitar Series 1 105mm macro lens in discussion.
Note: the focus ring is set at infinity but when you view through the viewfinder, it does not come to focus for objects beyond 25 feet.

Second image shows one of three slotted screws that holds the beauty ring in place. Unscrewing these 3 screws around the cover allow you to lift it up to access the three cross point screws underneath, see the same image or the next image. I used scotch tape to hold the beauty ring to the built-in hood and prevent it from falling.

When I partly unscrewed the 3 cross point screws on the focus ring. This does not seem to allow the focus ring to rotate beyond the infinity mark.

Next, I partly unscrewed the side cross point screw (3rd image a.k.a. JIS or phillips screw) on the outer side of the focus barrel ring. This will allowed me to rotate the Focus barrel ring beyond the infinity mark (see last image.)

Checking the lens through the view finder you see everything beyond 20+ feet can now be focus.

NOTE:
Putting everything back by reversing the steps, you will not be able to screw the cross point screw to the side of the focus barrel all the way back. When I screw it in all the way, the focus ring is lock and won't rotate. So I left this screw partly screwed in.

It appears to me this screw prevent the focus ring from rotating pass the infinity marking. I have not tried just unscrewing this screw without touching the 3 screws under the beauty ring. Whether this also allows you to get infinity focus to work. I suspect that it will work. I've tested the lens and it now all works beautifully from the closes distance to infinity.

I am disabled and have full use of only one hand. It was important for me to have infinity working so that my lens can work as a short telephoto lens without changing lenses which takes time, and allows me to capture a photo opportunity that arise (like the Pheasant in following thread - a missed opportunity.) Fortunately he stayed long enough for me to switch lens. That was the moment I realize it would be best to have infinity working and fixed.

Good luck!

Attached Images
       

Last edited by mjkwee; 05-14-2010 at 08:15 AM.
05-12-2010, 01:31 PM   #2
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Sample photographs after infinity adjustment

Attached are through the lens sample photos of before and after adjustments.
Images 1&2 are before close range.
Image 3 before focus at infinity or greater than 20 feet (out of focus).
Image 4 after infinity adjustment.
Image 5 after adjustment close up (still ok.)
Attached Images
         

Last edited by mjkwee; 05-14-2010 at 08:18 AM.
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