LOMO zoom 35OPF18-1 20-120mm

[Adnan Siddiqui]

HI,

 

I recently got a AS-IS LOMO zoom 35OPF18-1 20-120mm. See pic.

 

is there a way to self-diagnose the lens for internal damage?

 

Thanks.

Edited July 17, 2016 by Adnan Siddiqui

[Dom Jaeger]

Do you suspect there is damage?

 

You can do the fairly obvious things - check the body for impact marks, see how the focus and zoom barrels feel as you turn them, look at the glass against a light, check the iris, shoot some footage. Whether you can diagnose what might be wrong depends on what you find and your familiarity with how a zoom works.

 

Beyond simply being out of adjustment, there are typical wear issues in old zooms like play in the focus threads or worn zoom components that cause the focus to drift in and out through the range. Sometimes you can feel backlash in the zoom barrel, which might result in a different focus position depending on the direction of the zoom pull. Oil can leach onto the iris blades, causing reflections or more seriously make the blades stick together so that a quick iris pull can rip out the blade pins. Fungus, excessive dust, separation, edge black deterioration, moisture and other things can fog or damage an internal glass element.

 

Adjustment issues will be things like an incorrectly set back-focus causing the focus to drop off as you go wide, incorrectly set front focus causing the marks to be out, element centering or spacing issues causing image quality problems, tracking issues causing the image center to shift as you zoom in, etc. Those Lomo zooms tend to have less adjustment facility than similar vintage zooms from say Cooke or Angenieux however.

 

Most of these problems need an experienced technician to solve, or might be unresolveable without parts.