Andreas Thaler
Subscriber
This Minolta zoom is a recurring patient.
Its rear lens had already become cloudy and the aperture transmission often got stuck when the tube was pulled out.
Here is my report on the service from December 2023 describing how I cleaned the lens:
www.photrio.com
Today I took the zoom again to clean the rear lens. I also wanted to permanently solve the problem with the aperture transmission.
Let's go!
Removing the bayonet ring and dismantling the optical unit which contains the rear lens.
Heavy fog has formed again on the inside of the rear lens. I suspect it is caused by the lubrication of the helicoids turning into oil.
The lever that moves the aperture blades in the aperture register. It jerks and does not move smoothly. Although the aperture blades are dry, I suspect that it is a problem with oil contamination.
Oil and old grease can be seen everywhere in the tube where it doesn't belong.
Remove the rear second optical unit above the aperture.
First loosen it with the spanner wrench and then unscrew it securely with the plastic Spudger from iFixit.
Using the lens suction tool, I lift the optical unit out of the tube.
Here I put a few drops of Zippo lighter fluid, which spread instantly over the aperture blades.
After moving the aperture over the lever for some time and dabbing off the Zippo, I carefully dried the aperture blades with the Dremel Versatip butane gas burner.
I opened the aperture at intervals to use the Versatip to remove the Zippo condensate caused by the heat from the lens underneath.
Then I cleaned the lens.
To keep the aperture open against spring pressure, I made a gag out of a piece of rolled-up paper tissue, which I secured with adhesive tape.
Preparing small pieces from a Zeiss optics cleaning cloth.
I use a glass rod to apply some isopropyl alcohol to a piece of cloth. This allows me to measure the amount.
Its rear lens had already become cloudy and the aperture transmission often got stuck when the tube was pulled out.
Here is my report on the service from December 2023 describing how I cleaned the lens:

Minolta MD 35-135/3.5-4.5 (III): Rear lens cleaned. How I got an excellent magnifying glass
This new addition was presented to me in almost new condition, but with a cloudy rear lens, when I examined it: The lens, along with another, is housed in a unit that is screwed into place. Using a spanner wrench that I inserted into the two grooves on the top ring of the unit, I was able...

Today I took the zoom again to clean the rear lens. I also wanted to permanently solve the problem with the aperture transmission.
Let's go!
Removing the bayonet ring and dismantling the optical unit which contains the rear lens.
Heavy fog has formed again on the inside of the rear lens. I suspect it is caused by the lubrication of the helicoids turning into oil.
The lever that moves the aperture blades in the aperture register. It jerks and does not move smoothly. Although the aperture blades are dry, I suspect that it is a problem with oil contamination.
Oil and old grease can be seen everywhere in the tube where it doesn't belong.
Remove the rear second optical unit above the aperture.
First loosen it with the spanner wrench and then unscrew it securely with the plastic Spudger from iFixit.
Using the lens suction tool, I lift the optical unit out of the tube.
Here I put a few drops of Zippo lighter fluid, which spread instantly over the aperture blades.
After moving the aperture over the lever for some time and dabbing off the Zippo, I carefully dried the aperture blades with the Dremel Versatip butane gas burner.
I opened the aperture at intervals to use the Versatip to remove the Zippo condensate caused by the heat from the lens underneath.
Then I cleaned the lens.
To keep the aperture open against spring pressure, I made a gag out of a piece of rolled-up paper tissue, which I secured with adhesive tape.
Preparing small pieces from a Zeiss optics cleaning cloth.
I use a glass rod to apply some isopropyl alcohol to a piece of cloth. This allows me to measure the amount.
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