yashica mc zoom 35 -70 disassembling instructions/opinions

Suddenly it unscrewed for good.

helicoid grease looks old and there seems to be too much, it is gray and abundant, possibly it is standard hardware store grease.

I suspect from the badly assembled parts, the twisted diaphragm lever and the wobble of the mounting that somebody tried to repair it without proper calmness and minimal knowledge, reassemblng it hurriedly to prepare an ebay special ..

it is the second lens I receive this month being described as good while having a tuck diaphragm, this also having a badly wobbling mount.

i was able to completely clean and disassemble the iris, while dismantling the front triplet as well by drilling two holes in the ring with the lens name on it (I couldn't use a stopper since it was blocked so I drilled two holes and used a caliper as spanner).

However it doesn't focus when remounted and it is just another riddle as the iris (it was a good idea to learn how to reassemble such iris, it was a really nice school and I feel more confident when dealing with more serious primes eventually).

I do not know if such a cheap lens is worth another day of sweating.

The previous owner has also left many cleaning marks that affect coating, when looking at infinite (still in focus) image is good but this is not the best yashica lens for sure.

When framing landscapes in strong backlight it fails to convey workable images and i already have the c/y vario sonnar 35/70 as standard workhorse.

Well done on refusing to be beaten by the lens! As you say, it was useful as an educational process but it would have been simpler to buy another lens as the MC versions are quite cheap; they were not produced at Yashica's Tomioka facility but were outsourced, mostly to Cosina. You have to go back a long way to find the classic Yashica 35-70 lenses which are the constant aperture ML f3.5 and f4 versions that were made in the late 1970s and 1980s and built like tanks.

Your comments have reminded me of a possible issue with flare in the MC lenses.

I have been advised that those lenses that are 'MC', unlike the 'ML C' (Compact) such as the 135, 200 and 300mm versions, do not use the Yashica ML coatings but use the premium coating of the manufacturer to which the lenses have been outsourced. That may explain the flare problems.

Although the ML coatings are inferior to the Zeiss T*, they are pretty good and if you set the ML 35-70 f3.5 against the much-praised Zeiss f3.4 version, from f5.6, there is no difference in contrast or flare resistance between them.

Interestingly, Yashica made a short range zoom which is actually a match for any Zeiss zoom - the ML 28-50 f3.5. Back in its day, it was the second most expensive lens (only the Reflex 1000 f11 was costlier) made by Yashica in their Tomioka factory and the ML coatings work superbly. I have three of these lenses and have never suffered flare problems and the images produced show a lot of contrast. If I was asked by someone to recommend just one zoom from Yashica, the 28-50 would be the one; it's a Zeiss in all but name. Indeed, a UK camera magazine which reviewed it alongside Zeiss primes actually rated it as high for image and build quality as those Zeiss primes which included the Distagon 16mm fisheye - a famously sharp, contrasty lens! If you ever get the opportunity to buy one that's in good condition, grab it straight away - you won't be disappointed.

I do love the construction of my 35-70/3.5 ML. Have the MC Lens, too...but not used yet. The ML 35-70/3.5 also not really, i do use my Minolta 35-70/3.5 MD instead, because i do own 2 or 3 copies, just in case something goes ugly.