Help fixing Minolta MD Zoom 35-70 mm F3.5 Macro lens

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

I have a Minolta MD Zoom 35-70 mm F3.5 Macro lens the aperture ring of which does not have clicks. Otherwise it works correctly, i.e. the aperture can be opened and closed, but without the clicks it does not stay where I put it if I focus or zoom. I have looked inside the lens by taking the back part off, but could not find anything that could be of help. Searching the net I found only one Japanese guide (http://minolta.eazypix.de/lr/z35-70_3,5_md3/nmd_zoom35_70.html) for this lens, but it is of no help to me fixing the aperture clicks. Sending the lens for repairs would cost more than buying a new lens. I guess the fix is easy once you know what to do and I have the tools to take the backside of the lens (where the aperture ring is) apart. Anyone with a clue how to fix the lens?

dan_ · Expire: 2016-12-19

If you take off the MD mount and the diaphragm ring you'll notice that in the part of the lens body covered by the diaphragm ring is a very little circular hole. Inside this hole should be placed a little spring and a little metal ball and on the diaphragm ring should be some little vertical grooves - that is the part that makes the diaphragm to click when the ball passes through the grooves.
Most probably the ball and/or the spring got lost somehow when your lens was opened sometime before or the previous owner took them off on purpose to better use the lens for videos.

To fix that you should find a replacement ball (and spring, if necessary). You can take it from another lens or try to buy a new one - I've seen them for sale from time to time on ebay.

I had the same problem with my 35-70 MD and managed to replace the little ball with one taken from a crappy 50mm f/1.7 MD.

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

Yes, now I can see where the ball should probably go. So all I need is a spring and that little ball dropped into that hole?

dan_ · Expire: 2016-12-19

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

Oh well, I opened up a beaten up 135 mm F3.5 lens and I tried to be as careful as I can be, but the ball and the spring was gone the moment I peeked inside. I only heard a ping from a nearby metal shelf where the ball probably hit. I could not find either, as there is lots of stuff there. I don't have more lenses that are worth cannibalising, so I guess the 35-70 has to be without clicks for now. Sad

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

I guess I could buy a "for parts" lens somebody has for really cheap and take the ball and the spring from there, that time being more careful (doing it maybe inside a clear plastic bag).

miran · Joined: 01 Aug 2012 Posts: 1367 Location: Slovenia

You're not first who had that happen to them. Wink

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

I had my Minolta MD W.Rokkor-HH 35 mm F1.8 (the first all-metal version) fixed and cleaned up by a professional, who warned me about this spring and ball if I try to do it myself. He fixed the lens the aperture ring of which was not working at all and when I got the lens back, it was just like brand new lens, even though it's I think from the late 1960's. And excellent photographs too, I simply love the lens. The guy who fixed the lens said that come back in 40 years and the lens will go on being a gem. Smile

I'm not sure if the newer versions are better or worse, but at least mine is very, very good, the only downside being the weight. I'm not sure if I should try to find a later version of the same lens, but to me the pictures look as good if not better than the ones from the very expensive Sony Zeiss FE 35 mm F1.4 lens recently released. And they don't use automatic transmission on car races, do they, so manual focus feels like a sport, automatic focus feels like a click.

eddieitman · Joined: 12 Apr 2011 Posts: 1248 Location: United Kingdom

If you need a replacement ballbearing destroy a pen like a bic

tobenama · Joined: 01 May 2015 Posts: 6 Location: Finland

VLR · Joined: 05 Mar 2015 Posts: 86

Balls from ballpoints don't work in my experience, as they are between 0.9 and 1.05 mm in diameter. In my 50 mm Minolta MD, these gut stuck in the largest slit at f/16. The slits seem to be about 0.5 mm deep, so balls with less than 1.1 mm diameter just won't slide out. I then tried one with 1.3 mm, but that was way too tight. In the end, I got some 1.2 mm hardened steel bearing balls, which do work. Ironically, you don't even need the spring with the 1.2 mm, because they seem to be sligthly larger than the originals and therefore do not slip into the springs small bore. I guess the correct size will probably be 1.1 or 1.15 mm Rolling Eyes

Lloydy · Expire: 2022-01-01

I have used the spring from a disposable cigarette lighter, under the flint. I stretched it which decreased the diameter and cut a bit off with pliers.
My supply of balls comes from an old Canon FD Breechlock mount, there's a lot in there.

mowgli · Joined: 01 Oct 2014 Posts: 2 Location: Birmingham, UK.