Blues Dude

I'm taking my Nikon FM out of retirement, so I'm checking my old film lenses to be sure they still work.
My Sigma 35-105mm macro zoom has its shutter stuck wide open. f/3.5 is all I get.
The lens still focuses and the zoom works.
I'd really like to have a manual zoom lens, but do you think the Sigma is worth fixing?
Thanks for your advice.

fosis Loc: Pittsburgh, PA

Just a brief word of encouragement. If you got the aperture leaves (not the shutter) re-oiled for about $100, a night's nice dinner out, I'd think you'd feel affirmed every time you decided to take it out and shoot. And once it's fixed, you'd feel like you'd saved $300+ for not going out to buy a new one. Besides, you might actually be able to sell it down the road because it works!

woodyH

A technical slip there. It is the iris which creates the aperture that is stuck wide open. Did the lens perform well for you way back then? Probably not as well as some Nikon lens would, and some of these might be available at less cost than repairing the Sigma, at photo swap meets or online.

Drbobcameraguy Loc: Eaton Ohio

I believe you can pick up an old micro105mmf2.8 many focus Nikon for less than repair cost.

MrPhotog

I’d get it fixed. The iris isn’t usually lubed with oil, as that eventually dries up, hardens, or attracts dust; so a good cleaning should return it to ‘good as new’ condition. Then you’ll have it to use for another few decades.

One thing I’d try first: trying to move it during a long exposure.

Put lens on camera. Set camera shutter to ‘B’, cock shutter with film advance lever, press and hold down the shutter release button.

That action holds open the camera’s shutter and uses a camera linkage to force the aperture blades to close to the preset aperture before and during the exposure.

Now, while the camera shutter is open try to gently move the aperture ring on the lens. Sometimes the action is slow (due to old dry lube) and it needs a nudge to move a bit. Don’t force anything.

If this frees up the iris you can try snapping the shutter a dozen more times and see if it has started working reliably, or not.

Good luck.

redlegfrog

Ahhhhh - FM's

Robert Ley

Before you spend any money getting this lens repaired, check out ebay for a 35-105 f:3.5-4.5 Nikkor zoom. I have used this lens and actually had two of them at one time. It is a sharp lens that has a decent macro ability and will fit your FM very well. A great walking around lens. Just checked Ebay and you can pick one up for between $30-$60. Manual focus Nikon lenses are very cheap on the used market and are very high quality.

Bill_de Loc: US

Have you tried moving the lever on the back of the lens a few times to see if it loosens up?

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imagemeister Loc: mid east Florida

NO

amfoto1 Loc: San Jose, Calif. USA

No oil is EVER used on lens aperture blades. Oil is often what causes them to stick!

A tiny bit of graphite can sometimes be used to lubricate the aperture blades, but they are usually just run "dry".

By far the most common cause of stuck apertures is the greases in the lens leaking oil that finds its way onto the blades. This requires disassembly of the lens, removal of all optics and/or removal of the aperture assembly from the lens, then a thorough cleaning to remove all the oil from the blades, along with all the old "expired" grease in other mechanical components. The lens then needs to be properly re-lubricated. Various specialized types of oil and grease are used sparingly. Synthetic greases can be particularly helpful because they're less prone to "oiling off", are more stable at different temperatures, and don't dry out nearly as quickly as old petroleum based greases. There also are "damping greases" of different viscosities sometimes used to tune the feel and tension of focusing helicoids and zoom mechanisms... though I doubt those were used in a third party lens.

The little pins the aperture blades pivot on might be lubricated with a micro drop of very light oil in many lenses. Great care must be taken to keep the oil off the blades themselves, though. Even a little will cause them to stick.... making them sluggish, at best... or fully stuck at worst.

In this case, I would recommend simply actuating the aperture a number of times with the lever on the rear of the lens. That might free it up to some extent... enough so that you can stop the lens down a bit to see if there is oil on the blades.

There's another possible cause of a failed aperture. In most lenses it's spring-loaded. The camera holds the aperture until the moment of exposure, then releases it so that the spring(s) cause it to close down to the selected setting (either selected with the aperture control ring on the lens or by the camera's exposure control lever).

If that spring is broken or disconnected, it would cause the aperture to fail to stop down.

It's probably not worth repairing an old, manual focus Sigma zoom. A repair like this is labor intensive and would likely cost more than the lens is worth. Buying another copy of the lens *might* be a better solution... But who's to say it doesn't have the same or other issues. You might just end up buying someone else's problems.

It's often the case with vintage gear, that while you can buy it cheap, you'll have to spend more than it's worth to put it back into good, working condition. I've bought cameras for $25 or less and lenses for $5 or $10 that would cost $100 to $150 to properly "clean, lube, adjust" to be usable again. New light seals likely to be needed in a camera add cost. This is assuming there's not a problem require repairs, especially if replacement parts are needed. Even very nice examples can fail simply from sitting unused for a long, long time.

rehess Loc: South Bend, Indiana, USA

Old lenses are seldom worth putting much more effort into, especially an ‘off-brand’ item like this. I would look for a vintage Nikon lens to replace it. I had a Vivitar 70-210mm lens; I had an emotional attachment to it - I had spent my first bonus on it in 1982 - but I looked for a replacement as soon as I discovered that it had ‘issues’.