Deranged Aperture Blades

[Kevin Crisp]

I bought a decent older 210mm Componon lens. It came in a USPS box, with a bit of bubble wrap, and then some crumpled newspaper. Not a good way to pack something heavy like that.

The glass is OK, but the aperture blades have jumped out of position. I'll attach a photo. Nothing is broken, just out of position.

How do I fix this? I've done some shutter repairs, and lots of glass recementing, but I've always steered clear of aperture blades. Thanks for any suggestions. The lens body is sized Copal 1 if that matters.

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[r_a_feldman]

It looks like one of the blades is missing. Can you return the lens for a refund?

[Kino]

Edit #2: Wait, is this an enlarging lens? Forget what I formerly said, return it!

[Mark J]

Yes, agreed.
I received a 100 Componon-S from the US this week, it was loosely wrapped in bubble wrap, without any sellotape, and then stuffed into a Jiffy bag. I have no idea what some people are thinking. Luckily my lens was OK.

[Jim C.]

If it was an expensive lens return it, otherwise repair it, getting the aperture blades back in place takes a lot of patience.
Tweezers, dental tools are a must for manipulating the last few blades that are underneath ( under-lap ? ) the other ones.
Pay particular attention to the shape of the aperture blade when you take it apart, some blades aren't symmetrical.

[Kevin Crisp]

I came up with a Plan B. I remembered I had a box of G Claron barrel mounts left over from my taking barrel mounted lenses and putting them in shutters. One of them, from a 240mm G Claron, fits well and lets front and back elements of the Componon fully seat. The difference in overall length mounted in the G Claron barrel is 0.001". The marked apertures will be slightly off, but no big deal. Apparently some of us are bokoh hounds on enlarging lenses, but I think I can live with the 5 sides aperture.

[BrianShaw]

Not a bad plan... but in your spare time, if you can find a lot of it, you should really try to repair that aperture. Everyone should do that once... it's a real character building experience. That is how I became such a character. :)

[Kevin Crisp]

One plus is that you can actually read the stop markings off a G Claron barrel, compared with an older chrome Schneider barrel.

[ic-racer]

The 210mm Componon-S came with only five blades, so it is easier to re-assemble. With paitience, you should be able to get yours back together.

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This is how I do it on a mechanism with ten thin blades. Take all the blades off and start from scratch.
Clean the blades and the plate on which they sit.
Place the first blade.
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[ic-racer]

Work your way around, adding blades one-by-one until you get to the place where they start to overlap. In this example I'm working clockwise. In the case of this mechanism, there are thee free holes showing but seven blades yet to attach. So four will overlap.

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[ic-racer]

In this picture the blades are covering all the holes, but three more need to be fitted. I'm laying the blades clockwise. The first two blades that had been fitted can be pivoted toward the middle, thus exposing the next hole for the next blade. Make this blade fit under the first two blades.

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[ic-racer]

Here is blade #9 of 10 going in. It will fit underneath the three blades that have been pivoted toward the center.

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[ic-racer]

All done. Just don't sneeze or cough before putting the top piece in place to hold it all together.

This was a Cine lens aperture, about the size of a quarter. A large format mechanism is much easier.

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[Kevin Crisp]

Yikes. This is more complicated than I thought. Thank you.

[Mark J]

How do you know which blade to put on first, and how do you know whether they go on anti-clockwise or clockwise ?

[Jim C.]

Yikes. This is more complicated than I thought. Thank you.
You've recemented lens elements, this way less complicated to me :)

[paulbarden]

How do you know which blade to put on first, and how do you know whether they go on anti-clockwise or clockwise ?

You look closely at how they're configured when you take the thing apart, photograph it, and you'll have a reference.

[dsphotog]

The most common failure is when someone forces the aperture ring and breaks the locating pins off of the blades.

[Greg]

It's really not all that complicated... Once reset aperture blades in a shutter similar to yours. At the time instructions were impossible to find. First evening was tired so had a cup of coffee - bad idea. Finally fixed the blades. Memories are that it took a lot, I mean a lot of patience, but it wasn't all that complicated in retrospect.

[Kevin Crisp]

... but it wasn't all that complicated in retrospect.

That could apply to so much of this forum.

[domaz]

Aperture blades are really quite simple but for most of us rank amateurs it still takes a few hours to get it right. I heard the women working in the factory could assemble the blades in all of 5 seconds...

[paulbarden]

I heard the women working in the factory could assemble the blades in all of 5 seconds...

I don't believe that. I've reassembled hundreds of apertures and it's never taken me less than 2 minutes. A ten blade aperture can take 5 minutes or more.