Apo-Rodagon f2.8-50mm - Can it be opened?

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Ichthyophthirius
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Joined: Thu Mar 07, 2013 5:24 am

Apo-Rodagon f2.8-50mm - Can it be opened?

Post by Ichthyophthirius »

Hi,

I have an Apo-Rodagon f2.8-50 mm #75.050.01 enlarger lens in the "mid style" barrel like this one, in which the aperture clicks are engaged by pushing the barrel in and out:
http://www.photocornucopia.com/archive/ ... d%2090.pdf
https://www.mrcad.co.uk/product/rodenst ... ging-lens/
http://store.khbphotografix.com/Rodenst ... -Used.html

My question: Can the lens be opened safely to blow out the dust particles that are situated above and below the iris space? I have several Rodenstock lenses, usually the front group can easily be unscrewed by hand (if fact it's often loose on older lenses) but here I can't see the way in.

Regards, Ichty

ray_parkhurst
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Re: Apo-Rodagon f2.8-50mm - Can it be opened?

Post by ray_parkhurst »

I generally remove the front group on the similar 80mm lens by applying strong double-stick mounting tape to the front, and something strong like a shaped piece of wood to the other side of the tape, and then unscrewing the group. It leaves a bit of a mess but is easy enough to remove the residue. This usually works, but I've had some lenses where the front group was on too tight. I left those alone, but if necessary I believe the rubber grip on the aperture ring is removable and exposes the screw for aperture adjustment. Once removed the aperture ring should unscrew, giving you more "bite" to hold the front group with a rubber wrench or maybe even a gloved hand to unscrew it. Proceed with caution as I have never verified removal of the rubber grip. Most all the ones I've tried came off with the double-stick.

RobertOToole
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Re: Apo-Rodagon f2.8-50mm - Can it be opened?

Post by RobertOToole »

Hi Ichty

Rodenstocks have a front cell that screws into the iris mount. The correct and proper way to loosen the cell is to use the rubber puck (like a minuture hockey puck) type wrenches they sell on Amazon and eBay. The will open even the most stubborn top element cell. They are made of soft natural rubber.

https://www.ebay.com/sch/i.html?&_nkw=rubber+lens+tool

Best,


ray_parkhurst
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Re: Apo-Rodagon f2.8-50mm - Can it be opened?

Post by ray_parkhurst »

For sure that will beat the double-stick tape, though the idea is the same.

RobertOToole
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Re: Apo-Rodagon f2.8-50mm - Can it be opened?

Post by RobertOToole »

ray_parkhurst wrote:
Fri Mar 26, 2021 3:11 pm
For sure that will beat the double-stick tape, though the idea is the same.

These are made of soft gum rubber so they grip like sticky tape and I've loosen some super tight cells with this. I would avoid the harder yellow and gray plastic versions.

Best,

Ichthyophthirius
Posts: 1152
Joined: Thu Mar 07, 2013 5:24 am

Re: Apo-Rodagon f2.8-50mm - Can it be opened?

Post by Ichthyophthirius »

Hi Ray, Hi Robert,

Thank you! It worked. Beware of the shims :D

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