300mm Rodagon with Slight Edge Fungus

[domaz]

I got a spanner wrench and went at the rear retaining ring and man it would-not-budge! Any tips for loosening this thing? I'm pretty confident I can clean the fungus if I can get to it.

Acetone, as previously mentioned- also it always help to utilize a bench vise for situations like this. Either by using the vise to hold the lens (wrap it up in a rag so it doesn't scratch it) or by holding the spanner wrench. Either way you get a lot more levergae.

[Bob Salomon]

Acetone, as previously mentioned- also it always help to utilize a bench vise for situations like this. Either by using the vise to hold the lens (wrap it up in a rag so it doesn't scratch it) or by holding the spanner wrench. Either way you get a lot more levergae.

Assuming you get it apart, how would you assure proper centering and spacing when you put it back together?

[MartinP]

Acetone, as previously mentioned- also it always help to utilize a bench vise for situations like this. Either by using the vise to hold the lens (wrap it up in a rag so it doesn't scratch it) or by holding the spanner wrench. Either way you get a lot more levergae.

Also remembering not to use so much force, with the vice, that the housing of the lens is turned in to an oval and/or cracks an element. A couple of V-shaped bits of wood to spread the load around the lens periphery would be prudent. With the acetone, use a small amount, wait hours, use a drop more etc. etc.

[Conrad . Marvin]

Might be more dangerous for the lens to put it in a vise than to use it as is. If the pressure is enough to hold the lens without slipping, it also is probably making the lens somewhat oval and the retaining ring will be tighter than if it were round.

[FotoD]

Assuming you get it apart, how would you assure proper centering and spacing when you put it back together?

Using the same barrel and rings when you assemble it again?

I've had success with pipe clamps and a hammer with stubborn lenses. Just give it 1000 light taps instead of one hard blow, and make sure there are no set screws before you start.

I'd be careful with the solvents on a cemented lens.

[Bob Salomon]

Using the same barrel and rings when you assemble it again?

I've had success with pipe clamps and a hammer with stubborn lenses. Just give it 1000 light taps instead of one hard blow, and make sure there are no set screws before you start.

I'd be careful with the solvents on a cemented lens.

The requirements for spacing and alignment are much more demanding then simply replacing them.

[ic-racer]

Some of the shorter Compomom_S lenses can easily be reassembled with lens elements not fully seated (and not crooked either) and still with plenty of room to affix the retaining ring. Making it seem like reassembly was successful.