Jupiter 12 lens question?

nwcanonman · 10-04-2004

Hurray! The Jupiter 12 - 35mm lens kit finally arrived (after a month). It looks great, but I have a question. Not only did it come with filters (yellow and purple?), a 35mm veiwfinder and the plastic caps/covers for everything, BUT there is a black tube on the rear portion of the lens. I've read that people worry about protecting the extended back-end of this lens, so is this merely for protection? It looks just like a "extension tube" for use on SLR lenses.
Unexpected bonus was the Industar 50mm f3.5 lens included in the box. It wasn't listed in the Ebay ad, maybe it's how they apologize for taking so long to ship them

Laika · 10-04-2004

Normally the J12 comes with a very deep rear cap. It looks like yours has a short cap and they have used a extension tube lengthen it so it will fit. Good score to get a free Ind-50, they may be a bit slow but do produce nice images.

nwcanonman · 10-04-2004

Laika,
Thanks for confirming my guess. I'm wondering, since the tube is just longer than the rear of the lens and is the same thread, what would happen if you took a photo with the tube ON? Maybe I'll take one snap just to see. Also, I know the yellow filter is for B&W film, but the deep purple filter? Is that for I/R film?
Or just for listening to Jimi Hendrix songs - LOL

Laika · 10-04-2004

Quote:

Originally posted by nwcanonman
...what would happen if you took a photo with the tube ON? ...<snip>... Also, I know the yellow filter is for B&W film, but the deep purple filter? Is that for I/R film?

The extension tube will give you closer focus but you lose the ability to focus to infinity and the DOF is greatly reduced. They are really only useful on a SLR where you can see the focus point. There are charts to work out the focus distance but its much more hassle than it’s worth with a RF. A purple or magenta filter is used for florescent lighting to counter the green colour cast mainly with slide film, but that depends how strong the colour is, I’ve seen pink to light purple but not a dark purple.

Pherdinand · 10-05-2004

hey, a deep purple filter is a deep purple filter, don't mix it with the jimi hendrix filter!

Brian Sweeney · 10-05-2004

It looks like an extension tube, which would be useful on the Zenit 39mm SLR. It looks like a great idea for protecing that rear element! Users of other recessed lenses should take note, often the deep cap for those lenses become expensive. A BR-1 tube would make a great protector.

peter_n · 10-05-2004

Very good point, Brian! Pity that idea won't work on an M lens, I have two collapsibles that I'm not buying deep caps for because the prices are so ridiculous.

nwcanonman · 10-05-2004

I can find no letters or numbers, just the typical FSU lens symbol in white paint on the tube. It's just longer than the real element of the lens and is threaded on both ends (male/female).
I guess someone could ask one of the Russian suppliers about importing them, as it is very sturdy and will really protect the lens.
Good luck