Unknown brass lens

[cyberjunkie]

Any advice about the nature of this lens?
Found on the auction site (UK).
For the experts out there:
please have a look at the pictures and come forward with your advices.
Unfortunately the lens has been brasso'ed a little too much for my tastes.
What caught my attention were the dimensions (small: 4" extended and a little more than 2" retracted) and the weight (big: 2.5Kg).
There must be some serious glasses inside. Not a run-of-the-mill RR, i guess...
At first i thought that the small knob was there to control some lens adjustment, but a close look to the last picture seems to reveal the presence of a diaphragm.

I turned to very old lenses only recently, so i am very ignorant about the subtleties of lens collection. My main interest were immediately post/pre war objectives.

have fun

CJ

[cyberjunkie]

Edit:
I made a mistake, the lens fully retracted is 2 7/8". More likely...
I have just re-read the text of the auction, the weight seems not very credible.
If it's some kind of petzval, 2.5Kg for a lens of that length would be a little too much.
My bad, if i made the bid on the wrong assumptions! :(

have fun


CJ

[Richard Rankin]

The slash in it indicates it was probably a twist type magic lantern lens originally, so a petzval likely. My guess is someone later cut stops in it to use it as a photographic lens. After the seller was queried, it turned out the lens was only 790g packed, so I think the '2' was a typo. He gives the diameter (which I think is possibly incorrect) of the rear lens, but that is irrelevant becasue the iris makes it smaller. My guess is that you have a 4-5 1/2" focal length, f5 lens that should be fine for portraits on a 4x5.

Richard

[cyberjunkie]

I don't understand why most sellers don't publish their answers! In this case he didn't even change the text of the auction, after realizing he made an incorrect statement.
Sometimes i have the suspect that the self-proclaimed ignorance about photography is played-up a little :(

despite the small accidents... better to continue to just have fun

CJ

[Steven Tribe]

I didn't take the "slash" seriously as it didn't look functional and I don't remember seeing a magic lantern like this. My opinion was a late anon. petzval camera lens. Not that many magic lantern have been converted as magic lanterns continued longer in time than petzval use in general photography.

[Richard Rankin]

Looks like you didn't take it anyway...

[Steven Tribe]

This has been relisted - with the explanation that the seller and his mate messed up the description! What a complete idiot to think he can make up his own rules!

[Richard Rankin]

Given his comments, I suspect CJ asked to get out of the deal, not the sellers, but then, it's not really anyone's business except his unless he wants to comment on it.

What amuses me about this is that over the past few months, I've had a few problems on Ebay as to bad/incomplete descriptions, all of which were amicably resolved with no difficulty. But in each case, the (unrelated) seller claimed to be selling the item for an 80+ year old friend or neighbor who provided the incorrect info.

Is this the new 'sign of authenticity' for sellers or something? Or is it a new excuse for errors in descriptions 'because the old guy made a mistake'? I'm tempted to search Ebay descriptions for how many items are being sold for 80 year old neighbors and friends!

[Steven Tribe]

I suppose that is the case.
I thought it was the right price for what it is - time will tell.
It would much easier and less confusing to write the truth in a re-listing.