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Projector lens i presume
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PostPosted: Wed May 11, 2011 4:01 pm    Post subject: Projector lens i presume Reply with quote
hi

here are two lenses i desperately wanted to try

today if found a way to use one of them, the big projector lens ( i guess)
there is nothing written on it, an its not very good.



test shot (with the big lens)



now for the other one, it seems to need a great distance of at least 40 cm
between the end of the lens and the sensor.

if i would make tube, what kind of diameter will it need ?

and any familiar whit this lens ?

rectilineare extra rapide j.d.l.f (or j.d.e.f) 28 cm



ty

Last edited by KarelDH on Wed May 11, 2011 6:30 pm; edited 1 time in total


PostPosted: Wed May 11, 2011 4:27 pm    Post subject: Reply with quote
last one looks a large format wooden box lens. Due extra large negative 18x24cm glass don't need to be a super sharp lens Wink


PostPosted: Wed May 11, 2011 4:38 pm    Post subject: Reply with quote
Attila wrote:
last one looks a large format wooden box lens. Due extra large negative 18x24cm glass don't need to be a super sharp lens Wink


+1

Rapid Rectilinear lenses were corrected for rectilinear distortions so lines appear straight, not curved but not corrected for much else so CA, coma etc will be noticeable, this is long before colour emulsions so colour handling may be strange,

The bigger lens is from a magic lantern type projector, intended for projecting large glass slides, could be from anytime between 1860 and 1910.


PostPosted: Wed May 11, 2011 6:21 pm    Post subject: Reply with quote
Rapid Rectilinear lenses can be quite sharp, if stopped down. I suppose it depends mostly on the quality. Maximum aperture is normally f/8.

What you have is definitely a camera lens, it has an aperture mechanism.

A 28cm lens will be of course require 28cm between the camera sensor and the end of the lens at infinity. Because this is a long lens and not a telephoto it will also require a focusing mechanism that has enough travel to be useful, at least 100mm and maybe 150mm. I suggest if you want to mount it on a DSLR the best option will be to use a bellows, with a tube attached to the end to add length. The diameter of the tube is not really that important, probably it doesn't need to be bigger than 40mm on the inside.


PostPosted: Wed May 11, 2011 7:01 pm    Post subject: Reply with quote
luisalegria wrote:
Rapid Rectilinear lenses can be quite sharp, if stopped down. I suppose it depends mostly on the quality. Maximum aperture is normally f/8.

What you have is definitely a camera lens, it has an aperture mechanism.

A 28cm lens will be of course require 28cm between the camera sensor and the end of the lens at infinity. Because this is a long lens and not a telephoto it will also require a focusing mechanism that has enough travel to be useful, at least 100mm and maybe 150mm. I suggest if you want to mount it on a DSLR the best option will be to use a bellows, with a tube attached to the end to add length. The diameter of the tube is not really that important, probably it doesn't need to be bigger than 40mm on the inside.


+1

The original plate camera it came from will have had a lot of travel in it's focussing bellows.


PostPosted: Wed May 11, 2011 7:42 pm    Post subject: Re: Projector lens i presume Reply with quote
KarelDH wrote:
today if found a way to use one of them, the big projector lens ( i guess)
there is nothing written on it, an its not very good.

test shot (with the big lens)




Don't be afraid to post-process. Wink Some of these old lenses are actually a lot better than people realize at first.........



PostPosted: Wed May 11, 2011 8:42 pm    Post subject: Reply with quote
hi,

wow it looks pretty good actually !

thanks

( yust to confirm this is a test shot whit the big lens, magic lantern type projector lens). so i was not expecting allot, the tiny one i still need to test, looks pretty sharp on the wall).


PostPosted: Mon May 16, 2011 5:18 pm    Post subject: Reply with quote
luisalegria wrote:
What you have is definitely a camera lens, it has an aperture mechanism.

In general, enlarger lenses also have aperture mechanisms, as do some very few projector lenses, such as my Industar-58 75/3.5. I'm just picking nits here. Wink

True, most projector lenses have no iris. Sharpness can be improved somewhat by improvising Waterhouse stops to fit behind the rear element. One trick: If an M42 adapter can be fitted to the lens, I'll screw a 25-42mm step ring (big flat disc) into the mount. Maybe I'll look for similar adapters with smaller internal openings.

But I like to use projector lenses wide-open, even if only for the softness and glow of OOF areas. If find old Kodak Ektagraphic or Ektanar 100-150mm f/3.5 projector zooms to be quite interesting (and real cheap). I cut away the rear (plastic) lens body as needed, and glue on a section of cheap modular macro tube to use as an adapter.

Which leads to a general approach: macro tubes as lens adapters.

Narrow-body lenses can sometimes be fitted into M42 tubes. On my Pentax SLRs, I use cheap modular PK tubes (under US$8 per set, shipped) which have sections about 10-15-25mm thick, with male and female mount adapter sections. These tubes have an inner diameter about 56mm, with 60mm threads. (Tubes for other mounts like Nikon and Minolta have different thread sizes and diameters.) So if a projector or xray or other lens has some body section that is 56mm across, a tube section can be glued or taped on, and the mount adapter can be applied. Sometimes I also wrap rubber bands around the lens body, to easily stabilize it within the tube.


PostPosted: Mon May 16, 2011 8:48 pm    Post subject: Reply with quote
Yes, enlarger lenses also had aperture mechanisms.

However, there were few dedicated enlarger lenses until the 1930's, and not in any numbers until the 1940's. Until then popular photography depended on contact prints. Enlargers would mostly have used ordinary large format lenses appropriate for the paper size.

This lens is much older than the days of enlarger lenses - 1900-1910 at the latest I would say.


PostPosted: Mon May 16, 2011 8:52 pm    Post subject: Reply with quote
Also, there's a 99% chance that the Projector lens is a Petzval type. Very nice for portraits and other similar subjects. Try it out and don't be afraid to do some PP!


PostPosted: Mon May 16, 2011 9:01 pm    Post subject: Reply with quote
An d just this afternoon, while very bored, I used an old T2 mount that was missing the inner part, a 1 3/4" length of plastic tube chopped off an empty
mastic gun tube, lots of insulating tape, and an Isco Gottingen Projar 85 2.8 lens that I had to chop 1/8" off the back to get infinity focus.
Sliding the lens in and out of the plastic tube that is held in the bit of T2 adaptor with even more tape makes it a focusing lens. Once I've got used to the finer points of it's precision operation. Wink

But these were the better of the test shots.
Of the two looking up the church steps, one was focused on infinity ( kinda ) and one on the lower step. Rolling Eyes







The last one of the church clock surprises me, it's not great. But it's way better than I ever thought it would be.
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