Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!

SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Beseler 18" opaque projector lens
View previous topic :: View next topic  


PostPosted: Wed Dec 29, 2021 7:03 pm    Post subject: Beseler 18" opaque projector lens Reply with quote

The full inscription on the lens is: Charles Beseler Company, East Orange, N.J. U.S.A. 18" E.F. Series III.
And what is an opaque projector? Wikipedia says: "The opaque projector, epidioscope, epidiascope or episcope is a device which displays opaque materials by shining a bright lamp onto the object from above."
https://en.wikipedia.org/wiki/Opaque_projector

I'm not sure which type of 'scope my Beseler came from. But I do know it's a large lump of glass and metal:
diameter 135 mm, length 157 mm, mass 2.5 kg, focal length 18 inches (457 mm), speed approximately f/3.6.

For comparison, here's the lens next to some more familiar objects:


#1


#2



When I first saw the Beseler in an online auction, I didn't know what it was. But I was intrigued Exclamation
And because I was the only bidder, I won it for a low price.

The lens arrived in good condition except for some dust on the outside.
Internet searching told me this was a three element lens. And my reflections test appears to confirm that:


#3



So how to attach it to a camera? My first thought was a bellows and a connector of some sort. But the Beseler's approximately 35 cm register is too long for any bellows I have.
Eventually I realized the barrel of a long telephoto lens might work. And by luck, my Vivitar 500mm f/6.3 was just what I needed.

The Vivitar consists of several barrel segments screwed together. So when I removed the front end of the 500 (along with the front lens elements), it was nearly the ideal length. I also removed the single rear element from the lens.

Using the Vivitar gave me a focus mechanism, an aperture and a lens mount. It also has a rotating tripod collar for adjusting camera orientation. And the tripod mount proved useful as an attachment point to secure the barrel.

This is the Vivitar 500 f/6.3 intact:


#4




Next, I found a board to use as a platform for the Beseler and barrel. And wood scraps provided the material for a connector collar.
Last, some pieces were added to position the Beseler and Vivitar barrel. And inserting a T nut allows the platform to mount onto a tripod.


This is the result:




#5


#6





#7





#8




#9




#10




#11




Photos #8, #9 and #10 were shot wide open, #7 and #11 were stopped down. And for #11 (Black Capped Chickadee), that is the correct orientation. The Sunflower was actually facing down.
Someday I'll try to calculate what the f ratios actually are.

Thus far I've shot with 36x24 & APS-C digital cameras. I frequently use extension rings because of the long minimum focus distance. And I've usually added contrast to the images - either in camera or in post processing.

All the shots I've taken with this contraption have been around my own home and yard. The bulk makes the lens / platform difficult to use. And the rendering isn't sharp enough - or weird enough Very Happy - to make it worth the effort to take the setup out and around.

But the Beseler and I are still just getting to know each other. When I was "collimating" the setup, I saw some bizarre rendering while the Beseler was tilted. Twisted Evil
So I think this lens still has plenty of untapped potential. Wink


More about similar lenses (English)
http://charles.hollemeersch.net/2016/11/11/projection-optics-company-18-lens-review/

...and here (French)
http://blog-photo.guillaume-foucart.fr/2019/09/11/trois-objectifs-depiscopes-en-test/


PostPosted: Fri Dec 31, 2021 8:20 am    Post subject: Reply with quote

I was not prepared for the enormity of this lens, incredible! And the mounting configuration is inspired as well! I quite like it's rendition as well, even stopped down. I was expecting a lot of chromatic aberration, did you have to do a lot of correction?

Last edited by Paragon19 on Sat Jan 01, 2022 12:55 am; edited 1 time in total


PostPosted: Fri Dec 31, 2021 11:01 am    Post subject: Reply with quote

That last shot is really impressive!

I've picked up a bundle of lenses from projection TVs, which were also dirt cheap & similarly heavy (two of them are 2.2kg each)
Your method of mounting is intriguing and seems like an excellent option, I was thinking of drain pipe for extension, but your lens is a much better option.

I have to admit my job lot of lenses are all far less attractive than yours, with large plastic mountings...


PostPosted: Fri Dec 31, 2021 9:45 pm    Post subject: Reply with quote

Paragon19 wrote:
I was not prepared for the enormity of this lens, incredible! And the mounting configuration is inspired as well! I quite it's rendition as well, even stopped down. I was expecting a lot of chromatic aberration, did you have to do a lot of correction?

Yes, the size of the lens made the challenge difficult - and also rewarding.

And no, I don't consider chromatic aberration to be a problem. As I recall, I didn't correct for it in any of the sample photos.

Here's the worst example shot I could find. A snowy, silver car door with contrast boosted in post processing - but no correction of fringing. Stopped down to "f/11" on the Vivitar with a Sony A7ii:


#1


#2 cropped


PostPosted: Fri Dec 31, 2021 10:46 pm    Post subject: Reply with quote

DConvert wrote:
That last shot is really impressive!

Thank you. Our Chickadees are relatively tolerant so I was able to get close to that one.
The bird would've been almost dead center in the Beseler's image circle and I may have been at an ideal distance for sharpness.
That shot was stopped down to "f/11" on the Vivitar barrel with a Pentax K-5iis and an extension ring.
And I did sharpen and boost contrast in post processing.


DConvert wrote:
I've picked up a bundle of lenses from projection TVs, which were also dirt cheap & similarly heavy (two of them are 2.2kg each)
Your method of mounting is intriguing and seems like an excellent option, I was thinking of drain pipe for extension. . .

Yes, exactly! I also considered a large plastic pipe for my lens. And I don't know enough about optics to know what's feasible, but I've thought it would be fun to try to utilize more of the Beseler's image circle. And I'd also like to experiment with tilting.


DConvert wrote:
I have to admit my job lot of lenses are all far less attractive than yours, with large plastic mountings...

Heh, yes, I must say I like the look of my Beseler. But then, I'm a fool for almost any large, fast lens! Smile


PostPosted: Sat Jan 01, 2022 1:06 am    Post subject: Reply with quote

55 wrote:
Paragon19 wrote:
I was not prepared for the enormity of this lens, incredible! And the mounting configuration is inspired as well! I quite it's rendition as well, even stopped down. I was expecting a lot of chromatic aberration, did you have to do a lot of correction?

Yes, the size of the lens made the challenge difficult - and also rewarding.

And no, I don't consider chromatic aberration to be a problem. As I recall, I didn't correct for it in any of the sample photos.

Here's the worst example shot I could find. A snowy, silver car door with contrast boosted in post processing - but no correction of fringing. Stopped down to "f/11" on the Vivitar with a Sony A7ii:


#1


#2 cropped


Wow, surprisingly well controlled CA for a lens design that probably didn't need to consider it at all. I agree with DConvert as well, the last shot of the chickadee is very impressive as well.

I need to be careful, the urge to look for episcope lenses is rising now...


PostPosted: Sat Jan 01, 2022 6:22 pm    Post subject: Reply with quote

Paragon19 wrote:
. . .

I need to be careful, the urge to look for episcope lenses is rising now...


Best of luck with your search! Wink


PostPosted: Sun Jan 02, 2022 12:19 am    Post subject: Reply with quote

55 wrote:
Best of luck with your search! Wink


There are unsurprisingly few of them, but some interesting contenders. Do you mind if I ask how much you paid for yours?


PostPosted: Sun Jan 02, 2022 2:40 am    Post subject: Reply with quote

[quote="Paragon19"]
55 wrote:
. . . Do you mind if I ask how much you paid for yours?


Not at all. I bought mine three years ago for $22 (shipping included) on shopgoodwill.com. I was the only bidder.
But that was just opportunistic, blind luck for me as I'd never seen such a lens before.

Unfortunately, since I bought mine I can recall seeing just two similar lenses on shopgoodwill.com. - although I think one of them was within the past couple months. But if you live in the U.S., I'd recommend checking shopgoodwill as their prices will likely be less than ebay.

For searching, I'd suggest using brand names as key words since many sellers may not know what it is they actually have. Beseler seems to be a common brand, but there are others. The first link I included in my first post here shows apparently the same lens as my Beseler with the brand name "Projection Optics Company".


PostPosted: Sun Jan 02, 2022 3:22 am    Post subject: reversing the Beseler Reply with quote

By the way, just a footnote about using the Beseler:

A couple years ago I did a brief test to see how the lens performed when reversed. That is, with the rear of the lens facing forward.

Minimum focus distance was significantly longer and images were softer compared to normal orientation.
When I took digital shots of a tree far away, normal orientation showed just a bit of green fringing. When reversed, the tree was much softer and there was strong purple fringing.

I'd be curious to know how reversing individual elements would affect rendering Smile.
But I'm not brave enough to mess with my lens. I'd be afraid of damaging those huge elements.


PostPosted: Sun Jan 02, 2022 9:34 am    Post subject: Reply with quote

55 wrote:
For searching, I'd suggest using brand names as key words since many sellers may not know what it is they actually have. Beseler seems to be a common brand, but there are others. The first link I included in my first post here shows apparently the same lens as my Beseler with the brand name "Projection Optics Company".


Yeah, usually I just cast a wider net and look for anything unusual of interest, but you're right, with more obscure items like episcope lenses knowing the brand will help better. Looking for "Projection Optics Compan" on Ebay yielded the same lens too, but for a bit more than I'd want to spend.

55 wrote:
I'd be curious to know how reversing individual elements would affect rendering Smile.
But I'm not brave enough to mess with my lens. I'd be afraid of damaging those huge elements.


I haven't actually tried reversing elements in any lenses yet, I don't really know enough about optics to guess what kind of changes reversing different types of elements would yield. Seems like a big simple triplet like this would be easy to try on though.

55 wrote:
When I took digital shots of a tree far away, normal orientation showed just a bit of green fringing.


It looks like you've done a good job of reducing the fringing in post. I haven't been very good at that so far, how do you usually achieve it? If I could manage that I would enjoy my Adaptall lenses and adapted projector zooms better.


PostPosted: Sun Jan 02, 2022 10:06 am    Post subject: Reply with quote

Paragon19 wrote:
. . .
It looks like you've done a good job of reducing the fringing in post. I haven't been very good at that so far, how do you usually achieve it? If I could manage that I would enjoy my Adaptall lenses and adapted projector zooms better.


The credit belongs to Beseler's engineers, I guess. I'm not a skilled post processor, but with the Beseler I haven't needed to be.
As far as I can recall, I didn't do any de-fringing on the Beseler samples I've shared.


PostPosted: Sun Jan 09, 2022 3:11 am    Post subject: Speed Limit ? Reply with quote

The lens barrel I adapted to the Beseler 18" came from a Vivitar 500mm f/6.3. But since the Vivitar's elements have been replaced by the Beseler, I was curious to know what the new lens speed was.

To estimate the Beseler/Vivitar's maximum aperture, I took comparison exposures using the Beseler/Vivitar and some other long lenses. And I also used a measuring method found here:
https://apenasimagens.com/en/measuring-lens-aperture/

The approximate answer I came up with is f/5.0.

My knowledge of optics is limited, but I'd assumed the Vivitar's relatively narrow barrel would restrict the lens speed more than it actually does.
From several meters away, taken with a 400mm lens, here's the view through the wide open Beseler/Vivitar:


#1


PostPosted: Tue Jan 11, 2022 8:40 am    Post subject: Reply with quote

Great!
I work often with larg epdiascop lenses, but most times I don´t use them as they are, but use different knds of speedboosters. Some DIY speedboosters or at least the Kipon medium format speedbooster.
But yes, they are really usable and a lot of fun - often for small money!


PostPosted: Thu Jan 13, 2022 5:51 am    Post subject: Reply with quote

Thanks, ZoneV!

Hmmm. Speedboosters? I don't know much about them, but they sound interesting.


PostPosted: Fri Jan 14, 2022 1:18 pm    Post subject: Reply with quote

A very well found solution for the lens to be used adapted! Episcope lenses in plastic barrels could also render a very high IQ. Here is my test of Will-Maginon 200 which gives an impressive sharpness and small CAs.

A couple of shots from that series:





PostPosted: Sun Jan 16, 2022 2:30 am    Post subject: Reply with quote

alex ph wrote:
A very well found solution for the lens to be used adapted! Episcope lenses in plastic barrels could also render a very high IQ. Here is my test of Will-Maginon 200 which gives an impressive sharpness and small CAs.


Thanks for the link. I like your results!


PostPosted: Fri Jan 21, 2022 12:02 pm    Post subject: Reply with quote

Razz