Surplus Shed 6" f/1.25 Triplet

[papah]

I recently bought one of these puppies:
http://www.surplusshed.com/pages/item/l13001.html

I mounted it on my Cambo 4x5 (with gaffer tape, no lensboard), and made some images with my Camerafusion digital back and Nikon D3. Here is one:

http://hemingway.cs.washington.edu/portfolio/content/120-Soft%20Focus%20Project/Triplet/BRH5299__BRH5301-3%20images.jpg
This is a 36mm x 70mm (approx) crop from the center. Of course, there's no iris, so this is wide open at f/1.25.

Sort of large-format...

[Toyon]

Your image is out of focus.

[BarryS]

Interesting. $250 is a big leap of faith for a surplus lens of unknown qualities. I'm not sure I see a big difference from a dollar store magnifier lens, but it has some interesting qualities.

[BrianShaw]

I LIKE IT, BRUCE; Very Nice; Thanks for sharing! :)

[papah]

Thanks for the comments.

Here are several more from this lens, along with a shot from my 12" Kodak Portrait Lens at 4.8, shot through my office window during a Seattle monsoon.:)

If I can figure out how to mount and shade that huge glass, it might produce some interesting images.

(More in the Soft Focus galleries on my website...)

[BarryS]

Those are pretty cool--it looks like the fog rolled in. It might be interesting to take advantage of the incredible speed and shoot in some low light. Some good stuff on your site and now I completely understand why you bought the achromat.

[papah]

Daniel Buck posted a picture of this lens:

http://www.largeformatphotography.info/forum/showpost.php?p=519532&postcount=279

It's Large!

[Mark Sawyer]

I wonder if this was made as the positive front group of a telephoto, and is missing the negative rear element? Regardless, it's a fascinating objective. Excellent work, Bruce, and thanks for posting it!

[SteveKarr]

I think it's sharper than my 11" Verito wide open !!

[EdWorkman]

Mark wrote "I wonder if this was made as the positive front group of a telephoto, and is missing the negative rear element?

Surplus shed sez abot the 195 f1.9 "These were made for a custom camera, are slightly used, and in excellent condition. Original cost was several thousand dollars each. We have no specifics regarding the camera. Our L13003 negative achromat can be used with this to extend the triplet's focal length (came from the same camera).
AND for only $20 L13003:
"Multi-coated, cemented doublet negative achromat. Front element is 90mm diameter and back element has a clear diameter of 65mm. Focal length is -78mm.
This can be used with our L13001, 155mm diameter triplet to extend its focal length (came from the same camera)

Optics mavens please do the math for the combination?

[Tim Povlick]

I couldn't resist and purchased the lens and rear element. On the optical bench, using a Nikon FE, it looks like about the outer 1/3 of FOV is where the field curvature becomes evident, for a 1-meter target. Hopefully at infinity this will improve a little bit (won't be much).

The negative element looks like a field flattener. I do not have a clamp for this optic and can't test properly. The distance of the rear element to focal plane is typically critical (if this is indeed an FF on the order of +/- 1mm). Hand holding the FF, the magnification power of the negative element was larger the farther it is from the focal plane. Optimal distance was not determined.

In the low light, using ASA 100, the Nikon was showing 1/60'th exposure. The meter I user for large format, set at f/16 showed 8-second exposure. This lens smokes wrt exposure.

Regards,

_ .. --
TiM

[papah]

From Surplus Shed today:
"Here is some additional information that we have received from some of our customers:
The back lens is a high index glass with Barium and Lanthanum. We have a copy of the spectra.

The coating on the front lens has Niobium (improves the glass’s ability to transmit light without absorbing or refracting it and also makes it more glare-resistant).

One customer provided the following regarding the use of the L13003 smaller lens with the triplet: “I measured the distance to be 16.2 cm (between the back end of the objective and the small groove on the outside of the flattener) to get the flattest field. the distance is very critical. When properly adjusted the field of view is impressive, you could pave it with ccd's”

One mounted it on a 4x5 view camera and imaged with a Nikon D3 and was able to take some very interesting photos.

Most have advised that the lens is well corrected for color.

We found that a 6” PVC coupler available at Lowes works nicely as a barrel."