Please tell me what lens is it, Thanks

[highpeak]

My GAS is out of control, I dig everything on ebay now, what I got is a dirty brass lens in Unicum shutter. It has no name on it, just some labeling on the shutter says, "Bausch&Lomb OPT Co. PAT Jan, 6, 91. Aperture scale starts from F4, but I guess it could be F8 as to modern standard(I don't think this lens was made in 1991, is it 1891?)

After a bit cleaning the lens is OK, no fungus or separation, few scratches. What surprised me is the shutter works after the two cylinders got cleaned. One more thing if it's helps to identify what it is, there is a "W.A." label on the aperture scale.

Any info would be appreciated.

Alex W.

 

[k_jupiter]

My GAS is out of control, I dig everything on ebay now, what I got is a dirty brass lens in Unicum shutter. It has no name on it, just some labeling on the shutter says, "Bausch&Lomb OPT Co. PAT Jan, 6, 91. Aperture scale starts from F4, but I guess it could be F8 as to modern standard(I don't think this lens was made in 1991, is it 1891?)

After a bit cleaning the lens is OK, no fungus or separation, few scratches. What surprised me is the shutter works after the two cylinders got cleaned. One more thing if it's helps to identify what it is, there is a "W.A." label on the aperture scale.

Any info would be appreciated.

Alex W.

First off, what do you mean it has no name? "Bausch&Lomb OPT Co. "
Are there two aperture scales? If so, the lens is designed to be used with the front or rear element removed for a different focal length. W.A. ... Wide Angle.

Use it, abuse it, make it sing opera. You'll figure it out.

tim in san jose

 

[highpeak]

Tim, what I want to know is the name of the lens, not the manufacture of the lens. Sorry for the confusion.
It has only one aperture scale.

Yes I will use it, and name it afterwards

Alex W.

 

[Whiteymorange]

Probably Rapid Rectilinear, surprisingly sharp when stopped down a bit. The unlabeled ones I have all cover 4x5. For some reason, the 5x7 and full plate seem to have that written on them, though this may just be the case with the ones I've found, or simply a matter of manufacturing dates.

 

[TheFlyingCamera]

If it isn't a Rapid Rectilinear, given that it is Bausch & Lomb, it could be a Tessar design. If it is in fact a Tessar, the modern f4 is well within the realm of possibility for the maximum aperture. What is the diameter of the front element? More to the point, what is the diameter of the maximum aperture? Toss it up on a camera and focus to infinity to figure out the focal length. That coupled with the max aperture will give you the real fstop reading.

 

[Ole]

Probably not Tessar. I thought about an early Zeiss Anastigmat, but the patent year is wrong for all of them (!).

So my guess is Rectilinear, too.

If the aperture scale starts at 4 and goes on with 8, 16, 32 and so on, it's US. F:8 is a reasonable max aperture for a semi-wide Rectilinear.

 

[highpeak]

Thanks for the help guys.

Scott, the lens is fairly small, the front cell is 2cm wide, according to the focal length I measured, which is close to 7 inches, F8 is a reasonable number.

Ole, the aperture scale is marked as you described.

Whiteymorange, it covers 4X5, I will try to see if it covers more than that.

Looks like it's a Rapid Rectilinear, the reflection on each cell is two bright ones and one faint one.

Alex W.

 

[TheFlyingCamera]

If it is marked WA and the focal length is 7", then you're definitely in the 5x7/WP territory. More likely WP, as 210 (7") is considered normal for 5x7. Nice little lens there. Post some photos and show us!

 

[jimgalli]

There are lots of those little rapid rectilinear lenses in unicum shutters floating about. If it were a tessar it would say so. The little unicum ones were the cheapies that came with the 1890's folders. You can assume the lenses were ground by Bausch & Lomb also. They're usually about 165mm focal length, the diagonal of 3 1/2X5 or close. Stick it on a 5X7 and tax it a little.

 

[k_jupiter]

If it is marked WA and the focal length is 7", then you're definitely in the 5x7/WP territory. More likely WP, as 210 (7") is considered normal for 5x7. Nice little lens there. Post some photos and show us!

Actually Scott, 210 is about 8 1/4"; 180 or so is a 7" lens, just on the wider side (but not much) for 5x7.


tim in in jose

 

[TheFlyingCamera]

my bad with the math... oh well...

 

[highpeak]

Here are some pictures.

 

[TheFlyingCamera]

Cute little bugger, it is. It'll be interesting to see the pictures you make with it.