Mounting a 210mm f6.8 Wide-Field Raptar in a Shutter

[neil poulsen]

A while ago, I picked up a 210mm f6.8 "Wide-Field" Raptar (factory coated) in a barrel mount, and I'm thinking of having it mounted in a shutter.

Checking around, Kinglake refers to a "Wide-Angle" Raptar as a double-Gauss lens. Looking at this lens in a light, it has the tell-tale double pair of reflections (two storng, two faint) that would suggest this lens to be a double-Gauss.

I can't find a reference for an image circle, and Kinslake doesn't provide a half-angle. I have a reference that lists a Wide-Field Ektar 250mm to be 422mm at f16. Doing the arithmetic, I might expect an image circle for my lens at 253mm at f16. Stopped down, I'm thinking that I'd get pretty decent coverage.

Looking at S.K. Grimes, I'm wondering if I could use a Copal #1 lens. (?) Grimes would know.

Anyway, I'd appreciate any comments about the potential success/failure(?) of this project. I've never had a lens mounted in this fashion.

[Mark Sampson]

I've seen a lot of Rochester-made lenses, but have never even heard of this one. I'd guess it was meant to cover 8x10 but who knows? I'd try it- maybe four sheets of film- before going to the expense of putting it in a shutter.

[Bob Salomon]

Just point it out a window and hold a large piece of white board behind it. Darken the room and see how big an image it throws onto the board.
Then decide if it is worth a shutter for your use.

[Jim Noel]

Terrific economy lens. Yes, it will cover 8x10, but not at full aperture. I wish I still had mine.

[Dan Fromm]

Neil, "two strong, two faint" doesn't mean double Gauss. It means dagor type, as in three cemented elements. A 4/4 double Gauss type will have 4 strong, no faint reflections. A 6/4 will have 4 strong, 2 faint.

[Keith Fleming]

I have a 210 mm f6.8 "Graphic Raptar Wide Field Lens", which was described as a "reverse Dagor" when I bought it. LensN2Shutter put it into a Wollensak Alfax shutter for me about 10 years ago. I use it on both my 4X5 and 8X10. It covers the latter very well--at least for my purposes . As I remember, the description said it had a coverage of 15-inches.

I am not sure if the OP's barrel lens is the same item though.

Keith

[neil poulsen]

I have a 210 mm f6.8 "Graphic Raptar Wide Field Lens", which was described as a "reverse Dagor" when I bought it. LensN2Shutter put it into a Wollensak Alfax shutter for me about 10 years ago. I use it on both my 4X5 and 8X10. It covers the latter very well--at least for my purposes . As I remember, the description said it had a coverage of 15-inches.

I am not sure if the OP's barrel lens is the same item though.

Keith

Probably the same. I left off the "Graphic," but it's included as part of the name.

Perhaps as a reversed Dagor, this lens might be similar to an Angulon. (If I read Kingslake correctly, the Angulon is a reversed Dagor.) it would make sense, given that an Angulon is indeed a "wide-field" lens.

So, I'm wondering if a reversed Dagor would result in a "double pair of reflections (two strong, two faint)" reflection pattern that I described? By the way, my wording here and above was a bit poor. To clarify, I see four pairs of reflections (8 reflections total) in my lens, two pair that are prominent, and two pair that are faint.

[neil poulsen]

I have a 210 mm f6.8 "Graphic Raptar Wide Field Lens", which was described as a "reverse Dagor" when I bought it. LensN2Shutter put it into a Wollensak Alfax shutter for me about 10 years ago. I use it on both my 4X5 and 8X10. It covers the latter very well--at least for my purposes . As I remember, the description said it had a coverage of 15-inches.

I am not sure if the OP's barrel lens is the same item though.

Keith

Keith,

Practically speaking, what kind of movement are you able to achieve with your Graphic Raptar Wide Field Lens on 8x10?

How sharp is it; what kind of enlargement is possible, when you've used this lens with 4x5?

[Luis-F-S]

SKG has mounted many lenses for me, they currently have a 35” Artar for me. If you send it to them he can tell you what shutter it will mount in.

[Dan Fromm]

So, I'm wondering if a reversed Dagor would result in a "double pair of reflections (two strong, two faint)" reflection pattern that I described? By the way, my wording here and above was a bit poor. To clarify, I see four pairs of reflections (8 reflections total) in my lens, two pair that are prominent, and two pair that are faint.

Neil, an air-glass interface gives a strong reflection. A glass-cement-glass cement interface gives a weak reflection. Two strong, two faint means two air-glass interfaces and two glass-cement-glass. Front surface of the outer element and rear surface of the inner element are air-glass interfaces. The outer element's rear surface is cemented to the middle element's front surface, the middle element's rear surface is cemented to the rear element's front surface. That's two glass-cement-glass interfaces.

Draw a picture.