Reintroduction of an 'Old' Lens Design

I am looking into the possibility of making a WA lens capable of

covering 8x20. There are very few Series V or 3 Protars of 12" focal

length and Goerz never made any 12" WA Dagors.

 

Has/does anyone here tried something like this?

 

I was more inclined towards a 12" WA DAgor as the circle would cover

8x20 and be reasonably fast as well as having the least number of

elements to produce-3, since the lens is symmetrical I could match

cells up.

 

The other possibility is the Series III Protar but it has four elements

and is unsymmetrical, a more difficult proposition.

 

 

It sounds easy but from the small amount of research I have done its

not

going to be easy. If it does work out I'll probably have 20-30 made and

sell the spares on Ebay. Getting the shutter and mounting seems to have

been the easiest part so far.

 

Anyway just a thought, if not a desperate cry for help!!

 

CP Goerz.

The third possibility might be the Goertz Hypergon - widest LF lens ever made...

You're looking at a lens with a half-angle of 42 and a bit degrees. Say 85 degrees total cone angle to cover 8"x20" at infinity with a 300mm focal length. I'm pretty sure that the WA Dagor wouldn't stretch to that.<br>See <a href="http://www.largeformatphotography.info/classic-experts.html">this link</a>, which shows no useable image contrast beyond a 40 degree half angle.<p>The covering abilities of the Dagor are legendary, but in fact that legend is mainly built on myth, in my opinion.<br>Sure, the Dagor will project light out to a great radius, but the image quality of that light is actually pretty poor in the outer field.<p>I'm fairly sure that if the Dagor were being produced today, its field would be deliberately mechanically restricted to give better contrast, and to prevent the low quality outer field from being used.<p>I'm sure there are modern lenses already out there with the sort of coverage angle you're looking for though.<br>For example, I've got a 300mm Konica Hexanon GRII WA copying lens that appears to have nearly a 90 degree coverage when well stopped down. (I don't have a camera big enough to test it properly, I'm afraid.) It cost me £25 (about $40 US). Now you couldn't even buy suitably sized blanks of optical glass for that price!

If you're serious, talk to Ron Wisner. He had Schneider produce the "Wisner convertible plasmat" lenses, so should know what's involved. And I recall a "View Camera" magazine interview with Douglas Busch, who described a series of "de golden Busch" ultra-large format lenses that he sold for a while in the '80s. If I remember, the glass was by Rodenstock and the mechanics by Ilex/Melles Griot.

Is it April already?

A 12 inch Golden Dagor will just cover 12x20 so might work OK on 8x20. The 305 G-claron will just cover 8x20. The 305 computar will cover easily and sharply to the edges (covers 12x20 with 3 inches of rise). Might be easier to check out one of these before going to the expense of having lenses manufactured.

Hey there CP,

For twenty years I've been storing 37 pounds of thorium and lanthanum in a lead clad shed in my back yard.

Please stop by and I'd be happy to donate to the cause.

Three forms of ID, if you don't mind.

Through away the slide rule.

You can use my G4 for some parallel processing on those calculations.

BTW: Bon Ami winds up being an efficient and cost effective polishing agent.

See ya soon.

Why don't you talk to Cooke?

 

as for:

 

"For example, I've got a 300mm Konica Hexanon GRII WA copying lens that appears to have nearly a 90 degree coverage"

 

I just saw one of those on ebay (or was it the one you got).

I use an older 300mm 6.8 uncoated Dagor that will cover 8x20, also a 250mm Fuji SF hyperfocal focused will do (blurred edges), as well as a 165mm Rodenstock pantogonal, three element lens which is a killer.

Sorry, Andrew. I thought it was a troll. Twenty lashes.

Bill, were it not a troll, what was it? An idea to bake at home 20-30 lenses of optical quality? Com'on...

I'm not making a lens for the 8x10 sized format or even the 11x14 size. Anyone who has shot 8x20 and up knows that WA lenses that cover that size of neg are few and far between. Most 8x10 lenses can probably be used on 11x14, 7x17 takes a little more searching but not much. 8x20 is a whole different ball game.

 

First the format shape forces you to scan the print from side to side, your eye can pick up any softness within the blink of the said same organ. As rule #1 of photographic composition states,Start at the corners and work your way in. I'll be selling a few of these rule books on Ebay soon so stay tuned ;-)

 

Many lenses will 'cover' and 'look' like they can be used but when the first sheet comes out the fixer is when you see how good it actually is. A 12" Dagor won't do it, its strictly a 14x17 at max.When I first started shooting 8x20 I made the mistake of using a 12" Golden Dagor figuring that it was the best of the best and it would be perfect. Not one negative I shot with that lens the whole trip was any good, it was a total waste.

 

A 14" Dagor can just barely do it but has slight softening. A 16 1/2" Dagor is great as is a 14" WA Apo Nikkor. I do know about the Kodak Portrait and Rodenstock Imagon but they rely too much on stopping down to make the sharpness and there is a difference between a focused sharpness and an aperture sharpness, to use the laymans terms. The Pantagonal is a 'collectors' lens, I've had two and neither could be considered useable. The edges are so dim as to make them useless. They were originally sold with a green center filter that would work with the film emulsions of their day but not so with FP4, most of those filters are faded beyond all recognition now anyway. The specs on the lens are good if not fantastic but they aren't particularly sharp,I only had two to play with and maybe a not-so-good-pair at that possibly. A friend of mine has the largest, the 75cm one, its as big as a dinner plate he tells me.

 

This is why I am interested in making a WA lens for 8x20 because there are very very few lenses shorter than 14" out there that can. Please don't take this as any kind of a oneupmanship attitude its certainly not meant that way but unless you have shot 8x20 you don't really know how difficult it is to get the right lens, especially a WA.

 

Love and kisses to all,

 

 

CP Goerz.

CP,

 

Well, clearly you have thought this out a bit. I might add the suggestion that you make the lens cover at least a 12x20. I think there are many more 12x20 shooters out there than there are 8x20 shooters, so I think the market would be much larger if you accommodate them.

 

As you state, the majority of the lenses that ULF shooters use are not really designed for that type of work, and so we do nasty things to the lenses to fit a square peg in a round hole. This is the reason that most ULF shooters stop down as far as is possible with the lenses they use. It's normally not for depth of field, it's to improve corner sharpness.

 

Butch mentions the Computar line of lenses. They are similar to the G Claron line, but they often have greater sharpness in the corners. There is some field curvature with them, but the stopping down required for corner sharpness pretty much eliminates this problem. This lens is available in a 305mm version.

 

The 355 G Claron will easily cover 8x20, but you will need to stop down, as is the case with all the other lenses out there.

 

Otherwise, you need to convince Schneider to make a limited run of the Super Symmar XL lenses in a 270-300 range. Since the 210XL will just hit the corners of a 12x20, something in the 270 range will have room to spare. Of course, since you are using a format smaller than 12x20, the 210XL will cover it, with room for movements. I do not know if it will meet your sharpness requirements, though. Before you go through the hassle of having lenses manufactured, maybe you should check out if that lens will meet your needs.

 

---Michael