Triple convertible lens for 11x14 / 12x20?

Discussion in 'Ultra Large Format Cameras and Accessories' started by Markus Albertz, Mar 20, 2006.

  1. Markus Albertz

    Markus Albertz Member

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    Dear all,

    At some point in the future, I will take the plunge to 11x14 / 12x20 ULF. I already have a Nikon M 450 f9 but am looking for a triple convertible lens with enough coverage for ample movements; something equivalent to my Wollensak 13-20-25" that I am using on my 8x10 at the moment. I presume the desired focal lengths would be in the range of ca. 18-23-30" (?). I would appreciate any helpful suggestions, offers, etc. I am not in a big rush (this is a long-term plan) but want to keep my eyes open.

    Thanks & best wishes,

    Markus
     
  2. jimgalli

    jimgalli Subscriber

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    Markus, Wollensak made one for many years, but they were produced in about the same ratio as 11X14 cameras were to 8X10. 100:1? Anyways, they don't turn up very often. It was 16 1/4" 25 1/2" and 31". Well, 16 1/4" is close enough to your Nikkor that you wouldn't use it, and the more useable 20 and 25" on your 13" Wolly would cover the bigger formats anyway. Bausch & Lomb made the Protar VII in similar lengths but things get pretty crazy when those show up. The aerlier 360 / 600 Symmar convertible would be a good useable choice. I'm sure Gundlach made a similar TR series II but unsure what the lengths were. I stumbled onto an early Wollensak process anastigmat of 19" focal length for $45 a year ago. It is 8 element 2 group just like the Protar VII with useable 36" components singly. It's f9 or 10? so it's really compact. I've an 8X10 contact at home made with that lens that I was admiring again this weekend. Super nice contrast and very sharp. All the later process lenses were dialyt of course.
     
  3. wfwhitaker

    wfwhitaker Member

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    There was a Turner Reich triple convertible for 11x14. I had one, but don't remember the focal lengths. I found it to be a bit soft.
     
  4. Donsta

    Donsta Member

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    Well, I've been thinking about this for some time. Ultimately, I think you may revise your opinion on whether or not one should worry about space and weight saving triple convertibles when you actually start moving an 11x14 or larger camera around. They big, heavy, bulky beasts and a couple of extra pounds in lenses really doesn't seem to make too much difference. However, I have always been attracted to the Cooke XVa re-incarnation and finally received my sets last week (two lenses - one in the shutter and one without - the extra set allows two extra focal lengh combinations).

    The single set allows three focal lenghs - 311mm (12inch+-) - both elements; 476mm (19 inch) - rear element only and 646mm (25inch +-) - front element only. I haven't tested this lens yet, but these focal lenghs all provide coverage on 11x14 (i.e. no vignetting when focussed at infinity. The 311mm combination does not provide a huge amount of coverage but there's a little room for movements at f45. The other two combinations provide loads of room. With the extra set of cells, you can get a 273mm focal lengh (both rear cells) and 368mm (both front calls). The 273 covers 8x10 OK, but does not cover 11x14. The 368mm combination covers 11x14 just fine. I have not yet shot film with this lens, but will be testing these combinations later this week to check corner sharpness on 11x14 (with a 6xloupe on the GG it looked fine) to ascertain if this lens is going to work for me on 11x14 as well as 8x10 (I only contact print on these formats). One important detail - the flange focal distance of the 25 inch set-up is around 29 inches - you will need a camera with good bellows extension.

    Early indications are that the lens will work very well for 11x14. Combine a single XVa with a 240mm Kowa graphic or Computar and you should have a fabulous 2 lens outfit which should cover a huge range of needs... The Cooke has gained a reputation as having the finest multicoating of any modern lens available - apparently unbelieveably flare resistant. Of course, there is that little ugly sticking point - the price!! But for close to $3000 you get what is essentially three very lightweight (average the total weight) lenses with awesome coatings - doesn't seem so bad....
     
  5. jimgalli

    jimgalli Subscriber

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    What a great idea! I had a 2nd I was going to sell, now me thinks I'll keep it. I simply hadn't thought of that. The symmetrical pairs should be as good or better than the 19 and 26.5 are. Way cool!
     
  6. jamie young

    jamie young Member

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    I have a turner reich 15-24-36, which i think is also called the 11x14 lense
    The 36" group is the one I've used so far, and it's seems to be only about a 32.5" focal length, as I've found from measuring it to fit my #16 cirkut camera. I've gotten sharp images from it on that, which may not compare to a regular camera. I bet zeiss had some big old convertibles though. They had just about everything.
    Jamie
     
  7. Ole

    Ole Moderator Staff Member Moderator

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    The pre-WWII Schneider Angulon 210mm f:6.8 has an image circle of 500mm, and converts to 330mm f:12 (rear) and 450mm f:14 (front). It's about as sharp when converted as half a Dagor - usable in a pinch, but not as good as a whole lens.

    Zeiss made the Serie VII convertible Doppelprotar elements in focal lengths wgich included 41, 48, 59 and 69cm; and the somewhat cheaper Serie IV in 43, 50, 60 and 70cm. The usable image circle for each of these elements should be about equal to the focal length.

    Other possibilities were the offerings from Goerz (Pantar), Steinheil (Satz Orthostigmat Serie A), Suter (Anastigmat Serie I, Serie III and Serie IIIa), Plaubel (Satz-Orthar F/6), and also others from Steinheil, Voigtländer, Busch, Staeble, Rodenstock, Meyer and so on. The main problem with these lenses is to find thae: They are rare enough in the shorter focal lengths, and get progressively rarer with increased focal length.

    AND: For contact prints, there are meniscus sets of sufficient sharpness - like the Busch Vade Mecum which goes to 750mm.

    Most symmetrical and nearly symmetrical lenses can be "converted" if one is willing to lose a little bit of the ultimate sharpness. This includes Plasmats, Dialytes and Aplanats (=Rapid Rectilinears). Only you can decide if the results are sharp enough.
     
  8. df cardwell

    df cardwell Subscriber

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    Series VII Protar, whether from CZ, B&L, Krauss, or Ross are still superlative lenses. Because each cell is 4 elements, cemented together, they have no trouble from flare. Surely, the new Cooke and Wisner sets are fine, but they are expensive. The Protars did well for Edw and Ansel and generations of shooters before us, they are still more than viable.

    The Turner Reich convertibles are iffy: many were good, most were assembled poorly. The two strikes with TRs: huge numbers were made under gov't contract, the 5 cell design ( to avoid the Zeiss license fee ) made centering nearly impossible. Same problem with Goerz Pantars.

    All Series III Dagors are good. These, IMHO, are your classic, and current, choices !
     
  9. sanking

    sanking Member

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    I have tried a bunch of triple convertibles (B&L, Wollensak, Zeiss) on both 7X17 and 12X20. My experience is that the performance is not worth the trouble with the single elements. Performance on the corners is dismal, even with single elements in the 20-28" range. Same is true of the big modern convertible Symmars, say the 360mm. Great lens with both elements but indivudlaly the elements won't cover even 7X17.

    In my opinion you would get vastly superior performance with apo lenses in the 20" to 35" category.

    Sandy

    Sandy
     
  10. Donsta

    Donsta Member

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    Sandy

    Today I did a couple of test sheets with the Cooke XVa on 8x10 in every combination. I deliberately shot every sheet close to the edge of the image circle (as close as my camera would allow - I had two inches of shift and about 2 inches of fall where possible) because I would ideally like to use this lens on 11x14 (combined with a 240mm). Two sets of cells provide 5 different focal lenghs. They all cover 11x14 except for the back+back combination which is only usable on 8x10 (273mm focal lengh). The others look like this:

    Front and back - 311mm FL just covers 11x14 (can get about an inch of rise at f64)
    Back only - 476mm FL - covers 12x20 with quite a bit to spare
    Front only - 646mmFL - covers 12x20 with loads to spare
    Front and front - 368mm FL - covers 12x20 straight on

    The negatives are not yet dry, but I will report back tomorrow when they are and I have had an objective look. However, they appear to be plenty sharp right into the corners...
     
  11. sanking

    sanking Member

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    OK, look forward to your report after examing the dry negatives.

    Sandy
     
  12. Donsta

    Donsta Member

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    Well, they are dry and all of them look better than I expected! I expected the single element negatives to be easilty distinguishable from the pairs, but that is not the case. I wouldn't hesitate to enlarge all of them - so I'm pretty certain that even the most fussy of silver contact printers would be more than satisfied. I will probably shoot some 11x14 test sheets later if time allows.
     
  13. Donsta

    Donsta Member

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    A little more follow-up:

    I went out with the 11x14 yesterday and shot a couple of sheets of film with two different configurations

    1. Front element only - this has a focal lengh of 646mm and as expected, covers with more room than I could possibly use. I used it on a shot where I had significant front tilt and about 5 inches of front rise. The resulting negative is very sharp - right into the corners (which makes me very happy because I just sold my 600mm Fuji C).
    2. Front and Front elements - this has a focal lengh of 368mm. On one negative, I had a significant front tilt and 3-4 inches of front rise - razor sharp right into the corners. I know that this combination covers 12x20 with a little wiggle too, so perhaps it's time to loose the venerable 355 G Claron.

    This confirms for me that this lens has excellent potential for ULF - especially for 11x14 (or 7x17) shooters looking to loose some weight from their gear. I intend combining my twin set of XVas with a 240mm graphic Kowa and that will provide focal lenghs of 240mm, 311mm, 368mm, 476mm and 646mm.
     
  14. Markus Albertz

    Markus Albertz Member

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    Oh my, I need a bigger wallet... and I don't even have much time for photography at the moment. Well, this is quite useful to know. I wonder if the vintage version of the Cooke triple convertible would yield similar results. Thanks very much, Donsta, for posting it. Much appreciated!

    Best,

    Markus