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  1. #21

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    I've two B8s. Anybody care to have one?
    The one now in use has the 2 1/2 inch lens cone.
    I'm using a very nice metal 105 5.6 Nikor with 6x4.5,
    6x6, and 6x7. I can print any of those formats, with
    that cone and lens, from 3x5 to 11x14, maybe a
    little more. Shop Ebay. Dan

  2. #22
    CPorter's Avatar
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    Quote Originally Posted by dancqu
    I've two B8s. Anybody care to have one?
    The one now in use has the 2 1/2 inch lens cone.
    I'm using a very nice metal 105 5.6 Nikor with 6x4.5,
    6x6, and 6x7. I can print any of those formats, with
    that cone and lens, from 3x5 to 11x14, maybe a
    little more. Shop Ebay. Dan
    Dan,

    Can you tell me how I can get a 2.5 inch lens cone? I have never seen one.
    Thanks
    Chuck

  3. #23
    David H. Bebbington's Avatar
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    Quite a few here, Chuck:
    http://www.goodwinphotoinc.com/lens_...rds_cones.html
    including a 1 3/4" board which could well fill the bill.

    Regards,

    David

    PS: Out of idle curiosity, I dug out a formula which I haven't used since college:

    u = f(1 + 1 /m)

    u = object distance (lens to neg in an enlarger), f = focal length, m = magnification.
    Assuming for ease of calculation that 6 cm of negative is enlarged to 20 cm of print, the magnification will be 3.33. In practical terms, this means you will need a total extension (bellows + lens cone) of 1.3 times the focal length to make an 8x10" from a 6x7 cm neg. This is 13.65 cm for a 10.5 cm lens, 10.4 cm for an 8 cm lens (which, as others have said, will be borderline on coverage).

  4. #24

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    I've got a bunch of stuff for the B8, even two of them,
    both in very good condition, all from eBay. Shop eBay for,
    omega b8 , and for, omega cone , and any other key
    words which will locate.

    Also, via Google locate, classic enlargers . Omega is a
    specialty. Dan

  5. #25

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    Quote Originally Posted by Chuck1
    Regarding the Computar, who makes that lens? I'm not sure that I recall seeing it listed on B&H's site, but I will double check
    Chuck,
    as I already wrote, the Apo-Rodagon 4/90 and the Computar dL 4.5/90 are both discontinued. However, you can find them regularly on ebay and other second hand marketplaces. The Computar lenses were designed and sold by the US-Company of the same name. They have been manufactured by Kowa. The same lenses have also been sold under the Kowa label. These are more rare, but often even less expensive, because not everybody knows that they are identical to the renowned Computar (although they actually look the same). The Computar dL lenses have a typical design with large f-stop labels and an excellent mechanical quality that is immediately noticeable.

  6. #26

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    Quote Originally Posted by Woolliscroft
    I used to have a Rodenstock 105mm for 6 x 7, but now have a lens I have never seen anyone else using. It is a Taylor-Hobson, f4.5, 108mm Ental and will cover up to 6 x 9 ... I have no idea how old it is (does anyone know anything about the things?). It was made in Britain and we don't really have much of an optical industry any more so it is probably as old as me, but it is good.
    David,
    you shouldn't be that pessimistic about UK technology. Taylor-Hobson is not only still in the optics business, it is even a direct competitor of companies like Zeiss. They once made the famous Cook lenses and were the first ones that built zoom lens in series. AFAIK, they still make cine lenses.

    Ental was originally a Tessar (4-element) design. Tessars are usually top sharp and contrasty around the center of the image circle. With 6x7, you utilize mainly this part of the lens.

    I don't know when Taylor-Hobson stopped making enlarger lenses or when the brand name was discontinued (which could have been two different events). I guess it has been somewhere in the late 70s.

  7. #27
    Maine-iac's Avatar
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    Quote Originally Posted by Thilo Schmid
    Chuck,

    the 80mm Componon does not cover 6x7, so your observation should be normal. I don't know your enlarger, however, it makes me wonder that it does not have enough bellows for 80mm@1:3.5.
    Since when? I've been using an 80 Componon (first the old model, then the latest model for the past 8 years) and have never had coverage problems with 6X7. I have both a 6X7 Fuji rangefinder and a 6X7 back for my 4X5, and shoot this format almost as much as I shoot 645 or 6X6. I'm using a Beseler 45 with a Dichro colorhead.

    Larry

  8. #28

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    Good Morning,

    I had the same experience as Larry with the 80mm Componon. I bought one used back in the '70's and used it successfully with 6 x 7 for over twenty-five years. Eventually, it developed an internal haziness on the lens elements, so I had to replace it. As in Larry's case, I used it on a 45-MCRX enlarger. Coverage with 6 x 7 was tight, but very acceptable.

    Konical

  9. #29

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    Quote Originally Posted by Maine-iac
    Since when? I've been using an 80 Componon (first the old model, then the latest model for the past 8 years)
    Are we talking about Componons or Componon-S? AFAIK, there was only one Componon 5.6/80 and that dates back to the 60's. The later model Componon from the 80's have only been 28/35/60. Coverage depends, of course, on the mag-ratio. Even the current Componon-S 4/80 is not supposed to cover 6x7, which means that it does not fulfill the manufacturer's quality criteria for that format - at least at the declared maximum mag-ratio. Otherwise he would have written in the specs that it does cover 6x7.
    Last edited by Thilo Schmid; 01-25-2005 at 02:45 AM. Click to view previous post history.

  10. #30

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    Good Afternoon, Thilo,

    Mine had to be the older model. It was used when I bought it in the mid-'70's.

    Konical

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