"Commercial formula" lenses

Discussion in 'Classic Manual Cameras' started by dave_s, Jul 3, 2005.

  1. Here's a question I've wondered about for a while. Somewhere in some
    old newsgroup, Bob Shell (remember him?) stated categorically that
    the old chrome-shutter Mamiya TLR lenses are somehow sharper than the
    later black-shutter lenses. Yeah, I know this is counterintuitive.

    Apparently, he says, the chrome lenses were made to a 'commercial
    formula', and they made very stark unflattering portraits. In
    response to bleats from wedding and portrait photogs, who were
    primary users of the Mamiya TLRs, the Mamiya Corporation subtly
    altered the optics of the black series lenses, even though the lens
    formulas remained the same (for example, the 105 and the 135 were
    tessars, and so on.) Or so the story goes.

    So here's my question: what's the 'commercial formula' he's talking
    about, and what makes it different from any other lens? Is it
    corrected for more resolution? For more contrast? Does it just have
    more stringent quality control? Did Mamiya actually degrade the
    optics of the black lenses when they abandoned the chrome 'commercial
    formula'?

    To state it differently, what makes a 'Commercial Ektar' any
    different from any other tessar?
     
  2. It's all just words, and I wouldn't put much stock in the term "commercial formula". As for the Mamiya TLR lenses, every chrome lens I've owned has been markedly worse in contrast, than the later black shutter ones. I don't believe it's just a coating issue. Way back in high school I traded my Yashica MAT-124 for a used Mamiya system in nice shape. I thought I'd be getting improved image quality. I sold the entire setup soon after, purely out of dissatisfaction with the lenses. Even as a kid I knew something wasn't up to snuff, and I did do all the focus and alignment checks. Recently I picked up another system, and I can compare the results from the black shutter lenses to the earlier stuff- the black shutter lenses, at least the normal and wides, are better. Not to discourage those owning chrome lenses. I haven't tried all of 'em, and I did some decent work with them. I'm only one random datapoint. In color they could be very pleasing, and today in b&w I'd just hit 'em with an unsharp mask. FWIW.
     
  3. "Commercial Ektar" is just a name.

    As for the lens formula being downgraded, I suppose its possible, but I wouldn't bet on it. Photography has its own share of urban legends, and this may be one of them.

    This kind of thing is always reported second or third hand. We never hear from the guy who managed the shop.

    Everyone "knows" for instance, that old paper had more silver than new emusions. No one even knows how much silver is in paper now, much less thirty years ago!

    The Mamiya TLR lenses are great, except for the 250. It isn't as sharp as the others (at least mine wasn't). Use and enjoy!
     

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