Multiple Aperture Blades - Why?

Discussion in 'Classic Manual Cameras' started by John Seaman, Jan 10, 2021.

  1. Interesting conversation. Some of this must still be... at the very least, something that somebody somewhere cares a teensy little bit about. Although perhaps not so much, considering the basement bargain sales prices on these (and other) shaped-aperture "gobo" style lens inserts from Lomo?

    New Petzval 85mm Special Aperture Plates – Season 2
  2. It is hard to believe in our modern, micro-managed, marketing-led culture, but there was a time when "cost of mfr" and monetary exchange rates were not the driving forces behind design of everything. In the not-quite-distant past, all photographic equipment above box camera level was routinely very expensive: there wasn't any competitive advantage in cutting corners because nobody was offering any bargains. So it just didn't occur to European optics firms that "gee, we could shave costs off this lens by dropping back to a hexagonal iris" (it might even have been more costly to alter the production line for fewer blades). The tradition passed down from large format and motion picture lenses was a circular multi-blade iris, so that simply remained the standard across smaller formats until automatic stop down became a popular, then required, function.

    The exploding popularity of sophisticated Japanese SLRs like the Nikon F and the groundbreaking medium format Hasselblad 500c upended the old "Keebler Elves" mfrg ethos. More mechanical automation necessitated fewer aperture blades (tho Hasselblad and Zeiss really should have rethought their stark drop to just 5 blades: even Nikon was still at 7 to 9 blades with the early F-mount Nikkors). By the late 1950s lens iris designs (below press camera format) scattered to the winds: you could encounter anything from 7 to 16 blades in just one common preset Zeiss lens for Exakta. Questionable shapes like sawtooth and asterisk went in and out of production.

    There were always some photographers and art directors aware of what we now call "bokeh". They would choose lenses appropriate to different assignments, with some lenses developing a reputation for their distinctive "look". But it wasn't as discussed or obsessed over as it is now. Lucky for us, the all-metal, little to no plastic construction materials available back then allowed many excellent old optics to survive for our enjoyment today.
    Last edited: Jan 20, 2021
    John Seaman likes this.

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