Quote:
Originally Posted by clive milne
Errm... I am reluctant to point this out, but a 36" (910mm) focal length lens with a focal ratio of f/4 must by definition have an effective aperture of 9 inches (228mm)
I am guessing that 337mm mentioned in the advert is the diameter of the mechanical housing, not the clear aperture. The caveat to this is if there is an internal field stop for
the purpose of controlling vignetting, in which case the front element may in fact be 337mm, but in any event... it is effectively a 9" lens... period.
But you guys knew that, right?
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Regardless - I wish I have one like that. The beauty of the retractor (among of all other things) is that you can leave it covered by rubbish bag and trampoline on the pier in your backyard and unless you live in tropics or sandblast the lens, it will be just as good in twenty years time as it was when you first got it.