On 4/21/2013 8:41 PM, usher99@xxxxxxx wrote:
> It is a matched achromatic CU lens so it should outperform cropping a
> 1:1 image in most circumstances
I would expect so, but have not put the rubber to that road.
> but Moose's question how the CU lens with the 80mm on the autotube compares
> to the same
> mags on the bellows sans CU lens is intriguing.
One could do the testing all on the bellows, just restrict the extension.
> I have read that optically well matched TC's can induce fewer
> aberrations than extension
The 2x converter on the Tammy 90/2.5 is excellent.
> but have no clue about the CU lenses.
I've only encountered one other custom CU lens, for a Tammy 28-200, and it
appeared to be a simple, single lens on a
custom bayonet mount for quick use. I suppose there must be custom, 2 or 3
element CU lenses designed for only one lens,
one focal length and a very narrow repro range, but I've not heard of another.
> On the other hand the autotube with CU lens looses almost no light
> where one loses another stop going from 1:1 to 2:1 on a bellows with
> that lens
Ah yes, I'd forgotten that.
Achromatic Moose
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What if the Hokey Pokey *IS* what it's all about?
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