> From: "Piers Hemy" <piers@xxxxxxxx>
>
> Are you sure about the f0.8, Jan? Doesn't the Baveyes adapter limit the focal
> ratio "gain" with very wide aperture lenses?
Interesting… don’t recall reading that.
So, I pointed the 55/1.2 an an evenly-lit surface, with and without the
Baveyes. Without the Baveyes, I scanned around about the edges of the scene,
making sure the EV didn’t change within the wider angle-of-view of the Baveyes.
Without: 1/250th, with: 1/640th.
So by this totally unscientific comparison, it appears the Zuiko 55/1.2 is 1.3
stops faster with the Baveyes.
Quantization/rounding effects aside, there remains the question: what exactly
does “0.7” mean? Is that *really* the inverse of the square root of two
(0.707070707), which is what you’d expect for a full-stop of light-gathering
power? In which case, the 55/1.2 is actually a 38.89mm, f0.848 lens? Which is a
bit closer to the stated max aperture of 0.9, if you round somewhat and squint
at the numbers?
Or if you trust the Baveyes “0.7,” it becomes a 38.5mm, f0.84 lens. And just
how accurate can we assume the original “55/1.2” is? My guess is that is an
infinity figure, which changes with close focusing, anyway.
This whole thing also ignores the difference between F-Stop and T-Stop. It
could have the bokeh of a 0.8 with the light transmission of a 0.9, for example.
> That may indeed be part of what we are both missing in the Metabones Ultra.
Bottom line, without having done super-extensive testing, I like what the Kipon
Baveyes does, whether it’s f 0.8, 0.84, or 0.9.
I sure would like to play with it side-by-side with a Metabones Ultra, though.
:::: It takes a lot of courage to release the familiar and seemingly secure, to
embrace the new. But there is no real security in what is no longer meaningful.
There is more security in the adventurous and exciting, for in movement there
is life, and in change there is power. -- Alan Cohen
<http://www.lmgtfy.com/?q=Alan+Cohen>
:::: Jan Steinman, EcoReality Co-op <http://www.ecoreality.org/> ::::
--
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