On 8/6/2019 3:19 PM, Mike Gordon via olympus wrote:
<<<<I used to be a skeptic. "How can 'adding glass' make things any better?"
Look at the white paper by Brain Caldwell. The MTF clearly does improve with a
good focal reducer and I believe many of the rendering qualities are intact..
I don't know why I'm even discussing this stuff. I guess I can't resist what seems to me to be faulty logic. I can't see
how improved MTF and AoV reduction that throws away part of the original image circle can help but change the character
of the results. Seems like I'm arguing on behalf of folks like AG, who can spot the difference 'tween a 28/2 and 28/2.8
on a print at 20 paces.
Now the Speedboosters he designed are top notch.
Right, no argument. It's fine with me if they make all old OM lenses sharper than they ever were. I'm only saying that
they are then different.
The other benefit for MFT is that the Speedbooster FULLY corrects for the
thickness of the sensor stack which remains an issue mounting some WA OM lenses
on FF backs like Sonnie.
My real interest isn't in good OM lenses, but in various forms of optically delinquent old MF lenses. I have no idea
what my Tamron pre Adaptall, pre computer design 28/2.8 may have done on film. I only care what it does on the A7. If
it's "worse" and I'm looking for "bad", it may be "better".
Too bad a 0.5 focal reducer is just not practical/reasonable or possible
according to BC--at least with sufficient quality to pass his inspection. I
am less interested if the true FOV can not be restored and the MFT Speedbooster
can not be easily mounted on all OM lenses.
TC's really do magnify all the aberrations--I member putting one on the OMZ 50/3.5 with
horrid results. Some lenses just don't like them. "Matched optics" has always
been important and the Tamron 1.4 TC on the Tammy 80-200 always has worked well.
Boy, I just don't recall. The "matched" version works a treat on the 90/2.5.
Now with all the aspheric elements a TC may only be good for one lens.
Two, so far, in Oly's case, 40-150/2.8 Pro and 300/4 Pro, with the 150-400mm
F4.5, whenever it comes.
What if the Hokey Pokey *IS* what it's all about?
Themed Olympus Photo Exhibition: http://www.tope.nl/