At 10/1/2022 03:13 PM, Macro muser wrote:
>The announcement that the new Oly 90 mm macro is now official vaporware
>spurred more interest in higher mag macro. No one has taken over where Chuck
>left off on estimating working distance, but I did find his post. So the
>"effective fov" is about 180 mm FF equivalent but is the working distance
>anywhere close to that? Chuck said no. Just to get a very rough idea about
>working distance, will assume MFT needs to achieve 1:2 mag for 1:1 FF
>equivalent magnification. Now the mag purists will get out their knifes as
>mag doesn't really change as is a f(image vs object size) and MFT is just a
>crop, but even Oly surrendered on that and calls it FF equivalent mag. Now
>assuming a thin lens at 1:2, MFT the object distance is 3X FL so 90X3=270mm.
>A 180mm lens at 1:1 on FF will have an object distance at 180 X2= 360mm. So
>FF at 180mm will have much better working distance and the MFT for working
>distance considerations could be thought more like a 135mm lens on FF, if at
>other mags this r
e
> lationship holds. It is much more complicated as the lenses are complex, not
> symmetrical and have focal length shortening at higher mags, and these
> distances are not to the front of the lens, but the new 90mm is not likely at
> 1:1 to have enough working distance for some critters.
>On the other hand, it effectively goes to 4:1 mag if the announcements are
>true. The OM lenses that achieve this mag are much much shorter and Dean
>might really like this lens as a result. I hope we'll find out what the
>working distances are at higher mags.
>
>
>On another note, I partially viewed an Oly sponsored video on STF-8 macro
>flash and was disconcerted to learn that TTL function does not work in focus
>bracketing mode. The Oly cam manuals
>have flash instructions for this mode but the STF-8 manual doesn't explicitly
>say this, but TTL option is greyed out in bracketing mode. It will work in
>manual mode but accurate fill flash with bracketing isn't that easy. Very
>strange decision and a well-hidden deficit, IMO. I wish Oly updated a cross
>polarization option too.
>
>I think the LED option is looking better for focus bracketing of critters.
>Need to reinvestigate that. The FF twin macro flash options will work but
>have their problems too.
>
>Macro muser, Mike
I was having trouble following, so I started digging...
Not sure if this is of any interest:
https://blog.kasson.com/the-last-word/internal-focusing-100ish-macro-lenses/
Poking around, as I didn't remember what LoCA is, now I remember, the top
listing in search was
https://www.closeuphotography.com/loca-test
then the about says author Rober O Toole...
https://www.robertotoole.com/ Some great photography...
Oh, yeah, working distance... will the M.Zuiko 90mm macro have internal focus?
So 2:1 magnification is 4x in 35mm terms?
https://www.dpreview.com/news/7291224402/omds-developing-om-system-m-zuiko-90mm-f3-5-macro-is
somewhat confused WayneS
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