Where have all the Focal-reducers gone? (with apologies)

Started Feb 3, 2014 | Discussions thread
(unknown member) Regular Member • Posts: 496
Re: Where have all the Focal-reducers gone? (with apologies)

Tom Caldwell wrote:

5nex7 wrote:

EinsteinsGhost wrote:

EinsteinsGhost wrote:

Glad I read this little thread. I was thinking of getting one, but this put me off a bit. Maybe I should just get the SEL3518 instead.

The E35 is a nice little lens. But I am also expecting delivery of my Metabones SB (A-mount) tomorrow. The idea is primarily for portraiture. I will post feedback of my experiences here.

Interestingly enough, a lens I am really keen to see perform with SB is a cheap old Minolta 35-70/4. That lens is small and excellent wide open. On APSc, its weakness has been a limited range (50-105mm equiv), but with speed booster, it has the potential for a small and light 25-50/2.8 lens.

37 - 75mm / F2.8 ff equivalent on APS-C

I also have Minolta 70-210/4, which will become 50-150/2.8 with SB.

75 - 223mm / F2.8 ff equivalent on APS-C

Looking forward to the results.

And my 135/2.8 STF is really the lens I expect to use the most as it will become more useable as a portrait lens on APSc (95mm/2 equiv) when used on NEX-6 while a mid tele on a55 (200mm equiv).

143mm / F2 ff equivalent on APS-C

Yep, close to the FOV they were all intedended for while gaining on shutter speed.

IQ remains to be seen but on paper it looks very interesting. Based on the results, I might also convert my Contax Zeiss 50/1.7 to A-mount and that will give me an effective 35/1.2 APSc lens on SB.

Yes, IQ remains to be seen.

I have my doubts.. if I believe that a filter in front of a lens will degrade the IQ - and I do believe this, how could I believe that a complex optical system behind the lens would not degrade it, more, it would improve the image ?

I know that there are cheap "universal" tele-adapters which will destroy your image, and expensive, dedicated tele-adapters, matched with high quality 70-200/F2.8 lenses, which will only degrade the image...

You must read the white paper on the Metabones site which explains technically and very clearly why the focal reducer adapter behind the lens improves quality of the image and why a telephoto adapter degrades it. Also note that focal reducer adapters have been and continue to be used for astronomical observations and are reliably known to improve the image as has been claimed for focal reducer adapters for camera lenses.

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Tom Caldwell

I don't have anything against these adapters, or other adapters.

I agree that it changes the focal length, I agree that it changes the lens's character, I agree that it will increase max aperture by one stop, I agree that it will convert ~ full size lens image to APS sensor.

I don't believe that the lens+adapter will have a flat sharp all over the frame aperture, I will have to check it with my eyes, and I don't understand what "improved quality" means ?

For me it is only a technical discussion.

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