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Speed boosters

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Category: Equipment forums
Forum Name: Adapters and converters
Forum Description: Discussions for various adapters and converters
Printed Date: 16 June 2024 at 19:20

Topic: Speed boosters
Posted By: Phil Wood
Subject: Speed boosters
Date Posted: 16 December 2021 at 23:40

As I now have an APS-C E mount camera I am considering some adapters. I have the LA-EA4 and a basic M42 adapter, but I would like to use lenses at the field of view they are designed for.

Which leads me to the idea of a speed booster adapter. The speed boost seems a nice bonus, but it's the angle of view modification I am most interested in.

Looking online I see Metabones do them at £200-250 (ouch) while many unbranded (or unrecognisably branded) versions are available at £50-75.

Can anyone recommend one of these adapters that doesn't mess up the IQ too drastically but doesn't cost more than I paid for the camera.

I am most interested in M42, Minolta SR/MC/MD and Canon FD.

Posted By: 2manycamera
Date Posted: 17 December 2021 at 00:30
I have the Lens Turbo II for MD made by Mitakon. I don't use it as often, since I've bought more APS lenses in E mount, but it has been a good performer with an issue. Because of the design, the rear element of some lenses reach too far back into the adapter. This either limits focus at infinity, or in a few cases means it won't mount. In my experience, wider lenses seem to have had the most problems. All my MD's from 45mm and longer show no problems, and the results are very good. It might work better for M42 lenses that have a 45.46 flange distance compared to MD's 43mm flange distance. The Canon FD is even shorter at 42mm.

A lot of cavets, but if the lens mounts correctly, the Turbo II is an excellent adapter giving a 0.76x magnification and "about" 1 full stop faster. In the US, about $140 new at B&H in M42, and $149 for MD at Adorama.

7D a68 a99 a6600 a7Rii 16/2.8 24/2.8 28/2 35/2 50/1.4 100/2 200/2.8 24-70CZ 1.8/135 80-200/2.8 24-105 28-135 300/4 16-50DT 70-300G Tam 90/2.8, E55-210 E2/12 Sig E1.4/16,30 & 56, FE15/4.5V

Posted By: 4paul
Date Posted: 17 December 2021 at 00:39
Yeah Metabones is the gold standard, they (the Caldwell guy) literally invented it (or at least brought it to market). It's a reverse teleconverter, so it's the same as using a no-name 2xTC instead of a matched teleconverter, Metabones being the matched version.

I have the Zhongyi Lens Turbo for MD>E, and it does increase "sharpness" in the center of the frame, but only the EXACT center, the falloff is extreme. A couple hundred pixels from the center you can see halos even on in-focus areas at maximum aperture, and spherical aberrations get more uncontrolled toward the corners. Stopping down removes most of the ugliness (I personally love it LOL), but causes a color shift (towards blue).

The Metabones is invisible farther out to the edges even at max aperture, and stopping down will cause a color shift, but less so; the color shift is a property of the lens geometry and coatings, similar to "hot spots" in IR photography (I believe the lenses that have the worst IR hot spots have the greatest color shift when stopping down).

I have a first-generation Metabones C/Y>E I used with the C/Y Z 28/2, and at f5.6 I could get a 4x5 crop (cutting off the far edges) that still looked like Zeiss, but the edges were visibly worse. The coatings and optics were improved in later versions so I'm sure it's better. I haven't sprung for the Metabones MD>E yet but it's been on my list of things-to-do LOL.

Even the cheap turbo is not as bad as the MD>A glassed adapters, which are simple uncoated lenses without cement, and have enormous amounts of "character", again that's my thing but probably not yours.

I think you can download these if you want to pixel peep (I posted these a few minutes after you! LOL) - -

There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks. - Schrödinger

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