@lonely1

It is rare mount. Can be done, but I am not sure.

Seems to be something like 0.716x, and that's great really.

Anyway taken the Nikon F/G version, cause I have a friend of mine which has Nikon lens :)

With my sigma I can get a super fast 44mm F1.0 lens! But I was looking at some zoom, do you have any suggest? Was thinking at tamron 17-50 F 2.8 to have an F2.0 lens or even a bit faster..

The 50mm 1.4 is really the ability to use "1.4" actually f2 with the reducer, where the difference between 1.4 and 2 on the Ais lens make a big difference with the spherical aberration.

But looking at my other results, I'm beginning to suspect that, whatever technology and glass and coating is used to make the RJ Lens Turbo, the simplicity of the design of a focal reducer (in relation to the design of a 135mm or 28mm f2.8 lens) and the advances in Nikon's coating technology between 1971 and 1981 (the two years my 135mm f2.8 and 50mm 1.8 E were 'single-coated') makes it in ways superior to the glass I'm putting in front of it. And since the main issue with my 135 Nikkor-Q and Vivitar MC Wide Angle seem to be aberrations, the coating of the focal reducer appears to be improving the coating-related colour issues more than it is degrading the sharpness, resulting in an overall more usable and pleasing image. That might also explain why the Series E 50mm f1.8 I have, which was 'single-coated' in the early 80s, doesn't exhibit the apparent benefits-the problems don't exist.

Edit: Did a test with the worst lens I have, a Nikon 43-86mm at 86mm wide open (this lens just got more use than it will for the rest of its existence), as your statement, @vicharris , that you haven't seen a test making a lens sharper when used wide open after looking at my two tests showing a subjective sharpness increase using the reducer wide open, insinuates I am, at best, sloppy in my testing. I adjusted the colours to, I hope, show you evidence of my theory (there does appear to be a sharpness hit, but there is clearly an LCA benefit, and in the un-adjusted shot the subjective result is a subjective sharpness increase, making the shot totally unusable instead of complete and utter garbage). But this really is the last test, I'm happy with the reducer, with my lenses, for my purposes. If you have good old nikons that are sharp, but have aberration issues wide open, I think you would be amazed at what the RJ Lens Turbo does to those lenses. If you only plan to use the Sigma 18-35 f1.8 and $2000 f2.8 professional zooms, you'll have to do your own testing.

Full disclosure: I'm just a guy testing a product I paid for, giving an honest opinion. No one is giving me anything for my time, except @vicharris and his skepticism.

Last test for now, Nikon 50mm f1.8 Series E wide open, which seems to show almost no change in IQ, but with the added light etc (I had to double check that I didn't take two pics from the same shot). If you own older Nikon glass and a m43 camera of any kind, this product is well worth the price I paid (about $50 more than I paid used for the Voigtlander passive adapter used for these tests, and about $50 less than it goes for new). I do not own any f2.8 $1800 zooms or any 1.4G lenses, so I can't test those. If I did, I'd probably not balk at $549+tax locally for the Metabones, anyway. But this focal reducer has made the following lenses more usable on the GH2 and BMPCC: Nikon 50mm f1.4 AIS Nikon 135mm f2.8 pre-AI especially wide open Vivitar 28mm f2.8 making is usable wide open (f2-ish, showed the most improvement overall) I plan to get my hands on a Sigma 10-20 to test (ahead of purchasing) to get as wide as I can on the pocket and I won't hestitate to use it with this adapter, but I will post test shots of that when I can.

@inukhiphop Why don't you add light to the non booster test to remove all the variables. It doesn't make much sense to compare items if you have any sort of variable.

"Showing the benefits of the extra stop of light, the reason I purchased the RJ Lens Turbo focal reducer (getting the lens to be a ~35mm is not important, I have other lenses to cover that length). The Nikon 50mm AIS is 'usable' at f1.4, stopping down to f2 makes a big difference in spherical aberration (and, not shown in this test, coma). The focal reducer, though perhaps degrading the image (acceptably or otherwise) at smaller f-numbers, works to make this lens (as well as any lens that improves immediately from stopping down one stop, including a couple of other lenses that I already own, but this was the most important one for me in deciding to purchase the focal reducer) much more usable at a light transmission of 'f1.4'. Overall, early in my ownership of this affordable 'alternative' to the Metabones Speedbooster, I'm happy that I made the purchase.

I did have to make a slight adjustment to my lens, sanding down a few millimetres of a protruding piece of metal, but it was no big deal.

Shot on a GH2 (Moon T7) adjusting camera placement to keep framing the same, and as stated above, stopping down one stop with the RJ Lens Turbo to keep the exposure the same. Focus (using focus-assist) is on "What Can We Learn From Traditional Societies?" Voigtlander F-Mount to M43 is the first shot, follwed by the RJ Lens Turbo F/G to M43 shot.

When I purchase the Sigma 10-20mm (or Tokina 11-16) I will do a wide angle test (getting these lenses to 7-8mm would be the reason to use them on the focal reducer). But for the price, and if you already own a lens where the benefit of one stop makes a big difference such as the 50mm f1.4 AIS, I would already recommend this reducer."

The reducer arrived in Ottawa, Ontario, Canada, from China (with tracking, including with Canada Post for the last leg) within the 2-3 weeks stated (18 days)

Sorry Vitaliy, i'm trying to decide. I've with me a Nikon G lens as the Sigma 30mm 1.4 is. A very good lens, but it does not have aperture ring. With RJ nikon G adapter can i control aperture without problems? What about infinity focus? Would like to have this combo with omd for ibis, could be a good idea? Also, on Nikon G adapter can i mount Nikon F (Ai-Ais) lens? And the last thing: is the blue dot issue appearing at fast values (1.4) or darker (about f11, for exemple) of F? For the final price and to order, have i to send you pm? Thanks.

So, Rj and Mitakon are similar, the first better in corner but some blue dot issue in certain situations, the second better center but worst at corners.

The last question: both of them can't let you adjust aperture, right? Cause i've a lens without aperture ring, and would like to know if i can control from this adapter or from cameera directly (i hope but i don't think so..)

Rj speed booster & G6... look at this swiriling bokeh! Lenses : samyang 85t1.5, 14t3.1 and takumar smc 50 f1.4

Sorry the silly question, but RJ stands for what? Is Mitakon better than this rj?

Will there be minolta md version?

As far as I know answer is positive for Minolta SR mount.

@kellar42. My 24mm Nikon AIS didn't work because of a protrusion too. I filed it down and its working now. If you wish to do it. Do it at your own risk. Just make sure you have the back lens and all other areas around the protrusion covered. I used lens tissue to cover the areas.

I like mine a lot but I can't seem to get it to work with my Nikon 50mm or 18mm, I think because of a protruding piece of metal on those lenses.