[kerttamm]

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I have a request for information which, hopefully, somewhere around here is capable of providing.

For a backstory, I have a Sony a5000 which is a compact mirror-less thingy with sony E-mount and APS-C size sensor. I have also a Pentax K-x and a small number K, KA and KAF2 mount lens including a relatively recent addition of few legacy Pentax manual primes. After buying the Sony (as a replacement for a point and shoot that broke as a "mobile" camera) I stumbled in the net upon a thing called a focal reducer which, in essence is supposed to be a "reverse teleconverter" by providing approx 0.72x magnification by focusing light which should fall on full frame size from legacy lens down into an APS-C size which, in essence, gives one a bit wider view more similar to "full frame" size and a bit more light focused into the APS-C size. I have read about these for a little while but there seems to be not much information about these out there. What surprised me on a5000 was that the focus highlight seems to make using manual lens a lot more viable (with a simple mechanical adapter) than on a K-x with the default focusing screen (I just ordered a split screen for better focus for K-x as well but this one will take a while as its shipping all the way from China).

As far as I understand the situation with the two mentioned above is following. First iterations had some flare issues if a bright light source was in the picture. Lens Turbo II is in a nutshell Chinese premium brand thingy and is second iteration which supposedly has addressed the flare issues by using better coatings on the rear elements. Camdiox is a German brand but a bit simpler and cheaper. As the price difference between the two would be about 35 EUR (in favor ow Camdiox) I would be content to go with Lens Turbo II (which is supposed to be optically a bit better as its the second iteration), however, the catch is that they redid the mounting system when they re-engineered their adapter so it now has non-trivial mounting system.

So anyone here has a Lens Turbo II and cares to share his/her experience with it? How reliable is the mounting system in your experience/opinion? Can I lave the adapter on the body while I switch the lens or should I remove the adapter, mount it on the lens and then attach the whole thing to the body every time I change lens? Out of the two mentioned this one seems to have few reviews but almost all of these seem to go over the mounting system rather briefly skipping straight to optical quality. Which is supposed to be better now than the previous version. No direct comparisons with Camdiox unit as far as I'm aware.

Camdiox one seems to be a bit less common as there is almost no reviews for it and just few blog or forum posts. No one seems to think the mounting system needs any scrutiny and as far as I understand it is a straightforward thing. Just twist it in the E mount bayonet until it clicks and you can leave it on the body and switch lens on it as much as you want need? Would be great if anyone in here would be able to provide some insight into the experience of actually using one of these.

Or if there is any others which you would feel worthy of recommendation or highlighting I'm interested in these as well. Metabones (the original thing) is beyond my budget but something under about 150 EUR or so is still acceptable. for reference, Camdiox would be 95 EUR for me and Lens Turbo II is about 130 EUR for me. I would specifically like something that I can leave on the body while out in essence "sealing" it and reducing hopefully substantially probability that some stuff manages to stick to my sensor while I switch lens. After all mirrorless does not have a mirror covering the sensor so any time lens comes off the sensor is directly exposed to the nature and elements.

[surfar]

if you look on Youtube, there are very favourable comparisons in favour of the Lens Turbo over the Metabones(bang for buck)LT seems a safe bet


There are plenty of cheap versions on ebay at around 50/60% of the LT price, I'm also considering the LT and el cheapos....

[kerttamm]

Well - by now I have nailed the decision down to three options:
(1) - "Cheap chinese" - Focal Reducer Speed Booster adapter Pentax K PK lens to Sony E NEX-7 NEX-C3 | eBay
(2) - "Camdiox" - Camdiox Focal Reducer Speed Booster Pentax K mount PK lens to Sony NEX Adapter 7 | eBay
(3) - "Lens Turbo II" - New Turbo II Focal Reducer Booster Adapter for Pentax K PK Lens to Sony E NEX 7 | eBay

The distance between the price points is about 20 eur and about 30 eur. The cheap chinese is atm 64 eur, Camdiox about 85 eur and Lens Turbo II about 117 eur. Out of these mentioned the Lens Turbo II is the best documented, there is a review existing for Camdiox and for Chinese no-name thing no information whatsoever can be found in the net with my google skills.

I would be content going with the lens turbo II, however, unfortunately I have read also about unconventional mounting mechanism so I'm not so sure about it. Because of how far the rear element goes into the camera if the focal reducer is not mounted correctly (so it is able to turn while locked) it can damage the camera, apparently. Because of that reason I'm think I'll be probably going with the Camdiox unit which sort of seems to be middle of the road reasonably safe bet. Hard to tell from the pictures in the net it seems also to be the largest of the considered focal reducers but then again if one is already putting a legacy glass on the Sony it will not be a "pocket" camera anyway. Squeezing it in the pocket is already prerequirement for pretty large pockets if using the particularly compact kit lens on it. I am not convinced that the Camdiox unit would offer actually any better quality than a no-name Chinese knockoff but I am hopeful that perhaps it would be a mechanically better at least if I'm not picking the cheapest thing I can find in existence.

I am planning to go for the Pentax K mount unit for keeping the number of moving components down. While getting the one for EOS mount would allow wider selection of lens to be used by using the relatively cheap mechanical adapter on top of the focal reducer I at the moment have only m42 and K mount lenses and keeping it simpler sounds like a reasonably idea to my mind.

[kerttamm]

I ended up ordering the Camdiox unit. Will see how I like it once it arrives in a week or two.

[tonezime]

kerttamm, did you like it?

[surfar]

Ive just ordered an el cheapo FR for a canon EF mount to m43....around U$30 as well as some m42 to Ef adapter rings(one dollar ish), My Takumars will be rejuventated!


1.4 the FL with a stop more.

[kerttamm]

Yes. I did indeed like mine. Although to be honest I am not really able to see the difference (other than different FOV ofc) compared to using the lens with a dumb adapter. One of my lens tends to get the "blue dot" with the adapter but I can get that lens to blue dot even with the passive glass-less mechanical adapter.

Overall I'm not regretting buying one. When shooting outdoors with Pentax lenses on that mirrorless it is convenient that the camera body remains sealed even when changing lens because of the extra glass elements. I went with Camdiox unit because after considering pros and cons I decided that the lens turbo ii mounting mechanism is a bit too inconvenient for me.

[tonezime]

Where'd you order it from? I tried to find it a few weeks ago and didn't run into anyone actually selling Camdiox.

[kerttamm]

Where'd you order it from? I tried to find it a few weeks ago and didn't run into anyone actually selling Camdiox.

I got mine from ebay. Although at the time it was possible to order it also through the uk amazon site I believe - they just had a bit higher shipping fees than the seller in ebay whom I used. The one I have is from Sony-E to Pentax K-mount as I did not want to mess around with additional mechanical adapters.

[cauhai]

I have all three "kinds" of focal reducers: Metabones, Zhongyi Lens Turbo, and cheap no-name from ebay.
My experience:
- Metabones Speedbooster: best quality build, solid fit and finish. Little flare, working at all apertures, retaining lens characteristics. All good. Go for it if you can.
- Lens Turbo: Very acceptable, worse than Metabones in all respects, but just a little worse. Very useable, unless you want professional quality.
- Cheapo no name: No good. The build quality is okay, as much as a, say 20 USD Fotodiox adaptor. It's a little okay sharp only at centre, but 2/3 outside centre is very soft, even at f/5.6 or 8. Unacceptable, even for casual photographers. I will save money for Lens Turbo, or if Metabones I can afford.