Oh manual lenses. I just can’t stop.
When I first read about the new Speed Booster focal length reducer being marketed by Metabones, I was immediately intrigued. I own several inexpensive manual lenses of various manufacture – no Zeiss or Leica here – and their required adapters for use on my Fujifilm XE-1 and formerly an X Pro 1.
I enjoy manual focus (I started out on film many, many moons ago), the character and different rendering each of the lenses produces. The issue with using these great old lenses on a 1.5x crop sensor is that the effective focal length gets much too tight much too quickly. A 28mm lens becomes a 40 mm lens. A 35mm lens becomes a 50mm. A 50 becomes a 75. Too tight.
The Lens Turbo and Speed Booster are focal length reducers. That is, they employ a mounting plate for the digital camera you own on one end, a lens mount for the lens type you want to mate to the camera on the other and optics in between that translates a full-frame image circle down to a crop sensor sized rectangle. The conversion is not 1:1 but rather .72. Combining this with the Fuji’s image crop factor of 1.5, we arrive at:
50mm (lens focal length) x 1.5 (crop sensor factor) = 75mm * ~0.72 (lens turbo) = ~54mm focal length equivalent.
Since $400.00 is wayyyy out of my wheelhouse for a toy (and I don’t own any lenses in Metabones’s presently available lens mounts anyway) I elected to try out the challenger – a Chinese take on (copy of) the Speed Booster in the form of Mitakon’s Lens Turbo.
It took me awhile to pull the trigger between the Pentax K and Minolta mount. Eventually I went with the former as the tiny 50/2 that I own is really sharp on my XE-1 with a ‘dumb’ tube adapter. An additional consideration was the small size of the lens + adapter looking proportional on the XE-1. The same cannot be said about some of my other legacy lenses. Jonas Rask posted a review of the Minolta mount Lens Turbo with extensive sample images that you can read here.
The photography that I enjoy doesn’t require clinical, ultimate sharpness across the frame or perfect clarity. That’s good, because the Lens Turbo doesn’t deliver either of those. What it does deliver is a fun experience using old glass at close to its original focal length on a new camera body. That to me is worth the price of admission. Your mileage may vary.
In harsh lighting conditions, the Lens Turbo flares and ghosts. It softens corners. It affects image quality negatively, although not to a great extent. It introduces barrel distortion (correctable by bumping distortion to +12 for this lens). It sometimes creates weird blue reflections when there is a harsh light source shining at the camera in the frame, day or night. Depending on the angle of the light source, I see blue flares or not.
Center sharpness is good to great. Bokeh with the 50 is pleasing to my eye. Microcontrast is good. Without a harsh light shining into the lens there is no color cast that I can see.
Eventually I’ll buy the Fuji 35mm/1.4 and be done with it, but that won’t be anytime soon. In the meantime, this will satisfy my 50mm digital camera want. With the X100 and its 35mm equivalent lens, I’m all set.
I’ve included some images from a night time street photography walk from Wednesday evening. All of the following were shot on the XE-1 with Lens Turbo and the Pentax 50mm/f2 shot at 2.8 ISO3200 between 1/60 and 1/250. My copy of the 50/2 is usually resides on my nearly-30-year-old Pentax K1000, so there’s some sentimentality for that lens. Sentimentality aside, the glass is SHARP. I put it up against the Fuji 18-55 at 50mm with a regular rainbowimaging adapter and couldn’t see a difference at the same aperture. This is a good starting point to evaluate the Lens Turbo – the glass is good.
Back to the topic at hand: I missed a bunch of shots between my own focusing errors and the narrow depth of field in very low light. They were close, but not worth sharing. These were the keepers. Not to worry, I’ll get that shot that I missed (TWICE!) of the old barber reading his newspaper in his barber shop next time (with my X100, maybe). :)
In these photos you’ll see the blue cast in/near the center of some of the shots and of course the reflections I mentioned – the bike shot chief among them. Image quality is good but not great in these harsh conditions, and best when there are no headlights or other bright lights shining directly into the lens. I have adjusted exposure and minimally adjusted contrast (8-10) and clarity (never above 15) in the following photos as I shoot RAW.
Part two of this review will cover shooting with the same combination – XE-1, Lens Turbo and Pentax 50/2 – in friendlier, more controlled studio lighting. For the lead, though, I wanted to do a real-world, out-in-the-world torture test the focal reducer a bit so that readers would see some of the more glaring (pardon the pun) issues that can crop up (ohhh, see what I did there?).
I hope you enjoy the photos. None of these is intended to illustrate my skill as a street photographer as much as to demonstrate what the Lens Turbo contributes to – or indeed detracts from – the images. Rest assured I’ll post part two soon.
Click on any image for a full-sized file.