A Real World Performance Review of the Yi M1 Camera.

As it has somehow become fashionable to release “fake news”, I decided to perpetuate some of my own and announced the rumored release of a new Leica m43 camera body along with convincing images.  The new Chinese Yi M1 has borrowed a lot of minimalistic design cues from the Leica T camera although it is not machined from a solid piece of billet aluminum.  By sanding flat the red M1 square emblem, I attached an authentic red circle Leica emblem in place to complete the illusion.

The timing was good as the recently introduced Leica T was not selling well and Panasonic was introducing three new Leica branded lenses for m43.  Why shouldn’t Leica fully embrace the m43 format and introduce their own body.   I had many people believing the news until I was finally outed after four hours.

There have been many reviews of the Yi M1 so I won’t go into details or discuss the ergonomics and technical specifications of the camera.  This will be a review that will mainly interest the m43 loyalist and enthusiast.

There is much to like about the Yi M1 and in fact Olympus/Panasonic should pay attention if they wish to attract new users from the legion of smart phone photographers.  There are only two dials and two buttons and all camera setting are accessed by swiping the rear touchscreen’s GUI.   Recharging is intuitively accomplished through the mini USB port.  This is a full camera, not one diluted by being dumb downed.  There is  peak focusing, time lapse, HDR, and exposure/white balance bracketing , full sized histogram, a maximum 60 second exposure and 4k video.  Beginners can select Scenes with predetermined settings  or if doing portraits can have suggested pose outlines superimposed on the live view (but only when using Yi lenses).   For a street price of about $350 USD and having the latest Sony 20MP IMX269 sensor, I felt it was a very viable alternative to buying a Pen F as a compact backup body to my E-M1 (II).  With the small Leica 15mm f/1.7 lens, it would be a wide field camera to complement the telephoto lens invariably fixed to the E-M1.   4k video is a good trade for no IBIS.

But how does it shoot?

S-AF focus speed was tested by recording the sound of the shutter release ( a remote release was used except for the Yi M1 since it is not compatible with one) and the sound of the shutter tripping after focus was achieved, using Audacity.  The time track of the recording allowed very accurate measurements.

Either a Canon 200mm f/2.8 L series lens with the Metabones Speed Booster T Ultra 0.71x adaptor (shooting at 150 mm and f/2)  or the Olympus 40-150 mm f/2.8 Pro lens at 150 mm were mounted on a tripod.  The lenses were prefocused to the closest focusing position and aimed at a vertical fence picket about 40 ft away at the end of my backyard.  The smallest focus point was selected for all cameras except the Yi M1 which does not allow this adjustment.   The mean of three measurements are shown and the variance in the mean is so small as to be insignificant.  Time is displayed in the Y axis in seconds.

The Yi M1 does not work with the Metabones Speed Booster at all.  In fact the camera was seriously unhappy with the Speed Booster and required a hard reset by removing its battery before it could behave normally again.  It will work with legacy 43rds lenses but there is no AF  or aperture adjustment support.   The EPL-5 and E-M1(II) do not focus as quickly as the Canon T6i but the speed is very acceptable.  The Olympus 40-150 Pro shows it to be a superlative lens because the focus speeds for the EPL-5 is even faster than the T6i’s with phase detect.  It is essentially instantaneous with the E-M1(II).   A firmware update from  1.06 to the recent 1.20 clearly improved focus speed for the Yi M1 but it is still disappointing.  Yi appears to be quite responsive to feedback and has regularly released firmware updates so there is the hope that S-AF focus speed will improve.  Very occasionally the camera will believe it has reached focus with the green focus box lighting up and the camera chirping but there is no accompanying lens movement and the image is still blurry.  The lens needs to be removed and reseated.

C-AF performance for moving objects is also an important metric and one that made me an early adopter of the E-M1(II).  I strung a fishing line between a tree and my house and had my son’s old toy travel down it as a moving target.  All cameras were put in continuous drive mode (low mode for the E-M1(II) & EPL-5), C-AF mode, and a single central AF point used.  Images were shot from a position parallel to the fishing line so that the target was either receding or approaching.   The E-M1(II) had a 100% success rate, each frame was in focus.  The E-PL5 had about 15% success rate.  The Yi M1 had zero success, not one frame was in focus despite trying both firmware versions 1.06 and 1.20.  The C-AF function was so poor that the camera would not even fire at its specified 5 fps often hesitating for long moments before resuming.  Worse than blackouts, there is no update in the image on the viewscreen during C-AF.

Other reviews have reported that the image quality of the Yi M1 is very good, especially if you process the DNG based raw files.   To confirm this, the Zuiko 40-150 Pro was used and a ISO 12233 resolution test chart was shot with both the E-M1(II) and Yi M1.  The same focal length of about 125 mm was used to fully frame the test chart and the lens mounted on a tripod so that bodies could be swapped without altering the field of view.  Both cameras produced very similar MTF curves as analyzed by QuickMTF.  Likely the Yi M1 also has no antialiasing filter.

In conclusion, I am keeping the Yi M1 (especially as I can pass it off as a Leica!) because it produces images as good as the Pen F for considerably less and as a second body I’m not terribly concerned about its actual in hand performance.  Yi has demonstrated a commitment to this product as evidenced by its many firmware iterations.  With time this camera could evolve into a competent performer.  If I were traveling very light and could take only one compact body, I would go with the EPL-5 since that is overall a much more competent and refined camera.