From http://www.getdpi.com/wp/
The Leica SL with Leica M lenses
For many photographers using Leica M lenses on a mirrorless camera with an EVF
is the holy grail.
Currently the only full frame competitor for the Leica SL is the Sony A7 range
of cameras. Whilst these are undoubtedly excellent cameras and they do well
with longer focal length M lenses; especially at close to medium distances.
Problems do start to occur at longer distances (when the rear element is closer
to the sensor) and at shorter focal lengths (where the angle of incidence of
light on the sensor is more acute). This causes fairly intense ‘smearing’ at
the edges and corner of the frame, worse at wider apertures and wider focal
lengths, but in actual fact, the smearing is still visible in the corners at
f8 on the 50mm Summilux Asph. This isn’t really a criticism of Sony – why
should they design their sensors to work well with rangefinder lenses (which
they don’t themselves produce)?
Ron Scheffler has done a series of excellent and diligent comparisons between
the Sony cameras and the Leica M cameras in his Tech Talk sub site
(http://www.ronscheffler.com/techtalk/). The general consensus seems to be the
this smearing is a function of the thickness of the coverglass over the sensor,
the thicker the coverglass, the more the problem.
For me then, the $64,000 dollar question was whether the Leica SL would perform
well enough with Leica M lenses. To that end I dusted down my tripod and headed
to the Suffolk coast with my Leica M240, the Leica SL, and my son Silas’s Sony
A7 mark 2, together with a selection of Leica lenses which have proved
problematic. I took a leaf out of Sean Reid’s book, and did this properly,
shooting at f2.8, f4, f5.6 and f8 with each lens, with focus bracketing for
each set. I am intending to post the original files and the comparison between
the Sony A7 mark 2 and the Leica SL in a later article, but suffice to say,
that although the edges and corners of the M240 were slightly better than the
SL, the results for the SL were hugely better than those from the Sony A7 mark
2. Sadly, I didn’t have a Sony A7r mark 2, but the cover glass is the same
thickness as that on the A7, and there is no reason to suppose that the results
will be any better than the A7 mark 2.
I will be doing a separate article on the comparisons, Sean Reid has been doing
detailed comparisons between M lenses on the SL and on the Leica M240, together
with thorough testing of Leica R lenses on the Leica SL and several Field
Reports. You can read his reports at www.reidreviews.com.
The Leica SL with the T to M adapter reads the 6 bit code automatically and
inserts it into the exif, and uses the focal length for automatic ISO
calculations. If the lens is uncoded, then you can use the lens profile menu to
pick the correct M lens.
Just like the Leica M cameras the SL has in camera profiles for all the modern
M lenses so as to correct vignetting and colour cast, these are still being
perfected for the final production firmware, but they worked really well for
all the lenses I tested. I saw no colour casts, and what vignetting there was
caused me no problems – I suspect that Leica have avoided being heavy-handed
with this to preserve as much resolution as possible.
Frank Filippone
Red735i@xxxxxxxxxxx
