Three years ago Leica appear the M8, its aboriginal agenda rangefinder. The M8 looked agnate to the blur M7 but was a absolutely new body, with a 27 x 18 mm (1.3x FOV crop) 10 megapixel Kodak CCD sensor and no resolution-sapping anti-alias filter. However it wasn’t all apparent sailing, all avant-garde agenda cameras affection a bottle UV/IR clarify in advanced of the sensor, and in the case of the M8 the architecture was decidedly attenuate (just 0.5 mm) which angry out, in production, not to be able enough. We forth with several added testers acclaimed this issue, and anon Leica were bearing screw-on UV/IR filters for their lenses in adjustment to annihilate the furnishings of such ashen pollution.
In September 2008 came a attenuate update; the M8.2 was identical from a sensor and imaging sub-system point of appearance but added a few new features; a quiet metal shutter, detached bang re-cock, snapshot mode, azure clear awning bottle for the LCD and best chiefly the ‘stealthy’ atramentous Leica dot.
And now comes the M9, 'the world's aboriginal abounding anatomy camera', which on cardboard at atomic looks to be the ultimate agenda M; an 18 megapixel full-frame (36 x 24 mm) sensor, still with no low-pass clarify but now with a new UV/IR cover-glass clarify which agency no charge for lens filters. Here are some arresting angel affection accompanying credibility which came out of an account we conducted with Leica in Solms:
- A stop improvement in noise (ISO 1250 M9 = ISO 640 M8) - this comes from a range of significant re-engineering efforts - the sensor is effectively a scaled up version of that found in the M8 (the photosite architecture and pitch remain the same) but it has a different CFA dye to improve red sensitivity, the output stage has been improved, the signal paths have been shortened (new PCB design), two processors are now used for improved JPEG quality (and speed) and the firmware was written from scratch with improved noise reduction.
- 'Negligible' difference in corner fall-off between the M9 and M8 - the new microlens layout has increased offset at the corners to keep the effects of shading to a minimum. There is no limitation on the lenses which can used, even short back-focus ultra-wide angle designs will work without issue (we tested the M9 with the 16 / 18 / 21 mm Tri-Elmar-M and saw no obvious corner problems).
- New UV/IR filter cover glass - the M9's sensor now has a 0.8 mm UV/IR filter, which is not only thicker than that on the M8 but also made from a new material with improved IR cut-off properties (I'm sure Leica are happy to put that episode behind them).
Leica M9 vs. M8 / M8.2

Solving the corner vignetting problem
Because a rangefinder camera doesn't have a mirror box its lenses don't have to be retrofocus in design, meaning they can sit much closer to the film (or in this case the sensor). The problem with this comes with wide angle lenses (which are pretty much the main staple of the rangefinder camera). Towards the corner of the frame the angle of incidence of the light rays coming from the rear of the lens can be so severely off-perpendicular that they won't pass equally through the microlenses above the sensor, which can lead to fairly strong vignetting. Even a modest wide angle lens at this kind of distance could produce a difference of a stop or two between the center of the frame and the edges using a standard CCD sensor.
The M8 had a 27 x 18 mm (1.3x crop) sensor and some thought it simply wouldn't be possible to use a full-frame (36 x 24 mm) sensor on a rangefinder, but Leica appear to think otherwise. Their approach is the same as for the M8; use offset microlenses (instead of placing all microlenses directly over the photodiode they are gradually offset as you get closer to the edge of the frame - see below) and to know which lens is being used and apply some software correction.
Below is a diagram provided by Leica which does some way to explaining how microlenses at the edge of the frame are offset from the photodiode below them, compared to a normal microlens / photodiode combination in the center of the frame.

* Fewer moving parts (no mirror or diaphragm) means slower shutter speeds possible (-2 EV)
* More compact, discrete and quieter than an SLR
* Shorter shutter lag
* Lenses are considerably smaller than an equivalent SLR lens
* No auto-focus makes them less suitable for action shots (or at least doing so requires a lot more skill)
* Many users claim rangefinder focusing is faster than using a focusing screen
* Rangefinder
o You are not looking through the lens itself and do not have a focusing screen hence it is more difficult to get a sense of depth-of-field
o Framelines indicate the field of view of different lenses
o Because there is no mirror you have no mirror black-out
o Brighter than any SLR viewfinder, and not affected by lens maximum aperture
o Not as accurate as an SLR viewfinder, especially with longer lenses (or close subjects)
* Longer minimum focus distances compared to an SLR
* Virtually no telephoto lenses beyond 135mm
* Very wide angle or telephoto lenses require an accessory viewfinder, meaning focus and framing are separated
Leica factory tour
* M3 (1954 - 1966)
* MP (1956 - 1957)
* M2 (1958 - 1967)
* M1 (1959 - 1964)
* M4 (1967 - 1975)
* M5 (1971 - 1975)
* CL (1973 - 1976)
* M4-2 (1977 - 1980)
* M4-P (1980 - 1986)
* M6 (1984 - 1998)
* M6J (1994)
* M6 TTL (1998 - 2002)
* M7 (2002 - )
* MP (2003 - )
* M8 (2006 - 2008)
* M8.2 (2008 - 2009)
* M9 (2009 - )
Full disclosure - personal bias
