My previous blog from March this year described my first impressions of the Sony A7R mirrorless camera. I have used it intensively since, and shot nearly 4000 photos with it (since I am not doing sports/wedding/birding photography, this number is quite a lot for a hobbyist like me). I found that all my Canon EF lenses work well on the A7R with Metabones III adapter - same is true for a variety of MF lenses with Minolta MD, Canon FD, and Pentax M42 SLR camera mounts. A few of my older and cheaper MF lenses from Soligor and Tokina showed more distortion in the full frame corners and chromatic aberrations. But most others worked either well or in my opinion excellent.

There is only one issue - the combined size of camera body and lens. Sure, I was (and still am) used to carry my bulky DSLR with up to 82 filter diameter lens gear, but seriously - who really wants to do this? Especially when you are on photo trips or do some hiking, size and weight counts a lot. Attaching my 24 and 90 mm TSE lenses with adapter to my A7R is still heavy and bulky in size - but smaller TSE lenses are simply not available. But what about the "normal" focal length like 50 mm, small wide angle (35 mm) and wider (21 mm)? Regarding my shooting style, I am leaning more towards the wide side up to 50 mm, and only rarely use 100 mm and above for other than macro shots with a 100 mm macro lens. 

I read that the Sony A7R can be equipped through suitable lens adapter with Leica rangefinder M mount lenses. This caught my attention since rangefinder lenses are much smaller than SLR lenses but deliver outstanding image quality. There are three manufacturers which produce rangefinder lenses: Leica, Zeiss, Cosina/Voigtlander. All of them are MF lenses. AF does not exist in the rangefinder world - I suspect it would increase the lens size if equipped with AF. In times before mirrorless cameras, rangefinder lenses were mostly used on Leica M series cameras (hyper expensive but excellent rangefinder focus system). Now with mirrorless cameras like the A7R, the same lenses(?) can be mounted on the A7R. This is at least what I thought in the beginning. 

I first checked on available lenses, and was shocked about two things: (a) the price tag, and (b) the variety and naming conventions of rangefinder lenses. It took me hours to familiarize myself online about this. First I started looking for a rangefinder lens in the 50 mm FL range. My eye was caught by the Leica 50/2 Summicron-M lens which accidentally a friend of mine offered me for sale if I would be interested. In Leica terms, this lens is one of the most affordable Leica lenses and also one of the most reliable and proven/used ones. I decided to give it a try and bought this lens in the chrome brass version. It is a bit heavier, but still very small and compact in size, built like a tank. I am using a cheap Fotasy M-mount/E-mount adapter which is very small, too - I did not encounter any problems with this adapter so far. 

I have some good experience with 50 mm lenses - but this Leica one is by far the sharpest I ever owned. The word razor-sharp comes in mind when looking at the taken photos on my 27" LED screen. Wow. Also the colors appear very natural, none or only slight post processing is needed here. Focus peaking and magnification tools of the A7R camera make sure that the focus point is accurate even at f/2. Fast apertures are ideal for portraits or shallow depth of field effects. f/11 and f/16 make an ideal landscape lens with the Cron-50 lens. 

A7R, Leica 50/2 Summicron-M II lens @ f/16: Smallest aperture delivers still razor-sharp results ideal for landscapes

A7R, Leica 50/2 Summicron-M II lens @ f/2.2: still very sharp, allows to capture good portraits 

This got me hooked to further explore rangefinder lenses for my A7R. I was now looking in something wider, in the 35 mm range. Photographers often use a combination of 35 and 50 mm lenses which is also my experience. I landed a good deal for the Leica 35/2 ASPH (stands for aspherical) lens. Quite an investment, but since I was so satisfied with the Cron-50, what could go wrong having a killer Leica prime rangefinder lens combo. Of course I read reviews, and the 35/2 lens is described as performing extremely well - on Leica M series bodies. 

I received this lens and mounted it with adapter on my A7R - and was shocked. The lens performed well in close focus distances, but at infinity it was the worst I had ever seen - totally blurry corners, uneven focal plane in the middle of the frame also. What was going on here - a $2500 lens sucks? In one other thread online I found a Leica blogger describing similar issues of this lens with the A7 camera series. The explanation given is that the thicker glass on top of the A7 sensor leads to unwanted refraction especially visible in the corners of the frame. This didn't explain the uneven focal plane (I assumed some decentered lens) but after shooting many test shots providing me always with the same disappointing outcome, I decided not to keep this lens. I started digging for more information online about issues of rangefinder lenses on the A7 series, and found more hits. Unfortunately this information is very dispersed online in many blogs and forums. But in summary, rangefinder lenses can have issues at focal lengths shorter than 50 mm with Sony's mirrorless full frame sensor. In Leica terms, only the faster 35/1.4 ASPH lens seems to work decently well on the A7R in the 35 mm range - I excluded this one since its price tag was just too unreal for me. The Zeiss Biogon 35/2 might be an alternative, but I found something better:

By reading about 35 mm rangefinder lenes, I came across a short note mentioning the Cosina-Voigtlander C/V 35/2.5 lens. But it was a bummer - again issues in the corners with some color cast were reported here. Somebody mentioned that the more expensive C/V 35/1.2 Nokton II lens is a great performer on the A7R, so I tried to find out more about it. After seeing several positive reviews about this lens and its A7(R) performance, I decided to give it a try and bough a mint used one for a decent price. 

In my opinion this lens is a hidden gem - I never had a lens so small and compact, well built and sharp even at f/1.2 if focused accurately. This lens was another keeper for me fairly soon after I fired some test shots. This impression got confirmed after taking more photos at the Zombie Walk event in Asbury park and during some photo trips afterwards. This lens shines for portraits but is also stellar in landscape performance. And the best, you get a light sucker as a lens - you can shoot handheld in fairly dark indoor areas with ISO 6400. It can deliver wide open an outstanding bokeh caused in part by the 12 aperture blades used in this lens!

A7R, C/V 35/1.2 Nokton II lens @ f/1.4 (left) and f/1.2 (right): Fantastic blur-out effect, sort of 3D effect and simply amazing bokeh!

A7R, C/V 35/1.2 Nokton II lens @ f/1.4: with ISO 6400 and still 1/40 sec you can shoot handheld in dim areas.

A7R, C/V 35/1.2 Nokton II lens @ f/11: What else can you expect from a good landscape lens? 

In summary, going forward with rangefinder lenses proved the right thing for my style of shooting. I compromise in AF but don't mind at all focusing manually. Rangefinder lenses have a much better MF ring and "play" to focus accurately in combination with the focusing tools provided by the A7R. I also like the built-style of the rangefinder lenses with metal lens body - I trust it more than the commonly made of plastic lenses nowadays. Overall the combination of two rangefinder lenses and the A7R is still a lot more compact and less heavy than my Canon 5D MkII with 35/1.4 and 50/1.2 lenses. One thing which I am not sure about yet is the performance of rangefinder lenses in infrared. I am very curious about this application since my intention is at some point to convert a second mirrorless body to full spectrum or infrared. So far I did not find any information how those lenses will perform in infrared - likely a matter to test at some point. 

PROS of rangefinder lenses:

+ Size and image quality/sharpness if suited for the A7 series
+ Metal lens body
+ Better MF ring to focus accurately
+ Smaller lens filter threads allow to use smaller/less expensive filter sizes
+ Lower weight compared to DSLR lenses at similar lens speeds
+ More inconspicuous to use in public

CONS of rangefinder lenses:

- Price (there is no free lunch)
- Limited amount of rangefinder lens manufacturers
- Especially wide angle lenses can have issues with the A7 sensors (unsharp corners, color casts)
- Hard to find out about specs of older lens versions and their realistic market value
- High addiction potential (seriously!)