Last year I was given my grandfathers Leica camera equipment. Amongst which was a 1956 Leica Summicron 5cm, the collapsible Version I.

It was in fairly good condition. A few wear marks, but otherwise in good cosmetic condition. Optics were a tiny bit hazy, and minor scratches on the notoriously soft front element. Mechanically, the focus helicoid was stiff, dry, and the focus action had stiction. It was fun to use but it quickly became a little cumbersome.

I had tried a few attempts to take it apart and clean the helicoid, but always got stuck where the focus ring had to be unscrewed. The focus ring is made of two parts, whre the knurrled part unscrews from the ring with the distance markings. This ring would would not budge and I really questioned the repair guide as to whether this ring was infact two pieces threaded together.

In the mean time, all I could do was some superficial cleaning and greasing of the visible helical threads, which got the lens to usable levels. The focus still had some play to it and it annoyed me enough to not want to use it most of the time. The aperture ring was also pretty sticky, but that was an easy clean and it was clicking and turning smoothly in no time.

One day, after yet another failed attempt at removing this knurrled ring with some light heat treatment, it dawned on me to try the opposite and cool the darn thing. Obviously with the optical block removed, I left the rear part of the lens assembly in the freezer for an hour. With a cheap and small lens filter wrench the cold ring unscrewed with almost no effort. From there it was a quick clean, re-grease and tighten. I applied a slightly thicker grease than usual, which gives the lens a wonderfully slow, but not stiff, dampend focus throw. It is quite wonderful now.

I also braved removing the haze from the lens elements. This was a nerve wracking experience, but with lens cleaning fluid and pec pads, I wiped the lenses down one by one using only the weight of the cleaning pad. No rubbing, and no additional force. It needed several passes for each lens until they were clean. I was quite petrified to leave marks but it worked out really well in the end, and I made sure to clock the elements to the same position they came out of the lens. I’m really proud of the end result! The Summicron is a beautiful lens that I am excited to use where I can.

The Summicron 5cm V1 performs very nicely on the M10 Monochrom and M11. Overall contrast and local contrast is quite low at f/2, but improves rapidly by f/4. Imagine very fine detail veiled in a slight fog. Images have a unique and lovely rendering, with very high levels of detail but without that punchy modern contrast. Very refreshing. 

If analysing my images taken with the lens I would describe the performance as follows;

Wide open: Quite low contrast with a glow. Fine details visible but in a haze of spherical aberration. Astigmatism present off centre in the greater mid zone all the way to the edges. Moderately prominant vignetting.
Aperture f/2.8: There is a big bump in central contrast and sharpness, but fine details still rendered in a slight haze. Astigmatism present off centre in the greater mid zone all the way to the edges. Vignetting reduced but corners still dark.
Aperture f/4: The centre now boasts peak performance with very high resolution and moderate contrast. This lens isn't high contrast by modern standards, but overall it's almost evenly distributed across the frame. Astigmatism greatly reduced but still present in the mid zone and frame edges. Vignetting still present but very little.
Aperture f/5.6: Central performance still very high and extends a little further towards the edges. Quite sharp now throughout the frame with a mild mid-zone dip in resolution. Contrast is now high as it’ll get and evenly distributed across the frame. Astigmatism low enough to not be bothersome but still not completely gone. No vignetting.
Aperture f/8: Central resolution takes a slight dip, but overall still very sharp. The entire image has an almost uniform sharpness and contrast, but still sharpest at the centre. Astigmatism is not visible in images.

Like many older lenses, this lens has focus shift as one stops down. This is where the point of focus seems to move backwards as one stops down even though the focus ring has not been adjusted. My lens seems optimised for f/2.8 focusing which is perfect for my use. Others may have their lenses optimised for wide open performance. I know my lens has seen a service at Leica once in its lifetime, but it’s unclear if it was adjusted or just cleaned and lubricated. 

The focus shift present in this len is strong enough to render the subject blurry at f/4 and f/5.6 if focused for f/2. My lens with its f/2.8 focusing, will be acceptably in focus but not optimum at f/2, perfect at f/2.8, and acceptably infocus at f/4. At f/5.6 one needs to intervene with a slight focus adjsut ment. At f/8 the subject is acceptably in focus but not optimal. This is just the nature of these lenses, and its a simmilar behaviour with my Zeiss Planar 50/2 ZM and Voigtlander Nokton 50/1.5 ASPH II.

Strong light sources make the lens veil, and shooting into the light is can be quite a challenge to avoid flare and ghosting. But when used right, this veiling flare can create an atmosphere that is undeniably beautiful and classical. The Summicron 5cm is by today’s standards a little difficult to use. I think it's more a special-use lens, but that's not to say someone couldn't rock the ‘Cron lens as an everyday lens. Its drawing style is just so very different to what one sees these days and I find it works particularly well for B&W photography. I loved it on my M10 Monochrom.

Wide open, the background rendering can lend itself to be a little harsh at time, but it's not bad. Stopping down to f/2.8 helps soften up the out of focus regions in the greater central area of the frame, but overall from f/4 the entire image is settled down and has very nice blur characteristics. 

The lens can render strongly accentuated out of focus blur discs, especially if these are from specular highlights on out of focus objects. Below is an example crop taken from a frame corner. On the left f/2 and to the right f/4.  The blur discs have a bright ring akin to lenses which are over-corrected for spherical aberration. Also the cat eye shape of the discs can be seen, and sometimes this lens does produce some swirl; for better or worse. 

Interestingly enough, the Summicron 5cm doesn’t show much of any chromatic aberration. It's very well mannered in that regard. Low amounts of longitudinal chromatic aberration, no purple fringing, and little lateral chromatic aberration in the periphery. Overall, quite a clean render. At wider apertures, bright and contrasty out of focus areas do show some spherical aberration softness, but almost no colour aberrations are present that would otherwise foul up the image. 

I feel this Summicron needs to be used with intent and understanding of its strengths and weaknesses. It'll excel in some areas where modern lenses can’t replicate its look, but then also fall flat on its face in other situations where modern lenses wouldn’t falter. I’ve shot this lens successfully in strong backlit sittuations but it's hard work to control its propensity to flare. At times, in very strong backlit scenes, I’ve even seen the ghosted reflections of aperture blades in my images. Something I often only realised too late. The B&W image above of the Agapanther shows this to a small degree at the bottom left of the frame.

The lens does make a fairly good landscape lens and can render plenty of sharp detail across the frame with rich tonality. Again, its lack of strong modern day contrast makes it a great choice at times. Stopped down to f/5.6 or f/8, the lens renders a sharp image across the frame. Just a little field curvature gets in the way for planar objects at f/5.6, but that's usually not a big issue. Below is a simple beach landscape shot at f/8 with the Leica M10 Monochrom and below that a crop from the frame edge. Please note this image is unedited.

CROP:

On digital cameras like the M11 and also the Nikon Z6II, the Cron 5cm renders frame edges a little cooler than the centre. Older rangefinder lenses can show a bit of colour shading on digital cameras especially those wider than 35mm. The Cron's degree of shading isn't objectionable but something to be aware of especially if the image has large monochromed areas like the image below. Coding this lens in camera to a Summicron 50 f/2 11819/11825/11826/11816 doesn’t help mitigate this either. I’m not sure how other digital M cameras like the M9 or M10 behave with this lens’ shading, but for me on the M1 it’s unproblematic. 

The image below was shot at f/5.6 with the Leica M11, coded in camera for Summicron 50 f/2.

I don’t have all that many colour photographs taken with the Summicron 5cm, but that will come with time. I’ll ad more image to this page once I have them.