I love Paris. While I live in Japan, my business often takes me to Europe, and whenever it does, I always spend a weekend or so in Paris before moving on to wherever I need to go. Paris is of course a wonderful city for street photography. Henri Cartier-Bresson made a subject of the Paris streets for decades and never ran out of interesting people and scenes to photograph with his Leica. I find the same is true for me and my Leica M3.
While many people prefer a 35mm lens for street photography, for photographing people, I prefer the 50mm focal length, for which the Leica M3 is optimized. There are a lot of 50mm M-mount lenses to choose from, as well as several generations of most of them, including the Summicron f/2, the Summilux f/1.4, the Noctilux f/0.95, and the collapsible Elmar f/2.8 to name the most common, and this is to say nothing of the superb M-mounts of other manufacturers like the Zeiss Sonar f/1.5.
I have used a number of Leica 50mm lenses, and they are all wonderful. However, for street photography I prefer the fourth generation Summicron f/2, and that is the one I pack in my kit when I travel. Why the fourth generation? Ergonomically, I find it the best because of its focus tab and its weight.
When photographing people on the street, I have to move fast. Zone focusing is one-way of course, where I can preset the focus for a depth of field range, and release the shutter when my subject is in the zone. Of course, I have to guess that by sight. At f/8 or f/11, I have a pretty deep zone, so no problem. However, if I want to maintain a shutter speed of at least 1/250th, sometimes the light will permit only wider open than f/5.6. My zone becomes increasingly shallow, and guessing accurately is more challenging. Also, when I want to photograph someone from really close, say within a meter or two, the zone is even more shallow.
The tab of the fourth generation Summicron is a tremendous help in adjusting focus rapidly on the fly when I need to be spot on. Typically as I am shooting, I am walking toward my subject. I can set the focus to infinity, and as I am approaching my subject, and I easily adjust the tab with one finger until images in the focus patch of the finder align and then release the shutter. The focus throw of the fourth generation Summicron—that is to say the rotation from infinity to the shortest range—is only 120 degrees, which is just about perfect for both rapidity and accuracy.
Now you can use this rapid focus technique with any lens and any focal length. However, I find it more challenging when there is no tab, like with the current Summicron 50mm f/2 model, which internally is identical to the fourth generation, and early models like the Summicron 50mm f/2 Dual Range. My pre-aspherical Summilux 50mm f/1.4 also has no tab, and to make rapid focus even harder, the throw of the focus ring is about 180 degrees. That’s a full semicircle, and forget making that distance with one finger! And don’t even get me started on the contortions you have to perform with the Noctilux!
Also, you can forget about the ridiculously priced limited edition APO Summicron 50mm f/2 aspherical. It looks beautiful to be sure, but practically it makes no sense. The aspherical model adds nothing detectable to the sharpness, as the regular ‘cron is already exceedingly sharp even at f/2. And then there is no tab on the APO model, a real deal-breaker for me!
So if you are looking for a great M-mount lens for photographing people in the street, it’s the fourth generation Summicron 50mm that works the best for me. These are widely available used in both black and chrome, and more reasonablly priced the current Summicron model, even used.