Steve Huff recently posted his choice for the best budget Leica lens, the 35mm f/2.5 Summarit-M. It’s the second least expensive lens in Leica’s current lineup, and I agree that it’s the best bargain new M-mount lens you can get from Leica.[1. The company’s least expensive new lens, the 50mm Summarit-M doesn’t quite render as nicely as the 35mm version from this line. However, it’s still a bargain, and you find find used copies of the 50mm Summarit for as low as $600 on eBay.] However, one of the great things about shooting Leica is that there’s a robust secondary market for lenses. And for the price of a new 35mm Summarit, you can purchase a faster f/2.0 used 35mm or 50mm Summicron. You can even get the pre-ASPH version of the 35mm lens that people refer to as the “Bokeh King.” In fact, there are several used Leica lenses you can purchase for the same cost of or less than a brand new Summarit.
My favorite, and what I believe to be the best bargain lens for any camera system is the 40mm f/2.0 Leica Summicron-C. This lens was made for the Leica CL, and you can get used copies for $250-$400 depending on condition. (Note that the 40mm Minolta Rokkor-M is, essentially, the same lens with its own nickname, the “water lens.”) However, it will, contrary to what you might hear, work on any modern M-mount body. It renders very much like the 35mm Summicron but can be had for about 75% less. Put it on an M8, and it effectively becomes a 50mm lens with the 1.33x crop factor. The only problem is that most M bodies do not have 40mm framelines. However, it’s simple to modify the 40mm lens to bring up the 35mm framelines, which are more accurate and even precisely so on the original M8.
Moreover, the 40mm is probably the lightest, smallest lens Leica has made in the past 40 years. Mounted on a camera body, it makes for a very small, perfect package. The filter size is a little odd; a modern 39mm filter won’t screw all the way in, but it attaches well enough, and I’ve never had any problems with my filter coming loose or falling out. Finally, this lens works quite well as a portrait lens with the 2x crop factor of the Micro Four-Thirds system. If you’re looking to purchase a copy, check eBay and KEH. They both often have these lenses available, though you may pay a premium on KEH.
Here are some sample photos from the 40mm Summicron-C.