As of the summer of 2011, there isn't a Leica S mount telephoto lens longer than the Leica APO-Elmar-S 180mm f/3.5. Through the use of lens adapters, the gaps in the Leica lens lineup can be filled. In this case, I was able to test the venerable Hasselblad 350mm F/5.6 Superachromat on the Leica S2 using one of Dale Photo & Digitalís S2-V lens adapters .
I grabbed the S2, 350mm lens, and a Gitzo 3541XLS tripod and headed down to the beach around 9:30pm. I happen to live in condo country, so finding subject matter was easy. It took some practice to achieve correct focus, but thankfully the lens can be adjusted very precisely. Combined with the extremely bright viewfinder of the S2, focusing on the distant building was easier than I anticipated. Using the Leica S2 remote release, I fired off a few 32 second exposures at f/8.0.
After heading back upstairs, I pointed the lens westward and photographed a bit of the skyline of lovely Hallandale, Florida. The lens actually renders quite nicely, living up to its legend on a camera that Hasselblad's optics designers could never have imagined their lens attached to. On the S2, the Hasselblad 350mm Superachromat is a potent combination.
The lens is quite addicting to use. The following day, I pointed the lens down towards the beach, from about 200 feet up, to see how well it could really perform in ideal conditions. Needless to say I was again blown away by the quality of this lens at f/11 in bright sunlight. I will say it is almost impossible to hand hold this lens, due to the extreme fine tuning needed to get the perfect focus with so little depth of field. If you have a LOT of light and are able to keep your shutter speed above 1/800 at f/11 or more, I think it could be doable. Otherwise, a sturdy tripod and cable release are necessary to get the most out of this lens.
While Leica will inevitably introduce an incredible super telephoto lens for the S2, this solution is very effective in the interim. Of course it is not easy or inexpensive to acquire this particular telephoto lens, but thankfully there are a wide range of options to choose from. Hasselblad has made a number of 350mm lenses, and using Pentax 67 and Mamiya 645 adapters will allow you to choose from lenses like the Pentax 400mm f/4.0 ED-IF and the Mamiya 300mm f/4.5 APO.