Anyone using manual focus lenses with the Panasonic S1/S1R?

The S5 is a lot of fun with manual lenses. The L-mount lenses are somewhat few and expensive, so adapted lenses provide some economy and outlet for the GASeous.

The exceptional viewfinder of the S5 is really nice for manual focus along with all the other now standard mirrorless features such as peaking and focus assist. There is an "SCP" feature on both the G9 and S5 that does some sort of zoom from a button on the front of the camera that looks interesting, I have to read about it more. With just peaking I can keep focus on a walking speed moving subject.

A minor criticism, there seem to be less L-mount lens adapters around, a brand or two.  I'm used to M43 that seems to have more selection. Another minor criticism, and it's just the physics of it, but for a lot of the normal MF primes I feel the adapter adds much size to what would be a very small lens unit. Most of the vintage MF primes are smaller in size (not weight) than the Panasonic entry primes (the 1.8 35mm, 50mm, ...) for example. I have a Soviet era Industar 50-2 50mm f/3.5 M42 and the L-mount to M42 adapter is larger than the lens (and makes it look ridiculous).

MF lenses that fill a gap where you would otherwise invest a lot for Pan or Sigma:

• Tokina AT-X SD 80-200 F/2.8 Nikon F. Also found in FD I believe. This is a good optical quality ~70-200 f/2.8 lens for ~$150!  But its ridiculously HEAVY, not really a walk-about.
• Canon NFD 100-300mm f/5.6L, a pumper zoom. Bizarrely long and thin, but sharp and has a special macro/close up feature with very convenient long working distance.  It's nice for flowers and still to slow moving insects. It's an FD "L" lens, with the red line and all, and recently purchased for $145. This produces similar close up results and working characteristics as my Panasonic 100-400mm M43 lens. I'm going to try it with my Raynox next. 
• I got some Canon FD "work-horse" primes like 28mm and 35mm NFD 2.8's and 50mm f/1.4.  For low-light, both NFD 50mm f/1.2 and the the FL 55 f/1.2 can be had for $250 or less.  I have the FL, and while it can get a weird haze in brighter lights wide open, in low light produces nice images. These compete with somewhat more expensive contemporary cheap Chinese fast 50's.

Lenses just for fun and art:

• the M42 lenses are a lot of fun if you are into vintage look with unique bokeh, contrast, flaring etc... The Helios 44's are very characteristic with the swirly bokeh, basically $60 LensBaby's.  I've also been experimenting with S5 and a pair of Helios, a few Super Takumars, Jupiter and Zenitar lenses, all of which are $50-$200.  These all feel GREAT on the S5 body, compact size, solid build, and quality "chunky" style focus rings, if you like that kind.  Most are "fast nifty 50's", so are eminently usable.  A minor drawback to M42's is that it is a screw mount.  There is no lock.  So occasionally you are turning the aperture or focus ring and you feel your lens unscrew a little from the adapter and have to tighten it again.  The screw mount also makes it so the aperture control of the lens can sometimes be positioned to the side or even bottom.  The screw mounts aren't an exact science I guess.