Using it on the M9 at around f4 I found a sweet spot where the subject is sharp enough, I've covered any fickleness with the M9 focus, yet the background is soft.
Compared to the Planar design, the Sonnar's have more aberrations but tend to flare less and have greater contrast. It's an optical design found most often on rangefinders since the mirror on an SLR would interfere with the lens. There have been a few Sonnar designs in longer focal lengths such as the 150mm for the Hasselblad. I think if you want a pure sharp lens go for the Planar. If you want a lens with a signature look, then grab the Sonnar. For some reason they are tough to get in perfect focus on every M9 but they seem to work fine on all the film cameras.
At the local rodeo this week Robert Ball took a minute to pose for me. Robert had a dislocated shoulder and fresh stitches from a horse kick earlier in the week. He still tied onto a bronco this weekend and won the division.
Did I mention these guys are tough.
Nick Goncalves is one of the top bull riders in the area and is the subject of a project I'm shooting on rodeo cowboys. I like how the lens draws him sharp but the background is soft. It's a great look that works well for portraits.
My retail store for rangefinder supplies is www.rangefinderstore.com