I've been considering the options for a 15mm lens to replace my CV (which indeed is rather poor on the M9) and was looking at the ZM 15/4. But at ~$3500 *YIKES* it's only a marginal savings over a WATE. And then there's some risk of edge problems still.
Which leads me to wonder about the WATE in general and on the M9 in particular.
How does it perform? Handheld, wide open? If I put the camera on a tripod and stop it down to say f8, will it produce a well-defined image over the entire field? Is it sensitive to flare? How is it handheld - if I change focal lengths, will the camera notice for lens correction or do I need to manually change it? Or turn the camera off and back on? (Never used it on an M8 so sorry if this sounds dumb. ) Any center IR hot spot on the M9? Does it render like modern Leica ASPH lenses do in general in terms of color and contrast?
The more I think about the WATE, the more attractive it becomes, at least conceptually...
Help persuade me! Show me some photos!