How does the sigma sensor compare to the MM?
MM pros
- 18 million photo sites vs 15 million
- no Bayer array or aa means each photo site is interpreting the light in terms of a pure light strength value from 0 to 255. In a way similar to how b&w film would handle it
- no Bayer array means no guessing (Bayer algo and interpretations) on what the real color should be associated w/ the neighbor photo site or where true edge delineation is.
- better high iso
- full frame sensor
MM cons
- monochrome only
- need b&w filters to change emphasize just like real film (ie. Yellow, green, etc)
Sigma foveon pros
- each of the 15 million photo sites can handle all three primary colors
- no aa and no Bayer or xtran array means no need to interpret reality of true edge or color
- raw file retains all color info even if monochrome mode is used. This mode only sets a mono flag in the raw file for spp sw to use.
--- The choice of color or mono is retained for post processing
--- use of b&w filters is not required up front and can be a post processing option
- better tonal range then any Bayer array design
- tonal range probably as good as MM
- sd1 family, extremely wide range of Sigma lenses. The new art lenses leading the charge for good optics, performance and quality compared to the lenses designed even 3-5 years ago.
Foveon cons
- apsc vs ff
- sigma lenses only
-- unless u go the special mount replacement for Nikon lenses at expense of loosing af on the sd family.
- slow af focus about Fuji x100 speed prior to latest fw update for dp family and Nikon d200 or 300 af speed for the sd1m even though it is a true phase detect setup.
- Sd1m manual focus option much better than dp family though but focus screen is simple ground glass
- at each photo site, each color sensor is stacked on top of each other w/ blue at top and red at bottom, thus as iso gets higher true color accuracy decreases and noise increases.
- color good to around 400, ok at 800.. Noise starts to become issue by this time due to need to amplify red channel signal more vs blue channel.
- monochrome is good to 800 and ok up to 1600 w/ any special processing.
-- use of favoring info in the blue channel in post processing can increase acceptable iso up around 3200 or so.
- some weird color behavior at times when the sky is the theme. I suspect the blue channel (top location in each photo site) is being overloaded and is bleeding info into other color channels.
--- No such issue when in monochrome mode that I have been able to detect
If u are looking at this from purely resolution perspective, MM should be better (18 million photo sites vs 15 million to record monochrome info), but there are so many other aspects here.
Since I don't own any Leica digital m, all I can say is that the MM was the only digital Leica that truly tempted me to buy in.. After shooting w/ the sigma cameras both dp and sd families, that urge has disappeared. If by some miracle though, if the MM were to drop below 2k, I might one day buy one. But this is a big if currently.
Hope this helps to answer your question.
Gary
