Leica M9 and off-center color
http://diglloyd.com/diglloyd/2009-11-blog.html#_20091119LeicaM9OffCenterColor


Off-center color shift is an issue with all focal lengths on the M9, even 90mm and this is why Leica programs in settings for Leica lenses into the M9. With Leica lenses, or ones that are reasonably similar to Leica lenses (eg the lovely and value-priced Zeiss ZM 35/2 Biogon), you’re in reasonably good shape— you can manually choose the specific lens (for non-coded or non-Leica lenses) or set it to Auto for 6-bit coded Leica lenses. But even that is not perfect, because even Leica lenses vary from sample to sample.
M9的離軸偏色情形的確是個問題，所以Leica將鏡頭資料載入M9內。只要從選單選取特定的鏡頭或者使用有6 bit code的原廠鏡就會有偏色補正功能。若果你用的副廠鏡有類似的原廠分身(例如ZM 35/2)在選單裡照選用相應的原廠鏡，修正效果也相差不遠。
但就算用原廠鏡也不是每次完美，因為每支鏡都有點不同。

The wonderful variety of lenses in M-mount (or M42 with adapter) means that this issue is just not going away. I feel that Leica has a lot of homework to≠ do here to carry on the M tradition: non-Leica lenses deserve better support than just “closest Leica equivalent”, which doesn’t work well at all for some lenses.

For example, I have some Voigtlander M-compatible lenses coming courtesy of Stephen Gandy at CameraQuest. I will be shooting them this weekend for notes in my M9 review. With about 13 Voigtlander lenses and the same number of Zeiss ZM lenses and many others, Leica M users deserve more extensive lens support in their US$7K M9. It’s fair that Leica can’t do this all at once, but a camera system deserves that sort of commitment.
既然福仔和蔡司各有十幾支鏡頭支援M mount，Leica 理應善待M機的用家，讓身價七千美金的M9能更好的支援這些鏡頭。

All that said, I’ve developed as an experiment a layer mask for Photoshop which can largely eliminate the color cast issue even with the 21/4.5 Biogon. Not perfect, because the shift varies slightly with the lighting and aperture, but really much better than without. Black and white shooters can pretty much ignore the whole affair. I also have the Zeiss ZM 18/4 and 21/2.8 which I’ll be evaluating.
You can read another person’s analysis here, though it’s way too nerdy for even me to want to wade through.
我在Photoshop弄了個遮罩，修正我的21/3.5 Biogon造成的偏色。不是百份百完美(因為偏色程度隨光圈及光源而異)，但聊勝於無。

ADI 寫道:
那天就看到M9那個網頁
心裡就納悶---怎麼好像以前底片機時代的漏光??

如果老鏡表現差得這麼明顯
還有價值嗎???

ovm 寫道:
M9我可不清楚，但Kodak DCS Pro14n可是沒有AA filter的