Short tutorial: Which third party lenses will work fine on NEX cameras (without lens cast issue).
Image from Photozone. Also the famous lens review website noticed the lens-cast issue on the [shoplink 10350 ebay]Zeiss 35mm f/2.8 ZM[/shoplink].
A week ago I got my NEX-7 and I am going to use third party lenses on it (by using appropriate adapters). But is it really so easy and flawless to use whatever lens you want on your NEX?
There are is one fundamental thing you have to watch out before to chose your lens. The “lens-cast” issue which creates color shift (mostly cyan shift) in the corners of your image. That problem appears or is stronger under following conditions:
1) Lenses with symmetrical design are not optimized for digital sensors, while lenses with tele-centric design do work well.
2) Wide angle lenses do accentuate the problem.
3) Problem gets worse on bigger sensor. Leica M9 shows more color shifting than the NEX-5n.
4) Problem gets more visible on cameras with smaller pixels. The NEX-5n has less problem with lens cast than the NEX-7.
Example: The Voigtländer 15mm f/4.5 M-mount lens ([shoplink 11043 ebay]Click here to see it on ebay[/shoplink]) does a wonderful job on film cameras but isn’t that good on the NEX-5n and completely sucks on the NEX-7. This because it has a symmetrical design and extreme wide angle. Does it mean you cannot use it on your NEX? There is a solution: The problem can be fixed with the use of the CornerFix software (there are both Windows and Mac OS X versions). It can correct Sony RAW files and transforms them in DNG files.
But if you like me don’t have time to convert every single file than you have to really watch out for the design of the lens you want.An alternative for the Voigtländer is the Zeiss 18mm f/4.0 lens ([shoplink 11044 ebay]Click here to see it on ebay[/shoplink]). Unlike the Voigtländer it has a tele-centric optical design. Those lenses are usually bigger than symmetrical lenses. That’s why the Zeiss is still bigger even if it has more or less the same aperture of the Voigländer.
In general wide angle Voigtländer lenses, Zeiss ZM Biogon lenses, Older Leica lenses come with symmetrical design. All new Leica lenses, most medium and tele lenses and soem Zeiss ZM lenses will work fine. With the help of our readers I will now collect info about a huge variety of lenses you could use on your NEX. It should become a sort of general guide to see how good a lens works on NEX cameras. I will post 1-2 guides per week starting from the next week.
To read more about the problem read that short text at LL (Click here), the guide at Digitalhapeman (Click here) and an M-mount index at Ken Rockwell (Click here).