How come Contax G1 Camera is called "green stickered"?

Question

And what can I do about the extremely small viewfinder on G1? It is not easy looking through it. And where can I buy the 21mm lens for the G1? And how much is it?

Answer 1

That's a lot of questions.
* The green sticker:
The Biogon 21mm f2.8 and Planar 35mm f2.0 lenses were designed after the introduction of the Contax G1. A different technique is used to pass vital exposure and focusing information to the camera body than in the past and the G1 has to be modified to use these new lenses. The "sticker" is the loading-instructions sticker in the film-supply chamber. On pre-modification cameras, this sticker is silver. Late-production G1s that have already been modified by the factory to work with the new lenses have a green sticker, as do all G2 cameras.
http://contaxg.com/contaxuser/lenses.html
* The small viewfinder:
There are accessory viewfinders.
* The 21mm f/2.8 Carl Zeiss Biogon T* (and prices):
Try eBay and stores with a good 2nd hand selection, like www.keh.com It's is also available retail at places like B&H for around $1300. They have it in stock, even:
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=361537&is=REG&addedTroughType=search