Hi, I am about to buy an EOS 6 with 24-105 f/4L kit ($2200 new in NL) and want to buy a wide angle with it.
The candidates:
*
Tokina 16-28mm f/2.8
Bright lens (2.8) but heavy (nearly 1kg), $720
*
Sigma 12-24mm f/4.5-5.6 (second edition released 2011)
Really wide angle (112 deg over the long side) and nearly distortion free, but rather dim (4.5), also $720
Others are the Samyang 14mm f/2.8 (cheap, $350, but strange 'moustache distortion' and bad vignetting at 2.8) and the original Canon 16-35mm f/2.8L but price tag is not for me ($1250).
Uses: indoor photography, landscapes and Astrophotography. I have experiences with wide angles (long used a 17mm on a T90 film body and recently Sigma 10-20mm f/4-5.6). The Sigma 10-20 was a good lens (sold yesterday for a good price) for me but does not work on a FF body.
On the other hand, f/4 is not a bad idea on a FF as I can increase the ISO with 1 stop due to lower grain on a FF.
Does anybody have experiences ?