Originally posted by kent vinyard For those that want a 400mm f4.0 lens I would suggest that you save up at least $5,000--Take a peek at the price of canons 400 f4.0 at BH. I would love to have such a lens but the price will be huge. .
You cannot compare it to a Canon 400/4 lens. The Canon is a DO (and IS) lens and is consequently very expensive. A Pentax 400/4 will be significantly cheaper than a 300/2.8 lens. As most users of the latter uses it with a 1,4X conmverter glued on, a 400/4 makes a lot of sense....
..and if the speed is F:4, as oposed to of F:5.6 or F:4.5, it will retain AF when using a 1,4X converter; mandatory in todays ultra telephoto market.
If Pentax do indeed make such a lens, I promise not to switch to Nikon...