I know this must have been done to death, and is probably down to my own ignorance....but what is the point in the 16-35 F4 IS?
Is it to replace the 17-40 F4? If so and assuming this is for landscape then it will need to be very good quality as the 17-40 is fairly cheap these days. And again assuming this is aimed at landscape/building photography...do you need IS?
If it is to replace the 16-35 F2.8.....with an F4 lens? Sure the IS is welcome for handholding shots...but that will never replace faster glass when shooting low light (thinking weddings and events etc).
Seems like it is stuck in between two lens (16-35 F2.8 & 17-40 F4) to me??
Yeah, looks like Canon is making a range of consumer level 'L' lenses in full frame format, to suit the 6D
5D3, 5D2, Sony α6000, G16 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 2.0x III, 70-300L | E-mount: SY12 f/2, 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses