Sony 12-24mm f4 G vs 12-24mm f2.8 GM ?

[Dave Gurtcheff]

Hi all. I currently use for my wide to ultra wide kit a Voigtlander 12mm, 16 to 35mm f4 Sony, and 24 to 105mm Sony. I am thinking about reducing what I carry by selling the 12mm lens and 16 to 35mm lens and replacing both with a single Sony 12 to 24mm lens. This would allow me to cover 12mm to 105mm with just two lenses instead of three lenses. I do landscape/seascapes mostly at f11 to f16, so I do not need the the extra speed of the f2.8 lens. Does anyone have experience with the two 12-24mm lenses? I do make big 20"x 30" prints, so sharpness is important. I have read that the very expensive f2.8 GM version is outstanding, but how much better than the f4 G version? At small f stops would I see the difference?
TIA
Dave in NJ
P.S. I use an A7RIV

[shadowblade]

I've owned both. The difference in corner sharpness definitely makes the GM worth it, particularly at wider angles of view.

12mm corners on the f/4 are a gimmick - it's there if you need it, but, it something in the corner needs to be sharp and you have any way to avoid shooting at 12mm (e.g. by shooting at 15mm, or by stitching) you're better off doing that.

12mm corners on the f/2.8 are perfectly usable.

I'm talking stopped down - I generally shoot these lenses in the f/5.6-f/11 range.

Mind you, 12mm corners on the f/4 are still just as good as 12mm on any other non-Sony lens out there. Just that the GM is much better.

[chez]

Another option is to keep you 12mm and replace your 16-35 with the Sigma 14-24 2.8.