p.1 #1 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
I currently have the Sigma DG DN F2.8 24-70 and while I've used it over the years for landscape and some portraiture, I recently started using it for in-water surf photography (i.e. in a water housing) and have been troubled by how fast it focuses. To elaborate, in-water surf photography is very fast-paced with lots of distracting elements in the frame such as flying water droplets, potentially water droplets on the front of the port, and a moving wave and subject. Also I'm using a Sony A7R III but when using other Sony lenses like the 16-35 F4 or 70-200 GM II, I don't seem to have focus speed issues.
I'm considering whether I should move to a Sony-built 24-70 to improve my success rate. On one hand I love the sharpness of my Sigma and I've not been impressed by the reviews of the GM I or GM II (at that price point) due to variation in sharpness. I'm considering whether I should spend energy trying to locate a particularly sharp GM I, which would be hard to achieve but perhaps enabled by a kind soul on here, or shell out for a used GM II.
Alternatively, is there any way to set the focus distance similar to the 70-200 GM II's physical switch for 3m-infty for instance but in-camera instead? I'm not sure that discrete manual focus would be able to achieve this as I don't have access to the focus ring while the camera is in the housing.
Thanks for any insights or creative solutions!
Sean
An unfortunately "soft" example of typical framing and conditions
p.1 #2 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
The focus speed of the DN II is much better. It still has focus accuracy that is not as good as native Sony, but speed won’t be a problem. If you can get away with 28mm on the wide end look at the Tamron 28-75G2, very fast and accurate focus. I don’t think I would be interested in ver 1 of the GM.
p.1 #4 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
tschopp wrote:
The focus speed of the DN II is much better. It still has focus accuracy that is not as good as native Sony, but speed won’t be a problem. If you can get away with 28mm on the wide end look at the Tamron 28-75G2, very fast and accurate focus. I don’t think I would be interested in ver 1 of the GM.
Thanks! I agree the GM I is not so appealing in general unless one gets a very good copy. Reading https://dustinabbott.net/2024/05/sigma-24-70mm-f2-8-dg-dn-ii-art-review/ and another video I can't seem to find the link to right now, it seems like the DN II is indeed much faster than the DN I.
p.1 #5 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
seanderson wrote:
it seems like the DN II is indeed much faster than the DN I.
Yeah, I have owned both. The linear motors in the DN II are near instant like what you see in the Sony linear motors. Speed doesn't seem to be an issue. Even on something like a volleyball player diving for the ball. The camera might select something other than the player, but something is in focus, very rare to get a shot with nothing in focus.
I think the Sigma lens focus algorithm is not quite as good as the Sony, so it might miss by just a bit, but still useable.
p.1 #6 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
tschopp wrote:
Yeah, I have owned both. The linear motors in the DN II are near instant like what you see in the Sony linear motors. Speed doesn't seem to be an issue. Even on something like a volleyball player diving for the ball. The camera might select something other than the player, but something is in focus, very rare to get a shot with nothing in focus.
I think the Sigma lens focus algorithm is not quite as good as the Sony, so it might miss by just a bit, but still useable.
That's great to hear. I think I will look at picking up a copy of the DN II and trying to offload my DN I.
p.1 #7 · Focus speed of 24-70 F2.8: Sigma DG DN I vs Sony GM I & II
Please post your findings; I’ve been interested in a 24-70 and the new Sigma seems like a good option to me. I’ve given up on buying Sony lenses, just too damn expensive.
