Moving to Sony and want to make sure I cover all my options.
I do underwater photography for swimmers. I have almost always used 24mm as my base focal length, mostly the Canon 24 1.4, but also the 24-70 2.8 In a previous brief switch over to Sony, I used the 24 1.4 with pretty good results on a A7III.
Given that these images get stopped down to around f5, are there any other lens I should consider? I've read about the 20 1.8, had the 24 1.4 GM, so I'm looking for anything else I might should give strong consideration to. Will be used with either a A7R4 or A9II.
For autofocus, the new Sigma 24/3.5 or Sigma 24/2 from their 'i' series would fit the bill. Reviews are readily available for the 24/3.5 (sharp, little distortion, quite a bit of vignetting) and are just emerging for the 24/2; Dustin Abbot has solid reviews of both of them but you can also find Fred's review of the 24/3.5 here on the forums: https://www.fredmiranda.com/forum/topic/1687217/0
There is also the Batis 25mm, still a superlative lens though it's a bit expensive considering its newer competition.
There are a lot of MF options...Loxia 21 and 25, a pair of CV 21's...
TheEmrys wrote:
The Sony 24GM is pretty fabulous. I would pick it over any of the other AF options. Particularly as you are used to the focal length
Yes, it does nearly everything well, one of the truly great 'all around' lenses. Small, light, fast, sharp centrally wide open, sharp across the frame stopped down, admirably flat field...
Get both the 24GM and 20 F1.8... sell the one you don't want. They're cheap enough used, and won't lose much, if anything on re-sale if you shop smart.
I wonder how the Sigma 24/3.5 performs underwater in regards to AF. The brighter aperture lenses are are probably worth their size and weight in that environment but, with today's brilliant AF systems, it might keep up. It'd be an excellent choice for IQ, size, and price.
There might be good deals on a Batis 25 available. It's really approximately a 23mm lens as I understand it, despite the name, so don't rule it out on focal length grounds.
The Sony 24 GM is kind of just a "better" lens than the Batis... the Batis 25 has some CA at maximum aperture for example. But not at f/5, I don't think there's anything to criticise about it at f/5. And you might find a good used deal on it. There were Batis users who sold theirs for the Sony GM when it came along, and it's been out a long time, etc. Here's an old review of it that covers pretty much all there is to know about it.
Edit: For the sake of completeness, since you said you didn't want to miss anything and wanted to consider all options, there's a Tamron 24mm f/2.8 as well. It's very cheap and fairly sharp. But it has two flaws: slow autofocus and heavy distortion. Review.
The Samyang 24/1.8 is really a nice lens if:
a) You make sure you get a good copy (like not decentered).
b) You can live with the plasticy appearence.
On the plus side you get a surprisingly sharp lens that is sharp even into the corners, and also sharp wide open. It stands surprisingly good against flare and the sunstar is rather nice. It is also super light and super cheap so you get money left over to buy any of the other Samyang f1.8 lenses like the 35, 45 or 75 that also fits the above description.
