Whether you will be satisfied with that lens or not I think it depends on what type of photography you do.
If your copy of the EF 16-35mm f/2.8L II is not decentered and is otherwise in good working order, it would be fine for reportage, candids, scenics and travel, etc. I used one like this for years with good results. Its main weakness is softer corners and some chromatic aberration.
If you are into landscape photography or commercial work or just want the sharpest possible corners in a zoom, you would be better off with the Mark III version of that lens, or perhaps even better, the EF 16-35 f/4.0L IS, which I think most consider to be Canon's best EF ultrawide zoom.
In my opinion, the RF 16-28mm f/2.8 STM is a remarkable lens, sharp across the frame and with little CA. Though it does rely on software corrections for distortion and vignetting, which may be off-putting to some. But partly because of that, it is also considerably lighter and more portable than the EF or RF L-series lenses, even without considering an adapter. If portability is a consideration, it could be worth the added cost.
You can compare all of these lenses at the TDP site if you like:
I have owned the EF 17-40/4L, the EF 16-35/2.8L versions I and II, and the EF 16-35/4L IS. I think the EF 16-35/4L IS is the best of the bunch, for both tripod shooting, and for handheld shooting, with a camera that has decent high-ISO performance (e.g. 1DX, 5DIII & 6D, and since).
I can't help you with the RF lineup, as I haven't yet gone there, yet.
currently, my widest lens is the Canon 17-40 and I am looking to upgrade and see some good deals on the Canon 16-35 mk2 for around $400.
Is the mk2 worth it or should I just save up to get the rf 16-28?
I will primary use the lens for sport, like locker room and church group pictures.
Let me know your thoughts.
I think the Canon 16-35mm mk2 is a huge upgrade. I'm don't think the RF IS stm is optically superior to the 16-35mm mk2. The main advantages of the RF lens are a low weight yet providing f/2.8, and very good IS.
Maybe it's me, but having 35mm readily available over 28mm is a huge benefit imo. 35mm is a lot more normal than 28mm, which adds greatly to the versatility of a lens.
I can only recommend EF 16-35mm f/2.8L III and EF 16-35 f/4.0L IS if you want to adapt a used lens.
All RF- mount WW zooms are better than EF 16-35mm f/2.8L II especially in the corners.
I use the RF 14-35 f/4.0L IS now because I prefer 35mm on the long end and don’t need the f2.8 on the 15-35.
currently, my widest lens is the Canon 17-40 and I am looking to upgrade and see some good deals on the Canon 16-35 mk2 for around $400.
Is the mk2 worth it or should I just save up to get the rf 16-28?
I will primary use the lens for sport, like locker room and church group pictures.
Let me know your thoughts.
Get the RF 16-28 if you want a zoom. I had the 16-35/2.8 v1 and v2. The v2 was optically better/sharper at wider apertures but the differences evened out once stopped down. But my copy of the v2 was never good in the ~20mm range with really bad field curvature. Yet the several CPS loaner copies I had whenever I sent it back to try to get it fixed, generally were better than it.
I'd get the 16-35/4 over the 2.8, but I think the RF is the better lens if you are ok with 28mm. Just it's a lot more than $400.
I've owned all of the above and if you need f/2.8 for under $500 then the EF II version will do the job, but don't rule out the cheaper Tokina 16-28 f/2.8 if you don't mind the shorter FL. If you want a very sharp f/2.8 lens and you don't need 35mm, then stretch your budget and look at the Tamron 15-30 f/2.8 G2. Otherwise if you don't need f/2.8 and want perfection at f/4 then get the EF 16-35 f/4 IS.
If you have more money to spend there are tons of options, but I think the best bang for your buck would be the RF 14-35 IS used around $800-$900.
BTW, I have a minty EF 16-35 f/4 I'm getting ready to list soon. PM me if you are interested.
I see the f4 around $450-500, so I see if f4 is good enough for my use purposes.
I looked into the Tamron in the past, I ended up selling off all my Tamrons because they turn the opposite direction than Canon.
