Canon just announce Canon RF 20-50 F4L https://www.canonrumors.com/canon-officially-announces-the-rf-20-50mm-f-4l-is-usm-pz/.

With MFD of 0.24m, do you think this lens will work with WWL-1B? Or it should work better with 140mm or 180mm dome? I'm looking for a compact rectilinear wide-angle setup for Marelux housing.

Thanks in advance for your opinion.

I'm interested in this lens for use in the 230mm (primary) and 140mm dome (travel). I wonder if it will require a closeup diopter filter to focus on the inside of the dome, or if it can focus stand-a-lone.

2 hours ago, puttsk said:

MFD of 0.24m

The 15-30 has a MFD of 0.28 and works well behind a dome so it should be good on the 180 or 230mm. No idea on the 140mm.

I'll bet its front element is too large to work well with the WWL-1B, that later of which is really designed for small front elements.

This may be a nice lens for video (behind a dome and for certain shots), or stills if it works with an wet-mate or dry-mate adapter (WACP,WWL-1, Marelux Aquista) for a solution (with limited to 28mm and greater zoom...)

I'm looking forward to seeing some real world examples underwater!

There's no lenses listed working with the WWL-C from Canon apart from the little 24-50, if EF lenses nothing at all, the 28-70/80 kit lenses are said to not work with the WWL-1B, so seems unlikely this lens would work with either of the WWL.

I expect it should do pretty well behind a 180mm dome though.

The new Canon 24-50 is very close to the Sony FE 20-70 F/4 for full frame with the main difference being the Canon is internal zoom. The both have the same minimum focus distance and magnification so the results should be very close. I have used the Sony 20-70 extensively with Marelux 180, 210 and 230 ports. In my tests the 140mm port it was a bust in terms of corners and not really recommended. I have attached the front page of the review I did (in UWP back issues) along with photos at 20mm and close to 50mm (45ish) to give an idea of the range, both with the 180mm port. The Marelux 210mm acrylic port fits into the same case as the 180mm port and is a little bit lighter and works better for splits so it is my travel dome. The PZ feature on the Canon 20-50 saves the cost of a zoom gear and it has worked well for me on the Sony FE 16-35 PZ.

Regarding use behind a flat port with Nauticam/Marelux wet lenses this remains to be seen. More likely to work with dry lenses like WACP-1 and Aquista 135D which is coming soon.