5 hours ago, Chris Ross said:

There are a number of constraints when using lenses behind water contact optics, there is an entrance pupil constraint and there are also issues with zoom lenses that change length as they zoom

I looked into using the z24/1.8 with the wwl-c a while ago and this was the issue. Front element cause vignetting.

Edited 5 hours ago5 hr by Christian K

3 minutes ago, Christian K said:

I looked into using the z24/1.8 with the wwl-c a while ago and this was the issue. Front element cause vignetting.

Yes, it's unclear exactly what sets this and it varies between the WWL and WACP models as to which lenses they work with. I would guess that port charts for these optics are fairly complete and to get a better optic use the chart to help, but probably involves going to a WACP. I would think that the main limitation with some of these bigger lenses is the flat port size (port ID or the m67 port diameter causing vignetting), or some of the small primes a short enough port to properly accommodate them.

9 hours ago, Chris Ross said:

The other advantage of the wet optics is that shooting at f5.6-8 is possible where the corners would be pretty mushy on a rectilinear behind a dome.

Very good points Chris. To put it in other words: it’s a little bit like you would be using an upscaled almost APS-C sensor sized image. Due to using the center of the optical system, the corners - which are actually not real corners - improve, like would have cropped the image.

So the reward of improving corners and straightening the image goes to the air lens and lens corrections more than to the water contact correction optic 😉 if someone tries to frame this in a positive way.

The negative aspect the is certainly: why bring an expensive & bulky full frame system to water if you could have archived similar and same IQ with a more affordable and compact APS-C size rig?

Looking at the WACP - calculations show that this is closest to a stereographic projection fisheye,

Hey, where can you look at this? Really interested to dig into theses.