Still on the fence about the best option for me to buy when it comes to a versatile underwater zoom.

But I have a question for those of you who have shot both:

If you were to try and quantify the sharpness increase of using a WACP-C vs a 16-35mm and glass dome, what do you think we'd be looking at ?

Marginally sharper, or a substantial increase?

I do not have Sony 16-35mm, but I use the similar Tamron 17-28mm/Zen DP170 and also have WACP-C/28-60mm with A7R5...

In the center and midframe the Tamron is clearly sharper and has more contrast compared to the WACP-C combo.

The edges look different with rectilinear (Tamron) compared to moderate fisheye (WACP-C), it is not just corner sharpness that is different. I, personally, prefer the fisheye look (=object in the center enlarged and corner compressed (instead of stretched out as with rectilinear WA)). I guess that at comparable aperture WACP-C is sharper in the corners (this is what Nauticam says, but note that aperture values of the lenses alone (28-60mm vs. e.g. 16-35mm rectilinear are not directly comparable, as the wetlens changes the angle of view and, hence, focal length), but never did a a rigorous comparison myself (I find that corner sharpness not seldom is less important).

For me, personally, the Sony 20-70mm f/4 with Zen DP170 is enough when rectilinear WA is concerned with FF. At 20mm the "rectilinear distortion" is still decent and the image is tack-sharp with brilliant microcontrast i center and midframe (clearly sharper and more contrast than WACP-C).

When wider angles than 20mm are required (majority of cases), I prefer WACP-C/28-60mm (recently, since approx. 1 year), I prefer the Canon 8-15mm/2x Sony TC, which gives similar IQ, but has a more versatile zoomrange compared to WACP-C (for widest 180° diagonal angle the pure 8-15mm gives best IQ, but unfortunately one cannot zoom in))...

Wolfgang

Edited yesterday at 12:06 PM1 day by Architeuthis

Interesting, so you reckon that the sharpness advantage only really comes in the corners ? And not the centre ?

That's so weird, I would have thought that a WACP-C would out perform a zoom behind a dome substantially, otherwise what is the point of spending all that money on the optic haha...

6 hours ago, Hunting for Paradise said:

Interesting, so you reckon that the sharpness advantage only really comes in the corners ? And not the centre ?

That's so weird, I would have thought that a WACP-C would out perform a zoom behind a dome substantially, otherwise what is the point of spending all that money on the optic haha...

Sharpness and microcontrast in the center are not affected by a domeport and when Tamron 17-28mm or Sony 20-70mm are regarded, are better compared to the WACP-C/18-60mm combo (this is noticed in very clear waters only, otherwise the water is the rate limiting factor). This is not just my subjective opinion (I did not measure with testcharts, just by looking at the photos), but several others here have similar impression...

Furthermore, many (but not all) prefer the moderate fisheye look over the rectilinear WA look. The wider the angle, the more elongated the parts of the motif close to the corners become, when using rectilinear lenses behind domeport (I find this effect far from optimal). An exception may be motifs (e.g. wrecks) where there are straight lines that potentially can get distorted, but even here many (including me) still prefer fisheye and take care how to place these straight lines into the final photo so that the effect does not become distracting...

The WACP-C/28-60mm provides a useful zoomrange in a handsome package compared to many rectilinear lenses behind domeports (many here, BTW, say that WACP-C/28-60mm performs essentially the same as WWL-1/28-60mm (what is smaller, lighter and cheaper, but a wetlens)). It is difficult to predict how WA lenses perform behind a domeport. For most WA lenses, however, a 230mm domeport is considered to be required to give acceptable corner sharpness. The Tamron 17-28mm is an exception, since it performs already very well behind a 170mm (or 180mm) domeport...

Edited 12 hours ago12 hr by Architeuthis