I have just begun experimenting with an optical corrector port for wide angle underwater photography. My intention is to use it on my full frame SLR to give me improved image quality - especially corner sharpness when using non-fisheye wide angle lenses. The corrector was build by Carl Zeiss and adapted for my housing by Pete Ladell.
Here it is on my Subal ND4S housing:
I thought I’d start a thread to present and share my findings as I go along.
In theory the adaptor is afocal and can be used to correct any lens that will fit behind it, which is an enticing prospect to be able to use many different lenses underwater, including zooms, with theoretically a much better correction than a dome port. Basically turning any lens into a corrected underwater lens. Autofocus and everything else working as normal.
Of course, that is just the theory. I took it to the pool yesterday to try it underwater. I am not necessarily the biggest fan on pool tests and much prefer to evaluate optics with real world subjects. But this was a massive step into the unknown - so the first aims were to check that it didn’t leak and to check it even worked at all. This corrector was designed for a camera without a viewfinder - so nobody had ever looked through it before underwater!
Hooray, it seems to be keeping the water out - test shots of tiles:
The small port size offers possibilities for CFWA:
And yes, it works, the photo I was taking, above: