There was also a copy in the British National Oceanographic Library - which was the one that used to distract me from work!
I am pleased that this experiment is generating lots of interest.
Thanks, Adam for posting it on the front page. I must absolutely stress this is a work in progress. In fact, I am very early in the process, having only done one day of testing. I have commissioned a few more optical parts to test. At present I am having them made in acrylic - and when I see how they perform I will have them made up in glass.
As I mentioned above, for the first time for a few years there seems more general interest in this topic - normally it is just me and Pete Atkinson moaning to each other! I think a lot is driven by filmmakers shooting at higher resolutions and become more demanding about image quality. Despite the higher resolution of stills, moving pictures make poor optics more obvious, particularly when the camera pans.
Most people are looking at adapting water contact Nikonos optics. Which have advantages and disadvantages
I have received a number of emails and phone calls about the optical corrector - and interesting ground has been covered in them, which is worth summarising:
The system I am working on is different from the water contact lenses that people have been adapting to digital cameras, particularly ones from the Nikonos V and Nikonos RS. Those lenses were designed to work specifically underwater with water contact optics. The system above is one that aims to completely correct the water air interface so that any lens performs exactly as it does in air. The downsides are that it is more bulky and can’t be used with really wide angle lenses - I am yet to determine a wide limit through cut off.
It certainly can’t be used with fisheyes. Furthermore the system above consists of two parts, and the simpler, rear part must be attached to the camera’s lens. This further limits lens choice to optics that can accept them, the Nikon 14-24mm, for example, cannot take a supplementary lens. Zooms that change barrel length are also out.
The advantage is that many lenses can be used, including new and forthcoming optics. Early tests show I can use lenses that are wider and focus closer than rectilinear Nikonos lenses. I also have AF-S autofocus, etc etc.
The corrector should also allow me to shoot open aperture wide angle, for both technical reasons (it is really dark!) and artistic effect (shallow depth of field wide angle, without the problems of simply seeing the blur from virtual image created by a dome port, which is what happens if I try that now). Perhaps also to be able to realise the advantages of PC lenses properly underwater etc. Getting it working is really the doorway into a world of underwater image experimenting.
While the lens can still focus on land, it cannot be used out of the water because optically the image is stretched and suffers strong optical aberrations (the opposite of what is actually being corrected).