I cheekily ordered a larger dome port last week (8 inch instead of 4 inch), which should suffer less chromatic aberration (unsharp corners), but also make it easier to compose splitshots (or ‘over-under’ shots) where the top half is above water and the bottom half below water. I played around with this type of shot a bit before with the small dome (e.g. see here and here) but it should be much easier with a larger dome. Anyway, the weather was such that I did not immediately have a go at it, but this Tuesday I figured I could give it a try at Fistral Beach in Newquay, which has some good rockpools that are not directly connected to the sea at low tide and might be still enough. It was bloody hard to get a decent shot in the deeper rockpools I tried first, as the difference in ambient light above and below water really necessitates the use of strobes to result in an even exposure, As I struggle with strobe lighting for normal shots, this was a bit too much to ask. My fallback was the ‘cave of dreams’ a rather grandiose name for a small overhang containing scarlet and gold cup corals (Balanophyllia regia) and Yellow hedgehog sponges (Polymastia boletiformis) (amongst other sponge species). (Check out THIS OLD POST on the cave of dreams with some decent pics I took with my old Canon Powershot camera.) Crouching down, I could barely fit under the overhang. The picture above looks like it is a substantial scene, but I could only submerge my domeport halfway! Using strobes would have been too finicky and probably result in quite unnatural light, so I bumped the ISO to 400, lowered the shutterspeed to 1/30 and used a 6.3 F-stop to get sufficient exposure using my micro four thirds Olympus camera. I needed to go down to a shutterspeed of 1/25 and a 5 F-stop for the close-up shot below. Here is to more experimenting this spring/summer!
P.S. the sponges have been going strong for a good while, see these pics from 2014/2015!