sully

Hi nirkarpel, I use a tripod on many occasions for wrecks, reefs and any shots where more than a 1/8th of a second is requird. Just go and buy a nice cheap regular tripod, a second hand one is a good idea. Make sure it is sturdy enough for your camera set-up and you can use all your camera functions in both portrait and landscape positions. Then go for 'it'. Just make sure you give it a good soak in fresh water when you have finished and lubricate all moving parts before packing it away. I have done this for years and have only wrecked one tripod because I didn't give it any lubrication after use. Salt water is after very hard on steel and aluminium. Hope this helps. Sully

Many thanks for the answer to my question. Now I would like to hear from another diver who has seen one of these very pretty urchins. Is it a rare creature, or just shy and well hidden. sully

Does anyone know the name of this Red Sea sea urchin? The picture was taken on a night dive in the Gulf of Aquaba. Thanks in advance, Sully

Does anyone know the name of this Red Sea sea urchin? The picture was taken on a night dive in the Gulf of Aquaba. Thanks in advance, Sully

Hi Wolf eel, Try using this tried and tested formula as follows: f=2d where f= focal length of dome d= diameter of dome so for a dome with a 20cm diameter, its focal length will be 2x 20= f40cm and its effect will be to act as a negative lens to the camera lens. To compensate for this negative effect a positive supplementary lens of f40cm is needed. these supementary (close up) lenses are often expressed in diopters. to find the power in diopters divide the focal lenth in cm's into 100. ie a lens of f40cm will be 100/40= 2.5 diopters. my gues would be that you require a dioptre of +4 but do the calculation. best regards Sully.