Stig

I found a similar food container for my Nauticam 100mm dome port:

Just back from Cozumel & Playa del Carmen. The dive centre (Pro Dive) at the Allegro resort only did boat dives but one guide said there are some suitable snorkeling sites further south -apparently signposted from the road so you can park up and walk in. I guess you'd have to find a nearby dive centre that will rent you tanks & weights. Most, if not all, of our dives were drifts with variable strengths of current so the region may not be ideal for shore diving.

If the stick-on lenses are flexible then I guess that would work. It wouldn't work for rigid lenses stuck inside a prescription dive mask though as the inside surface wouldn't be flat.

I hadn't thought urchin, again because of the width of the spines, but that's very likely what it was. Thank you.

Spotted these on a dive in the Maldive last week. At first I thought they were some kind of razor shell but also wondered if it was just spines of a lion fish hiding in a hole although they seemed a bit thick for that.

Yep, I've used YS-25's for a few years and on setting 1 it will fire on the first (pre) camera flash but only have enough juice for the second (exposure) camera flash on very low power with a very pale subject. Put it on setting 2 (as Pandit presumably has been) and use both strobes on manual (well, the YS-25 will try to adapt to the scene brightness). After one of my YS-25's died I got an Inon S2000 and that combination seemd to work OK (Inon in manual), but I've only been on one trip since then so can't claim a wealth of experience.

Aqaba, Jordan would be an alternative to Egypt, mostly small stuff there but not the diversity you'd get in Philippines . Should be direct flights available in Feb.

There are a couple of articles describing the technique. A non-technical one: https://www.scientificamerican.com/article/sea-thru-brings-clarity-to-underwater-photos1/ And a technical paper for geeks like me: http://openaccess.thecvf.com/content_CVPR_2019/papers/Akkaynak_Sea-Thru_A_Method_for_Removing_Water_From_Underwater_Images_CVPR_2019_paper.pdf

Sorry, I can't see what to click on there either. Sea&Sea Motormarine MX10

I tried a cheap +10 dioptre "close-up" lens in water and can confirm that it does work. Sure, you don't get +10 in water - it's more like +4 but that can still be useful. Having had a play with it on a couple of trips I then bought a 'proper' Nauticam CMC with flip holder and that's got noticeably better corner sharpness and a bit more magnification but it was the flip holder that made it worth the money. Be careful if you try using a dioptre inside the port that the combination still fits and doesn't hit the glass port when zooming or focussing as getting any scratches out would be a pain.

I've been using an Oceanic mask with bifocal lenses - top 2/3 is flat, bottom 1/3 is +1.75 dioptre (or similar) for a few years now (I tried the XS Scuba one initially but it didn't fit my face very well so sold it on). I find that in good light I can look through either part to see the reef but need to look through the bottom part for the camera screen. In poor light (esp. night dives) it's a bit restrictive as I can only see the reef clearly through the top part (unless it's really close but I don't like to be that close in case I hit something ) The idea of only correcting one eye wouldn't work for me as I'm very left eye dominant and never get a sharp image with just my right (lazy) eye.

Kevin at Aquaphot was recommended to me: http://www.aquaphot.co.uk/ He was very helpful when I called him about my old YS-25A a couple of years back (sadly there aren't any spares for it any more).

I just meant that 1/2000s shutter might be cutting off some of the strobe pulse which is about 1/1000s long (well, that's what mine are). Strobe power settings generally work by shortening the pulse duration so a big pulse from a more powerful strobe at, say, half power (i.e. duration) would work better that a full duration pulse from a weaker strobe when using such a fast shutter speed. Probably a pretty rare issue in practice though.

Cool, that makes sense. I didn't realise the RX100 could flash sync at that fast a shutter speed, I guess it's down to electronic rather than mechanical shutter. Mind you, 1/2000s is going to start cutting into the flash duration requiring you to have a more powerful flash to compensate...

Really? It's a smaller sensor than full frame so gets fewer photons. For the same sensor technology a larger sensor is always going to have better sensitivity. The difference in f-stop is down to the different focal lengths required to get the same angle of view.