John Liddiard

I have shots taken at night, in wrecks and in caves where the focus light shows as a slight hot spot with a slightly red tinge from the difference in white balance. For macro photography its less of an issue. The key is the focus light acts over the entire exposure time. Hence, for example, a wide angle shot from beneath a dark overhang or inside a wreck with portholes would often use a slower shutter to get some of the blue, but that exposure time also increases the opportunity for a focus light to create a noticeable spot. Sometimes similar techniques are used to lighten the background for a macro shot. Without an auto cutout, a focus light needs to be as weak as usable with a diffuse beam (no hard edges). i.e. Buy cheap or expensive, but probably not in the middle ground.

A tray with a slight ridge at the back A thin strip of rubber or silicone between camera and tray

When I moved to M4/3 I could fit nearly everything for the camera system into a carry on and my hold baggage shrank by a bag. Camera system less vulnerable to baggage bashing. Camera system no longer susceptible to pilfering in dodgy airports. I save on hold baggage fees. First flight with M4/3 system I saved £70 each way. I have given up counting, but given enough dive trips it will pay for itself.

As you already have a video light, start with that and learn your way round the camera. Its an easier starting point. Or/and have a go at macro with the built in flash. TG7 has a great microscope mode, more magnification than most big cameras with a macro lens and works great with the limited capabilities of the built in flash or a video light. Its really good for slugs. The standard lens (ie, not in microsope) is good for fish portraits, again within the range of the built in flash or video. The #1 starting mistake I see is trying to take pics of things too far away, then attributing lack of success to needing more light, when the real lesson is to get closer. Then with all that out of the way and comfortable with everything you already have, upgrade to a strobe or two. That way you don't have to learn it all at once. If you want to do that one strobe at a time, you can use a white card to bounce some of the light from a single strobe back and take the edge of any hard shadows.

How often do boats 'nudge' the reef without becoming stuck and without any official report? In my experience, it is not unusual. Even for a highly skilled boat captain, there is always an element of randomness in the behaviour of the boat. Then we have to admit that boats are under commercial pressure to give us divers the perfect drop off to start a dive and then have to pick up the those who ignore instructions and surface too close to the reef or do not swim out after surfacing or limit the captains ability to manoeuvre by swimming into danger areas such as by the propeller before being given the all clear by the crew. Whilst captains bear ultimate responsibility for their boat, divers often do not help them to realize that responsibility.

In the past having everything powered by sets of 4xAA batteries was useful for all the reasons given by others. The universal AA has saved me on multiple occasions. But cameras now have manufacturers' dedicated batteries, most decent dive lights have dedicated batteries. The benefit of commonality has been broken, so strobes also having dedicated batteries would not deter me. As an old school Inon user, I have 4 x Z240s. About 20 years ago I replaced some woefully unreliable S&S strobes with a new pair of Z240s, then more recently obtained a second pair used 'just in case'. None of my Z240s has ever failed. The most I have needed to do is clean up battery contacts. The UI is awful. I still don't have my phd in Inon. But reliability trumps everything.

First off, I am glad Tim and everyone else escaped. There must be an enormous temptation to "just nip inside" for passport, wallet and $X,000 of camera system. Every time I hear of a boat fire or sinking on a reef, I am shocked by how often I realise I have dived from the boat concerned. Is that a statistical thing, or just a bit of sub-conscious psychology and my mind kidding me? Same for how often we hear of boat fires, reef sinking and capsizes. Has the frequency increased, or is it just better reporting now we have the internet? I did a tour of a boatyard in Egypt where Red Sea dive boats of all sizes are built and repaired. Most are constructed of wood frames and planks, covered with thin sheets of ply and an epoxy based paint to achieve that polished hull look. By contrast, in 'pure' GRP construction the hull is usually moulded as one or more panels, then joined and strengthened with ply or composite frames. I would guess that there are many hybrid variations, especially once repairs are taken into account. The inside fit with both constructions will be predominantly wood. I doubt if there is much difference in flammability, toxicity or unstoppable progress once a fire gets established in the basic structure.

I got tired of trying to educate old-school publishers of this years ago. The other stupid thing they asked for was 50 Mbyte files. 50 Mbytes of what? I suspect (and could be wrong) that the stupidity came from film and the default output from drum scanners. So I just gave them files tweaked to match the stupid specifications.

I clicked the link. £36.80, €46. Is that a regular razor blade in the image of the cutter? I am guessing that a 1-off use of a fresh razor blade will give an even cleaner cut than a stanley blade. Maybe one of our 3-d print experts could come up with design for printing such a block. I don't have a printer, but expect I could machine similar from aluminium or delrin. For individual use, it wouldn't need to last for 1000s of cuts. Edit - seems there are plenty in the £10+/- range on ebay

A friend once built a pressure pot by cutting in half an aluminium scuba cylinder that had failed test and making a perspex lid for the bottom half, then tapping in a pressure feed. It was only for a few bar, so a cylinder that had failed a 200 bar + test pressure was not a bad risk. It was part of an undergraduate engineering project. The trick on safe use is to completely fill with water, then only use a little air to pressurise - just like they do when cylinder testing, but only to a few bar. Unfortunately it wouldn't be big enough for a real camera housing, but could probably have worked for a compact. He used it to test and calibrate old analogue depth gauges against a lab quality guage.

The clue is in the name. Rinse. Not soak. My usual strategy is to train the crew to put my camera straight into the basket beneath my spot on the kitting up bench. That gets it well out of the way from places it could fall from or get sloshed and knocked or otherwise be mistreated by other divers and their kit. Then once all divers are recovered and I am de-kitted and the general melee is over, I give it a few minutes rinse while twiddling knobs and pushing buttons. I never leave a camera unattended in a rinse tank for any period of time. I have seen many more (other photographer's) cameras leak in the rinse tank than I have seen leak underwater.

A neoprene strap or cover is a guarantee it will slip off in a back-roll. A plain rubber or silicone strap is more dependable for sticking in place. Just position the strap lower on the back of the head than 'text book' I have done many back roll entries with camera tucked into my chest and hand on mask. Never had a camera issue. My body makes a hole in the water and the camera follows me into it. On the right boat, it can also be practical to do a forward half-roll/slither/dive - start with the camera already danging in the water on lanyard and follow it in head first. Great for a seriously fast negative entry. In general, I have found that even for a negative entry boats position sufficiently up-current to allow for some faff, with the consequence that completing a seriously fast negative entry can under-shoot the target. For lenses, when I did a Galapagos trip a photo I took with a macro lens got a highly commended in the wildlife photographer of the year. The pic was more luck than judgement, but it wouldn't have happened without the macro lens.

Since photography went digital there has been software that aimed for similar with varying degrees of success and some of the software was marketed as intelligent or AI. Before photography went digital, folks did it the slow way with paintbrushes, masks, scissors, magnifying glasses and a lot of skill. Based on its training and the data available a generative AI makes a well informed prediction of what the missing detail should be. With good training such a prediction can be accurate. There will be cases where the prediction is plausible but wrong, and further cases where the prediction is stupid. All generative AI image 'improvement' has done is to take another step forward in a process with a very long history.

Consider what the lighting will be where the prints are shown. Different types of print and paper are suited to different kinds and levels of lighting. If framing, consider the kinds of glass available. For example, viewing a high gloss will be more susceptible to reflections. So it wouldn't be a good choice where a light or window would reflect when viewed from an angle.

Larger sensors actually have a smaller depth of fields