techniques

Shallow depth of field

Painted Goby (Pomatoschistus pictus), Loch Goil, Scotland. Nikon D200, Nikon 60mm macro lens with +5 diopter. 1/200s, f/18, ISO200

I was very pleased to be placed in the top four images in a recent BSoUP competition. The theme was “shallow depth of field”. My image was of a Goby taken a few years ago in Loch Goil, Scotland. This shot has been lurking in my catalog without being shown and it has been nice for it to see the light of day.

These tiny fish are found in large numbers in the very shallows of many of the Scottish sea lochs, flitting about on the sand.

I often spend time shooting these guys at the end of a dive. Although they look a little plain from a distance, when you see them close up, they have wonderful markings on their scales.

They tend to keep very still and then, without warning, dart a short distance. This means they are quite tricky subjects and you don’t get long to work an individual. They home in on any disturbed sediment, hoping for a tasty snack. The best technique is just to lie very still and let them move into range.

This image was taken with a 60mm macro lens with a Marumi dry diopter on the front. This provides greater magnification at the cost of depth of field. With lens alone, a wide aperture of around f/4 seems to produce pleasing shallow depth of field, but this image was shot at f/18 and still has a very shallow depth of field.

I don’t usually crop my images very much, but in this case I felt the image had more impact in portrait format than the original landscape orientation. I was very pleased with the pose, giving a nice curve to the fish with its mouth open, but unfortunately its pectoral fin on image left was not extended. This was why the shot has not been shown before, but for this competition, I wondered if it could be improved. I copied the splayed pectoral fin, gave it a mirror flip and then moved it into position on the image left. I was very pleased with the result and so, it seems, was the competition judge.

equipment

Dome port repairs

I had a bit of a shock as I stripped my housing down after my previous dive, when the “dome” of my dome port fell off! I discovered that my vacuum leak detection system had been all that stopped my housing filling with water in a catastrophic way. Looking up the replacement cost of the dome gave me a great encouragement to make a DIY repair…

The dome, which is a Sea&Sea mini dome, is constructed from an aluminium base, with an acrylic dome held in place by a bead of sealant. I have been using this dome since 2004 and has done hundreds of dives. I was able to gently pull the whole bead of sealant off, which left not a trace on the acrylic but some residue on the aluminium base. I carefully removed the latter using a flat plastic blade I made by applying a scalpel to a “bic” pen lid. I then carefully cleaned both parts with alcohol.

I did notice that I’d managed to make a hairline scratch on the *inside* of the dome (presumably through careless cleaning or handling), so I took the opportunity to polish the inside using my kit… Whilst I had easy access to the inside surface.

A question on the BSoUP Facebook page directed me to a product called TSE399 from a company called Techsil. Whilst some have used standard bathroom sealant to make a similar repair, this seems to have mostly been “in the field”. The difference between the Techsil product and standard bathroom sealant is that the former flows and the latter does not, as well as being quicker setting.

The acrylic has a groove around the edge, whilst the aluminium has a rebate, into which the dome sits. It seems that this is what provides the seal, as well a large creating a bead to hold the dome in place. The TSE399 is said to have excellent adhesion to both plastic and metal; I hope so, as it’s all that’s holding the dome in place!

To fit the dome, I decided to run a thin bead of sealant into the rebate on the port base. I let this cure for a few minutes, with the idea of creating a bed for the dome to sit on. This didn’t work as well as I hoped, as it did not set enough, so when I placed the dome in place, it sank into the sealant and a small amount overflowed. The final step was then to run a thin bead into the groove in the acrylic. It’s important to keep the dome flat until the sealant has solidified, as it will flow, which creates a smoother finish than I think I could have achieved with something similar to bathroom sealant.

Having left the dome alone for 36 hours for the sealant to cure, the final step before pressure testing was to give the exterior of the dome a quick polish to remove the one or two scratches it had picked up in the last couple of years; I’m sure these did t show in the images; tiny scratches fill with water and disappear from view underwater, but I wanted everything to be as shiny as possible before returning to use.

dives, techniques

Long exposures

I finally broke my 2021 duck with a dive at Capernwray quarry in Lancashire; the weather was unkind, so a sea dive was not an attractive option. Capernwray is blessed with good visibility and the trout patrolling the shallows are an enticing photographic subject.

I chose to try various long exposure techniques to give an impression of movement. Using an exposure time of 1/4s whilst moving the camera briskly to “overtake” the subject gives a pleasant motion blur (and it tends to hide the backscatter too). A burst of flash at the beginning of the exposure freezes some detail on the subject and adds some colour. In order to maintain a decent depth of field, an aperture of at least f/8 or f/11 is needed and that necessitates as low an ISO setting as possible. The small aperture also forces a high strobe output.

I also tried a zoom blur. It is quite tricky to get the zoom action quick enough to show in the exposure, but it’s probably easier with the camera housed. Underwater, the zoom is accomplished with a flick of the finger on the zoom wheel (rather than gripping and rotating the zoom collar when holding the camera by hand).

I was most pleased with the results when the camera was close to the subject (for these large trout, less than 30cm) and when there is some object in the background. This generates significant motion blur on the background and allows the strobe to illuminate the subject.

These trout are quite large, so too big for any of my macro lenses. I chose my trusty Tokina 10-17 lens, but struggled to get enough opportunities with the fish close enough to fill the frame. A longer lens would have perhaps been better; next time I might try a teleconverter to bring the subject a little closer.

This technique requires a lot of trial and error, and the “hit” rate is pretty low. Nevertheless, I managed to capture half a dozen “keepers”.

Photo talks, presentations

RPS Photo talk

I’m giving an online talk to the Royal Photographic Society Nature Group next Saturday, entitled “Beneath UK Seas” and I will be talking about how to shoot the amazing wildlife to be found all round our coast (as well as lakes and rivers!). I hope to dispel the commonly held misconception (among non-divers) that UK waters are dark, murky and offer little to see. Follow the link if you’d like to attend: https://rps.org/events/groups/nature/2021/february/beneath-uk-seas/

dives, trips

Shetlands – day 6

Our final day aboard MV Clasina began with a dive on another klondiker (like the Lunokhods-1 we saw earlier in the week), the Pionersk. This huge fishing factory ship foundered in the 1990s, but is rather shallower than many of the other wrecks we dived. Consequently, it is more kelp encrusted and sadly the vis was rather poor, so I was limited to very close focus photography. The fact that we were so disappointed with the vis on this dive (“normal” UK vis – approx 3-4m) just goes to show how good the visibility had been on the other dives of this trip. Good weather – calm sea and bright light – helps, as does the sandy sea bed under most of the wrecks we saw; however, the lack of large amounts of algae in the water here is a massive help too (many of my shots from this week have a bluish tint, rather than the pea soup we have come to expect in the UK.

Our week aboard Clasina finished on a highlight with a return full circle to the first site we saw – the Fraoch Ban. This marvellously intact and upright wreck on white sand did not disappoint, and we saw angler fish and octopus in addition to the flatfish on the sand, spiny spider crabs on the hull and shoals of small fish around the superstructure we saw last time. A fitting end to an excellent stay aboard MV Clasina.

The dives were finished early, to allow the disembarkation of the mountain of gear which ten divers bring onto a live aboard. Rob and I bade farewell to our buddies from East Cheshire BSAC, as they were on the afternoon ferry. It was a more leisurely end to the day for us, as we had a couple more days left on Shetland.

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<– Shetland day 5

Uncategorized

Shetlands – day 5

Divers on the stern of the Gwladmina

On our cruise back south to Lerwick from Unst, our first stop was the Gwladmina, a large Victorian steam ship which sank upright in 38m. Most of the cargo seems to have been recovered and, descending the shot line amidships, we were able to complete a circuit of the ship – bow first and then astern along the exposed prop shaft and then to stern with rudder blown off to salvage the prop.

Our first sight was the Gwladmina’s substantial boiler
Wreckage as we move aft
Deck gear fallen into the wreck, as the tops decayed during their century underwater
Almost to the stern (see top image)
We had time to view the bow as well
Is this what remains of the bosun’s stores, or perhaps the remnants of previous buoylines to the site of Gwladmina?
A brief inspection of the triple expansion steam engine as we return to the shotline for our reluctant ascent to the surface (not forgetting the deco stops…)

The second dive was not a wreck, but a scenic site for a change. The Giant’s Legs is an iconic geological feature at the southern end of Bressay, where the headland has been eroded into a series of broken stacks. Underwater, the terrain consists of series of submerged stacks. We saw many nudibranchs, but I had camera problems and had to return to the boat, before getting back into the water agains. Two dives for the price of one!

Polycera faeroensis munching on the abundant bryozoans
A tiny juvenile scorpion fish hiding amongst the kelp
An impressive Dendronotus frondosus feasting on the bryozoan mat covering the weed

Links:

dives, trips

Shetlands – day 3

Another morning, another wreck!. In this case, the Jane, a cargo ship which came to grief in 1927. The wreck lies on its side, with a large propellor and rudder visible. It stands several metres proud of the sea bed but shows signs of collapse in several places.

Our second dive was a drift off Burra Ness, on our way to Balta Sound. The sea bed consisted of maerl and coarse sand with very large undulations caused by the tide. We saw many hermit crabs, one or two nudis and a huge plaice.

The evening saw us in Baltasound, where we chatted to the skipper of the Björn, a gaff Cutter rugged ketch flying the Norwegian flag. In fact the owner was from Iceland and had sailed to Shetland via the Faroes, on his way to Bergen and points south in Norway to overwinter.

We also walked up to Balta Light, the most northerly pub in the UK. In these Covid times, we decided not to stay inside and drank our pints in the surprisingly cold beer garden.

DCIM/100MEDIA/DJI_3937.JPG

Baltasound has several other notable landmarks, including the John Peel memorial bus stop (currently sporting a “2020 vision” theme in “honour” of a certain Mr Cummings) and also a memorial to the crew of the WW1 submarine E-49, the site of our dive the next day.

Links:

trips

Shetlands – day 1

NOTE: I wrote these blog posts at the time of the dive trip, but was not able to post them at the time, so there’s roughly a week’s delay between the date of posting and the day they were written.

The Shetland Islands is a place I have long wanted to visit and I was lucky enough to be invited by my buddy Rob Bailey to join him on a week-long charter aboard the new liveaboard MV Clasina skippered by Bob Anderson.

We arrived in the attractive town of Lerwick first thing this morning off the overnight ferry from Aberdeen, and transferred a small mountain of gear onto Clasina. Rob and I had met our fellow divers on the ferry and, predictably we all got on well – an experienced group from East Cheshire BSAC.

Our shakedown dive was a corker, on a trawler called Fraoch Ban (gaelic for White Heather), a trawler whose internal bulkhead had failed, causing its catch of sandeels to shift, which capsized and sank the boat.

The first thing that struck me was the amount of light. Like many of the best Shetland wreck sites, the Fraoch Ban lies upright on sand, which reflects a lot of light. The visibility was about 15m, which meant we could see from one end of the wreck to the other. A large winch and gantry sit on deck and a large shoal of fish swirls around the site. I spotted a new (to me) species of spider crab and others saw octopus and angler fish.

The second dive was close by at Noss Head, a cliff dropping into the sea with a series of deep gullies. This exposed site has wonderful purple rock formations and many anemones – dahlia, Devonshire cup corals and even patches of jewel anemones.

The surge reduced the visibility but the gullies made for an interesting swim and I was buzzed by a couple of seals – the female coyly checked me out from just beyond camera range and my buddy told that a large male was watching me from behind; as is often the way, I was not even aware he was there.

Link: Shetland trip day 2

dives, trips

Shetlands – day 4

My buddy Rob inspecting the conning tower of E-49

As we pass the halfway point of the trip, this day was a real highlight – a site so good, we dived it twice. This wreck was the E-49, a British WW1 submarine which hit a German mine in March 1917 and tragically was lost with all hands at the mouth of Baltasound. The life of a submariner must have been terrifying and heaven knows what those men experienced when the mine exploded. It is always sobering to visit such war graves and though some feel that these sites should not be dived, I think that these wrecks are a memorial to the bravery of our forebears. What struck me was how small the submarine is; this 55m tube must have been an incredibly cramped place for the 30 crew to live.

She lies upright in 32m on coarse sand, which provides stunning light and visibility. The bow section is blown off and lies a few metres away from the main wreck, which lies mostly buried in the sand. The conning tower is broken off and lies to the port side. The stainless steel periscope is clear to be seen and many other details of the gears which operated the ballast tanks, winches and hydroplanes are visible. The wreck tapers off into the sand, with the propellor just visible.

The bow section, which was blown off by the mine which sank the submarine
Much. of the. external plating has corroded away, revealing the pressure hull
The conning tower has broken off and lies on the sand
looking down the. conning tower
Wonderful to see the. whole wreck spread before us
Reluctantly ascending from the E-49

Having finished our pair of dives, we returned to Baltasound and got a taxi to see the amazing colonies of Skua, Gannet and Fulmar at Herma Ness and which also gave us a marvellous view of the light house at Muckle Flugga. This marks the northernmost reach of both Shetland and the UK. It was amazing to think that the was only the Arctic to the north and the whole of the Atlantic to our west.

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