Step Down

The above short film brings together footage from our regular springtime cave diving trip to the Lot region of France.

We’ve captured video of some of the dives before (particularly of Fontaine du Truffe (here and here), which typically has great visibility, and also the Résurgence de Crégols), but usually this has been with older SD cameras, or a mixture of mis-matched sources and with little other than on-camera lighting.

This is the first trip where we’ve been in a position to shoot full HD video from big chip digital SLRs both above water and on the dives themselves, with on and off-camera lighting. It’s been a learning experience for me, but more on that later.

The Diving

Our week typically starts with a shake-down dive in the shallow section of the Émergence du Ressel to check everything survived the long trip down to south west France and to acclimatise to cave conditions again. The housing I had selected for the diving camera was Japanese and the factory had been affected by the earthquake/tsunami earlier that year. As such, worldwide stocks for this particular housing and port were very low, and after a mad scramble before the trip to get everything together (literally from the far corners of the earth), it unfortunately left me with no time to test the set-up in-water in the UK. Therefore, we also did a “short” second dive in the Ressel to play with the new camera gear. I’m not sure that Os was best pleased when we surfaced 75 “short” minutes later, but, whilst the footage from that dive was not really useable, it was time well spent and invaluable in helping us hit the ground running for the video dives later in the week.

After abandoned dives in Résurgence de Cabouy and Émergence de la Dragonnière (for the full diving report, Os’s blog has more detail), I was excited to hear that conditions in Source de Landenouse were fabulous. Whilst me and Os had been flapping around like mudskippers in Dragonnière trying to find enough water to submerge, Andy and Matt had been in Landenouse and reported that the visibility was excellent. So good, in fact, that they were keen to go back the next day.

It’s one of my favourite dives in the region, but I can’t remember when conditions in this cave were quite this good for me (perhaps not since my first trip here in 2006). As you’ll see from the video, the access to the cave is very unusual, with a huge cistern having been built right over the top of the cave entrance. At times, this does fill up, meaning entry is no more difficult than stepping into a swimming pool, however most of the time (and especially as the region had seen no rain for the previous couple of months), the water-level is nearer the bottom of the well.

Although you can see two in shot, this is only one of the “two ladders” that inspired (OK, so it’s not that inspiring…) the film’s subtitle. The old yellow ladder is no longer used, having been replaced with a much better aluminium one last year.

With two bottom stages each, we planned to just breathe these leaving the gas in the tanks on our backs in reserve. A leisurely pace (for which I was grateful, having to push a large camera with lights maybe 1.5m apart through the water) saw us turning the dive just as we caught up with Matt and Andy on their way back out (having reached the point where the cave drops down deep), and so we were able to swim out together for some of the way, including at the very impressive switchback where the cave corkscrews back on itself in a shaft rising up from -23m to -9m in depth. Somewhat of a happy accident, this really added some dimensional depth to the shots, with Os, Matt and Andy’s lights all spaced out down the shaft.

A big dive in the Ressel the next day meant no video camera (though a scooter mount will be high on the list for next time), so by the end of the week I was keen to do some more filming. Matt and Andy headed off to the Fontaine de Saint George, but conditions are rarely good there in the springtime (as they confirmed), and so me and Os went to Source de Marchepied instead.

This is a great little cave that we had dived only once before (in 2009) and thought we might not get to do again. Its entrance was originally dug out in 2004 by two CDG divers (Clive Stell and Tim Chapman) having obtained sole permission from the landowners. When we last dived it, word of this cave was only just beginning to spread around, unfortunately along with often contradictory and inaccurate information as to land-access and permissions. Shortly afterwards, the situation was clarified with information published on the French diving forums and “no diving” signs erected by the landowner. Fast forward two years and our local information this time was that the situation had now changed, and therefore we decided we would make the dive again.

Update: please note that since this film was made, the landowners have now made it clear that they do not wish to allow divers to cross their land in order to access the cave.

Missing this time was the marchepied itself (French for stepladder, I think), after which the cave (and now, somewhat nonsensically, my film) is named. However, compared to Landenouse, it’s not much of a step down to the water, and no trouble at all for us using a sidemount configuration. Other aspects of the dive were made considerably easier by using this set-up. Believe it or not, last time we made it through the two entrance restrictions with double 12 litre cylinders on our backs (though reviewing the footage now, I’m not quite sure how!). Those two squeezes lead to an awkward 20 metres of so of passage, a cross-shaped rift that catches you out with either configuration, and certainly when trying to hold a steady shot with a camera. Well worth the effort though, the cave then opens up into a charming passage with many twists and turns, beautiful scalloped walls in places and stunning visibility throughout. It’s a really beautiful cave, some of which I hope comes through in the film.

The Camera Equipment

Ninety-nine per cent of the above-water footage was shot with the Nikon D7000 using a variety of lenses but mostly the Tokina 11–16mm ƒ/2.8 and the Nikon 105mm Micro ƒ/4.0 AI. I had originally planned to house this camera as well to take advantage of its great low-noise high-sensitivity sensor, but after looking at the options and following a suggestion after speaking to Paul Duxfield at Cameras Underwater in London (now trading as Ocean Leisure Cameras), I ended up buying a different second camera for dedicated underwater use.

Never one to baulk at the idea of acquiring yet more cameras, it did actually make some sense this time (honest…). I chose a Canon 550D (or T2i, depending on your region) which, for video at least, gives comparable results to the more expensive 7D (same noise performance and full manual controls in live view mode, etc.), along with a Sigma 10mm ƒ/2.8 fisheye, a Sea & Sea RDX-550 housing and dome port, and all for pretty much the same kind of outlay as it would have cost just to house the Nikon in anything but the cheapest (and bulkiest) housing.

One advantage I had hoped this would give (and it did), was having separate (and comparable) cameras to shoot both topside and underwater. It gives you the benefit of being able to prepare the underwater camera and seal it in the housing the night before and then leave this ready to go for the dive the next day. Meanwhile on the surface you have the luxury of another camera with which to shoot topside footage pretty much right up until the start of the dive. That, and the fact I can now enjoy having a foot in both camps in the eternal Nikon vs. Canon arguments!

The 10mm fisheye is, as you would expect, very wide, and I was initially a little concerned that I’d overdone it in terms of field of view. The more popular and established choice for underwater still photographers using DX cameras would be the Tokina 10-17mm fisheye, but, given that my output would be video (and therefore I didn’t have the lighting power that strobes would bring to a still shot) and be filmed in the inky blackness of caves, I really felt I would need to squeeze out the extra light-gathering capabilities of the Sigma’s wider aperture. The Tokina’s variable maximum aperture would only give me ƒ/3.5 at the wide end (not too bad) but closing down to ƒ/4.5 at 17mm, which, with a big black cave and limited lighting, I figured wasn’t going to get me very far. Being a fisheye, the trade-off (i.e. the loss of depth of field) is really negligible, even shooting wide open at ƒ/2.8.

In the end, I’m very pleased with the Sigma. Both the build quality and IQ is excellent and, if you keep divers out of the edges of the frame, the optical distortion isn’t much of a problem underwater. For caves like Marchepied, it’s probably the only lens that would have worked as well. The shot you see of Os coming through the entrance restriction is filmed from an area that is barely big enough for two divers to occupy at the same time and yet Os passes inches from the lens whilst remaining fully in view.

Most of the underwater footage was shot at 640 ISO, which I found worked well with the lights I had (though I may experiment further). It was also captured using the Cinestyle picture style profile from Technicolor. This puts the camera into a logarithmic colour space which effectively flattens out the contrast allowing you to capture more highlight and shadow detail (and believe me, there’s lots of shadows in caves!). The idea is then that you can add back the contrast in post but have much more latitude to manipulate the image when grading the footage.

I also loaded the camera with the Magic Lantern firmware upgrade. It’s not supported by Canon and its author does warn that it could “brick” your camera (yikes!), but virtually all users have reported no issues: an experience I too shared. What it does give you though is an enormous amount of fine control to the basic camera together with such “pro” video camera features like bit rate control, zebras and real-time waveform monitors, etc. Two of the features which proved very useful for underwater video were the extra controls over both ISO and white balance.

The ISO benefits were both in terms of granularity and menu control. Out of the box, the standard 550D will only allow you to set sensitivity in whole stops from 100 ISO which is often not precise enough for what is now the gain control when using this as a video camera. This limitation also doesn’t allow you to take advantage of the “native” ISOs on Canon DSLRs which have a natural base ISO of 160 rather than 100 and should give cleaner results when set to increments of that number. Also, the one button that the Sea & Sea housing does not have is one to control ISO, which would be disastrous when trying to manually shoot any kind of serious video. Without the Magic Lantern interface, there is no way to set ISO on the 550D from the menu controls (and therefore, when in the housing, no way to set ISO at all). However, the firmware upgrade gives you a couple of different ways to set this without touching the dedicated ISO button.

The other feature that is missing on this entry-level camera is the ability to set manual white balance “by the numbers”, i.e. to dial-in the desired colour temperature in Kelvin. I used to shy away from this concept when shooting stills, but it’s really quite simple once you get an idea of where certain types of lighting lie in terms of warmth on the scale. Also, for videoing in caves, where there’s no ambient light, there’s no need to keep rebalancing as you change depth, so finding (or knowing) the colour temperature of your lights makes setting white balance very precise and very simple (though see below on using a mixture of lights).

The Magic Lantern firmware also allows you to select 1/48 as a shutter speed, which equates to exactly a 180 degree shutter angle when shooting at 24 fps. I’m not sure that this makes any appreciable difference over filming at 1/45 or 1/50 on the unmodified camera, but it gives me a warm fuzzy feeling inside from knowing that it’s bang on the money!

The lighting we used was a combination of on and off-camera HIDs and LEDs. Mounted to the camera on Ultralight arms, I had borrowed Os’s twin Halcyon 18W HIDs with video reflectors (dimpled parabolic reflectors made by Lumedyne). These worked well, although one of the camera tray’s handles kept working loose (it required a very odd-sized allen key that no-one had brought with them and even André’s well-appointed tool shed didn’t have) meaning I had to manually hold one of the arms in place to stop the light swinging into frame. Off-camera, Os had his regular light (though only really as a ‘practical’ light source to make him look like a normal diver, rather than contributing much to the overall exposure) together with a Mangrove 4,000 lumen LED light from Aditech. I’m reasonably happy with the Mangrove light, and think that LED is certainly the future, but in-water it just doesn’t seem to have the punch or reach of metal halide equivalents for the amount of light it promises. There really is no substitute at the moment, it seems, for an HMI or other large metal halide light for quality underwater video, so I think I need to start saving!

One issue I discovered on the check-out dive in Ressel was that the LEDs were really quite differently balanced to the HIDs in terms of colour temperature. In theory, I thought that a “cool” LED would be quite well matched to the output of the HIDs. In practice though, the Aditechs are around 5,000 K which is noticeably different (at least as viewed by the camera) to the 6,500 K or so that the Halycons (both on-camera and our model’s handheld ‘practical’) kick out. Fortunately, I had a set of flash gels with me and, although not perfect, a half-cut of CTB gaffer-taped across the front of the Aditech balanced the two quite well.

One or two additional shots were made with a Contour HD camera mounted atop a five metre painter’s pole. I had hoped to make more extensive use of this for establishing shots, etc. but hopefully I’ll get to use it again for future projects. The Contour was originally bought with an underwater housing as a scooter cam, and whilst we did try this briefly in Cabouy, the results were disappointing as it needs a lot of light and the visibility wasn’t the best on that occasion.

Editing the final film

I didn’t really have any kind of plan for the week’s filming. The diving footage kind of takes care of itself and topside I just grabbed what random footage I could. It’s rather difficult when you’re not a dedicated videographer: everything you see the guys do on film in terms of prepping gear or getting ready, I have to do too, but then find enough time to film the others and not hold everyone up too much before going and doing the dive. As a result, after getting back home and downloading the footage, I open up the editor and only then decide what kind of film I want to make. It’s a very backwards way of doing things and I’m going to try and do it the right way around in future (i.e. have some ideas first and then go and out shoot the footage to cover them).

In a rare moment of foresight, I did find the time to interview Andy during the week. He took some persuading (the red wine with the evening meal may have helped), but I did a quick set up on the porch of the cabin we were staying in. The original idea was to have the sun setting in the background with Andy lit by one of my battery-powered LED panels as a key light and a small (but powerful) SSC-P7 flashlight providing a rim light. The lighting worked OK-ish (well, you can see his face anyway), but not the sunset. It was just about visible when we did the first take, but the stupid sound guy (OK, so that would be me…) forgot to turn on the microphone, so by the time we repeated some of the questions, it was dark. In the end, I only used one segment, but hopefully it adds some interest to the set-up sequence.

I had hoped to grab some other short interviews during the week, including one of Martyn Farr who we kept bumping into, but in the end I ran out of time. So, back home, the only other person I could “interview” was me. Reluctant as I was to do this, I think the film would have been strange with just the one short interview segment of Andy, and I was determined to try and keep that in to add some variety.

The opening was an attempt to do something with the series of shots I got on the road on the first evening. There’s some nice stuff in there (the shot of driving through the goods wagon on the Eurotunnel at blue hour is a particular favourite) which I wanted to keep in but didn’t feel like it warranted being the main event. That’s when I had the idea for a title sequence flipping between shots on a poster. The “poster” was inspired by a movie poster for Point Blank that I saw advertised on the London Underground. I’ve no idea what the film’s about, but I thought the layout would work well for what I had in mind. What sounded like quite a simple idea in my head turned into a bit of a nightmare trying to achieve in editing, but I’m quite pleased with the final sequence.

For the diving sequences, these really are just the typical footage set to music pieces that are the mainstay of amateur diving videos on the internet. That accepted, I wanted to do it well to try and do justice to the underwater footage which (compared to anything I’d ever shot before, I was quite excited about). The music was therefore chosen first. I’d found the piece Moon Glide quite early on in the process and new it would be perfect for a serene edit conveying beauty. That’s pretty much what the dive in Marchepied was like, so I didn’t have any worries about that. The great thing about Audio Network plc is that, because it’s all composed as production music, most of the tracks are recorded with multiple versions, some of different lengths and some with different instrumentations. I was therefore able to use a piano only version as a pad behind the interview before fading into the full version with the cello for the diving sequence.

My choices for the Landenouse sequence I wasn’t quite sure about. I liked both of the tracks, but wasn’t sure they worked for the mood of the dive. The tracks Journeying and Orion are respectively haunting and epic, and a cave dive (assuming everything goes to plan) should be (and was) neither of those things. In the end, I went with my first instinct to use them and figured that the idea of cave diving probably was either a little scary or exciting to some people who hopefully might watch the film. I probably over-reached my editing ability towards the climax of Orion when I ran out of usable footage to intercut with the main sequence. The increased pace suggests faster cutting and although the continuous shot whilst barrel-rolling down the shaft at the switchback was quite exciting at the time, it doesn’t really match the charging pace of the final bars. No matter, I think the end result turned out quite well.

I hope you enjoy the film. Any constructive feedback is always welcome (though be gentle…).

Update: Bonus Content

Here is an 11 minute edit of Step Down that was shown along with other videos after dinner at the 2011 Global Diving Conference in Kiel organised by GUE.

Advertisements