Alister Chapman, Cinematographer, DIT, and Educator – Personal Website

Supercell 4K. Severe storms and tornadoes, shot in 4K.

So here it is… a short compilation of clips shot across 10 days in the US this May. To get these shots I drove over 3,500 miles criss crossing the states of Oklahoma, Texas, Nebraska, Kansas, Colorado and South Dakota. It was a trip that started and ended with some tragic events and left me quite unsure of my own emotions and thoughts with regard to storm chasing, something that has been a very big part of my career, business and life for nearly 15 years.

 

The aim of the trip was to start building up a library of 4K stock footage to supplement the extensive (200+ hours) of high quality HD storm and natural extremes footage that I already hold and sell worldwide, almost all of which was shot using Sony XDCAM camcorders of one type or another. To help share the costs I opened up the trip as a week long workshop and I was to be joined by Les from Scotland and Michael from Australia. A few days before my scheduled departure from the UK to Oklahoma I was looking at the long range weather forecasting models (a vital part of storm chasing) when I noticed that a highly dangerous weather pattern look set to hit Oklahoma the following day. A quick call to the airline and some frantic bag packing saw me heading out in a rush on the first available flight to Oklahoma City on May 19th.

My shooting kit included my PMW-F5 with R5 raw recorder, a selection of DSLR lenses (Canon mount), a Miller Solo tripod, media, batteries, chargers, and a whole bunch of storm chasing electronics and computers. When your packing in a hurry like this a check list can be a life saver. Forgetting something as simple as a cable when you won’t have time to find a replacement can ruin a shoot. 24 hours later, me and my 75Kg of gear were in Oklahoma City.

Rainbow under a severe thunderstorm.

The morning of May 20th was like many spring mornings in Oklahoma. Warm, humid and a little overcast. The local TV stations were all warning of the possibility of severe storms, but this isn’t uncommon in tornado alley in the spring. I spent a couple of hours fitting all my storm chasing gadgets to the car and analysing weather data, trying to figure out where the best chances of seeing a storm or tornado would be. I didn’t need to go far. By lunchtime I was near Lawton in Oklahoma and soon after the first storms of the day started to get going. I followed a storm south of Oklahoma City that produced a brief tornado. I couldn’t find a safe place to stop and shoot it so I didn’t get any footage, frustrating! Meanwhile on the mobile weather radar in the car I could see another very strong storm approaching Oklahoma City. At 2.56pm this storm produced a large, violent tornado that struck the Oklahoma suburb of Moore. Listening to this unfold just a few miles away on local radio stations and watching it on my mobile radar was quite shocking. The storm had developed very quickly, very early in the day (storms don’t typically get going until early evening) and it was obvious it was going to be a killer. I didn’t chase it, it was in a busy city and congested roads and panicking people would make it a dangerous place to be.

That evening in my hotel the full story of the Moore tornado (http://en.wikipedia.org/wiki/2013_Moore_tornado) was on every TV channel, sadly 23 people were killed, over 12,000 homes were destroyed, 30,000 people displaced.  While I love seeing the power and beauty of mother nature, it deeply saddens me when things like this happens, but happen they will whether I am there or not. Little did I know that terrible things would come even closer to home later in the week.

The next day and more storms were forecast, this time in Texas, so on with the storm chasing. I was shooting with my PMW-F5 with the R5 raw recorder docked on the back. The more I use this camera the more I like it. One of the big issues with storm chasing is the speed at which things change. So I needed an all round lens that could shoot wide panoramas one moment but then also get in tight for action shots. In addition I needed to be light and very portable. This meant using a DSLR super zoom. I was going to use a Sigma 18-250 but that went faulty just before I was due to leave home, so I used a Tamron 18-270mm lens (the Tamron focusses back to front which is why I prefer the Sigma). This is an image stabilised lens, very useful when shooting in high winds! To get the stabilisation to work you have to use a powered mount with electronic control. This means a Canon mount as no one makes an active Nikon mount. I used one of my prototype servo zoom handgrips with Canon iris and remote focus control. Other mount options would include the MTF Effect or Optitek Canon mount. I shot at 23.976p in 4K raw and XDCAM HD, this would give me a little over an hour of 4K on a single AXS card. Why XDCAM and not XAVC for the secondary (proxy) recordings? Well simply because I can edit the XDCAM material with any application, XAVC isn’t at the time of writing supported in Premiere and that’s what I currently edit with (it’s coming in Premiere CC due very, very soon). In addition a 32GB SxS card holds 60 mins of footage just like the 512GB AXS card and 24p raw, so I have the same clips on pairs of cards rather than all over the place.

The 3rd day was when I was joined by Les and Michael, it was also a chase day so an early start as we headed out to the Texas Pan Handle. The storms that formed that afternoon produced some very strong winds, hail the size of baseballs and dust. Tons and tons of dust from the parched Texas farmland was getting sucked into the storms and then blown back out again creating zero visibility sand storms. By the end of the day everything was covered in sandy, gritty dust. The cameras, the car and us. The F5 being solid state just carried on working despite the dust, but did require a good clean with a soft brush at the end of the day. If you have a dust covered camera don’t use canned air or compressed air to blow the dust off. The compressed air can blast dust in to the cameras interior  and do a lot more damage than good. A soft paint brush will quickly remove dust from the cameras exterior. If you have dust on the optical port a gentle puff with a hand held puffer  can be used to blow the dust off before you wipe it with a clean high quality lens cloth. Also keep your lens cloth in a sealed bag like a ziplock bag. Cleaning a lens or other optics with a dusty or gritty  lens cloth is not a clever thing to do.

Storm Chasing in the USA with the PMW-F5

As the week progressed we were to see some incredible storms. One one night we witnessed one of the most impressive lightning shows that I have ever seen. A spinning Supercell thunderstorm was throwing out bolts of lightning every few seconds and we had a grandstand view. While the Sony F55 uses Frame Image Scanning to eliminate rolling shutter artefacts the F5 like most CMOS cameras does not, so it suffers from a degree of rolling shutter. A trick I learnt some time ago when shooting lightning, strobe lighting or flash photography with a CMOS camera is to use the slowest shutter speed possible. So this means turning the shutter off and using straight 23.976p for lightning during the day. At night I use a 2 frame slow shutter. Shoot like this and 90-95% of the lightning I shoot is not affected by rolling shutter effects. Sadly my budget wouldn’t stretch to the F55, I could only afford the F5. For my lightning shoot in Arizona later in the year I’ll probably hire an F55.

As the end of my planned  storm chasing shoot drew near, while I had shot some amazing storm footage I had not yet captured a big tornado in 4K. With a lot of money invested in the shoot I was starting to feel a little disappointed. But the weather gods decided to play ball. My morning weather forecast had suggested Salina in Kansas as a good place to target for the day, so off to Salina we went. As we approached the town the first storms of the day started to fire. After briefly chasing one short lived storm we were soon parked up right in front of a second, almost stationary Supercell thunderstorm. You didn’t need to be a weather expert to see that this storm meant business. The clouds above us were swirling and turning. Just a short distance ahead a wall cloud had formed, this angry, looking low cloud was spinning rapidly and soon a small tornado formed. Trying to accurately expose when your in a hurry, fighting strong winds and have only moments to get the shot can be difficult at the best of times. I was shooting raw, so I was able to take advantage of the F5’s built in look-up tables and Cine EI gain. By dropping the EI gain to 800 EI (use 640 EI on the F55) and with just the smallest hint of zebra 2 (100%) starting to show on my brightest highlights I know that my exposure is good and bright but not quite clipping. This gives me nice low noise levels after grading and is an easy way to shoot.

Quick frame grab from the F5.

The tornado didn’t last long, but then just a few minutes later a second tornado formed. This was a big one, a powerful one. In the viewfinder I could see it getting bigger and bigger, yet it wasn’t moving left or right. This isn’t normally a good sign, normally you only have a few moments to get a quick shot of the tornado before it’s time to run away, but this tornado barely moved at all, it was just simply getting bigger and bigger. It’s slow movement  allowed me to get some great shots, some wide, some close up. Now I was happy! Following storm chaser tradition we celebrated that night with a steak diner.

Me shooting the tornado with the PMW-F5 and AXS-R5

At the end of each day I made a backup of my footage. Using a the Sony ACS-CR1 card reader, a retina MacBook Pro and a 3.5″ 2TB desktop hard drive I had space to backup up the equivalent of 4 full AXS cards, a little over 4 hours of material. A full card taking about 30 minutes to transfer. Once the cards were transferred to the 3.5″ drive a secondary copy was made to a 2.5″ drive overnight. The 2.5″ drives are much slower, but it’s easier to hand carry them on flights. The SxS cards were backed up to a NextoDI, NVS-Air. These are great stand-alone devices for backing up SxS cards. You simply pop the card into the slot in the NVS-Air’s side and select the backup mode you want, fast or secure and off it goes, backing up your card. A 32GB SxS card can take as little as 6 minutes to backup. It’s simple, it’s fast and you can even plug in a second drive to make two simultaneous copies.

Even though the weather pattern for the next few days was great for storms I had to break off the chase to go to Los Angeles for the Cinegear trade show. As I left Oklahoma City early on the 31st of May I was aware that there was a significant risk of tornadoes in Oklahoma that day. Oh well I thought, I’ve done well, got some great footage, time to move on.

Friday the 31st of May is a day that storm chasers around the world will remember for a long time. A Supercell storm near the town of El-Reno in Oklahoma exploded in size and ferocity. It produced the largest tornado ever recorded, 2.6 miles wide, a tornado that was erratic and violent, rated at EF5, the strongest tornado strength rating. The storm caught many chasers out, many literally driving for their lives creating storm chaser traffic jams on narrow roads as they tried to escape the rapidly expanding storm. Some didn’t make it. Several cars were swept up by the tornado.  Tragically 4 storm chasers were killed by the storm. 3 of them I knew, one was a friend. The 3 chasers I knew were researchers measuring the wind speeds around tornadoes in an attempt to better understand them. They were some of the most experienced storm chasers out there. I think every storm chaser knew that one day a chaser would get killed by a storm, but no one expected it to be theses guys, highly experienced, professional, researchers. Not hung-ho adrenalin junkies just there for the thrill of getting as close as possible. I have to admit that this was a bit of a wake up call. I’m not a big risk taker and I do like to keep a a little distance from the storms, I’ve always had the greatest of respect for their power, in the future I’ll be avoiding chasing in areas where large numbers of chasers can lead to traffic jams and blocked roads, most notably around Oklahoma City in May.

Once back at home it was time to review the footage shot and to put together a short demo clip. Using my off-the-shelf 15″ Retina MacBook pro I cut together a short sequence using Premiere Pro with Sony’s raw plugin. I edited directly off the single 3.5″ hard drive, no raid or anything else. Once I was happy with the edit I exported an AAF file from Premiere which I then took in to DaVinci Resolve. I used Resolve to grade and finish the footage rendering it out overnight. It did take about 3 hours to render the finished 4K project, but I used a little noise reduction on many of the clips and this takes a lot of processing. Lets face it a laptop isn’t the best way to work with 4K material, but it can be done. I’m currently putting together a workstation specifically for Resolve that will have dual graphics cards to really boost the render performance. I have to say that I am delighted with the quality of the material. The detail in the corn fields is incredible, the lightning bolts are detailed and crisp. There are no clipped highlights in any shot. Now all I need to do is to go back through the entire 4 hours of footage that I have, clip it down into stock footage sized chunks and write all the keywords and metadata for the stock footage libraries and my clients.

PS: On my last day in LA I had an interesting discussion with a production company about a 4K, 3D storm shoot. Maybe I’ll be back chasing storms in July with a pair of F5’s!

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