Wind shear

15 June 2009 Stormy sky time lapse

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• published: 19 Jun 2009
• views: 6384

June 15th 2009 was quite an extraordinary day across the UK. Thunderstorms were forecast across almost the entire country, something you do not see too often! I recall watching the BBC forecast, the previous night and my favourite forecaster, the extrovert Rob McCelwee, started off by stating "tomorrow will be a good day for storm chasers!!". Wow, I thought, never heard that term mentioned on UK tv before. I was excited. I made a concsious decision not to go chasing storms on the Monday for the simple reason they were too widespread. Experience has shown me that some days it is more productive to sit tight and let evrything come to you. As it happens this was a wise decision. My next wise decision was to perform a form of phtography I don't use that often, but when I do, and the subject is right, it can be nothing short of breathtaking. This being time lapse photography. Not via a video but dslr camera. Using a still camera for capturing time lapse offers many practical and quality advantages over its video counterparts. Skies in motion are one of the best mediums for showcasing time lapse work. Mondays fast moving storms would provide just that. I invested in an external time lapse controller unit (PClix) a few years ago and it is one of the most useful bits of kit I have. A tiny unit (not much bigger than a matchbox) which automatically fires the camera for any period or frequency of time. Quite a powerful piece of kit and at £99 it won't break the bank. The Olympus E3 does not have a built in intervalometer but its waterproof capacity allows me to leave it out all day in all weather. I set up my Olympus E3 camera primed with a wide angle lens (7-14mm), together the time lapse unit and mounted the tripod in a field at the bottom of my garden. The settings are pretty straight forward. I downgraded the in-camera image resolution to small/normal, which yields a 1280x960 image of around a couple of hundred Kb. Huge resolution/quality images are pointless since utlimately a 640x480 resoultion video file will be produced. Use a mid range aperture (F5.6) and in 'A' mode (the camera would then automatically choose the shutter speed for the changing light levels throughout capture) and manually lock the focus. Using the power battery holder (HLD-4) on the E3 gives me nearly 10 hours of continuous shooting....and that's exactly what I did. The camera was positioned in the morning and stayed there until sunset, some 10 hrs later. The time lapse unit was set to capture (via a cable which runs from the PClix unit to the E3's RC port) a single image every 8 sceonds. I have learned to guage the interval time with observations of cloud movements through experience and 8s would be just perfect for this day as clouds would be moving along at 'jogging' speed. A broad rule I have adapted when deciding interval times based upon cloud movement speed is as follows: Walking - 8+ secs Jogging - 4-8 secs running - 2-4 secs The camera was setup and started clicking away approximately 1100hrs. I was at home all day working on various things and closely monitored the weather radar as convective showers piled in, one after another. It was fascinating to watch too since, coincidently, the surface pressure charts had my location smack bang in the centre of the low pressure system and which almost became stationary all afternoon. This meant surface winds (and cloud movements) were veering constantly all around me, creating crazy looking cloud structures, almost swaying to and fro, as the air masses above me were wrapping around and circulating the low pressure core. I knew this would look fantastic on the time lapse and I could not wait to play it back. This was, alas, a long way off yet, however I did keep walking back to the camera to check battery status in an almost paranoid fashion. Hour after hour passed and with it came the most torrential convective showers. Water was running down my drive creating huge lake type puddles, such was its intensity. Another good test for the camera I mused. Ten hours later and after waiting for the sunset shadow to relieve the camera of its torture, I wandered back outside, retrieved all my equipment and got staright to work. Now it was play time and here is my post capture workflow: Download over 4000 images from camera to PC. Batch resize/rename to 640x480 resolution. Import, via image sequence, batched images into QT Pro at 60 frames per second (This can be reduced depending on number of hours/frames captured). 4000 images have now been converted into a single minute of movie file. Add music. Save raw original finished movie file. Export to Mobile Me and share (creates compressed m4v file) via a nice sexy interface! After all that post processing I sat down and watched the fruits of my days labour. As it played, I screamed out an initial burst of 'Wow', which rudely awoke the dog who subsequently fell off her bed! It must have been good, and boy it was. The 10 hours of footage conver

15 June 2009 Stormy sky time lapse

• Report rights infringement
• published: 19 Jun 2009
• views: 6384

June 15th 2009 was quite an extraordinary day across the UK. Thunderstorms were forecast across almost the entire country, something you do not see too often! I recall watching the BBC forecast, the previous night and my favourite forecaster, the extrovert Rob McCelwee, started off by stating "tomorrow will be a good day for storm chasers!!". Wow, I thought, never heard that term mentioned on UK tv before. I was excited. I made a concsious decision not to go chasing storms on the Monday for the simple reason they were too widespread. Experience has shown me that some days it is more productive to sit tight and let evrything come to you. As it happens this was a wise decision. My next wise decision was to perform a form of phtography I don't use that often, but when I do, and the subject is right, it can be nothing short of breathtaking. This being time lapse photography. Not via a video but dslr camera. Using a still camera for capturing time lapse offers many practical and quality advantages over its video counterparts. Skies in motion are one of the best mediums for showcasing time lapse work. Mondays fast moving storms would provide just that. I invested in an external time lapse controller unit (PClix) a few years ago and it is one of the most useful bits of kit I have. A tiny unit (not much bigger than a matchbox) which automatically fires the camera for any period or frequency of time. Quite a powerful piece of kit and at £99 it won't break the bank. The Olympus E3 does not have a built in intervalometer but its waterproof capacity allows me to leave it out all day in all weather. I set up my Olympus E3 camera primed with a wide angle lens (7-14mm), together the time lapse unit and mounted the tripod in a field at the bottom of my garden. The settings are pretty straight forward. I downgraded the in-camera image resolution to small/normal, which yields a 1280x960 image of around a couple of hundred Kb. Huge resolution/quality images are pointless since utlimately a 640x480 resoultion video file will be produced. Use a mid range aperture (F5.6) and in 'A' mode (the camera would then automatically choose the shutter speed for the changing light levels throughout capture) and manually lock the focus. Using the power battery holder (HLD-4) on the E3 gives me nearly 10 hours of continuous shooting....and that's exactly what I did. The camera was positioned in the morning and stayed there until sunset, some 10 hrs later. The time lapse unit was set to capture (via a cable which runs from the PClix unit to the E3's RC port) a single image every 8 sceonds. I have learned to guage the interval time with observations of cloud movements through experience and 8s would be just perfect for this day as clouds would be moving along at 'jogging' speed. A broad rule I have adapted when deciding interval times based upon cloud movement speed is as follows: Walking - 8+ secs Jogging - 4-8 secs running - 2-4 secs The camera was setup and started clicking away approximately 1100hrs. I was at home all day working on various things and closely monitored the weather radar as convective showers piled in, one after another. It was fascinating to watch too since, coincidently, the surface pressure charts had my location smack bang in the centre of the low pressure system and which almost became stationary all afternoon. This meant surface winds (and cloud movements) were veering constantly all around me, creating crazy looking cloud structures, almost swaying to and fro, as the air masses above me were wrapping around and circulating the low pressure core. I knew this would look fantastic on the time lapse and I could not wait to play it back. This was, alas, a long way off yet, however I did keep walking back to the camera to check battery status in an almost paranoid fashion. Hour after hour passed and with it came the most torrential convective showers. Water was running down my drive creating huge lake type puddles, such was its intensity. Another good test for the camera I mused. Ten hours later and after waiting for the sunset shadow to relieve the camera of its torture, I wandered back outside, retrieved all my equipment and got staright to work. Now it was play time and here is my post capture workflow: Download over 4000 images from camera to PC. Batch resize/rename to 640x480 resolution. Import, via image sequence, batched images into QT Pro at 60 frames per second (This can be reduced depending on number of hours/frames captured). 4000 images have now been converted into a single minute of movie file. Add music. Save raw original finished movie file. Export to Mobile Me and share (creates compressed m4v file) via a nice sexy interface! After all that post processing I sat down and watched the fruits of my days labour. As it played, I screamed out an initial burst of 'Wow', which rudely awoke the dog who subsequently fell off her bed! It must have been good, and boy it was. The 10 hours of footage conver