Andy Perrin Posted August 6, 2022 Share Posted August 6, 2022 I did a short video of clouds using the EL-Nikkor 105mm lens with a DB850 and Tiffen#12 stack. Hue rotated 45 degrees to make the sky blue, and contrast adjusted. Speed has been increased by a factor 10x relative to normal life. Link to comment
dabateman Posted August 7, 2022 Share Posted August 7, 2022 I think that demon cloud is about to consume you Andy. You better watch out. Would be interested to see it in SWIR or with a 980nm filter. I wonder if the darkness of water would be uniform through the cloud. Link to comment
Nate Posted August 7, 2022 Share Posted August 7, 2022 Nice, I once tried a time lapse of clouds, but didn't turn out this good. Link to comment
Andy Perrin Posted August 7, 2022 Author Share Posted August 7, 2022 4 hours ago, dabateman said: I think that demon cloud is about to consume you Andy. You better watch out. Would be interested to see it in SWIR or with a 980nm filter. I wonder if the darkness of water would be uniform through the cloud. I’m not even sure clouds would look very dark in SWIR. The droplets scatter light really well and they are very small. Even at the darkest peak at 1450nm, for very small droplets the absorption would be negligible while the scattering is high. So they should probably be at least light gray. I can check I guess Link to comment
Doug A Posted August 7, 2022 Share Posted August 7, 2022 What a neat video! Excellent idea and execution. I never think to try video. Thanks for sharing, Doug A. Link to comment
Stefano Posted August 7, 2022 Share Posted August 7, 2022 5 hours ago, Andy Perrin said: I’m not even sure clouds would look very dark in SWIR. The droplets scatter light really well and they are very small. Even at the darkest peak at 1450nm, for very small droplets the absorption would be negligible while the scattering is high. So they should probably be at least light gray. I can check I guess Rain might look dark in the distance, you could try that. Link to comment
lukaszgryglicki Posted August 7, 2022 Share Posted August 7, 2022 For me it looks like an explosion of smoke in slow-motion - great video! Link to comment
Andy Perrin Posted August 7, 2022 Author Share Posted August 7, 2022 3 hours ago, lukaszgryglicki said: For me it looks like an explosion of smoke in slow-motion - great video! This actually isn’t far off, physically, from what’s happening here. A parcel of warm air in the middle of the cloud is shooting upwards very fast due to buoyancy, causing the outer layers of the cloud to roll turbulently. The parcel in the center will continue to rise until the temperature of the parcels cools to match the temperature of the local atmosphere. This is also what happens in an explosion, where the explosives suddenly heat an air parcel and then the same process plays out. Link to comment
Andrea B. Posted August 8, 2022 Share Posted August 8, 2022 Woo!! Love that vid!! Thunder will soon be booming. Link to comment
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