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Author Topic: Snow/Ice for Master's Project  (Read 1908 times)

MountainRunner

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Snow/Ice for Master's Project
« on: April 18, 2018, 10:33:36 PM »
Hey there guys, I'm a photoscan newbie but I'll be using it for my master's project. I'll be making 3-D images of a snowfield high up on a volcano. I know that this will be a challenge but first I want to figure out if its even possible. I plan on going up I May where snow blankets almost the whole volcano. Will it be difficult for photoscan to put together an image because of the lack of features in the landscape? I'd really appreciate any advice on how to proceed.

Cheers

JMR

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Re: Snow/Ice for Master's Project
« Reply #1 on: April 19, 2018, 03:33:21 AM »
Not sure without seeing the photos of the actual case, but normally, snow exhibits more features in a photo than one expects
Try to use relatively wide aperture (f4 or f5,6 are usually the sweet spots for most lenses in terms of sharpness), and if this aperture requires shutter speed that exceeds what is possible with your camera, then use a neural density filter to reduce exposure without stopping down the f number.
if the snow does not cover the entire frame, it can help, but in this case you should pay attention to exposure and maybe use manual to avoid highlight clipping when automatic adjustment tries to expose better the rocks or vegetation.
In this example at 3000m altitude flown at 120m over the snow the ice surface came out quite well, don't you think so?
https://www.pointbox.xyz/clouds/59ceff26dec41c00108c3ed8

MountainRunner

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Re: Snow/Ice for Master's Project
« Reply #2 on: April 19, 2018, 08:42:48 PM »
Not sure without seeing the photos of the actual case, but normally, snow exhibits more features in a photo than one expects
Try to use relatively wide aperture (f4 or f5,6 are usually the sweet spots for most lenses in terms of sharpness), and if this aperture requires shutter speed that exceeds what is possible with your camera, then use a neural density filter to reduce exposure without stopping down the f number.
if the snow does not cover the entire frame, it can help, but in this case you should pay attention to exposure and maybe use manual to avoid highlight clipping when automatic adjustment tries to expose better the rocks or vegetation.
In this example at 3000m altitude flown at 120m over the snow the ice surface came out quite well, don't you think so?
https://www.pointbox.xyz/clouds/59ceff26dec41c00108c3ed8

Wow! This helps me out so much! That surface came out really well. I'm hoping to get something just like that. Unfortunately, where my project takes place is a strict no UAV zone, so I'd have to take more of the shots on foot. Do you think this will affect the resolution in any way?

SAV

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Re: Snow/Ice for Master's Project
« Reply #3 on: April 30, 2018, 10:21:42 AM »
Hi MountainRunner,

You should have a look at this:
http://fairbanksfodar.com/snow-depth-paper-published

 ;)

All the best for your Master's project.

Regards,
SAV