So I’m working on my scifi short which has gone from ‘Invasion London’ to ‘Invasion Earth’! Once more the front room’s been transformed into a greenscreen studio and I’m doing some shots of the spaceship model.
Here’s a short test video. One of the main issues so far has been getting smooth panning shots. My initial attempt at building a platform on wheels and sticking the camera tripod on that met with limited success. It can possibly be refined but I’m now kind of stuck between seeing if I can do everything hand held and buying a glidetrack for £250!
This shot was done with the tripod supported on my shoulder. I don’t mind the hand held thing necessarily but if you want shots looking like the ships flying past you probably need something smoother……
Another issue I ran into was pulling a clean matte from the footage. My greenscreen setup’s OK but I’m always limited by the space I have available (my font room and the length of the greenscreen) and the lighting (some dodgy photography lights I got off ebay).
I’ve attempted to get round this in the past, most recently for Beast of the Air, by shooting outside so that I have natural lighting. This introduces other problems though, like trying to set up a greenscreen in gale force winds!
Anyway, in this case while I could pull a decent enough matte from the footage I was getting alot of noise in the resulting video. I guess this was due to a combination of the DSLR video and the chroma key filter (Keylight in this case). After some experimentation I came up with a way of getting round this.
Keylight allows you to output a ‘screen matte’ which is effectively a black and white representation of the areas of the image that are transparent and opaque. Normally I’d just use this to see how good my matte was, however this time I’m actually using the screen matte in a different way.
After Effects allows you to use black and white/grayscale images in a number of ways. One method is to use this as a ‘Luma Matte’ that takes the black and white values from one image and use them to define which areas of another image are transparent and which are opaque.
I was therefore able to use this screen matte:
to remove the background from this image (minus the support pole which I had to mask out manually). The result is you get all the transparency but none of the image noise.
There are probably some After Effects ninjas out there who will go ‘yeah so what, that’s obvious‘, but hey, screw you ;0)
I’ve also been working on an intro sequence that sees us flying tthrough the solar system and approaching Earth, inspired in no small part by Carl Sagan’s Contact, but in reverse.
I also wanted to include some famous space images so I’ve been working on my ‘Sagan Flare’ to recreate Carl Sagan’s famous ‘Pale Blue Dot‘ image using an optical flare as the Sun passes out of frame.
Here’s Sagan’s original Pale Blue Dot video, it’s really quite beautiful.
I’ve also got Earth Rise in there as well as taken by Apollo 8. It is a good idea to show so much from a video you’re working on? Probably not but it’s not like anyone actually reads this ;0)