This is the first week of VFX with Jon, in this week we learnt about the implications of 2D tracking, which situations are the best to use it and how to use it in Adobe After Effects. The premise of 2D tracking is to use tracking points using the X and Y co-ordinates in order to create visual effects within the video. The tracking point on After Effects follow a small cluster of pixels from one frame to the next. So for instance if you have a tracking point of an orange sticker on the end of a finger, it would track the cluster of orange pixels that you would have set when using the track motion option in the tracking window of After Effects. This process takes a little while due to the amount of work that is going on. Although we mainly used contrast Jon did tell us that you can track using luminance in order to find a key cluster of pixels to fix upon.
I found out from Jon that it is best to shoot with a high shutter speed to reduce motion blur, this is because the tracking markers find it hard to track on to certain specific pixels when the whole shot is blurry from motion. Jon also told us that you should always shoot with your VFX in mind, so if you have a high contrast between the foreground and the background and you want to do a sky replacement then you should get the foreground correctly focussed and then leave the sky over exposed so that it will be easier to key out in post production.
I understood the overall idea of 2D motion tracking and what it can and cannot do in terms of adding elements to a shot. For example there are many ways that could hinder an editors tracking of a shot like objects moving in front of the tracking point or the tracking point moving off the screen, if there is too much motion blur and also if the shot uses depth on the Z axis, adding a third dimension which 2D tracking will not work for.