I think I will share some of my tricks about picture editing with you. Hope it will help somebody
So one of the things that helps a lot for blurring the background without any problems with the rider like this
is to have the rider in a different layer.
It means you need to select the whole rider and cut it out of the background. Lots of guys do it with laso or pen tool, but it is pretty time consuming.
So I discovered this way of how to do it, i know I'm not the first one who did it, but I figured it myself while playing around in photoshop :p
I use photoshop CS5, but I think those tools I use are in any version of PS possibly in gimp too.
Step1.
Lets start ingame.
You found the right position, angle, etc. and take a screen,
now skip some frame back/forward so the rider get off the screen and you have the same area without the rider.
Now take another shot
Step2.
Get to PS.
Open the pictures in photoshop, so you have them as
Now set the blending option of the layer with rider to difference,
you will see something like this.
set the foreground color to black,
and go to Select --> Color Range,
set the fuzziness to 0 and just to make sure click the background,
you will get something like this(depends on the preview you select(I use grayscale)
Now click OK and you will have selection around the rider.
It can happen that you will have some bad selected pixels on the rider (fix it with manual selection).
Delete the selection and change the blending option of the layer back to normal.
Deselect(ctrl+d).
Should looks like this (with hidden background layer).
Step3.
The problem is the selection now is pretty jaggy, but don't worry.
Select pixels of the layer(crtl+LMB on the thumbnail of the layer).
Go to Select--> Refine Edge
Now play with the setting of the Adjust Edge area.
I useually go with Smoothing around 5,
Feathers around 0.5,
rise the contrast a bit,
and lower shift edges,
it's all up to you to make it looks smooth and not loose details
as the last step in this area select the output type, I use selection, because I don't know too much about masks and it's using....
Now click OK.
Invert the selection( Ctrl+Shift+I)
and Delete again,
this should be the result, smooth looking rider without any background.
Step4.
Unhide the background layer and apply any kind of blurring to it(motion blur, lens blur, etc.).
You should get a clean rider on blurred background
I hope someone find this useful
I know it's not that precise as manual selection, but compared the time it takes, it's great result IMO, anyway if you are not happy with the result, you can manually edit the selection after Step2. (before deleting) and skip the rest
It doesn't work all the time, if you have roosts or trees in the near of the rider, they can be visible on the selection too, but you can always fix it with some small manual selection as well
If you have any question, don't be afraid to ask!
Enjoy!
