TF2 finished filming, and expected length.

[griffin]

From here:
http://www.tfw2005.com/transformers-...-movie-166276/

"one new bit of info I can tell you is that the movie will be a longer than the first one (probably)"

Additionally, Roberto explained that the footage shown at the recent wrap party was not a trailer but rather select footage only, and did not show any footage of the robots. He does confirm though that to the best of his knowledge, all of the designs for the 'bots are pretty much finished.

The first movie was 2 hours 20 minutes, so if the second is at least that length, it's no wonder the filming has taken so long to do.
That leaves about 6 months for post-production. Seems a bit tight, considering the amount of robot action we should expect in this second movie.

[G1Optimal]

From here:
The first movie was 2 hours 20 minutes, so if the second is at least that length, it's no wonder the filming has taken so long to do.
That leaves about 6 months for post-production. Seems a bit tight, considering the amount of robot action we should expect in this second movie.

Maybe the CGI Animators ( or whatever they are called ) have bit more experience this time around, unlike the first movie?

and/or

They have been working on the scenes, that have already been filmed?

[MV75]

They have access to faster hardware.

A run of the mill ati 48xx card has currently ~1Tflop of processing power that can be used for physics calculations, rendering, etc. Far dwarving even an array of quad/octo core computers, and they can have up to 8 of these in a typical computer.

[SofaMan]

Also, this time they're not modelling all of the robots from scratch. They'd be able to reuse most of the models from the last film.