I am unable to find out how to watch movies in full screen when watching through my PS3
I assume you mean, you have got the black bars on the top and bottom of your screen when watching certain movies ?
If this is the case, this is how the movie has been shot by the movie studio.
However, on some TV's you can expand the screen out to stretch the picture.
On my TV remote, there is an "Aspect button" feature with an option to zoom the picture out (makes the picture fill the screen), but i don't use it, due to that it makes the picture look unnatural to me.
By the look of it, you haven't had the OP reply, but I have had exactly the issue detailed: When I stream programmes on my PS3 they display with 'letterboxing' at the top and bottom and the image is vertically 'squashed'. (If it was displaying without the letterboxing it would be correctly proportioned). It is not letterboxed when I am using the menus of the PS3 Now TV app - the letterboxing only appears when streaming programmes.
If you have any advice on how to change the in-programme aspect ratio, I'd be keen to hear it.
Turn Auto aspec ratio mode OFF on the HDMI input of the HDTV...
Select manual mode... then Save to that HDMI input channel preset... it then no longer keeps trying to guess aspec ratio...
Due to the many Different Brands the setting may then have a different name and then manual Zoom controll scaling setting after...
One for Height and width each...
Then one each for input resolution and the upscale needed...
With mine being a cheap fell of a back of a lorry and reject QC version it only has fixed option to select but saves them per HDMI input