Old Movies released on Blu-ray

[i2lens]

Am I missing something here? If a movie that was filmed before the day of HD is put on BD, how is it HD? The original format for whatever movie that was not filmed in HD must be up-converted to HD, correct? Of course this is done using high-end equipment so the quality should be improved.

I purchased the original PS3 when it came out 2 years ago. I have purchased several BD movies since then. I personally do not see much difference between watching a movie on my PS3 than on my up-converting DVD player. I watch movies on a 108" HD SIM2 projector in 7.1 Surround. Now the sound improvements is worth the price of admission, but the film quality is questionable.

Perhaps someone can explain to me that if the movie was not filmed in HD, what is the process of releasing the film on an HD medium, BD? Do they simply upconvert it and save it on BD.