BluRay. Can someone explain to me the Conversion Process?

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Hi,

I've wondered about this for a while.

How are DVD's converted to BluRay?
What is the process?

And, how can they take a movie that was filmed in SD (like a film from the 80's or 90's) and make it HD?
Surely the best they are going to get in the conversion is the same quality as the original source (master copy), are they not?

 

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So you don't need a digital camera to shoot HD material?

I mean the cameras they were using back in the 70s/80s did not use the technology the movie studios use today.

I was under the impression that they used a modern camera to pick up the extra detail????

 

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35mm which most films are filmed with is a much higher resolution than blu-ray.

what res is 35mm?