Originally Posted by HendersonD
I have seen a few threads talking about how high definition video is much sharper than high definition film. I am a big movie buff but know little about the differences between these two. Why is HD Video (much of it from places like HD Discovery) so much sharper than HD Film?
Since I do not have my theater done, I have not seen this difference myself but people have described it as significant. HD Video has been described as having a wow factor and like looking out an open window.
If HD Video is so much sharper why aren't feature films shot with this technique/equipment/materials?
While I think this has been a very interesting thread raising many valid points about digital video, I don't think anyone properly addressed the op.
Everyone agrees that HD video seems to have that wow factor, sometimes described as a sharper, through a window, almost 3D look. Typically, this is because HD video seems to have a greater depth of field (meaning almost everything you see seems to be in focus). Whereas feature films, even ones shot on new HD digital cameras, do not usually have a great depth of field all the time. They usually have a somewhat shallow depth of field (meaning only the things the director feels are important are in focus, and the rest becomes blurry). There are many, many reasons for the aesthetic differences between video and film, but I'd like to mention two.
1) CCD size vs. film size. There are inherent differences between film and video cameras, and the same differences are mimicked in digital cameras designed for the film industry, and those designed for video (and TV). The lens on a digital/film camera has to focus the image on a 35mm frame or equivalent CCD which is roughly over 1 sq. in. Whereas a digital/video lens has to focus the image onto a CCD which is usually half the size (1/2 to 2/3 inch). All else being equal, this difference increases the depth of field.
There are further differences that I won't go into, such as different lenses and focal lengths needed to compensate for the size differences. But the gist is that digital/video always has more depth of field than digital/film. Although, great lengths can be taken to create a film-like shallow depth of field look.Here
is an excellent primer on the differences between film and video from a video point of view. And here
is the white paper it is based on.
2) Consider the nature of the medium. Film is meant to be projected on a big screen. It is impossible for the human eye to focus on the entire thing (unless you are sitting very far away). So directors typically only put the important bits in focus. TV, on the other hand, started out for screens merely inches wide. So it was easy to take the entire image in. They usually tried to keep the entire image in focus. Even with today's ever increasing TV sizes, they are still nowhere near the size of a movie screen, so it will always be easier to see the entire image on a TV.
Also, film is more of an artistic/narrative medium. They are trying to tell a story, and must guide you visually, besides narratively. So varying depths of field and selective focus are common tools directors use to get you to see what they want. TV started out as more of a documentary/representative media. So it was more appropriate to show images as more realistic, i.e. more depth of field, so that it captures everything without seeming to manipulate the image or you.
Regarding television programming today, you can see a real difference in filming techniques depending on the subject matter. Narrative TV shows like 24 and Heroes try to mimic a film look because they want to tell a story. Non-narrative programs like sports, news, Discovery HD stick with the typical video look to represent reality without manipulation/distortion.
Taking all this into consideration, you have to realize that home theater is a relatively new phenomenon. The film industry still makes movies for the big screen, yet the general public does most of its watching on a small screen. We are used to seeing the entire image in focus on our small screen from TV. Yet, when we are in the theater, we don't mind seeing the image only partially in focus on the big screen. But once we get the film out of its original environment, we want it to conform to our typical viewing preferences, i.e. deep focus. Take a look at the Tier threads in the HD DVD and Blu-ray forums. More often then not, the ones placed near the top have more deep focus scenes. People's aesthetic preferences seem to be developed in the TV world, and are now applying those preferences to the film world. Deep focus is ingrained in our collective TV-watching conscious as representing reality. And we want our movies to be realistic. Therefore we want our movies to have deep focus.
I am not saying either aesthetic quality is better than the other. But there are reasons for those qualities, and in my opinion, it is up to the director to choose. In my opinion film is art, and this is one of many aesthetic choices that are made for a reason. As a compromise for those who prefer deep focus, I say just get a bigger TV and sit much closer and you won't notice it.
Sorry this is so long. It's just something that bothers me about these forums.