Digital Video vs. “Old fashioned” Film: Is there a difference?
Shooting video is a lot easier these days compared to years ago. Today, you can make a movie in just about any format and still be taken seriously, but you better have a great story and good production value.
Prior to the digital revolution of the 1990s, things were a lot different. If a movie was shot on anything other than 35mm, it was not considered a real movie. The standards were so ingrained in the industry, that even today, old school filmmakers say that digital does not compare to film.
But today, we have affordable, high-quality digital cameras and they capture amazing HD footage.
The following study about comparing the key differences between digital and film from filmschoolonline.com
Note: the study below is based on classic HD with 1080 lines of horizontal resolution. In 2007, the first ultra HD camera was introduced featuring an amazing 4,520 lines. Keep that in mind while reading!
Comparison
There are two factors that can be compared: color and resolution. Most casual observers will agree that, assuming a quality TV monitor, HD color is truly superb. To avoid a longwinded mathematical argument, let’s accept this at face value and focus on comparing resolution, which is the real spoiler.
Resolution is the visible detail in an image. Since pixels are the smallest point of information in the digital world, it would seem that comparing pixel count is a good way to compare relative resolution.
Film is analog so there are no real “pixels.” However, based on converted measures, a 35mm frame has 3 to 12 million pixels, depending on the stock, lens, and shooting conditions. An HD frame has 2 million pixels, measured using 1920 x 1080 scan lines. With this difference, 35mm appears vastly superior to HD.
This is the argument most film purists use. The truth is, pixels are not the way to compare resolution. The human eye cannot see individual pixels beyond a short distance. What we can see are lines.
Consequently, manufacturers measure the sharpness of photographic images and components using a parameter called Modulation Transfer Function (MTF). This process uses lines (not pixels) as a basis for comparison. Notice the lines in this resolution chart:
Since MTF is an industry standard, we will maintain this standard for comparing HD with 35mm film. In other words, we will make the comparison using lines rather than pixels. Scan lines are the way video images are compared, so it makes sense from this viewpoint, as well.
HD Resolution
As discussed previously, standard definition and high definition refer to the amount of scan lines in the video image. Standard definition is 525 horizontal lines for NTSC and 625 lines for PAL.
Technically, anything that breaks the PAL barrier of 625 lines could be called high definition. The most common HD resolutions are 720p and 1080i lines.
35mm Resolution
There is an international study on this issue, called Image Resolution of 35mm Film in Theatrical Presentation. It was conducted by Hank Mahler (CBS, United States), Vittorio Baroncini (Fondazione Ugo Bordoni, Italy), and Mattieu Sintas (CST, France).
In the study, MTF measurements were used to determine the typical resolution of theatrical release prints and answer prints in normal operation, utilizing existing state-of-the-art 35mm film, processing, printing, and projection.
The prints were projected in six movie theaters in various countries, and a panel of experts made the assessments of the projected images using a well-defined formula. The results are as follows:
Conclusion
As the study indicates, perceived differences between HD and 35mm film are quickly disappearing. Notice I use the word “perceived.” This is important because we are not shooting a movie for laboratory study, but rather for audiences.
The typical audience cannot see the difference between HD and 35mm. So does it really matter? As a filmmaker, the question should be what is best for my project?
