A Technical Explanation On How Film And Digital Films Differ

One of our trusted Fstoppers readers sent us this video, and I found it really interesting. Digital cinema specialist Rob Hummel recently gave a lecture at Cine Gear Expo 2011. In his lecture he described exactly what is going on when both film and digital mediums capture light to form an image. The graphics in his presentation help explain why old fashion film can still produce more aesthetically pleasing images than digital. He also describes a little known secret about how gamma rays present at high altitudes can actually destroy camera sensor's pixels. I've personally flown with a bunch of cameras dozens of times with no pixel problems but maybe my cameras are able to mask the destroyed pixels through software? Either way, the exciting news I took from this video is that digital sensors still have a lot of potential gains that can make our images even better in years to come.

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Mike Garza's picture

Wow, that was some good information.

Been shooting film since I was 8 and don't plan to stop.

This video floored me for two reasons. One I didn't that about film vs video and what it looks like applied to a big budget film like Superman, and two because I didn't know that gamma rays were killing pixels. He talks about how he had issues with his canon digital camera and one of the head guys asked if he had been flying and if so, that was why he saw black bands. For most of us, this is not important, but for those using Red Cameras and shooting big budget commercials and film that require post production, this can be a big problem as he stated with Superman.

I don't want dead pixels when Im flying with a $40,000 Hasselblad. 

This is great! Definitely explains a lot of things. Didn't know about dead pixels and high altitudes, but that probably had a major impact on my d90's steep decline in quality since my night on Mauna Kea. Now all I'm afraid is of those old school film buffs scoffing at digital. The guys is right - 200y vs. 40y - that's amazing evolution gap. I still like how good the shots look when done with old Yashica TLR; some problems just don't exist in film world.


I work for Spectral Instruments (www.specinst.com). We design and build both CCD and CMOS cameras for high end scientific applications. Our cameras are black and white (no Bayer masks, no anti-aliasing masks). Some of the comments made on this video are a bit puzzling. It is true that radiation can harm the sensors.  The Hubble Telescope has been in space orbit for years, and it's CCD camera is working fine.. that is a harsher environment radiation wise then a simple plane ride. We sell cameras to the guys at the National Ignition Center (https://lasers.llnl.gov/) and these cameras are subjected to a massive radiation load. The new cameras use a CMOS sensor because it is much more tolerant than a CCD sensor. Most DLSR manufacturers (with the exception of Nikon) use CMOS sensors, so they should be even more safe on a plane ride.

All of the CCD's we use are 100% fill factor. See this link: http //www.e2v.com/assets/media/files/documents/imaging-space-and-scientific-se... and this link: http://www.sta-inc.net/wp-content/uploads/2010/08/STA1600A_011408_Rev5.pdf  for two different manufacturers. That last sensor is 10590 pixels x 10590 pixels.... 112meg pixel sensor!

CMOS sensors do have a much smaller fill factor, but all of the CMOS sensors that I am aware of that are used in DSLR cameras have a micro lens on top of each pixel to effectively increase the fill factor.



Thank you so much for sharing, you have quelled my fears or flying with my Canon T2i and only shooting digital.  

Garrett Graham's picture

Very informative, but would have been more convincing if the graphics used in the presentation did not look like shape images from PowerPoint ;-P

This guy is blowing things way out of proportion ... Someone in another forum had a great quote that sums everything up perfectly:

"So, I guess the moral of the story is don't ship scientific equipment via military reconnaissance aircraft on polar routes during energetic proton cosmic ray storm activity."

The likelihood of a CMOS censor being damaged from a commercial plane flight is slim to none. In fact, your camera is more likely to destroy pixels just sitting for years at ground level stored on a shelf somewhere...

I think a lot of people are refusing to listen to what this guy is saying. He is not an uneducated person on this issue. In fact some would say he could almost be an expert. When he says not only are pixels being destroyed, but that he experienced this first hand, I would trust him on that. Nothing is being blown out of proportion as this video was not even about pixels being destroyed, but about film and digital. The destruction comment was just a very small part of his presentation. 

Simply denying what he says is true would be short sided. He gave specific examples of block buster films where this occurred, thus this is not only likely but an actual occurrence. 

If you decide to fly with your equipment, that is your choice. Most people wont have to worry because their stuff will only be on Vimeo or Youtube anyway and their line of work doesn't require them to produce high enough quality work to be shown on a cinema screen.

Do I think pixel damage can occur? Sure, he just said so. Do I think that many of us will even notice, no. Is there anything you can do about it anyway? Not unless you are rich and have many boats. 

Cosmin Moldovan's picture

This guy hasn't got a clue about what he's blabbering on with his "gamma radiation". If one would need hundreds of meters of concrete in order to be protected from these "gamma rays" at 30,000 ft, all landing airplanes would be filled with dead fluorescent people, singe gamma radiation is one of the most dangerous to all living organisms. Heck, they even use them to sterilize medical instruments during the manufacturing process. So, to keep it simple, you would be long since fried before your camera starts losing any pixels. Had he used any other term than "gamma rays", maybe I'd have bought it. As I see it, he just took advantage of the ignorance of his attendance regarding this subject.

Ma's picture

Interesting, yet confusing. However crude, his animations were pretty informative. I often read about how film base  works, but not digital sensors.
As far as the gamma thing goes... Isn't that the type of post-nuclear, or cancer theraphy radiation? The "he just said so" argument doesn't really fly, excuse the pun, with me.