How do they put CGI effects into film?

[cmyk]

@scm1001

Are main feature films being shot now in digital rather than film? That would seem to make things easier all round?

More and more big blockbuster, visual-effects-driven films are shot digitally, yes. There are still many major motion pictures that are shot conventionally, as well. I’m sure it won’t be long until shooting on film is pretty rare.

A lot of the benefits of shooting movies digitally can be related to the switch from analog 35mm photography to 12 megapixel digital photography in our daily lives. So much of the film industry is driven using software and computers now-a-days, it only makes sense to take out any analog format in your workflow, so long as it doesn’t drastically sacrifice quality.

[Rigamarole]

@scm1001

Are main feature films being shot now in digital rather than film? That would seem to make things easier all round?

It’s becoming more common, but they still transfer the digital images onto 35mm for showings. (very, very few theaters have digital projectors)

The OP’s question as I interpret it is about the physical process of getting the digital files onto film, so it’s still relevant.

[Chronos]

It’s becoming more common, but they still transfer the digital images onto 35mm for showings. (very, very few theaters have digital projectors)

I don’t think any film-projection theaters are still being built any more, though. It seems like the new ones are exclusively digital.

[coremelt]

@GuanoLad

The biggest stuff I’ve ever worked on is only 1080p HD, I’ve never done proper film. What kind of resolution do you work in? 2k? 4k?

What kind of challenges are there to making digital elements look like film elements?

most feature film compositing work is done at 2K resolution however working with color ranges greater than 8 bits ber channel (24 bit RGB color).

Scans are usually done in the cineon or DPX file formats which use 10 bit log color per channel. Eg the difference in brightness between 1000 and 1001 is much greater than the difference between 20 and 21. This is because the human eye can distinguish much greater differences at low light levels than it can on extremely bright objects.

The challenges to making digital elements real include motion tracking, matching depth of field, matching grain on the film stock, matching subtle lighting changes and color grading CGI elements to match real lighting conditions. It is extremely time consuming, the average 4 second complex VFX shot on a big budget film might have had 20-30 hours of compositing work and gone though 10-20 versions before being approved. Counting the rotoscoping, matte painting and 3d time a 4 second shot might have over 100 man hours of post production.

And yes it often still doesn’t look right, if elements haven’t been shot correctly in the first place in order to match then sometimes there is nothing the compositor can do to make it look convincingly real.

[commasense]

@Rigamarole

…(very, very few theaters have digital projectors)…

More than you might think.

According to this press release from Cinedigm, a digital cinema systems integrator, they have installed 4,000 digital screens in the U.S. Elsewhere they claim that they have 61% of the market, which would mean that there are more than 6,500 digital screens out of about 29,000 screens in the U.S.

This means that nearly one quarter of all U.S. theaters are now digital.

Cinedigm expects to install another 10,000 in the next few years, so adding in other suppliers, more than half will be digital by 2012-2013.