General rules

Planning is essential

As in most aspects of television and film production, planning is essential so that all members of the team from DOP and director to Visual Effects Supervisor are aware of what is to be achieved. Each member of the team will have their own requests and trying to accommodate all or most of these should ensure a successful result and avoid fixing costly mistakes in post production.  

Making it look convincing

The goal is to create a believable result by making the CG (computer generated) element look like it's "really there" and there are many techniques which help to achieve this. The CG element needs to interact with the real world backplate by casting shadows and picking up reflections of its surroundings as it moves. The CG camera must move exactly as the camera moved when you filmed the backplate so that the shift in parallax looks convincing.

Take notes and record data on location

To use these techniques, the compositor needs as much information as possible about the physical environment you filmed for your backplates. So as well as bringing back the images, you also need to collect lighting references, distance measurements and lens data. Although it can be time consuming, accurate recording of these measurements is extremely important and will go a long way towards making your CG sequence a success.

Andrew Hunter:

“I’m always very keen to have a proper meeting with the crew who will be shooting the backplates for a sequence, especially if I or a member of the graphics team can’t attend the shoot. A lot of people have a decent grasp of how to shoot backplates but there are also a number of common misconceptions which, if left unchecked can cause enormous problems later on. Not only does this usually cost money to fix, but often, the end result is not as good as it could have been which is a real shame. We've all heard on set: 'Oh, don't worry about that ..... they'll fix in in post!' Sadly, that's not always the case and what could have been a simple fix on location can become a major issue in post production."

“I like to storyboard the sequence and action first. Even if you haven’t recced the location in advance, it’s much easier to refer to your storyboard to workout where to film the wide, mid and close up backgrounds you need to cover the sequence.”

"Filming in Guatemala for National Geographic Channel's 'Dino Autopsy' meant it was too costly and time consuming to recce the shoot, so we sent storyboards to the fixers in Guatemala and they sent back stills of possible locations. When we arrived in Guatemala, we already had a very good idea of how it was all going to work and, more importantly, the fixers knew what we we were trying to achieve visually. Within a day of landing we'd scouted most of the locations and over dinner that evening we used the storyboard to plan the rest of the shoot. This level of preparation definitely saved us a lot of time"

General Rules

• Try to shoot on the highest quality format available. So if you’re shooting HD then it should be 1080 lines, and stills should be at least 10 Mega pixel resolution

• If blue or green screen compositing is involved, the shooting format is critical and should be discussed with your CGI designers and probably your broadcaster too, long before the shoot takes place.

• Storyboard your sequence

Essential "Must do's"

• Always take a digital stills camera 

• Cross photograph the ‘set’ for reference from at least 2 angles, 4 if possible.

• Shoot as many reference shots as possible and collect texture details of trees and foliage, rock and ground cover.

• Where possible isolate plant elements with a blue or green screen either as stills or moving image to assist with the integration process of the cgi.

• Use prime lenses whenever you can. They're optically better than zooms but the main reason is that you know their true focal length. The focal length markings on a zoom lens aren't very accurate, so you may think you've set your zoom to say 85mm but really, it could be anything from 80mm to 90mm. This means that the computer won't be able to match the CGI to the backplate and some shots will be severely compromised or at worst, simply won't work at all.

• Ensure an even exposure across the sequence of shots or stills. This is especially important if shooting stills for a tiled backplate.

• Shoot a lens reference grid on each lens at the beginning of the shoot.

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• Shoot HDRI Stills for lighting reference. These should be 180 degrees min. Bracket the exposure as shown.

• Shoot a grey ball for overall lighting reference.

     See Shooting lighting references

Note the following essential information for each shot: 

• Make and model of camera

• Focal length of the lens

• Lens type (Prime or Zoom)

• Camera height (distance from the ground to the centre of the lens)

• Distance from the camera to foreground, mid ground and distant objects

Additional tasks. Do these if at all possible

• Even once you’ve completed shooting the “must haves” for your storyboard, it’s a good idea to shoot some more options. Ensure a good mix of frame sizes, angles, heights and safety shots just as you would for real action, so that in post secondary decisions can be made without compromising the whole sequence. For example if a dolly shot doesn’t track very well in the computer or a certain frame size isn’t working, then it’s good to have some options. 

• Unless the effect is part of the concept and has been well discussed beforehand, avoid: lens flares, dust, mist, smoke or elements that will adversely effect the composite or that can be replicated more efficiently in cgi. 

• Try to shoot during golden hour. It's usually best for lighting.