Depth of Field and Scale

Next in our production process is accounting for depth of field and scale.

Depth of field is the technical term in photography that describes how much of the scene is in focus or not. When working with a shallow depth of field, like in film, as subjects move further away from the point of focus, they gradually become more and more blurry. This is an issue with backdrops since the drop itself is usually much closer to the set then the actual view would be on location. For example, a view across an average city street would be 50 to 60 feet in the distance whereas the backdrop of that view would only be, at max, 24 feet from the set. This would bring the drop closer to being in focus when filming then the view would have been on location. To account for this, a slight blur needs to be added to the backdrop before printing. Through testing, we have narrowed down the exact amount of blur needed for our backdrops based on final pixel height of the artwork and hanging distance on set.

Scale refers to how large or small the view in the backdrop appears compared to the actual view on location. Typically a true 1:1 scale is utilized, which ensures the view in the backdrop appears to be the same size as the view itself would look in real life. However, there are instances where the scale could be increased or decreased. For example, a skyline in the distance could be too small at a 1:1 scale to be recognizable, so utilizing a 2:1 scale in the backdrop would bring the city closer and be more impactful. Conversely, if an elevated train was directly outside the location window, using a 1:1 scale would create a backdrop that was mostly just the train platform. A 1:2 scale in this case would push the platform further away and allow for more information in the view.

Producing the desired scale is more complicated then it may seem and it must be accounted for both on location, when photographing the backdrop, and in post production, with the final crop. After thorough testing with our lenses, multiple prints and comparisons to interior location photography, we are able to take into account shooting position on location, focal length of the lens used, final print height and hanging depth on stage to ensure we produce a backdrop with the exact scale required on a per project basis. On the right, please see a screen shot of one of the excel calculators we created, taking all of these variables into account, that provides us with guidance on the exact lens and crop to use. Due to the effort we put into producing this tool, our focal lengths have been obscured with Greek letters to prevent others from simply copying our work.