Getting distance marks is essential as a camera assistant to keep a shot in focus. That’s why there are so many different tools that can be utilized to achieve this task. I usually have attached to me at any one time a soft tape measure (the kind that winds up on a spool
Soft Tape
Wound up in a spool and made of fiberglass, this tape measure is referred to as soft tape because it’s flexible and hangs loose. It is the de-facto tool of the old school camera assistant and it is usually the best for getting precise measurements. To use it, there is usually a hook of some sort on the camera at the film plane that the soft tape attaches to, then you walk out with the spool until the desired distance. Because you walk along with the tape measure to pull it taut, it can give very accurate measurements.
Soft tape should be used whenever possible and definitely in situations where there is very little depth-of-field. It is also ideal for situations in which you need to get multiple marks because you can swing round to one character, grab the mark, then pull the tape a bit further along in the spool and grab the second mark. There are some times, however, when soft tape isn’t ideal. Even though mine goes up to 50 feet, it takes time to wind that back into its spool, let alone walk 50 ft. and back. I’d say anything less than 15 feet is appropriate. This is the most time consuming method.
Bonus tip: Soft tape, because it is flexible and not made of metal, has the tendency to stretch or breathe over time. Periodically check it against a steel tape measure to make sure it is still accurate.
Hard Tape
Hard tape is a good ol’ steel tape measure. This is likely the tool that everyone knows how to use because they have fond memories of helping Dad measure stuff as a little kid. One thing I think is important to stress is to not go cheap on this tool. The cheap ones are flimsy, their locking mechanism breaks, and they often don’t go very far. I have many times recommended a FatMax tape measure with some pimped out modifications. It has a stand out distance of about 11 feet — though 13 feet is my record — meaning it will protrude that far without snapping.
On set, I use my hard tape the most. When working fast, it is the most ideal. It allows me to stand by the camera and whip it out and place it near an actor’s eye. Sometimes actors — the trained ones at least :P — will be kind enough to grab the end of it and hold it up to their eyes to help me. I like those actors and like to think Michael Caine is one of them. Anyway, this is best to use in a situation where you need an accurate mark fast and the soft tape approach is too time consuming or going to be too noticeable (remember being invisible is important). Just be wary about hitting anybody with it and make sure you are holding it against the film plane mark on the camera.
Laser Tape Measure
Now, I’m sure many of you have been reading this and wondered why I said hard tape is good for accurate, fast measurements but did not mention the laser tape. Well, it’s complicated. Laser tapes ARE fast and they ARE very accurate. But there is the whole issue of shooting a laser around the set. It can be distracting for the actors and tough to shine a laser right at their forehead without the risk of shining it in their eyes. That’s why when I use my laser tape, I usually am shooting it at their chest. This is best in situations where you have a large amount of depth-of-field and the short difference between the eye’s distance and the chest’s distance can be accounted for. With that said, these tools are very accurate if measuring exactly on an object.
But don’t think that laser tape measures are good only for quick, dirty close marks. In fact, where these tools really shine is situations that demand a long, long distance or an inaccessible location. An example could be if you’re on the shore of a lake shooting two characters on a boat some 100 feet away. Both the soft and hard tape won’t be able to reach there, but a suitable laser tape measure will do it no problem. And don’t worry about hitting actors at their eyes, aim it at their chest; at that distance the few inches will likely be well within acceptable focus with the depth-of-field.
Bonus tip: Though both soft and hard tape measures will go past distances of 20 feet, it can be tough to grab those marks quickly. Using a laser tape at these distances and above can help grab fast marks.
Soft Tape is Most Accurate, Laser is Easiest
Soft tape, in my opinion, is the most accurate measurement that can be obtained because of how it is used. It has to be pulled out and measured by an AC and also is able to get multiple marks at one time. It is, however, a slower process than the other options and can be cumbersome to measure anything past 15 feet. Thus it is best when used for close ups and medium shots.
Hard tape is accurate as well, but is also faster than soft tape. It can be used from beside the camera, meaning there is less of a process to grab a mark. It will only stand out so far, however.
Laser tape is best for quick approximate close distance measurements, but ideal for long distance measurements. It should be used with caution when shining at a person to not hit their eyes. That risk means the other two options are usually better than the laser when dealing with talent.
All three of these tools measure distance, but they all do it in different ways. Some are more suitable for certain situations than others. Part of being a good camera assistant is having the right tools and knowing the right time to apply them. When grabbing a distance mark is essential to keeping a shot in focus, don’t skimp on the resources used to complete this task. At the very least a camera assistant should have a soft and hard tape measure in their pouch, on their belt or stowed in a front box.
Also, don’t be afraid to use a 2nd AC or camera trainee to help grab marks. Believe it or not, they’re there to do more than clap some sticks!