From coating your lenses with Vaseline to creating pinhole cameras, we all love experimenting with camera and lens hacks from time to time. While it's hardly a new found trick, and while it's not as harmful as it sounds, lens whacking can give you impressive effects to give your footage just that extra bit of finesse and adds a lovely romantic element overall, especially when combined with slow-motion footage.
You can undoubtedly overlay light leaks in post, but I feel it's always better to do things in camera first and take it further when sitting in front of the computer.
But let's get down to the nitty-gritty details first.
The art of lens whacking is basically detaching the lens from the camera body to allow light to stream in from all directions while holding the lens in front of the camera and manipulating the movement slightly to create an almost tilt-shift feel to the footage when recording a video. While you can use it for stills, the real magic happens when you use this technique in filming. Just take a look at this video below from James Miller.
The footage has a certain dream-like and romantic feel overall. While you can spend the time replicating this effect in post, I feel there's something more tangible to create this effect in-camera.
Say for example you're using a Canon 5D and keen to create your first lens whacking film. Using Canon lenses are not going to work as the lens' rear element is made for Canon and you'll need something smaller to get closer to the sensor. For this to work, you'll need something similar to a Nikon lens. No EOS adaptor is necessary. The reason for this is simply because the Nikon's rear element is small enough to be held just past the lens mount while still moving it around slightly to get the tilt-shift "bloom" effect we want to achieve.
It's important to note that the type of lens affects the kind of effect you want to achieve. On full-frame cameras, 50mm primes (30mm on cropped sensors) with a wide open aperture are considered the best. Make sure the lens' focus ring is set to infinity and stopped down to the lowest f-stop. Usually, f/2.8 works best, but you can stop down even further if your lens allows it. If you find it too difficult to focus on your subject, you could try closing down the aperture by a stop. Hold the camera with your right hand while using your left hand as a hinge to hold and make adjustments to the position of the lens. Also, make sure the camera right against your chest as this will ensure better stability while shooting.
While it takes a bit of effort and practice to get the desired effect, the more you try, the better you'll become at it. I have to stress that if you do not want dirt or dust on your sensor, rather don't risk using this technique. But if you do, I'm sure you won't stop as this effect dramatically enhances the quality of your footage.
Have you tried using this technique to take your films to the next level?