Aperture and Shutter Speed in Filming

Aperture in film:

As discussed before, Aperture controls how much light is being let in to the camera, it also variates in focal length with depth of field (using f/ stops). I wanted to test this knowledge out further with examples using different types of lenses. I used a 50 lens which offers low apertures up to f1.4 and a standard 18-55mm lens which can only go as low as f3.5. I discovered when using a water bottle as a subject, I was able to capture only that with the background completely out of focus - this is with f2.8. I was intrigued to see the middle stage so I also practiced with f8 and found the focal point to deepen, although not fully in focus, I am able to make out the writing on the bag behind. Finally, F16 allows me to see the bag in focus with a much clearer background - however as a result of me not decreasing the shutter speed, I found that when I was increasing ISO, the footage becomes visibly grainier.

I did another comparison outdoors, to familiarise myself with controlling a low aperture in natural light and I found this difficult. Although I could increase my shutter speed, I couldn't lower my ISO any further than 100, so my footage for f2.8 became a slight bit overexposed. I didn't want to increase my shutter speed dramatically as this could cause further issues later on when editing (videos looking different to others).

Shutter Speed:

Shutter speed and frame rate are two separate settings. The frame rate consists of how many frames are shot per second (25fps is usually used for a film look, 60fps is used commonly for slow motion). However, the shutter speed controls how long the shutter is open for, which can also control the exposure. When the camera is filming 25fps, the shutter speed should always be double of this. In the video attached, I have screen shotted a freeze-frame of my dslr camera filming in three different settings. 1/30, 1/50, 1/250. As the camera was filming in 25fps, we can see a motion blur within 1/30. 1/50 and 1/250 are much clearer.