FRAME RATE
So starting out you first decide the frame rate you are going to shoot at. Many people showing things on the web shoot at 30 - people looking for a little more of a cinematic feel shoot at 24 quite regularly. For the best results, pick a frame rate and use it for everything you shoot on a particular project.
Once you know what your project frame rate is going to be, you pick your shutter speed that is most appropriate. If you are shooting at 24, you want a shutter speed that is going to be either 1/48th or 1/50th (depending on the camera you are filming with they do not always have both choices). If you chose 30 FPS (frames per second) you would want to keep your shutter at 1/60th. You will notice that the number in the shutter speed is about double the frame rate.
SHUTTER SPEED
Now we have a frame rate and shutter speed. These two together give us a combination of motion that will look very natural and pleasing to the viewer. If you shutter speed is too slow for the frame rate you will get frames that seem to blur far too much with any movement. If you have a shutter speed that is too fast you will have video that appears to stutter. For example if you are showing footage at 24 frames per second but recording with a shutter at 1/100th you could theoretically take 100 pictures in a second if each from is 1/100th of a second (the camera might not mechanically be able to do it, but the "slices" of the second are 1/100th. And since you are only showing your footage with frames at 24 per second there are technically "gaps" between your frames that become noticeable. The ratio I outlined above works and is the tried and tested method. There are exceptions to this rule - but we are just going to begin with the basic rules.
Now that we have those 2 things determined, there are 2 other items we need to control the look and exposure of our footage. We will be using aperture and ISO to get the right depth of field and light to the camera sensor.
APERTURE
Aperture can have a big impact on the look of our footage. It can determine the relative sharpness for the way our footage feels and it can determine what is in focus and what is intentionally blurry. We have a range of 2.8 to 11 to work with on the
P4P lens. Here are the general rules of thumb for when you use one extreme or another:
2.8 - lets light in quicker so use it in lower light settings. Shallow depth of field - use it if you want part of the footage focused and part softer / blurry.
11 - lets light in slower. Use in brighter conditions. Large depth of field - meaning everything will feel more in focus across the whole picture.
ISO
Because ISO acts as our light amplifier, we use it to help make all of our other selections work together to get the right exposure.
For example, lets call this our exposure equation:
Shutter speed + aperture + ISO = Proper Exposure.
We know our shutter speed can not get adjusted because that is based on our FPS of the finished video. If we want a shallow depth of field (2.8 aperture) we need to use a lower ISO because the 2.8 aperture lets light in quickly. If we pick 11 for aperture we might need to raise ISO because 11 lets the light in much slower (and our shutter is still not going to change) so we need to amplify the light to get to the right exposure.
To use random extreme examples of the equation above this might be the case:
1/60th shutter + 2.8 Aperture + ISO 100 = a great exposure...just like
1/60th shutter + 11.0 Aperture + ISO 400 = a great exposure
Take a minute - digest that and let me know if it is making sense. I have been a camera guy for a very long time - just not sure I have ever tried to do a written explanation like this before!
