this week I'm going to go over exposure while filming and how to use your light meter. last time we talked about the basic settings for your camera. many people are confused about exposure. NO, not that kind of exposure so put your pants back on! no, we're talking about your images exposure. Pictures require light, and in a motion picture We need to make sure that we're getting the right amount of light for each frame.
There's three common terms when talking about camera exposure. underexposed, overexposed, and proper exposure. Exposure is determined by four factors with three of these being controlled by your camera's settings shutter speed, aperture, and ISO this is called the exposure triangle each setting affects our camera's exposure the final factor is "scene luminance" or how much light is actually present in the room or the space such as outdoors. A proper exposure is when the dark parts of the image are very dark, the bright parts are very bright, but we don't lose detail in any of those areas an overexposed image makes the highlights too bright (otherwise known as being "blown out") when we blow out the highlights the bright parts of the image lose detail and become solid blobs of white.
These parts of the image are so overloaded with light that the pixels have no detail. this can't be recovered in post, because they are burned into the image. just like when someone turns the lights on in a dark room and the light begins burning into your retinas the other end of the spectrum is an underexposed image where the shadows have lost details and brightening up the image in post won't change these areas filled with black.
So our job is to use the camera settings to make sure that the light collected from our camera is the right amount. in a motion picture, one of the three settings will not be at our disposal for changing the exposure. This, is the shutter speed – as we learned in the earlier video your shutter speed should be set according to your frame rate, and will be locked down to double your frame rate; 24 frames per second will be naturally brighter than 60 frames per second due to this fact so that leaves us with aperture and ISO.
You will be mainly changing the aperture to set the proper exposure here, the grass is blown out and is just the white mess by turning the aperture setting higher we let in less light and we get back details in the grass. Too high, we under expose the image. the general rule is in low light, you'll be using a low aperture number in highly lit scenes, you'll be using a higher number. the ISO can also change the lighting. For instance, if you want to have a shallow depth of field you will be locking the aperture down to a low number, so the only setting left is the ISO. This will need to be adjusted up or down to properly expose the image. Our camera also has a useful tool to measure our cameras exposure. this is called the "light meter" it is the line that usually starts with minus 3 and goes up to plus 3. in the middle is where the camera thinks is properly exposed. this is a good guideline, but is not always accurate. This is most important to know when we're using auto ISO to let the camera automatically expose our image this is because the camera simply takes the brightest parts of the image, the darkest parts, and then averages them out to somewhere in the middle; which I call middle gray.
This works for a majority of the time, but for instance in high contrast scenes or scenes with mostly white, or mostly black; the camera will compensate too much o,r not enough here is the image using auto ISO our subject, the tree, is properly exposed but background is still blown out if we still want to use auto ISO we'll have to use a setting built into the camera called Exposure compensation. This shifts what the camera thinks is a proper exposure, to either darken or lighten the overall image that way, it tries to keep it at a specific exposure This is important for white scenes, where the camera sees lots of white and overcompensates, leaving us with whites that actually look gray (the) same thing with night scenes, where the darkness is seen as too much black and the camera pumps up the ISO to make the blacks look closer to grey. but with exposure compensation, we can ensure night scenes stay night; and snow scenes stay white, while still letting the camera adjust as the lighting changes the light meter is also helpful in manual mode to let you know where you should start or if the image is too bright or too dark.
This is helpful when you're outdoors and have a low aperture and the ISO is already as low as it can go. The meter will tell you that the image is too bright and then you can change the aperture to compensate with a properly exposed image we have the room to make creative choices and post-production due to keeping as many details as possible don't worry if you have to slightly underexpose an image to ensure the highlights aren't blown out dark areas naturally have less detail so it's okay to underexpose slightly you can bring the shadows back up in post for a balanced image.
With the image in post we can either make it look darker, or brighter, depending on what look we're going for one issue you may run into is filming in daylight, where you want a shallow depth of field, since this requires a low aperture, your scene may be too bright; even with the ISO as dark as it can go. In this case you will need to purchase an ND filter which is essentially sunglasses for your camera this will darken the image allowing you to get a shallow focus during the daytime without over exposing the image I hope this helps you understand a little bit more about exposure. if you have any questions post them in the comments below are we going over more settings in the next videos so be sure to subscribe so you can be up to date and as always thanks for watching and I'll see you next week