In this tutorial, I aim to demystify the seemingly complex technical aspects of photography. If you delve deep enough, yes, there are some very complex formulas that go into shooting a photograph, but with today’s camera technology it’s not necessary (but can be very useful) to know about all that stuff. Still, you want to be able to control the look of your photos, and learning how to use manual settings is the best way to do that. Be aware that not all cameras will have fully manual controls (M mode), and if this all seems like beginner stuff keep reading anyway. There will likely be some stuff you don’t know – even if you already shoot with manual settings.
My point here is to get to the essence of photography – which can be broken down into balancing the three most fundamental components utilized in achieving a proper exposure: Aperture, Shutter Speed and ISO. The very first thing you need to learn is how to control the balance between the three, and what their different settings mean in relation to the resulting effects produced in photos.
Before I start to delve too deep into the mechanics of exposure, you need to become acquainted with the three variables through which you will set your exposure. [For more on the mechanics of exposure see my previous post Explaining Exposure] First, I’ll go over aperture.
Use of Aperture:
The larger the aperture, the better the light can enter to reach the film or sensor. The size of the aperture is one of the variables that determines the Depth of Field (the other’s are focal length and focus distance). The Depth of Field is the area that appears sharp in an image. The larger the aperture the more this narrows. This means you will get more blurry (bokeh) areas and will be able to shoot in lower light. Small apertures widen the depth of field so that parts of both the foreground and the background will appear in focus, but this also lets in less light and you will need to compensate by changing your Shutter and ISO settings. You can set your camera to Aperture Priority (AV) so that you determine the aperture and the ISO, while the camera decides the shutter speed to use. This is useful for getting quicker shots while maintaining control over the depth of field.
Use of Shutter Speed:
Slow shutter speeds will capture elapsed time in low light (or with Neutral Density Filters). Faster shutter speeds freeze motion, and by using the Reciprocal Rule you can avoid camera shake as well (more on this here: The Reciprocal Rule in Photography). On a normal lens (around 30-50mm) a shutter of 1/60 or faster will be enough to freeze motion, while 1/30 will capture motion blur. For longer focal lengths you will need faster shutter speeds to hand hold the camera. Even if you have your camera set to Aperture Priority you still want to pay attention the shutter speed, OR set it to Shutter Speed Priority (TV). In this setting, you select a shutter speed and ISO while the camera determines the aperture. This is useful for maintaing control over motion blur and for freezing action.
Use of ISO:
While it is ideal to use the lowest ISO available in order to achieve the greatest image quality, using a higher ISO will increase the depth captured in a photo – particularly coupled with the use of a flash. The reason for this is that a high ISO picks up more ambient light so you get the most detail out of a low lit scene. It will also help balance the flash and ambient light in low light situations, AND use less powerful flashes so there is less recharge time. This is a good technique to practice when shooting events or on location in low ambient light situations where you want to capture as much background detail as possible to avoid flatness from the use of a flash. Just be aware that using high ISOs will increase file size due to increased noise. The more noise there is, the more variation in pixels. The more variation in pixels, the more stuff that needs to be recorded.
The Key is Balance:
To get a correct exposure, you will usually have to make a compromise unless you have completely controlled lighting. If there isn’t enough lighting even at the highest possible ISO and largest aperture, you will just have to use a longer shutter speed. If there is too much light (and there is never really too much light) you can purchase Neutral Density (ND) filters that will allow light to pass through without affecting the balance of lights and darks and take your exposure down as many stops as the filter indicates. This allows using large apertures in very bright light so you can get very shallow depth of field.
If you haven’t already read my post Explaining Exposure you should probably do that right now. It has more information that you can use in conjunction with the knowledge in this tutorial.