Moving from Auto to Manual mode is part of growing as a photographer. When I shoot in Manual it means I have nearly full control over how an image is generated. Auto mode makes most of the below choices for me. With Auto mode the camera pre–analyzes the scene and determines which settings will give optimum exposure and sharpness. But the problem here is that the camera isn’t a photographer. It can’t decide a photo would look better with a small depth of field to leave the background beautifully blurred or a large depth of field to have the background mountains nice and sharp as well as the subject in front. It won’t realize you’re trying to make a silhouette of a person in front of the sun and instead want an underexposed subject. Whenever I want to get creative with my shots, which is 99% of the time, I want to be shooting in Manual.
Autofocus is a wonderful tool but it has its limitations. It does not always know exactly where I want to place my focus, especially when using very shallow depths of field. Sometimes autofocus will lock onto a nose or ear when I want to capture the eyes of my subject. And if I’m shooting wildlife autofocus is very easily confused by trees, branches, and other obstacles between me and my subject.
Manual focus is required here. When I switch to Manual focus I have to look through the viewfinder and adjust the focus ring on my lens. The image will gradually shift from blurred to razor sharp. The human eye is quite adept at recognizing this point so trust your intuition and don’t pan back and forth too many times trying to be certain.
Adjusting aperture is a very important part of operating a camera in Manual mode. Aperture is how large or small the hole that lets light into the lens is. A large hole lets in more light but has a small f/stop number, like f/1.4. A small hole lets in less light but has a large f/stop number, like f/11.
Aperture also controls depth of field. Depth of field is how much of a scene is in sharp focus. If I use a large aperture like f/1.4 then I get a very narrow depth of field. My main subject will look crisp and sharp but the background will look dreamy. Often the background elements will dissolve into dreamy blobs called bokeh that are especially beautiful in portrait and macro work.
Using a small aperture, the background is kept in sharp focus just like the foreground. Landscape and nature photographers often want to use larger f/stop numbers for maximum detail in a given scene.
Light sensitivity is the next consideration. Anyone who has used film will recognize ISO numbers. In digital photography the ISO values are the exact same. I can use a low ISO number when shooting in bright light, such as ISO 200. And increasing the ISO value increases the light sensitivity.
If I’m shooting in the city at night I might use ISO 6400 for decent captures. Many cameras today have even higher values like 25,600 or even 51,200. But as ISO values go up so does image noise. These extreme ISO values will give you images even when shooting in moonlight but they will usually be terribly grainy. It’s much better to adjust aperture and shutter speed to let more light into the camera.
Shutter speed is the easiest element of manual focus to understand. This is how fast or slow the camera shutter blinks. When I use a fast shutter speed I can freeze action in a scene. The faster the movement the faster the shutter speed I want to keep the photo from showing any motion blur. But the downside to fast shutter speeds is that less light can enter the camera in that brief timeframe. So ISO and aperture need to be carefully watched to make sure my image does not become underexposed (too dark).
Slower shutter speeds let in more light which is great for even exposure. But if my subject is moving too slow of a shutter speed will show blur around the subject. If I want that as a creative element that’s fine. But if I’m shooting handheld with a slow shutter speed I can get blur as well. And handheld blur never looks good. Slower shutter speeds are tricky and best managed with a tripod. When shooting portraits we usually want to use slower shutter speeds to ensure we get perfect exposure.
There are several factors to consider when shooting in Manual mode. Auto is so attractive because the camera thinks for you and keeps you from having to stretch your creative muscles and learn. But getting confident with Manual mode allows you to create any sort of photo you wish. All it takes is a little bit of practice!