I recently bought a dedicated camera - the Olympus OM-D E-M10 Mark IV - with the idea to take print-quality images of my cat and hang them around the house. My decision was primarily informed by Wirecutter’s reviews of mirrorless cameras, but I also had quite a time learning about the features of a camera and the differences they can make while shooting and in the final image. This post documents what I’ve learned.
The three pillars of exposure (whose technical details are worth its own post) in photography are ISO, shutter speed, and aperture. ISO is the sensitivity of the sensor to light, shutter speed is how fast the sensor is exposed to the scene, and aperture is how wide the hole that lets in the light is.
ISO ranges from as low as 60 to over 60000. The higher the number, the more sensitive the sensor is to light. Higher ISOs allow you to shoot pictures with darker lighting but also introduce more noise in the image. Cameras with bigger and more sensitive sensors perform better since they have the ability to capture that additional light instead of rendering it as noise.
Shutter speed can be as fast as 1/5000th of a second to multiple minutes or even hours. The faster the speed, the sharper and darker the image is and the slower the speed, the smoother the image is (which makes it great for long exposures of the nighttime sky).
Aperture is measured in the ratio of the diameter of the lens that is open to its focal length, also known as f-stops. The wider the hole, the shallower the depth of field and the more light that comes through. A narrower hole has the opposite effect by creating more depth of field and darker images.
How do these characteristics influence shooting pictures in practice? Photography is mostly about balancing each of these features to emphasize the positive aspects of each without needing to negatively compensate too much with the other features. Cameras have modes where the user can set one characteristic and the system will automatically set the others to maintain a “good” exposure. Most professional photographers shooting keep their cameras in _ Aperture priority_ mode, so they can control the depth of field and the amount of bokeh the final image will have. Bokeh is the blurry effect on parts of the image that’s not in focus and is one of the qualities that make a photograph looks good. This allows them to quickly adjust from taking portraits with lots of blur in the background to capturing large scenes with people and the background in focus.
Lens properties also influence the photograph. The prominent specification of a lens is the focal distance, which can have values from 12 mm to over 400 mm, and describes how far the lens is from the sensor. Shorter focal distances result in wider fields of view, and longer focal distances enable zooming into smaller parts of the scene, allowing pictures to be taken of subjects very far away. Portraits are usually taken around 50 mm focal distances (which is also approximately equal to the field of view of a human eye), and nature photographs usually require upwards of 100 mm lenses to capture animals from far away without disturbing them. Lenses come in two flavors - prime and zoom. Prime lenses have a fixed focal distance whereas zoom lenses are able to change the focal distance (TODO - explain how it does that.
Another feature to consider when buying cameras is sensor size. In general, bigger sensors capture better pictures. The best sensors are full-frame sensors, which are also known as 35 mm sensors from its origins from film cameras. Manufacturers have developed smaller cameras that are more affordable. One step smaller is ASP-C and one step further is Micro Four-Thirds. Because these sensors are smaller, they are positioned closer to the lens. This affects how the images are cropped; the smaller sensors have a narrower field of view compared to a full-frame sensor with the same lens. The end effect is that the image is magnified. ASP-C sensors have a crop factor of 1.5 and Micro Four-Thirds have a crop factor of 2.0. What this means in practice is that the 50 mm lens that one would usually use for a portrait with a full-frame sensor only requires a 25 mm lens on a Micro Four-Thirds sensor.
What did this mean for me after all this research? It means the Micro Four-Thirds camera with a zoom lens from 14 mm to 42 mm that I bought was the most practical decision for a beginner like me. The smaller sensor is affordable (compared to full-frame) for someone to get their foot into photography, and the zoom lens allows me the flexibility to experiment with the kind of shots I like. In future posts, I hope to share some actual pictures I’ve taken and the additional lessons I’ve learned after playing around with my new camera.