Part-1: Know the gear- Photography for beginners

Ever think of a night you lost in a desert or forest far away from the city life? Scary, isn’t it? Wait… What if you have a camera with you? Perfect time to capture some Photons originated from some mysterious world light years away, if you’ve got the right gear for astrophotography. Let’s do this.

Know the gear for Astrophotography

Camera

Camera is not something odd in 21st-century life. One way or another most of us pause moments around us. Let’s have a look at the science behind the camera before moving towards capturing light.

Light is directed to the camera sensor by lens attached in front of it. Camera sensor comprised of millions of light-sensing elements or Sensels arranged in a grid. Each Sensel registers the intensity of light at that particular point. Every sensel isolates light at some particular frequency to determine the colour (RGB). The data from the sensor are written as a Digital image file.

There are different types of cameras out there in the market, but for our purpose, I’m limiting my words to only two types of Cameras – DSLR and Mirrorless.

Digital Single Lens Reflex (DSLR) cameras have a mirror in front of the sensor which reflects the light to the viewfinder. When you look through the viewfinder you are seeing the actual image formed by the mirror. When you click the shutter button, the mirror moves up mechanically allowing light to incident the sensor. It means you are blind while taking the photo as the mirror is no longer reflecting light to your eye.

Nikon D series (D5600, D850), canon 6d, canon 5d mark (i, ii, iii, iv) are some examples

Mirrorless cameras, as the name says, the mirror that reflects light to your eye is totally removed. There is nothing in between lens and camera sensor. What you see in the viewfinder is the digital view from the sensor itself.

Sony A6000, Sony A7R (i, ii, iii, iv), Canon EOS R series, Nikon z series are some examples. 

Advantage of Mirrorless over DSLR is that by reducing flange distance ( distance between lens and sensor) high image quality can be achieved. Also, you can experience the realtime view of the image that you are going to capture, without drawing your eye off the viewfinder.

Next thing that does matter in a camera is the camera sensor itself. There are different types of camera sensors on the basis of size. Full Frame, APS-H, APS-C, four-thirds are some examples. Larger the sensor size, larger would be its light-sensing ability. The larger size offers a wider field of view as well. For Astrophotography, I do prefer Full Frame camera because of its comparatively low noise to signal ratio on higher ISO(light sensitivity rating of the camera) values.

Moving on to the last and very important part, The lens. It is obvious that different lenses picture the same scene from the same camera differently. What makes it different? The first factor is the Focal length. It is determined by the distance between the lens and the image sensor when the subject is in focus. A lens focal length is generally represented in millimetres. It gives us the angle of view for a given lens, or how much of a scene will be captured using that lens. The smaller the length, the wider the field of view. The higher the number, the more narrow your angle of view will be.

Focal lengths

* Wide angle lens (short focal length): A wide-angle lens takes in more of the scene than what’s perceived by the human eye. It provides a wider field of view or angle of view. 8mm to 35mm are common focal lengths. Suitable for Landscape, Cityscape and Milkyway Photography.

* Normal lens: 50mm lens, A focal length that corresponds to the human eye.

* Telephoto: A longer focal length lens than normal, this lens allows one to get close up without being closer. It provides a narrower field of view than a normal lens. It is suitable for Wildlife and Deepsky Astrophotography. Focal Length ranges between 85mm and 2000mm.

* Zoom lens: Zoom refers to the lens being able to change the focal length. It can be a wide-angle lens, a normal lens, a telephoto zoom lens, or a combination of lenses. Eg: 16-35 mm lens , 24-70 mm lens, 70-200mm, 150-400mm.

* Prime lens: This is a fixed focal length lens, and often has premium features like wider aperture for shallow depth of field. Eg: 35mm, 24mm, 50mm, 85mm.

Aperture

Aperture can be defined as the opening in a lens through which light passes to enter the camera. It is an easy concept to understand if you just think about how your eyes work. As you move between bright and dark environments, the iris in your eyes either expands or shrinks, controlling the size of your pupil. In photography, the “pupil” of your lens is called the aperture. You can shrink or enlarge the size of the aperture to allow more or less light to reach your camera sensor.

The values are shown in a specific format called F-stop. You can see the maximum and minimum aperture values on a lens usually written as f/1.8, f/2.8, f/8, f/16 Hopefully, you know how fractions work. 1/2 cup of sugar is much more than 1/16 cup of sugar. By that same logic, an aperture of f/2 is much larger than an aperture of f/16.

Larger the opening(Aperture) of a camera means a larger amount of light it can pass into the camera.

For dark night sky shoots, we need to capture all that tiny amount of lights. So we must need a lens having an aperture size of minimum f/2.8.

Now you might’ve got an idea about the gear you have or the one you are planning to buy in the future. What you read is common and a starter, that every camera operator should know. From the next part, we will focus specifically on Milkyway photography in which we will cover the gear you need for Milkyway Photography/astrophotography. Until then, try shooting with what you have and capture some photons.

-Abhijith Prakash

Read : ‘Part 2 – What all gears?-Milyway Photography‘

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