Having expensive gear is not everything in photography. It won’t make you a great photographer as well. Things do matter in the area of a photographer’s skill and ability to control his camera. Manufacturers compete with each other to add features and modify settings on their products. But three remain unchanged in a camera, which I believe will make a significant difference in our final image – Aperture, Shutter speed, and ISO.
Cameras are predefined nowadays to adapt to various external conditions, in fact, it could auto adjust everything according to the light available. Whatever a machine can do, I believe that it can’t compete with a human brain. So we need to create a picture ourselves rather than letting the machine do all the tasks with the presets. That’s what photography really meant to be.
You can see various modes on the top dial of a camera. It includes Auto, Auto without flash, Aperture priority, Shutter priority, fully manual mode, etc.
Auto mode is basically for beginners and for those whose primary priority is to take a photo without any exercise. Camera measures and decides everything here, like how much light is incoming, so what should be the aperture value, ISO and Shutter speed. ‘Auto without flash’ means exactly what it sounds. The camera itself would do every job except that we can decide whether to trigger flash or not.
In Aperture priority, we can control the Aperture manually, and the camera will auto adjust everything else. We have the option to manually set ISO as well. This is commonly used for Portrait photography because the depth of field depends very much on Aperture values. In a similar way, Shutter speed can be manually controlled in shutter priority mode.
The mode of our interest is in Manual mode. Here we are the artisans, and the output depends mostly on our skill only. First, we measure the light and we will later decide upon the appropriate settings in astrophotography. For Milkyway, or any type of Astrophotography, you should set the camera in manual mode. This is very important. You’ve to set the lens into manual focus as well. I will explain more about that in the coming lectures.
Prime Settings in astrophotography
In manual mode we how to manually set Aperture value, Shutter speed, and ISO.
1. Aperture
Aperture is the size of the opening of the lens, through which light passes to reach the camera sensor. We need to collect the maximum available light at night. So set the Aperture to its maximum value available for your lens. Although f/1.4 to f/2 is the perfect range, you can go up to f/2.8. Any value less than f/2.8 is not preferable. You can refer to part 1 of this astrophotography series to know more more about Aperture settings.
2. Shutter speed
Shutter speed is the exposure time of the camera sensor to the incoming light after clicking the shutter release button. We need longer exposure times to fetch every possible photon. To set the shutter speed, we have to use 500 rule (refer part 2 of this series).
500 divided by the focal length of the lens will give you the approximate shutter speed value. If you are using a 16mm lens, 500/16 = 31.25 sec, so that’s the limit of your shutter speed. If you go above that value, star trails begin to appear (refer part 2). It’s better to reduce shutter speed by 3-5 seconds than the actual value that you got from 500 rule though.
3. ISO
ISO is the measure of light sensitivity capability of the camera sensor. It varies from camera to camera. Lower the ISO value, lower will be its light sensitivity. We do want high light sensitivity as the amount of light is so low. But if we go above ISO 800, we can see a lot of noise or grains in the final output image. ISO 800 is still not well enough to capture night shots. I usually set ISO values around 2000 but it can vary based on the camera. There is not an actual value that I can quote here for ISO but it should stay in the range of 1600-6400. Obviously we can correct some noise during post-processing in software like Adobe Photoshop and Adobe Lightroom, but better to keep it as low as possible. Full frame cameras got the better signal to noise ratio than cropped sensor cameras.
Apart from these one important thing is that, do shoot in Raw format all the time. There are a lot of benefits to shooting in raw. You can record all the details and can dramatically improve under/overexposed images during post-processing if you shoot in raw. This is not just for Milky Way photography but for all types of photography.
There are certain settings option that you can find in-camera settings like “ reduce noise on long exposure”. Turning it on will reduce the grains but you’ve to compromise on details. Take some test shot toggling it on and off, compare the results, and decide.
Even though I use these settings most of the time I do Milky Way photography, I’d say experimenting will definitely end up with some surprising results. Good or bad, never care, learning gains experience. In the next lecture, I will come up with the planning and shooting of our galaxy. Until then grab your camera, run around, watch some flowers blooming, rivers flowing, play with the settings, and sketch the moments.
Now that you know what settings for astrophotography, learn how to get ready for your big day in the next article of this series
Next: Part 4 – Planning and Shooting
Check out our Online Astrophotography Session by Sarath Prabhav (AASTRO-Kerala) to know more about affordable astrophotography
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