A Guide to Astro-Photography// PART ONE
Updated: May 20, 2020
So if you haven't noticed already, I'm an aspiring photographer. I don't have a particular style, my laptop is full of photos, from portraits, to sports photos to landscapes and still life (though I tend to steer clear of still life, it's a little too still for me). 😆 However, I will forever and always love taking star photos, there's something really awesome at recording the beauty of night in a photo, though it's not easy. I'm completely self-taught and I'm definitely no expert. My photos are still definitely a work in progress, but my goal with these posts is to help develop other people's skills in any way I can help!
Partly as a record, and partly to spill everything I know, I've decided to write this series. I've divided the posts up into two sections, so that I don't end up mixing tips and repeating myself.
1. Taking The Photos
2. Different Compositions + Editing
Here is an example of some of the star photos I've taken over the years, starting from two years ago when I took my first shot.
I took the last photo about three days ago using my Dad's Canon EOS 70D at a focal length of 18mm. Most professionals would use a wider lens/camera body, that has the capability to have an even lower aperture. The lowest aperture I can get my camera to is f3.5, whereas some can get down to around f1.4.
TAKING THE SHOTS -
QUICK GUIDE - REGULAR SHOTS
- Use a Tripod!
- Manual Mode
- Manual Focus
- Aperture - As low as possible (F3,5)
- Shutter Speed - Between 20-30s depending on conditions
- ISO - Between 3200-6400 depending on conditions
- RAW file
Here's the rundown:
Before you go anywhere, make sure you have a Tripod with you! Most of the photos take around 20-30s to shoot, and you cannot hold the camera still enough to get a good, clear shot of the stars if you are holding it! You can attempt to get away with balancing the camera on something, but it's hard to find something that points upwards, and guarantees you aren't picking up the haze of the atmosphere. Another tool I recommend is using an app that maps the sky for you, so that you are able to see where the most concentration of stars is, (usually the milky way), as this gives you the most interesting shots. I highly recommend Sky Safari, it even enables you to search and track particular objects in the sky, such as comets, meteor showers and satellites,
Manual Mode is important for astro-photography, as it means you have full control of the three main settings, shutter speed, aperture and ISO. On my camera, there is a dial on the top left, displaying a big M. This should be similar for most cameras, however other brands may have different names/placement of this setting.
Manual Focus is very important as well. The switch between Auto and Manual Focus should be on your lens. Automatic Focus will not be able to pick up the stars, so you must manually focus them in. This is one of the most frustrating and time consuming parts of astro-photography. I believe about 40% of my time is spent focussing, 10% fiddling around with other settings and the other 50% waiting for the photo to be taken. I've read multiple articles about how to avoid blurry stars (you can see in some of my photos, the stars are more blurry than others, as you follow my learning curve), but I've found I just need to take as many practice shots as possible before I can take that one 'banger of a photo.' If you're really into it, there's actually particular lenses you can buy that focus to infinity, which would be absolutely amazing, but personally I don't have the money for that. 😂 I have also seen articles that advise focussing on the horizon during the day, and then waiting for night to fall, but stupid me managed to unfocus it while I had all my camera stacked on my shoulder trying to get into the paddock to find the right spot. Another way to help with this, is the use of Live View, which shows your photo through the screen instead of the viewfinder. If you're lucky, sometime it picks up stars and you can pick up if you're in focus or not. Be careful though, sometimes when flicking between Live View and viewfinder it changes the settings, as the capabilities of Live View ends at a 1/30th of a second exposure on the 70D. We need 30 whole seconds! I would also recommend using a Timer, or a Remote, as this eliminates any chance of camera shake when you press the shutter down.
Aperture is how much the lens opens when taking a shot, or how much light is let in. It directly affects your depth of field, or how much blur/focus is in your photo. If you have a large aperture, for example f22, the lens will let hardly any light in and, everything in your shot will be in focus, with no background blur. However, if you have a small aperture around f3.5, which my camera can go down to, there is a lot of light let in and everything except the subject will be blurred.
Because stars are so dim, and hard for the camera to pick up, it's important to have the aperture as low as possible, as to pick up the most amount of light.
I found a few photos a while ago to help visualize what's going inside the camera.
The next setting is Shutter Speed. My camera is capable of going automatically up to 30s, which I believe is the same for most mid-range cameras. Depending on how big your lens is, you can usually get away with about 25s of exposure before your camera starts to pick up star trails, which I will touch on later in the post. There's actually a calculation you can do, which will give you the amount of time for an exposure before your camera starts to pick up the earth's rotation depending on your lens focal length. This is called the 500 Rule.
Divide 500 by the length of your lens; for example my lens is an 18-135mm lens, so I will divide 500 by 18mm which equals 27.7s. I can get away with around 27 seconds of exposure before the earth's rotation gets picked up as a star trail in my photo.
ISO is basically your camera's sensitivity to light. I looked up what it stands for, as I've always wondered in the back of my mind, but turns out it stands for:
"The International Organization of Standardization, which is the main governing body that standardizes sensitivity ratings for camera sensors (among many other things)."
Kinda wacky right? I actually had to search it a few times because I thought it would be standing for some scientific analyzation of the mechanics, not the name of an organization. (They could have at least got the letters round the right way.) 😆
But anyway, the lower your ISO the less light your camera will pick up, and therefore the darker your image will be. Sounds pretty simple, just put the ISO up as high as possible right? However, there's a catch, the higher the ISO, the more grainy your photo can be. While in some daytime shoots that can be trendy, it can make star photos looks quite pixelated and rough. I usually have ISO as low as I can without it taking away from my photo, about 3200 usually does the trick. However, depending on your conditions, for example if the moon is out and you can work with the pain of shooting with the moon, your ISO will be lower as there is more light for the camera to pick up.
RAW Shooting is pretty much making sure your camera collects all the data. Most default shooting setting will be set to JPEG, which means a smaller file. To get the file smaller some information has to be dropped, which includes important detail to the photos. Because every camera is different, I can't tell you exactly how to change this, but on the 70D, under the first drop-down when you press menu is a setting called Image Quality. You get the choice of RAW (20MB), MRAW (11MB) and SRAW (5MB), which of course is size of the photo. As well as this there is a choice between size of JPEG, but this setting should be set to the dash, so that you're shooting in RAW only. I had my settings accidentally in RAW + L which meant I actually got a duplicate photo for each shoot, a RAW file as well as a large JPEG. I think my storage had a heart attack.
So that's everything I can think of for taking the photos themselves, and I will write up a second part to this for my next post, for now I hope you got something from that, I'd love to hear from you!