C
Chavezshutter
New member
- Feb 4, 2022
- 142
- 194
Hi š.
As promised here is a guide for how I shoot and stack my star shots for anyone interested in astrophotography.
I am going to break down this guide into 2 sections - the first is how I capture a star image or light frame as they are also called in astrophotography and the thought and planning that goes into a star shooting session, the second part will be how I use Sequator to stack my star photography. Astrophotography is a very unique and technical style of photography that I believe should be experienced by any photographer to learn the wonders of the nightsky that can be captured by a camera. Star photography pushes the limits of modern sensors so it is not an easy task and that makes it very rewarding. There is a few concepts and technical aspects to discuss so let's begin...
Capturing a star image
Things you will need:
If your camera does not have an intervalometer function built in you will need to buy one, they can be purchased online for quite cheap. Please note that you want the ability to choose increments of 1 second, some inbuilt camera intervalometers only allow increments of 5 seconds when using longer shutter times. You will of course need a camera, good low light performance helps but most modern cameras can do a pretty good job. A tripod of course is a must for the exposure times we need.
The 500 rule:
Before even pointing our camera to a star there is a few things to keep in mind, the most important would be the concept of the 500 rule which I have mentioned in the past in previous posts. This rule is a guide which gives you an approximate amount of time for how long you can open your shutter before earth's rotation begins to create star trails instead of sharp star dots. The rules is simply 500/your lens focal length, the result of which is measured in seconds but we are going to add a sensor factor to cater for different sensor sizes and this needs to be calculated first so the updated version of this formula is :
Your lens focal length X sensor size factor (1 for fullframe, 1.6 for crop and 2 for MFT) and then 500/the previous result.
A typical astrophotography lens is a 20mm (FF, which would be about 14mm in crop) if we use this as our chosen focal length and we are using FF the 500 rule would look like this:
20(mm) x 1 (FF) =20 and 500/20 =25 seconds
If we are using a 16mm lens on a crop camera the 500 rule would be:
16(mm) x 1.6 (crop) = 25.6 and 500/25.6 = 19.5 seconds
Using this 500 rule we can a get a good approximate of how long we can set our shutters, I like being under the 500 rule by at least 5 seconds but you can experiment with this to see what works best for you. Camera's with higher MP should switch to the 400 or even 300 rule, which is a simple matter of using these numbers in the above formula instead of 500.
Shooting location:
So we have our equipment and we know our shutterspeed, but now we need to look at our shooting location. Ideally you should scout a location during daytime to check for nice foregrounds and any dangers to be aware of at nightime. Running around at night time carrying camera equipment in unknown locations is a bad idea. Phone planning apps can tell you where to expect to see the Milky way and you can then plan accordingly. If you don't use one of these apps you will need to look at something like this to workout the direction of the milky way prior and use these directions to workout where to frame your shot. Avoid having to face a major city or town to get less light pollution in your image. It is worthwhile trying to get to the darkest, least light polluted place you can get to get better end results. Find online the months when the milky way core is visible in your part of the world if that is what you want to capture.
Framing and composition:
With all that in mind and hopefully at a shooting spot with low light pollution and a night around new moon (avoid full moon for astrophotography). We are ready to frame our shot but we need to get past the issues of how to frame a shot in the dark. I personally prefer astrophotography with some foreground element to "ground" the final image, but you can play with that and try different compositions. Using a foreground there are few ways to get your composition in the dark, the torchlight is a good way, raising your ISO, or increasing your LCD's brightness can all help. Doing a photo with only night sky is going to be much harder to frame but possible with some of the tips I gave earlier. Once we have done our framing we are ready to look at focusing.
Focusing on stars:
Before I continue here I would like to point out that autofocus here is not what you want to use, not only are the chances that you will get good focus using AF low, we dont want the camera's focus to shift when we later have to take multiple shots for stacking. Manual focus is what we want to use.
It is a good idea also to set you other camera's settings before getting focus to make sure there is no accidental bumps that could affect focus, this means you have to set your aparture to the widest it can go, you can now set your shutterspeed we calculated earlier and your camera should either be fired remotely with an intervalometer or have a shutter delay timer to prevent vibrations from pressing the trigger. Turn off any stabilization and consider using an electronic shutter for less vibrations if you have one in your camera. The last setting you want to do before focusing is to set your ISO, this will vary with camera, aparture and conditions so it will require some testing but a good general starting point is ISO 3200, raise it or lower it to match your settings but do try to stay lower rather than higher to avoid too much noise. And now unto focusing.
The goal of the photographer is to focus to infinity to get sharp stars, there are a few ways that focusing can be achieved:
EDIT NOTE; I have written a good chunk of the second and final part of this, but I want to post what I have so far to "get the wheels turning" for anyone interested in shooting stars while I get some video and screenshots to help with next section. Feel free to comment while I get the next section done over the next few days,
Cheers,
Aaron
As promised here is a guide for how I shoot and stack my star shots for anyone interested in astrophotography.
I am going to break down this guide into 2 sections - the first is how I capture a star image or light frame as they are also called in astrophotography and the thought and planning that goes into a star shooting session, the second part will be how I use Sequator to stack my star photography. Astrophotography is a very unique and technical style of photography that I believe should be experienced by any photographer to learn the wonders of the nightsky that can be captured by a camera. Star photography pushes the limits of modern sensors so it is not an easy task and that makes it very rewarding. There is a few concepts and technical aspects to discuss so let's begin...
Capturing a star image
Things you will need:
- Camera, of course š
- A intervalometer, if your camera has an inbuilt intervalometer function you can use that instead. You don't need an intervalometer for a single (non-stacked)star shot * See more below
- Wide, preferably fast lens. * See more below
- Tripod.
- A good, strong torchlight or headlamp.
- Good weather with no cloud cover or very little.
- Night sky, ideally with low light pollution. Seek out the darkest skies available to you. Use this to help you find dark skies. * See more below
- A night around new moon, full moon will reduce the amount of stars you capture.
- Planning phone apps like Photopills, Stellarium and others can help but its not a neccesity. * See more below
- A lens warmer like this for longer shooting sessions or cold climates is very helpful to fight condensation and dew on your lens, you will need USB power to power it, I use the same USB powerbank to power my warmer and camera for long shooting sessions.
If your camera does not have an intervalometer function built in you will need to buy one, they can be purchased online for quite cheap. Please note that you want the ability to choose increments of 1 second, some inbuilt camera intervalometers only allow increments of 5 seconds when using longer shutter times. You will of course need a camera, good low light performance helps but most modern cameras can do a pretty good job. A tripod of course is a must for the exposure times we need.
The 500 rule:
Before even pointing our camera to a star there is a few things to keep in mind, the most important would be the concept of the 500 rule which I have mentioned in the past in previous posts. This rule is a guide which gives you an approximate amount of time for how long you can open your shutter before earth's rotation begins to create star trails instead of sharp star dots. The rules is simply 500/your lens focal length, the result of which is measured in seconds but we are going to add a sensor factor to cater for different sensor sizes and this needs to be calculated first so the updated version of this formula is :
Your lens focal length X sensor size factor (1 for fullframe, 1.6 for crop and 2 for MFT) and then 500/the previous result.
A typical astrophotography lens is a 20mm (FF, which would be about 14mm in crop) if we use this as our chosen focal length and we are using FF the 500 rule would look like this:
20(mm) x 1 (FF) =20 and 500/20 =25 seconds
If we are using a 16mm lens on a crop camera the 500 rule would be:
16(mm) x 1.6 (crop) = 25.6 and 500/25.6 = 19.5 seconds
Using this 500 rule we can a get a good approximate of how long we can set our shutters, I like being under the 500 rule by at least 5 seconds but you can experiment with this to see what works best for you. Camera's with higher MP should switch to the 400 or even 300 rule, which is a simple matter of using these numbers in the above formula instead of 500.
Shooting location:
So we have our equipment and we know our shutterspeed, but now we need to look at our shooting location. Ideally you should scout a location during daytime to check for nice foregrounds and any dangers to be aware of at nightime. Running around at night time carrying camera equipment in unknown locations is a bad idea. Phone planning apps can tell you where to expect to see the Milky way and you can then plan accordingly. If you don't use one of these apps you will need to look at something like this to workout the direction of the milky way prior and use these directions to workout where to frame your shot. Avoid having to face a major city or town to get less light pollution in your image. It is worthwhile trying to get to the darkest, least light polluted place you can get to get better end results. Find online the months when the milky way core is visible in your part of the world if that is what you want to capture.
Framing and composition:
With all that in mind and hopefully at a shooting spot with low light pollution and a night around new moon (avoid full moon for astrophotography). We are ready to frame our shot but we need to get past the issues of how to frame a shot in the dark. I personally prefer astrophotography with some foreground element to "ground" the final image, but you can play with that and try different compositions. Using a foreground there are few ways to get your composition in the dark, the torchlight is a good way, raising your ISO, or increasing your LCD's brightness can all help. Doing a photo with only night sky is going to be much harder to frame but possible with some of the tips I gave earlier. Once we have done our framing we are ready to look at focusing.
Focusing on stars:
Before I continue here I would like to point out that autofocus here is not what you want to use, not only are the chances that you will get good focus using AF low, we dont want the camera's focus to shift when we later have to take multiple shots for stacking. Manual focus is what we want to use.
It is a good idea also to set you other camera's settings before getting focus to make sure there is no accidental bumps that could affect focus, this means you have to set your aparture to the widest it can go, you can now set your shutterspeed we calculated earlier and your camera should either be fired remotely with an intervalometer or have a shutter delay timer to prevent vibrations from pressing the trigger. Turn off any stabilization and consider using an electronic shutter for less vibrations if you have one in your camera. The last setting you want to do before focusing is to set your ISO, this will vary with camera, aparture and conditions so it will require some testing but a good general starting point is ISO 3200, raise it or lower it to match your settings but do try to stay lower rather than higher to avoid too much noise. And now unto focusing.
The goal of the photographer is to focus to infinity to get sharp stars, there are a few ways that focusing can be achieved:
- If you have focus magnification zoom into a star with max zoom and then turn your focus to create the smallest star possible.
- Another way to get focus is to use the infinity marker symbol ā on the lens, however, you need to confirm first that this is indeed infinity focus as not all lens are acurately marked. This should get you close even if it may need some fine tuning later
- You can also try to achieve infinity focus during daylight by focusing on a far object, use tape to prevent the focus ring from moving or use a mobile to take a photo of where true infinity focus is and then use this same setting to shoot.
- Another good option which gives great results fast is a Bahtinov mask, here is a link of it in action and they can be purchased online for quite cheap
EDIT NOTE; I have written a good chunk of the second and final part of this, but I want to post what I have so far to "get the wheels turning" for anyone interested in shooting stars while I get some video and screenshots to help with next section. Feel free to comment while I get the next section done over the next few days,
Cheers,
Aaron
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