Long exposure Tutorial

My brother was wanting to learn a bit more about taking long exposures at night, so we decided to go out on New Years Eve (after all of the festivities had died down) in our parent's neighborhood. I got a few pretty interesting photos, and I think that he learned a lot about it.

For those of you who might have the same questions, I'll try to make this as informative as possible. 

I was using my Nikon D4 and D800 with 14-24mm f/2.8  lens and my Fujifilm X-T1 with their 14mm f/2.8 lens.

D4 14mm f/2.8 20s ISO 400

Since Colorado has quite a bit of light pollution down the front range, and since the moon was so ridiculously bright that night (it had to be close to full), it was a bit hard to really get any stars, but despite the cold and light we went out anyways!

D4 14mm f/2.8 20s ISO 400

D4 14mm f/2.8 30s ISO 100

While I was using high level gear, you can definitely get pretty good results using even the entry level gear from any manufacturer out there, be it Nikon, Canon, Fujifilm, Pentax, Olympus, Sony, Panasonic, etc. All you really have to know are a few basics to get you started:

1. Long shutter speeds: This is what will allow you to pretty much turn night into day. The longer the shutter is open on your camera, the more light it will gather, and the better your exposure will be at night. As could be seen in the data I included in the pictures above, all of them were around 20-30 seconds long. Pretty much every camera that allows manual controls will let you get shutter speeds this long.

Another thing to be aware of with the shutter speed when taking photos of stars is a phenomena called star trailing. Because the earth is rotating that means that the stars are actually moving in the sky, albeit very slowly. So if you get a shutter speed longer than around 30 seconds or so you will start to pick up this slight movement. Now there is a rule regarding this if you want to get sharp, pin-point stars in your photos. This is called the 500 rule. Pretty much you have to take the focal length of your lens, say a 14mm, multiply it by the crop factor of your camera, or 1.5x for my Fujifilm X-T1, and divide 500 by this number. So 14x1.5=21mm, and 500/21=23 seconds. So I can theoretically have a 23 second long exposure with that lens without really getting any star trails in my photo. 

2. Tripod: This is a necessary accessory in order to achieve a sharp long exposure. If there is any camera shake at all during your photo, then it will show up as some blurring in the photo. So you will want to get your camera as stable as possible, so don't buy a $20 plastic Wal-Mart Tripod and expect it to stand up in the wind.

D800 14mm f/16 212s ISO 400

D4 14mm f/2.8 12s ISO 3200

D4 14mm f/2.8 10s ISO 1600

As you can see in my photo above from about a year ago, the longer the exposure and the more things that at moving the more you will get differing results from what your eyes can see. 

3. Aperture: Because of how the physics of light work with how small stars are relative to the size of the aperture of your lens, you will want to let in as much light as possible, so you will want to have as wide open of an aperture as you can get. For me this is usually f/2.8 on either my Fujifilm 14mm or my Nikon 14-24mm, but for most plastic kit lenses it is somewhere around f/3.5 or f/4. This is fine, you will just have to compensate a bit for the lack of light there with bumping up your ISO or having a longer shutter speed. 

However, that being said if you want to get a really long night exposure and there aren't really stars in the frame, then feel free to stop that aperture down to f/5.6, f/8, f/11, etc to get what you want. In the photo above I was at f/16 for something like 4 minutes. So it depends on the look you want. 

4. ISO: This is the sensitivity of you sensor to light, so the higher the number the more sensitive the sensor. But there is a trade off. The Higher you ISO goes, the more digital noise, or graininess, is introduced into the photo. A lot of the time when I am shooting stars or the Milky Way I will be shooting at ISO 3200 or 6400 for 20-30 seconds so as to avoid what is called Star Trailing. 

D800 24mm f/2.8 20s ISO 3200

And last but not least:

5. Cable Release: While not necessarily necessary, a cable release really can help you avoid camera shake in your photos by allowing you to take an exposure without touching your camera shutter button at all. Most cameras with manual controls will have the capability to take a cable release or a wireless remote, and they are relatively cheap, so I don't know why you wouldn't get one. Generally, I prefer using a corded cable release, as a lot of the time I am shooting night photos out in the cold and it is just one less battery to worry about going flat too fast. It is easier to keep track of the battery meter on your camera and not have to worry about anything else. 

That is pretty much it for now. I'll post a couple more photos here below, just to show my final image from new years eve in Fort Collins, and to compare 14mm on a crop sensor to 14mm on a full frame sensor. 

D4 19mm f/2.8 10s ISO 1600

D4 24mm f/2.8 17s ISO 1600

Fujifilm X-T1 14mm f/2.8 30s ISO 200

And my final image that I am quite proud of:

D4 14mm f/2.8 20s ISO 100

As you can see, the full frame 14mm is significantly wider, which really is one of the strengths of Full frame cameras, I must admit.

Thanks for reading, and of you have any more questions feel free to ask in the comments.

Kevin Fedde
Fedde Studios