Long Exposure Photography Lesson 3 (Of 4)

Long Exposure Photography Lesson 3 (of 4)

1) Night landscape photography a) Stars as points b) Star trails 2) Assignment

All night landscape photography is long exposure photography because it is dark. For this reason, no filters are needed or should be used. The dark is acting as your filter. I have divided this category into two types – stars as points and star trails. Both are long exposures, but star trails are longer exposures of a similar scene. Star tails, also known as star streaks, are the result of a long exposure that includes a starry sky. So why do the stars trail? Since the earth is moving to the east, the stars appear to move to the west. It’s not the stars that are moving; it’s us here on earth. “Stars as points,” on the other hand is a bit of a misnomer. Because the earth never stops moving, the stars will always show apparent movement in a photograph. The key is to use an exposure time that is short enough that the star movement or ‘trailing’ cannot be detected by the human eye in the resulting image. The keys to shooting these special types of long exposures are discussed in detail in this lesson.

• Night landscapes with stars as points in the sky

When photographing night landscapes when your goal is to have the stars appear static, or as points, there is an easy rule that will help you find a starting point for the exposure time that will keep them as close as possible to points (rather than trails). It is called the 500 Rule:

Divide 500 by your effective focal length* to get the approximate maximum number of seconds you can expose before the stars begin to trail

* Effective focal length takes into account whether you are shooting with a full-frame camera or crop-sensor camera. If using a full-frame camera, then the effective focal length is the nominal focal length of your lens (e.g., 25 mm = 25 mm). However, if you are using a crop-sensor camera, then you need to calculate the effective focal length by multiplying the nominal focal length (e.g., 25 mm) by the crop factor for your camera. For Canon, the crop factor is 1.6; for Nikon, 1.5; Sony, 1.6; Olympus, 2.0, Pentax 1.5, etc. So, for a Nikon crop-sensor camera, for example, the effective focal length for a 25 mm lens would be 25 x 1.5 = 37.5 mm.

As indicated, this is only a starting point, and often you will need to decrease the exposure time to keep the stars from trailing unacceptably. The point at which the trailing is no longer acceptable when you zoom in on the image on the LCD monitor is very subjective. There is no right or wrong exposure time; however, you will need to consider how large you may want to print an image when making the decision. If you hope to print a very large image, then you may want to reduce the 500 Rule to the 400 Rule or even the 300 Rule so that the trails are less apparent. Remember that by doing that, you reduce your exposure time to the point that you may have to increase the ISO to get the light needed onto your sensor for a correct exposure. This is a trade-off and one that must be considered.

The 500 Rule

EFFECTIVE FOCAL APPROXIMATE MAX LENGTH EXPOSURE TIME 14 mm 36 seconds 20 mm 25 seconds 24 mm 21 seconds 35 mm 14 seconds 50 mm 10 seconds 100 mm 5 seconds 200 mm 2.5 seconds 300 mm 1.67 seconds 500 mm 1 second

It is important to take into consideration the direction that the camera is pointed. If pointed north or south toward the poles, the stars will appear to move more slowly, giving you a little more wiggle room with the 500 Rule. If you are pointed east or west, however, the stars will appear to move more quickly, and you will have to be more conservative than the 500 Rule allows.

25 sec, f/2.8, ISO 4000 No filter Nikon Df, Zeiss 25 mm f/2 lens © Beth Ruggiero-York

• Star trails

It follows the explanation of stars as points that the longer you open your shutter, the more the stars will trail. The trailing is not random; rather, it is in rotation around the poles. So if you point your camera to the north in the Northern Hemisphere or the south if you are in the Southern Hemisphere, the resulting long exposure will show circular star trails around the pole.

2601 sec, f/4, ISO 200, 21 mm Nikon D7100, Nikkor 14–24 mm f/2.8 lens @ 21mm effective focal length

Taken in Rhyolite, a ghost town in Nevada, this is a single long exposure lasting approximately 43 minutes facing just east of north. Polaris is the star that © Beth Ruggiero-York

appears almost at the center of the star trail circles, indicating the northerly direction.

In the Northern Hemisphere, we have the advantage of a star very close to the actual pole called Polaris (aka, North Star) to help us locate the North Pole. By locating Polaris, you can plan your night landscape composition to include circular star trails in the background sky. The apparent movement of the stars as the earth rotates is about 15 degrees per hour horizontally; they do not move vertically. To locate Polaris, you must first find the Big Dipper in the night sky. Follow the two stars at the end of its ladle upward to the last star on the handle of the Little Dipper – this is Polaris.

Follow the two stars at the short end of the ladle of the Big Dipper upward to the first star on the handle of the Small Dipper. That first star is Polaris.

Another helpful fact for finding Polaris is that its altitude is at the same number of degrees as your current latitude in the Northern Hemisphere. For example, at approximately 33° north in Phoenix, if you look up 33° in a northerly direction on a clear night, you will find the approximate position of Polaris.

To shoot long exposures of star trails with any type of foreground requires some preparation, which was discussed in Lesson 1 under the “Technical Stuff” section. Be sure to have the needed camera gear and review the focusing © Beth Ruggiero-York techniques. Just as important is to scout out your shooting location while it is still light. Night photography has its challenges to begin with, but setting up and composing in the dark just compounds the challenges. Find your desired location ahead of time in daylight, walk the site and determine possible compositions. Look for hazards in the terrain.

Below is a detailed description of what items you need when photographing after dark and how they will serve you.

Night Photography Equipment

One of the most common initial questions students ask when taking their first steps into the field of night photography is “What equipment do I need?” The answer is that, while greater capability and flexibility come with more advanced camera bodies and lenses, you can create excellent images with entry and midlevel DSLRs with moderately priced lenses. For the type of night photography being addressed in this book, however, I would not recommend a point-and-shoot camera. Here is a list of equipment I recommend. Required items are marked with an asterisk:

1. *DSLR with Bulb Mode capability (ability to expose for over thirty seconds with the use of a remote release) One of the advantages you gain with the newer, higher-end DSLRs is better high-ISO capability. With the longer exposures required for most night photography, your camera’s ability to handle high ISOs cannot be ignored. Additionally, it is generally recognized that a full-frame DSLR is the best choice for night photography due to better high-ISO handling, rather than a crop-sensor (APS-C) DSLR. As I indicated above, though, this absolutely does not mean that your crop-sensor camera can’t be used for successful night images; I am simply pointing out the preferred tools.

2. *Sturdy tripod This is just as important as the DSLR. I have seen way too many students struggling to set up their cameras on flimsy tripods with extended center posts. There are good-quality, stable tripods available for a reasonable price (e.g., Induro, Vanguard, etc.). Of course, if your budget allows, Gitzo and Really Right Stuff are the highest quality. Ideally, your tripod will be tall enough when fully extended for you to stand © Beth Ruggiero-York

behind it at eye level without having to bend down to look through the viewfinder. Many smaller and less expensive tripods have a center post, a column that extends upward to increase the height of the tripod. If your tripod does have a center post, using it should be avoided because it creates a less stable platform for the camera. If you have no choice but to use it, there are ways to stabilize any tripod that are worth considering. One is to hang your camera bag from the hook that is attached to the bottom of the center post or, if your tripod does not have a center post, the hook is where the tripod legs meet at the top. Not all tripods without center posts, however, have a hook, but you can add an after-market hook.

3. *Remote cable release, preferably an intervalometer Aside from the usual reason for using a remote release— eliminating camera shake caused by manually pressing the shutter release—there are other important reasons why you need to have a remote release for night photography. When you get into exposures of more than thirty seconds, which you will at night, a remote release is required to keep the shutter open for those long durations. This is a technical requirement for your camera’s Bulb Mode. There are wired, wireless, and infrared remote releases, as well as wired and wireless intervalometers (see explanation below). Based on my experience with all three, I recommend sticking with the wired version of either. The wireless releases, and especially the infrared releases, can be unpredictable at times, and when you have spent time setting up a shoot and calculating your settings at night, the last thing you want to deal with is a temperamental remote release. Infrared releases are even more temperamental, so they should not even be a consideration for your night photography. Too much time is wasted in the field during night workshops trying to resolve issues with wireless remotes. Save yourself the headache. An intervalometer is simply a remote release that has a timer function and can be programmed for multiple shots for a specified time and a specified interval between the shots. There is also the ability to delay the program for minutes or hours. If you want to shoot star trails using the stacked method (Method 2), you will need an intervalometer. If you purchase a name-brand (e.g., Nikon, Canon, etc.) intervalometer, you can expect to pay between $130 and $160. However, if you buy one of the third-party brand intervalometers, such as Vello, © Beth Ruggiero-York

Polaroid, Neewer, etc., you will pay less than half that amount for an equivalent product. Judging from the identical design and functioning of many of these items, I would guess that they are all manufactured in the same factory in China. Once again, I advise against the wireless variety (besides, they are more expensive). There is another alternative to the conventional intervalometer or cable release. It is a free app called TriggerTrap for your smart phone. It has all the functionality of an intervalometer and more. While the app itself is free, you do have to purchase a dongle and a camera-specific cable to attach your phone to the camera. These can be purchased at the company’s website, www.triggertrap.com. The advantage of TriggerTrap is its user-friendly interface on your phone. It is much easier to program and operate than the conventional intervalometers, and it has so many more features, such as bulb ramping (aka bramping, which automatically adjusts exposure settings to maintain one exposure value (EV) throughout the duration of a time-lapse sequence), and time-lapse. The one possible limitation of using this system is your smart phone’s battery life. If you choose to use TriggerTrap, plan on buying a phone case that is able to provide extra charging on-the-go. The battery cases provide 100 percent to 150 percent extra power to your phone, depending on the model you buy, and are available for both iPhones and Android. Even with a battery case and a fully charged phone at the start of your shoot, you should make sure all your other apps have been closed so that they are not draining your phone battery unnecessarily.

4. *Fast, wide lens A fast (ideally f/1.4 or f/2.8), and wide (35 mm or wider) lens for night landscape photography and skylines is needed. For urban street photography, which is the only type of night photography that can be done handheld, a fast, normal lens (e.g., 35 mm to 50 mm, f/1.4) is ideal so that you can get the fast shutter speeds needed to get sharp images. Why use a fast lens? Because you need the widest possible aperture to gather as much light as possible, thereby decreasing your exposure time, which at night is already by default a long exposure. Whether shooting night landscapes with stars as points or handholding the camera for street shooting, only with the shortest possible “long exposure” times will you be able to capture stars with as little trailing as possible, or get the sharpest possible handheld image, and avoid higher © Beth Ruggiero-York

ISOs. Another way of decreasing your exposure time is to increase your ISO, but depending on your camera model, this will begin to introduce high ISO noise. Sometimes you have no choice, but remember that ISO is your last resort for decreasing exposure time. Why use a wide lens? For the same reason you want to use a fast lens: when photographing stars as points in night landscapes, you need to gather as much light as possible for the correct exposure without resorting to higher ISOs. When using the 500 Rule described later in this book, you are able to get the longest exposure times possible with a wide lens while keeping the stars as points and not increasing ISO. Another reason for the wide lens is that, for images of night landscapes as well as skylines, you want to include broad scenes. The sky is vast, and for most night landscapes, allowing the viewer to see its expanse creates more of a wow factor. For skylines, you want to encompass as much of the skyline as is desirable. [Note: Another option for photographing a skyline is to do a multi-image panorama to be merged in Adobe Lightroom, Photoshop, or other panorama software.]

Here are three lists of suggested wide-angle lenses for night photography, using both crop-sensor and full-frame lenses, at different price levels:

Crop-sensor camera lenses for night photography—under $1,000:

• Sigma 10–20 mm f/4-5.6 EX DC HSM • Rokinon 10 mm f/2.8 ED AS • Tokina 11–16 mm f/2.8 AT-X116 Pro DX II • Tokina AF 12–24 mm f/4 AT-X 124 Pro DX II • Canon EF-S 10–22 mm f/3.5–4.5 USM

Full-frame camera lenses for night photography—under $1,000:

• Rokinon 14 mm f/2.8 • Rokinon 24 mm f/1.4 • Sigma 24 mm f/1.4 Art Lens • Sigma 35 mm f/1.4 Art Lens • Sigma 17-50 mm f/2.8 EX • Tokina AT-X 16–28 mm f/2.8 Pro FX • Canon EF 17–40 mm f/4L USM © Beth Ruggiero-York

Full-frame/crop-sensor camera lenses for night photography—over $1,000:

• Nikon (Nikkor) 14–24 mm f/2.8G ED AF-S • Tamron SP 15–30 mm Di VC USD • Zeiss 25 mm f/2 Distagon • Zeiss 21 mm f/2 Distagon • Zeiss 15 mm f/2.8 Distagon

The lenses I have listed above can vary greatly in the quality of the images they produce. Sometimes you get what you pay for, but not always. The Rokinon lenses can be an excellent choice for a very reasonable price, but be aware that they are manual focus only. It is worth noting that the Sigma 24mm f/1.4 Art lens listed above under “full- frame camera lenses for night photography under $1,000” has been released, and it is of the same high quality as the first two “art” lenses Sigma recently released (35 mm f/1.4 and 50 mm f/1.4).

5. *Flashlight A flashlight serves several purposes in night photography: safety as you walk in the dark, general lighting as needed on your camera or camera bag, and light painting. Many photographers use headlamps, but I do not recommend this if you are shooting with others. If you are shooting alone, the headlamp is a very convenient tool for lighting the way as you walk or, if you do not know your camera controls as well as you should, for shining a light on the camera body to see what you are doing. If you are with other photographers though, using a headlamp runs the risk of ruining someone else’s shot or their night vision. After numerous workshops and field sessions with students wearing headlamps, I have realized that a bright light (red or white) on your forehead shining in someone else’s eyes or shot is nothing but a hindrance and annoyance. It temporarily blinds the other person, or it ruins the other person’s long exposure. The reason for the red light option, which I do recommend for the flashlight you use at night, has to do with night vision. Without getting into the physiological reasons, it is important to know that your eyes need several minutes to adjust when transitioning from a light to a dark environment. If after adjusting to the dark your eyes are exposed to a bright light again, they have to start over again with the adjustment process. In other words, several more minutes are needed. Red light, © Beth Ruggiero-York

however, does not affect your night vision, which is why astronomers use red lighting at night. So you may be wondering why a red headlamp is not a good solution. It is because a headlamp, whether red, white, or any color, will find its way into your shot or the shot of your fellow photographers. What I recommend for illuminating your way as you walk around at a night photography site when other photographers are present is a small flashlight (white, red, or both) that you keep turned off in your pocket or around your neck on a lanyard. When you need light, cover the light with your hand and then turn it on so that it is dimmed. Use the light in this way to guide your steps or to illuminate your camera just enough. When done, turn it off immediately with your hand still over the light.

6. Smart phone Today’s smart phones have countless apps available to help with your planning and execution of night photography. They range from in-depth planning tools, such as The Photographer’s Ephemeris, The Photographer’s Transit, and calendars for planning, to depth-of-field calculators and identification aids for night sky objects. New apps are always coming out, but some of my favorites that are tried and true are listed below.

Apps for Night Photography

Ø The Photographer’s Ephemeris (iOS for iPad, $8.99, as well a free web app for your laptop or desktop) and The Photographer’s Transit (iOS for iPad, $8.99) for detailed planning of your shoot. These are the premier planning apps available, and I consider them requirements for successful shoots, day and night. Ø Moon Calendar (iOS only, $1.99) for finding out moon phase and related times Ø PhotoPills (iOS and Android - $9.99) for detailed planning of your shoot as well as helpful tutorials on their website (www.photopills.com) © Beth Ruggiero-York

Ø Stellarium (iOS and Android, $2.58), SkyMap (iOS and Android, free), SkySafari (iOS and Android, $2.99), Planets (iOS and Android, free)—all planetariums for your phone or iPad Ø DOF Master (iOS, free) for calculating depth-of-field and hyperfocal distance Ø TriggerTrap (iOS and Android, free app, dongle and camera-specific adapter must be purchased, about $40.00), an intervalometer on your phone that does a lot more than a conventional intervalometer

7. Magnifying loupe While not a requirement, a 1:1 magnification loupe, such as the Hoodman HoodLoupe, is a great tool for night photography when checking your focus on the LCD on the back of your camera.

8. *Gaffer tape I recommend keeping a small roll of gaffer tape in your camera bag for general purposes at all times, but even more so at night. It will be very helpful when focusing at night. Gaffer tape is a heavy cotton cloth tape that has strong adhesive properties and is widely used in the film and television production, photography, and theater. It is easily available on Amazon.com and in hardware stores. After achieving focus, you will switch the camera to Manual Focus, if it wasn’t already there, and gently place a small section of the tape on your focus ring to lock down the focus. In this way, any bumps or stray movements of your hand on the lens will not accidentally move the focus position. Gaffer tape is recommended rather than duct tape because duct tape will leave adhesive residue on your lens. It should be noted, however, that in extremely cold temperatures, the gaffer tape loses much of its adhesiveness.

9. *Extra charged batteries Two factors of night photography result in the need for keeping extra charged batteries with you. Long exposures, such as single-exposure star trails, will drain your batteries. Some cameras have longer-lasting © Beth Ruggiero-York

batteries than others (e.g., Nikon and Canon), but it is always good to have a couple of extras with you in the field.

Two Methods for Photographing Star Trails

Method 1: Single longer exposure

The first method is simply taking a single very long exposure using a fast lens (e.g., f/2.8). Use this method when the moon is not visible (new moon, before moonrise, or after moonset). Because of the exposure time used for this method, typically thirty to forty-five minutes, the sensor will heat up. For this reason, the temperature should ideally be below 50° F, at most 60° F. The sensor will still heat up, but not as quickly, so the resulting noise will be less. If you still want to shoot a single long exposure when there is a crescent moon, be sure not to expose for longer than ten minutes. In all cases, start by taking a High ISO Test Shot (explained below). You want to expose for 30-45 minutes, so you need your test shot results to be 30-45 seconds. Be sure to understand the concept of the test shot explained below.

1810 sec, f/4.0, ISO 200, 24 mm Nikon Df, Rokinon 24 mm, f/1.4 lens

This was a single long exposure of about 30 minutes. The temperature was in the 50s (Fahrenheit), so sensor overheating was not an immediate concern.

Method 2: Multiple shorter exposures for stacking

Fifteen 2-minute exposures, f/2.8, ISO 200 Nikon D800E, Nikkor 14–24 mm f/2.8 lens @ 24mm

This second method involves multiple long exposures of the stars taken at the shortest possible interval between shots and then “stacking” the images in post-processing. The long exposures for this method are much shorter than the one for the first method, and it allows for more flexibility in post-processing.

After setting up your camera, you will determine the exposure settings using the “High ISO Test Shot” (discussed below). You then program your intervalometer for the desired number of exposures for the exposure time you determined with the test shot at the shortest interval allowed by your intervalometer (usually one second, unless you are using the TriggerTrap app or CamRanger). When deciding how many exposures you need, aim for a total of at least 45 to 60 minutes of exposure (the longer the better—some situations © Beth Ruggiero-York may warrant many hours), such as thirty two-minute exposures or fifteen four- minute exposures.

When capturing images using Method 2 for stacking, be sure to:

• Turn off Long Exposure Noise Reduction (LENR); • Expose to the right of the histogram without overexposing the highlights; • Base the total exposure time on your desired star trail length; however, the longer your total exposure time, the better, because this allows you flexibility to choose the best shots for the final stack; • If desired or needed for a dark foreground, add light painting on the first or last exposure;

The process of stacking the images in post-processing is not difficult, and there are many options. The simplest of these is using a free program called StarStax (http://www.markus-enzweiler.de/software/software.html) for both PC and Mac. It is a simple program to use and has many features. A drawback of StarStax is its inability to handle RAW images. Another more versatile option is to stack the images in Photoshop, for which there are multiple methods.

High ISO Test Shot

A high ISO test shot is a very useful tool to determine camera settings for long exposures at night without spending a lot of time and battery power. The test shot needs to be taken when under the same lighting conditions as the actual shot that will follow. In other words, if you are planning a landscape image with dark, starry skies, take the test shot when it is fully dark. If the moon is still up, but your shot is planned for after the moon sets, then wait until the moon sets before taking the test shot; otherwise, the settings determined by your test shot will not be accurate.

For the test shot, set your camera to the following:

ü Manual mode ü Long Exposure Noise Reduction OFF ü Lens at desired (widest or close to widest) aperture ü Starting test shot exposure time = 1 second © Beth Ruggiero-York

∗ ü ISO = Lowest native ISO (LNI) + 6 stops

Then focus and take the test shot. Check the focus, composition, and exposure.

The test settings above translate to the following formula:

x seconds @ (LNI + 6 stops) = x minutes @ LNI or, Number of seconds @ (LNI + 6 stops) = Number of minutes @ LNI

If the test shot is a perfect exposure, then your settings will be one minute at LNI for your camera. More likely, you will have to do a few high ISO test shots before deciding on the correct exposure for the scene. Fortunately, they are quick and easy to perform once you get the hang of it.

ASSIGNMENT

Using the techniques in this lesson, shoot one correctly exposed image at night with stars as points. Do not post-process the image.

Then, do high ISO test shots (as many as necessary) to determine the correct exposure for a single long-exposure star trail image (i.e., 30-45 minutes). Then use those settings to shoot the star trail image. Submit the one high ISO test shot that gave you the correct exposure time for the star trail image along with the star trail image. Indicate your settings when you submit the images. Do not post-process the images.

Also include any comments or questions you had while making the images.