The popularity and portability of smartphones and tablet computers make them ideal tools for the far-flung landscape photographer. Impressive computing power to solve a field problem is as close as your shirt pocket or camera bag. The following are a few of the apps I use and recommend.
These apps indicate the sun and moon coordinates at any global location during any date and time and overlay them on satellite imagery. The most popular is The Photographer's Ephemeris, or TPE for short. They also have a free web-based application with fewer features (unless you pay for an upgrade). Another popular contender is PhotoPills that includes many photographic aids not found in TPE.
The Photographer’s Ephemeris (TPE)
The TPE screenshot below shows an example how this app basically works. You position a red pin on a location, select a date, and the rise and set directions of the moon and sun are displayed relative to the red pin. In addition, you can animate the sun and moon positions as you scroll the timeline in the bottom screen.
Another feature is the “grey pin.” Wherever you place the grey pin you can determine the distance, elevation, and terrain profile between the red and grey pins. You can also search future dates and times for when either the sun or moon is in a particular alignment, which is extremely handy when planning future shots.

TPE: Yellow is sunrise, orange is sunset, light-blue is moonrise, and dark-blue is moonset. Thin light-orange line is sun’s current direction at the selected time of day.
PhotoPills
PhotoPills does essentially the same thing as TPE plus it offers tools not found in TPE. They include tools relating to depth-of-field, exposure conversion, star trails, and time-lapse photography to name just a few. If you do a lot of astrophotography, you’ll certainly want PhotoPills. I have both apps and use primarily TPE because I find it easier to work with. I keep PhotoPills as a backup for whenever I need one of its special features that I’ll demonstrate in a later chapter.
This amazing app addresses a common vexation for landscape photographers: how the sunrise or sunset lighting will appear across the landscape. That’s where TPE 3D steps in and literally shows you a ground-level 3D-visualization of the lighting. TPE 3D runs only on iOS 10 (and up) and can be purchased bundled with TPE and The Photographer’s Transit on the Apple App Store.
Example
Below is a sunrise shot of Lundy Lake in the California Eastern Sierra taken in October. While the reflection is nice, the image suffers from lopsided lighting (along with a bland sky). Setting TPE 3D to the same time, you can see in the next image that it does a good job at simulating this particular lighting event.

Lundy Lake: Taken in early October, the sunrise lighting is lopsided.

TPE 3D Simulation: TPE 3D provides a remarkably accurate depiction of the same scene.
To find a better time when the lighting is more symmetrical, I used TPE to determine when the sunrise shines through the middle of the lake (which is late August). Then, I used TPE 3D to preview what it will actually look like, as shown in the image below. TPE 3D also shows the sun, moon, and star movements as you advance the time line.

Lundy Lake Simulated in Late August: This simulation visually confirms a more desirable lighting scenario in late August.
What about Google Earth?
Prior to TPE 3D, the only other option was Google Earth’s sunlight tracking slider when viewing the terrain at a 3D angle (or with the Street View option). While it was the “only game in town," the simulations were rough at best. Below is Google Earth’s simulation of Lundy Lake in early October at the same time as the TP 3D example. Notice how the left mountain is shown illuminated while in fact it should be in total shadow.

Google Earth: A rough approximation that erroneously showed the left mountain illuminated.
A popular technique in landscape photography is to add an ethereal effect to a water scene or cloud movement using an extremely long exposure, ranging from several seconds to a few minutes. To achieve long exposures you need the aid of one or more neutral density (ND) filters that cut the light by several stops. The procedure is simple: compose and meter the scene, insert the ND filter(s), and then increase the shutter time by the number of ND filter stops. If you are using a square ND resin-filter, make sure the light is blocked between the filter and lens.
The last step requires some math gymnastics. For example, say you’re combining a 9-stop and 4-stop ND filter and the metered shutter speed is 1/125. To determine the corrected shutter time, you calculate 213 (8,192) and multiply it times 1/125, which is 1 minute and 5 seconds. Of course you’ll need to set the camera to Bulb and likely use a watch to time it. This is a doable procedure, but you can make the process easier with NDTimer by Three60 (iOS only). As shown below, the interface is self-explanatory: select the shutter speed, dial in the ND filter value, and the adjusted time is shown above. The bonus feature is a timer for exposures that exceed your camera’s maximum shutter time (usually 30 seconds). There are many similar apps for Android phones, for example: ND Calc by Brian Dorey.

NDTimer
You have two options to frame compositions without dragging out the camera: an optical director’s viewfinder that was covered in the last chapter, or a smartphone app. Smartphone apps are essentially like composing a normal picture with your smartphone camera except the focal length (corresponding to your camera type) is displayed for any zoom setting. You can also vary the aspect ratio. They cost a fraction of an optical viewfinder and you can record the image for later reference. The drawback is when trying to compose a scene with a washed-out LCD during bright daylight.
Available viewfinder apps are: Mark II Artist’s Viewfinder (iOS only); Artemis Director’s Viewfinder; and Cadrage. I use the Cadrage and it works as advertised, providing seemingly accurate framing. The Cadrage simulated zoom range (for full-frame) is 31.5mm to 290mm on an old iPhone 6 and widens to 13mm on the iPhone 12 Pro. For older phones, you can extend the wide-angle coverage to approximately 20mm with a 0.65X clip-on lens. I tested my iPhone X using an inexpensive 0.65X lens adapter. It worked, but the framing accuracy suffered slightly due to the barrel distortion caused by adapter.

Cadrage Viewfinder: The app supports most camera brands and models. One nitpick is the zoom control (circled red) is finicky to use.