Definitions, Software, & Apps


We may occasionally use an unfamiliar photographic term in these posts, so we have included these definitions to assist those unfamiliar with the details. If we use a term you don’t understand, please leave a comment so we can improve this site.

Circular Polarization Filter

A circular polarization filter is attached to the front of a lens to reduce light reflections (think of polarizing sunglasses). The filter is rotated to the best angle to reduce reflections from objects or sunlight bouncing around the atmosphere. This enhances photographs by increasing color saturation (resulting in bluer skies and brighter colors) and contrast.

Crop Factor

Crop Factor is a camera sensor’s diagonal size compared to a full-frame 35 mm sensor. It is called this because when using a full-frame lens on a camera with a smaller sensor, the smaller sensor effectively crops out this much of the image. This has the same effect as using a longer focal length lens designed for the camera/sensor. The Crop Factor of our cameras is 1.6 so that a 100mm full frame lens yields the same image as a 160mm lens. One advantage of this relates to the construction of lenses: nearly all lenses are sharpest at their centers, and quality degrades toward to the edges. This means that a cropped sensor effectively discards the lowest quality portions of the image.

Depth of Field

Depth of Field is the distance between the nearest and the farthest parts of a subject (or objects in a scene) that are in acceptably sharp focus in an image. Depth of field can be calculated based on the focal length of the lens, the distance between the camera’s sensor and the subject, and the aperture (lens opening or f/stop). In simple terms, the closer the camera is to the subject, the smaller the resulting depth of field.

Extension Tube

An extension tube is used with cameras and interchangeable lenses to increase magnification, most often in macro photography. An extension tube contains no optical elements – its sole purpose is to move the lens farther from the camera sensor. The farther away the lens is, the closer its focus and the greater the magnification. Extension tubes frequently come in sets with different lengths so that various combinations can be used, as needed.

Focus Stacking

Focus Stacking – A digital image processing technique where multiple images, each with a different part of the subject or scene in focus, are combined in a separate app such as Photoshop or HeliconFocus. The resulting image has a greater depth of field (DOF) than any of the individual source images. This is frequently the only method to achieve a good image in macro photography where the depth of field can easily be only a fraction of an inch.


High Dynamic Range (HDR) – A technique used in imaging and photography to reproduce a greater range of exposure (light and dark areas) than is possible with standard digital imaging or photographic techniques. HDR is useful for many real-world scenes containing both direct sunlight and extreme shadows.

The goal is to present a similar appearance to that experienced through the human visual system. The human eye, through adaptation of the iris and other methods, adjusts constantly to adapt to a broad range of light present in the environment. The brain continuously interprets this information so that a viewer can see clearly in a wide range of light conditions, a much wider range than any camera can in a single exposure.

In digital photography, the desired result can be achieved by capturing the same subject with multiple exposures, and then combining them using editing software such as Lightroom or Photoshop, or specialized HDR software such as Aurora HDR. The software selects areas that are properly exposed in each of the images and merges them into single image which provides a greater exposure range. In simple terms, the darkest areas would be selected from otherwise overexposed image while the brightest areas would be selected from otherwise underexposed image.

Macro Photography

Macro photography is the art of making small things look big. The technical definition is an image where the subject is reproduced to at least 1:1, or that the image on the camera sensor is the same size, or even bigger, than the real-life subject. In general, the term macro photography is used for very close-up photography. My macro lens is 1:1 at it closest focus distance and with the 1.4x teleconverter and extension tubes the reproduction ratio is 3:1.


In photography, a panorama is a wide view or representation of a subject (frequently a landscape or vista). It can also apply to painting, drawing, or a three-dimensional model. The motion-picture term panning is derived from panorama.

In digital photography, the most common method for producing panoramas is to take a series of overlapping pictures and merge (or stitch) them together, using specialized software such as Lightroom or Photoshop. To successfully merge multiple images into a panorama, the pictures must be taken from the same position (to avoid alignment errors between adjacent images), and there must be sufficient overlap in adjacent images that the software can identify features common to both; the recommended overlap is about 30%.


A teleconverter is a second lens mounted between a camera and its interchangeable lens which increases the effective focal length of the lens by enlarging the central part of the image obtained by the lens.

Software and Apps

I use a number of apps on my 27″ iMac computer and my smartphone to assist with the photography process. I will mention them here in case anyone is interested in using them.

Aurora HDR

Aurora HDR is computer software created specifically for editing High Dynamic Range (HDR) images. It can be used as a stand-alone editor or as a plugin to Lightroom so photos in Lightroom can be combined in Aurora directly, without having to save Lightroom edits, open and combine them in Aurora, save the result, and then import it into Lightroom.

Geotag Photos Pro

When turned on, this smartphone app periodically records my GPS location and time and uploads it to a website to create a trip log. Using a corresponding app on my computer, the app will read the website data and add the GPS location to the metadata of matching photos saved on the computer. Configurable settings control the minimum distance between tagged locations and how frequently locations are saved. The app supports multiple ways to save and access the data.


HeliconFocus is computer software used in stacking a group of images (Focus Stacking). It works much better and faster than Photoshop, the file size of the resulting images is smaller, and the developed images typically are sharper, have better color, and have less noise than those from Photoshop. It can be used as a stand-alone app or as in conjunction with Lightroom so photos in Lightroom can be combined in HeliconFocus directly, without having to save Lightroom edits, open and combine them in HeliconFocus, save the result, and then import it back into Lightroom.


Lightroom is an image management and editing program developed by Adobe (the same company that created Photoshop). Using Lightroom, photographers are able to organize, sort, and process their images, and eventually export for printing and sharing. One major advantage of Lightroom is the image edits are non-destructive — they are saved as a series of commands in a small text file that is applied when the image is displayed, printed, or exported. Thus, any change can be easily reversed and multiple versions of the same image with different edits can be made without using significant disk storage. In addition to more common image editing tools (e.g. exposure, contrast, color correction, sharpening, noise reduction), Lightroom is able to merge multiple images into a panorama, merge multiple exposures into an HDR image, and combine multiple images taken at multiple exposures into an HDR panorama in one step.

Moon Seeker

This smartphone app shows the path of the moon (compass direction and elevation) for any city or GPS location and any date. For the selected date and location, it also displays the % illumination and the next phase of the moon.


PhotoPills is a smartphone app for planning photographs ahead of time It helps you be at the right place at the right time to capture the best possible photos. Visual and map data  are available for sun, moon and milky way locations and paths including an augmented reality that superimposes the sun, moon, or milky way on the desired subject to help determine the optimal location and time for the desired photograph.


Photoshop is a photographic image editing program developed and published by Adobe. It was originally created in 1988 and has become the industry standard not only in image editing, but in digital art as a whole.

Photoshop’s basic functionality can be extended by add-on programs called plugins which typically provide a specific functionality. most plugins are developed by third-party companies.

Photos Exif Editor

This computer app allows me to edit the Exif data associated with a digital camera image. This data can include camera and photograph information such as camera make and model, lens make and model, camera exposure data, date and time, and metadata such as keywords, copyright information, image title and description, image size, and GPS location.

rGPS (Really Good Photo Spots)

This smartphone app helps photographers find great photography locations near them, search for locations in distant locations, add their own locations, and share photos of the best spots. Shared photos are geotagged and reviewed by professional photographers who rate the photos and confirm the GPS coordinates.

Sol: Sun Clock

Sol is a smartphone app that identifies the time of multiple light conditions for any day and location. The conditions identified are Morning, Solar Noon, Afternoon, Golden Hour PM, Civil Dusk, Nautical Dusk, Astronomical Dusk, Solar Midnight, Astronomical Dawn, Nautical Dawn, Civil Dawn, Golden Hour AM.

Starry Landscape Stacker

This computer app is for making images of the night sky with stars and reducing noise. Digital noise in digital photography is similar to grain in film photography. High speed (high ISO) films were grainier than low speed films. It uses “stacking” or “image averaging” to combine a group of images that were captured in rapid succession with identical exposure settings and the camera in a fixed position. The result is an image with stars and much less noise than you could achieve with a single exposure. It works because digital noise in an image is random, so averaging multiple exposures reduces the  noise in the final image. The app recommends 10 exposures minimum and 20 exposures preferred.

Sun Seeker

This smartphone app shows the path of the sun (compass direction and elevation) for any city or GPS location and any date. For the selected date and location, it also displays the shadow ratio and path length.

Topaz Labs

I use four computer software programs from Topaz Labs: Topaz DeNoise AI, Topaz Sharpen AI, Topaz Gigapixel AI, and Photo AI. All of these programs use very specific Artificial Intelligence algorithms to perform their functions. Each of these programs works either as a standalone program or as an add-on external editor for Lightroom and Photoshop and each has a specific purpose related to its name – DeNoise AI reduces noise in images, Sharpen AI sharpens fuzzy or blurry images, and Gigapixel AI increases the size of an image without adding blur and noise or pixelating the image; Sharpen AI and Gigapixel AI also reduce noise while they perform their primary function. Photo AI is the newest program and combines the functions of the other three programs into one.