# Photograph Field of View and Pixel Size Calculator

How much can I capture in a photo, and how big will my pixels be?
Use this calculator to determine the approximate coverage (field of view) and the ‘ground’ pixel size of a particular lens and camera at a given distance.

Note this calculates for a plane parallel to the camera image plane. If the object/plane at a distance is at an angle to the camera image plane then this coverage holds only for the distance provided.  Note that lens distortion is also not accounted for which will affect coverage a bit.

## Why?

Typically this calculator is used in planning – that is, before you take photographs or maybe even before you have a camera.  It has a general use for any digital camera photography, but two specific uses relate to photogrammetry in fabrication tasks:

1. If you are doing photo-digitizing (digitizing patterns and templates) you want to know two things:  a) with a particular camera and particular room size, what is the biggest pattern I can capture in one photo, and b) with a particular camera and distance from the pattern, what will be the best precision that I can get when digitizing edges of patterns.
2. If you are measuring boat decks, where you might be working in a confined space, you need to check the camera will be able to see the details you want.

1.a) relates to the coverage calculation below, and 1.b) and 2. relate to the pixel size calculation below.
You may have a camera or maybe planning on buying a  camera, and it can be useful to know how much it will capture in one photo, given constraints like distance from objects. And it may be useful to know how big the pixel will be on the object because this defines the precision.  This will impact your camera purchase decision.

## How to use the calculator

Mouse over the information icons to get a description of the inputs and outputs. You can look up your camera on google to find a specification sheet. Search something like “Nikon D7000 specs”, or “Canon M100 specs”, etc. If your camera has a removable lens you may need to get the lens focal length separately.

Pick your desired units (metric or imperial) in the third column for both inputs and outputs. As you change any value on the form, the calculations are done automatically and in realtime.

1. Focal length
Focal length is usually shown on the front of your camera’s lens or can be found in the camera’s spec sheet online. Use the true focal length and not the ’35mm equivalent’.
mm
2. Format size
Format size is the size of the image chip in the camera. This can be found in the camera’s spec sheet online. Alternately use 2b below to fill in these values.
 Width Height
mm
2b. Format size preset
Format size is the size of the image chip in the camera. Digital cameras have standard sizes and the camera’s spec sheet online will sometimes list it as one of these standards. Changing this fills in the values in 2. above.
3. Distance of camera to object
Enter the distance, and units of measure, for the expected distance from the camera to the object.
4. Allowable coverage
For those doing photogrammetry projects, we recommend not photographing right to the edge of the image frame. Perhaps 80% or 90% coverage is more realistic.
5. Resolution (optional)
The number of pixels in the camera’s image sensor in mega-pixels. Usually provided in the camera’s spec sheet online. If you enter this value, the estimated size of a pixel, projected at the given distance, is shown below.
mega-pixels
Computed coverage
This is the size of the area covered by one photo from this camera at the given distance for a plane parallel to the camera’s image plane.  This is modified by 4.
 Width out width Height out height
Computed pixel size
The size of one pixel at the given distance. This is useful because it will let you know the limit of precision and sometimes accuracy. Note accuracy may be lower than precision due to calibration, etc.
manual marking=2x For manual marking of images, you normally can’t mark better than 2 pixels. This will be your precision.
subpixel=1/20th For subpixel targets, the precision will be 1/5th to 1/20th of a pixel.
dot-size=8x If you are making dot targets, the dot should be no smaller than 8 pixels across (at the farthest distance).
pixel size
pixel size 2
pixel size 20th
pixel size 8