One of the most overlooked topics I see is the mystery of image size in terms of dots per inch (dpi), width, height, and sensor size when it comes to aspect ratio. All these measurements come to play for every image a photographer uses. Each aspect comes into the calculation for final image size as well. Let’s clear up some of the mystery.
Lets Talk About Your Camera
To start off, lets talk about your camera first. The digital camera is based on its image sensor. That’s the little plate that sits behind your lens and shutter. Its filled with millions of light gathering pixels, small dots that comprise the construction of the sensor. These pixels collect the light focused from your lens, and then electronically record the light gathered from the pixels into an image file.
To better explain some of the terms utilized here as a preface for differentiating between digital cameras and respective aspect ratios and sizing:
- Sensor Size: As illustrated on the graphic on the next page, there is a huge difference in sensor sizes between different types of digital cameras. For instance, the typical point and shoot digital camera will have a small sensor, around 7m X 5mm. The next step up is the digital SLR, typically starting at 23mm X 15mm. Full frame digital SLRs sport the same size sensor as 35mm film (hence the name “full size”) at 36mm X 24mm, 5 times larger than a compact digital camera, and almost twice the size of the standard digital SLR sensor.
Keep in mind ahead of time, while shooting, that you may be cropping the image when you work on it in Photoshop or Elements. With that in mind, you’ll want to compose the scene at a slightly wide angle than usual. You’ll be thankful later when editing your image on your computer, and you have the “extra” areas of the image in which you can crop out in order to get to the image size you want.