- by Thomas "TJ" Gillespie
What is ISO on a camera?
ISO represents the speed at which the cameras digital sensor can capture light. The lower the number, the slower the “absorption” rate, the higher the number the faster the “absorption” rate.
The lower the number, the higher the quality* of the photo. The higher the number, the more noise (digital artifacting or grain) and hence lesser quality. Traditionally ISO is incremented by a doubling in the rate of sensitivity to light starting at 100, then 200, 400, 800 and 1,600. Today’s cameras can range from 50 to 51,200 or more!
How do I use ISO or why would change ISO?
The largest deciding factor on when to change ISO is light, or more specifically, the amount of light. Generally, with more light, typically the lower the ISO, with less light, typically the higher the ISO.Stopping fast moving objects such as children playing, live sports, excited pets, etc… might require ISO 800 even in full sun. Portraits, architecture, still life, landscapes, etc… can normally be photographed at ISO 100.
*Quality is very subjective and can be measured by many aspects. There are aspects that are controlled through, or limited by, equipment such as: definition, color depth saturation, contrast, clarity, exposure, auto focus, grain/noise, etc… or aspects directly controlled by the artist: composition, exposure, blur, manual focus, etc… You will have to decide for yourself what attributes contribute to a photo of high quality.
Purchasing a spot in my group photography class at my online store will automatically get you reserved on the date you selected during your purchase. You will receive subsequent emails from me regarding your specific class.
All students can retake scheduled group sessions for free, unlimited, for 1-year after first instruction. Only limitation is that class sizes never exceed 10 and classes are first come, first serve.
Find me on:
- Great starter book
- Medium sized travel book. Beginner - Intermediate
- Capturing the Eye, Fall Colors and Unreal Blur (PDF)
- Portraits, Flowers and Silhouettes (PDF)
- Unusual Point of View, Glowing Light, Stopping Action and Showing Action (PDF)
- Ultimate Field Guide to Photography (PDF)