Auto ISO
Auto ISO – A Modern Helper
ISO has come a very long way. In the days of film photography, ISO wasn’t something you could change from shot to shot. You chose a roll of film — ISO 100 for bright days, ISO 400 for indoors, maybe ISO 800 for sports or dimly lit events — and that was it. Your choice of ISO was fixed until you finished the roll. If the light changed halfway through, tough luck. You simply had to work around it.
When digital cameras arrived, something remarkable happened: ISO became adjustable. Suddenly you could switch from ISO 100 to ISO 800 with a single tap. Early digital cameras often tucked ISO away in menus or on small buttons, but the ability to change ISO instantly was nothing short of revolutionary. It meant photographers could adapt to changing light without swapping film or compromising on exposure.
As cameras evolved, ISO controls moved from hidden menus to dedicated buttons, dials, and wheels. With each generation, ISO became easier and faster to adjust — and modern sensors grew better at handling higher ISO values with less noise. All of this set the stage for a feature that many photographers now consider indispensable: Auto ISO.
What Auto ISO Does
Auto ISO is beautifully simple. You set:
• the Aperture you want
• the Shutter Speed you want
• and let the camera choose the ISO needed to achieve a correct exposure
This is enormously helpful whenever the light is changing quickly — walking from sun to shade, photographing moving subjects, or shooting indoors with mixed lighting. Instead of constantly fiddling with settings, you can concentrate on composition, timing, and your subject.
From Aperture Priority to Manual With Auto ISO
Many photographers have used Aperture Priority (Av) for years. It’s reliable and sensible: you choose the aperture for creative control, and the camera selects a shutter speed to match.
But modern cameras have grown so capable and flexible that a new approach has become extremely popular:
Manual Mode + Auto ISO.
In this setup, you take charge of the two creative settings:
• Aperture — controls depth of field
• Shutter Speed — controls motion
And the camera adjusts only the ISO to maintain the correct exposure.
Why is this so useful?
Because you get complete control over how the image looks, while still allowing the exposure to adapt automatically to changing light. You decide whether the motion freezes or blurs. You decide how much of the scene is in focus. The camera simply makes sure the image isn’t too bright or too dark.
It’s a surprisingly sensible and efficient way to shoot, especially in unpredictable lighting — indoors, outdoors, at events, or anywhere you can’t afford to miss the moment while adjusting three different settings.
A Modern Way of Thinking
Auto ISO represents the natural evolution of exposure control. From fixed ISO film to physical dials to fully automatic sensitivity adjustments, cameras have become smarter at filling in the gaps while still giving you artistic control.
You’re no longer chained to the light. You’re free to move, adapt, and react — with the reassurance that your exposure will keep up.
And in the end, anything that helps you focus more on your subject and less on your settings is a tool worth knowing well.