Exposure Modes – Technical Fundamentals Course

I’ve mentioned exposure modes in passing several times by now, but it’s time to talk about the different modes your camera uses. They’re all just different ways of arriving at an exposure, and each one simply give emphasis to different aspects.

Program Exposure Mode

“P” or Program is the simplest of the exposure modes, and can be best described as fully automatic. In program mode, the camera chooses all 3 of the exposure facets, and you just shoot. Simples.

Program exposure mode
“P” Program exposure mode

Obviously the big drawback with this mode is that you relinquish all creative control over an image. As such I’ve only ever used it a tiny handful of times in my entire 20 year plus career. If you use program mode, and you’re trying to learn about exposure and how to operate your camera, you won’t learn very quickly at all, so stop using it! You can generally choose which ISO to shoot at, and some program modes allow you to “shift” the exposure. What this means is that if it suggests an exposure of 1/125s at f8 (for example) but you want to shoot at 1/250s you can shift the exposure and it will shift to 1/250 at f5.6. It essentially allows you to choose from a range of equivalent exposures until you come across one that suits your needs better.

Aperture Priority Mode

This is the auto mode I turn to when I’m not in manual. In this mode, you select an aperture, and the camera selects an appropriate shutter speed. This still gives you an element of creative control, and I use it on shoots where I’m moving about a lot, and the light is changing rapidly. Generally speaking you can also set the ISO as well.

Aperture Priority Expsoure Mode
“A” Aperture Priority exposure mode

Shutter Priority Mode

You can probably guess how this mode works – you select a shutter speed, and the camera selects an appropriate aperture. I don’t use this mode, because I’m old-fashioned, and when I started in photography in the early 90s, aperture priority was by far and away the most common auto mode, and old habits die hard! As with aperture priority, ISO is usually yours to choose.

Shutter priority expsoure mode
“S” Shutter priority exposure mode, sometimes called “Tv” for “time value” on some cameras.

Manual Mode

Here we go – this is what we’re after! Having worked through these videos you should by now be pretty familiar with “manual” – the most basic of the exposure modes. I shoot at least 95% of my work in manual mode, as I like to be in control of things. Needless to say, manual means just that – you choose the aperture, shutter speed, and ISO that you want, and away you go. Full creative control is the massive plus, along with it being a much better way to learn how your camera works. The downside is that you can very easily get shots that are very under or over exposed. Your camera’s meter may point out to you if you’re off, but sometimes when you’re shooting quickly you can miss this, so do be careful.

Manual Exposure Mode
“M” Manual mode – it’s all up to you now!

Picture Modes, green modes, and “Intelligent Auto”

Many modern cameras have pretty pictures on their mode dials, of people running and things like mountains. They may also have a big green icon, or something marked with iA. You can safely ignore all of these, and stick to the modes listed above. I never touch them, and hand on heart, never have.

Sports Expsoure Modes
“Sports” exposure mode, because all Sports pictures are of course, identical……

Oh alright, I’ll briefly explain why. The “picture” modes – the ones with the silly icons – are what you’re supposed to use when you’re taking those sort of pictures. So, switch to the running man icon for sports pics, the mountains for landscape, you get the idea. For the totally ignorant camera wrangler out there, these may help make their pics from those shoots a bit better, but we are way beyond that. All these modes do is give priority to the creative aspects of exposure that most suit that type of photography, based on those same maths that we mentioned earlier, created in a magical lab somewhere. That sounds great, except that you have no idea exactly what the camera is doing, and once you start to get the hang of things, you’ll definitely want to be in charge of what settings the camera uses, so as to get the best shots from any situation.

Green Mode
“Green” mode – fully automatic

Green mode is fully automatic, without even the option to shift the settings in any direction. I get physically sick just thinking about it. Marginally better is what’s sometimes called “Intelligent Auto” which often allows you to shoot automatically, but make some changes. In my experience though, it’s much quicker to shoot in manual once you know what you’re doing.


One automated feature that I don’t get worked up about and ignore is a relatively recent invention called “Auto-ISO”. This has only existed in the digital era, as it’s only possible with a digital sensor.

Auto ISO
Auto ISO settings in a Nikon menu

If you turn auto ISO on, you can tell the camera to change ISO to ensure the correct exposure for your aperture and shutter speed setting – if you’re in manual mode. If you’re in aperture priority mode, you can be really clever with it – you can pick your aperture, then tell the camera not to go below a certain shutter speed. The ISO will then change accordingly to make sure you still get a decent exposure. You can often set a top limit to how high you’re happy for the ISO to go, in case you’re worried about too much noise.

I’ve used this setting lots of times, particularly when shooting sports and action. The ability to set the aperture, and relax in the knowledge that the shutter speed won’t drop below, say, 1/250s is a real godsend.

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