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Digital Photography Tips: Why Shutter Priority Mode is Useless

Skill Level: Intermediate

Aperture Priority ModeYou know all those shooting modes on top of your camera? Well here's the deal: most of them are useless. In fact, once you know what you're doing, pretty much all but 2 of them are useless. Once you get a good handle on shutter speed, aperture, and ISO, the only modes you need are Aperture Priority Mode ("Av" or "A" mode) and Manual Mode ("M"). All the full auto and "Scene" modes don't give you enough control, so the creative decisions are in your camera's hands, not yours. That's not good. Same with Program Mode ("P"). Sure, you can control the ISO and the exposure compensation, which is a huge improvement over full auto, but the camera is still taking care of the all-important aperture and shutter.

So then what about Shutter Priority Mode ("Tv" or "S" mode)? Yep, that's useless, too.

Okay, okay. This is where some advanced amateurs throw up their hands in protest. "How could shutter priority mode be useless? What about when you want to control the shutter? How about when you want to freeze action with a fast shutter or get that silky water looks with a slow shutter? You need to be able to select the exact shutter speed you want."

I hear what you're saying, but Shutter Priority Mode is still useless.

So here's the deal with Shutter Priority looks good on paper and it's easy to make it sound useful, but it just isn't. In fact, camera makers know Shutter Priority Mode is useless. That's why they didn't even put it in cameras until quite a long time after they invented Aperture Priority Mode. They had the technology to do it once they invented Aperture Priority Mode, but they just didn't put it in their cameras because they knew it wasn't a logical way to adjust your settings. This is also why you'll rarely find a pro using Shutter Priority Mode.

Alright, quick disclaimer: I'm sure there are one or two really rare and ultra-specific exceptions where using Shutter Priority Mode would work just fine. But I promise you that in these rare instances you could just as easily get your settings in Aperture Priority Mode, and these instances are so uncommon that it's not even worth addressing. Actually, I can't even think of an example, so that should tell you something.

So let's look at why this mode is so useless:

1. The shutter doesn't need to be that specific

Here's the number one reason Shutter Priority Mode is useless: the shutter speed just never really needs to be that specific. It's not logical to put in an exact shutter speed in 99.9% of situations because there's just no reason for the shutter speed to be super specific. Often times the shutter speed can fluctuate hugely on a given subject and the picture will look no different.

Let's consider a simple landscape. You're on a tripod photographing a mountain. You're not going anywhere and the mountain's not going anywhere, so it doesn't matter if your shutter speed is 1/8000 or 30 seconds - nothing's moving and so nothing will look different.

Alright that's an easy one, but what about sports?

Same deal. Let's say you're photographing a soccer game and you've decided that 1/1000 will freeze your athletes. Well what happens if you use 1/2000 instead? Of course, they'll be just as frozen. And what if you use 1/4000? Yep, still frozen. 1/8000? Frozen.

Okay, so then it's not that you need 1/1000, you need 1/1000 or faster. You don't need an exact shutter speed, you need a range of shutter speeds.

Shutter Priority Mode is Useless

This was taken at 1/2000, but it would
look no different at 1/1000 or 1/4000

How about doing some portraits with a 50mm lens? Well, your model is posing nice and still for you, so all you need to freeze is your camera shake. On a 50mm lens, camera shake is frozen at 1/50 or faster. So again, what happens if you use 1/100 or 1/250 or 1/4000 instead? Everything will be just as frozen. You don't need 1/50, you need 1/50 or faster.

See the thing with motion and the shutter speed is it's just like water. Once it hits a certain limit, it's frozen. Once water hits 32-degrees Fahrenheit, it freezes. It's not any more frozen at 10-degrees or 5-degrees or -20-degrees. Once it's frozen, it's frozen - same goes for moving subjects and the shutter speed.

Then what about when you want to blur motion, like getting that silky effect on a waterfall? Same deal here. The waterfall will look completely silky at about 1" (1 second). So what if you use 2"? Still silky. What if you use 10"? Yep, still silky. Once motion is frozen, it's frozen, and once it's moving, it's moving.

Shutter Priority Mode is Useless

This was taken at 2.5 seconds, but it
would look no different at 1" or 10"

Even when you're going for specific effect on the motion, like trying to get some motion blur, but not too much motion blur. In that case, it still doesn't need to be exact. Typically a range of shutter speeds will create virtually the exact same effect on motion blur.

Shutter Priority Mode is Useless

Like in this photo of a helicopter, I want some motion in the blades, but not too much. I used a shutter speed of 1/160. But the motion would have looked nearly identical at shutter speeds from 1/80 to 1/250A minor change in the shutter speed equates to a minor change in how motion is rendered.

2. The aperture is too important to let the camera control

If you're controlling the shutter speed as you would in Shutter Priority Mode, then the camera is controlling the aperture. The aperture affects depth of field (background blur). So as light fluctuates and the camera adjusts the aperture to compensate, the background blur on your images will fluctuate, too.

Let's consider the soccer game example again. And let's say I put in a shutter speed of 1/1000 using Shutter Priority Mode. As I point the camera up the field, my camera chooses an aperture of f/4.5. Then I follow the action down the field where the light is a little different because of the angle of the sun. In this new light, my camera chooses f/8. F/4.5 creates a smaller DOF than f/8, so now all my pictures pointed up the field have blurrier backgrounds than my pictures pointed downfield.

But let's try the same situation in Aperture Priority Mode instead. I decide that I want a blurry background, so I put in f/4.5. When I point my camera upfield, wouldn't you know it, my shutter comes out to 1/1000. Good - I need 1/1000 or faster to freeze the action. Okay, now I follow the action downfield again to the different light. My aperture won't jump to f/8 this time because I have it locked in at f/4.5. Instead, my camera adjusts the shutter for the changing light, bringing it up to 1/3200. No problem there, 1/3200 will freeze the action just as good as 1/1000. So the result is a consistent background blur (because the aperture didn't change) and consistently frozen motion (because the shutter speed stayed above my threshold of 1/1000).

By controlling the aperture directly in Aperture Priority Mode, you're not leaving the all-important DOF up to the camera. Background blur is simply too important to let the camera control! Because after all, a small change in the aperture can dramatically alter the photo, but an identical change in the shutter speed often results in no noticeable difference in the image.

3. The shutter is less likely to hit a "dead end"

Let's look at the entire range of available shutter speeds:

30   25   20   15   13   10   8   6   5   4   3.2   2.5   2   1.6   1.3   1   0.8   0.6   0.5   0.4   0.3   1/4   1/5   1/6   1/8   1/10   1/13   1/15   1/20   1/25   1/30   1/40   1/50   1/60   1/80   1/100   1/125   1/160   1/200   1/250   1/320   1/400   1/500   1/640   1/800   1/1000   1/1250   1/1600   1/2000   1/2500   1/3200   1/4000   1/5000   1/6400   1/8000

Now let's look at the entire range of available apertures on a typical pro lens:

f/2.8   f/3.2   f/3.5   f/4   f/4.5   f/5   f/5.6   f/6.3   f/7.1   f/8   f/9   f/10
f/11   f/13   f/14   f/16   f/18   f/20   f/22

You can see that there are many more shutter speeds available than apertures. But in every situation you take pictures, there needs to be an aperture to match your shutter speed. So here's an all-too-common problem with Shutter Priority Mode: often times you'll pick a shutter speed that has no matching aperture. In other words, you've selected a shutter speed that is too fast (lets in too little light) or too slow (lets in too much light) and there is simply no aperture to match it. The aperture hits a dead end.

The camera warns you when this happens, by the way. If you choose a shutter speed that's too fast or too slow for the apertures to match it, the camera will flash the aperture number at you or indicate "HI" (for "high light") or "LO" (for "Low Light") where the aperture number should be. This is the camera telling you that it's trying to find an aperture to match your shutter, but it hit a dead end and can't go any further. As a result, your picture is going to come out too bright or too dark.

But if you shoot in Aperture Priority Mode instead, you're controlling the variable with fewer options (the aperture). And so the camera will pretty much always be able to find a shutter speed to match your selection on the aperture. In other words, the camera won't hit a dead end because there are just so many shutter speeds available.

4. You have just as much control over the shutter in Aperture Priority Mode

This is where beginners ask, "Then what about those times when the shutter speed is your top priority, like when shooting sports or wildlife? Shouldn't you be in the mode where you can control the shutter so that you can ensure it's correct?"

No. You don't need to control the shutter speed directly in order to make it come out right. Sure, Aperture Priority Mode doesn't let you control the shutter speed directly, but that doesn't mean you can't control the shutter speed (wow, man, that's deep).

Here's what I mean: so long as you're in control 2 of the 3 exposure variables (shutter speed, aperture, and ISO), you essentially have control of all 3. With 2/3 control, the camera will be forced into a corner on the third and you can get what you want out of it. So, if you don't like your shutter speed in Aperture Priority Mode, just do what you would do in any mode: change the ISO and/or the aperture. Need a faster shutter? Just raise the ISO or open the aperture - that's what's going to have to happen anyway, regardless or what mode you're in.

So bottom line is this: don't bother with Shutter Priority Mode unless you have a really good reason to do so. Aperture Priority Mode is a much more useful mode and will afford you all the same control over the shutter as Shutter Priority Mode. And don't let anyone try to convince you of the usefulness of Shutter Priority Mode...that's a red flag that they might not know what they're talking about.

To learn more about shutter speed, aperture, ISO, exposure, and much more, check out my Introduction to DSLR Photography Online Course for beginners and my Understanding Exposure for Beginners Photography Class in Orange County, CA.