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Shutter Speed – Frozen In Time

We’ve covered basic composition and aperture settings in the first two articles. The next piece of the puzzle is shutter speed, which directly affects both Depth of Field and exposure.


This is a good representation of some of the most common aperture sizes found in today’s camera lenses. As stated in the previous article, the smaller the f-stop number, the larger the opening in the lens. Beyond determining Depth of Field (DoF), this will impact your shutter speed setting. Why?

Think about a water faucet and a bucket. The faucet will act as the aperture and a timer for the shutter speed. The bucket is a properly exposed photograph.

• When you open the faucet all the way (f/2), water rushes out so you fill the bucket in a very short time (1/1000 sec). This would let in a lot of light for a short time.
• When you open the faucet just a little bit (f/16), water barely trickles out and takes much more time (1/15 sec) to fill the same bucket.
• It doesn’t matter which combination you choose, the bucket is filled the same amount, just like a photo can be exposed the same amount by various aperture and shutter speed combinations while also controlling motion and depth of field.

Another useful analogy that applies to the shutter speed – aperture relationship is that of a seesaw. As one person goes up a given distance, the other falls by the same amount but their average distance from the ground is always the same. In photography, when you change the shutter speed or aperture to let in more or less light, you must also change the other setting in the opposite direction to keep the exposure constant.

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slickwill

Okay at Grattan I need you to use a REEALLY slow shutter speed so that it looks like I'm doing 160mph.

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nhfirefighter13

I'll see what I can do.

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bwhip

For most of my track shots I've just been using the auto "sport" mode on my camera, but I'm not sure what shutter speed it uses, or how much it balances shutter speed vs. aperture. If I were to use the shutter-priority setting and let it set the f-stop, what shutter speed(s) would you generally recommend? The camera will do up to 1/8000, but obviously the higher the speed, the more light I'll need. The pictures I took last week at Miller were not as crisp as I would like, and I'm not sure how much of that was the shutter speed vs. the lens vs. operator error. Thanks!

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nhfirefighter13

Sport mode is kind of like an automatic shutter priority mode. The camera will pick the fastest shutter speed it can for the lighting conditions.
Try Av mode next time and if you want a little faster shutter than what the camera is offering you, bump up the ISO setting to 400 or so.

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TAZ

More on panning shots

I have a slightly different approach than does NH when looking to do motorsports panning shots. Rather than using Aperture-priority mode, I like to use either full manual, or shutter-priority mode.

(For reference, "M" is full manual exposure mode on both Nikon and Canon. On Nikon models, "S" mode is "Shutter priority"; and on Canon models, "Tv" (meaning "time value") is shutter-priority mode. NOTE: Not all Canon and Nikon bodies make aperture and shutter priority modes available. If you're shopping for a Digital SLR, and you're interested in making more than snapshots, be sure to buy one that has M, Av, Tv, and P modes (Canon), or M, S, A, and P modes (Nikon), in addition to any other modes those models may have.)

I prefer the Manual or Shutter-priority modes because in Aperture-priority, you will get unpredictable results. Here's what I mean: As Chris explained, in Aperture-priority mode, the photographer selects the desired aperture value (i.e. f/11), and the camera decides which shutter speed to use for that aperture. But if the amount of "light" the camera sees changes, the camera will adjust that shutter speed as it feels necessary to maintain the proper exposure. If you had set the aperture to f/11, and you see that the camera had responded with a shutter speed of 1/180, that would be fine, as long as your composition did not suddenly contain more or less reflected light (i.e. a bright white sky, or a dark shaded area such as a building or woods). IF the composition (or the reflected light that the camera sees) changes, and you're using Aperture-priority mode, the camera will select a new shutter speed, which may be faster or slower than you wanted to use. If the shutter speed is too fast, there won't be as much motion blur. If the shutter speed is too slow, there will be too much motion blur (and the subject itself may become too blurry).

This will not happen if you instead dial in the exact shutter speed you're looking to use. You can do this using either shutter-priority mode (in which you select the shutter speed and let the camera decide which aperture is appropriate), or full manual (exposure) mode, in which you set both the shutter speed and the aperture.

About depth-of-field and panning shots:
The amount of depth of field (see NH's previous article) in a panning shot is pretty much a moot point. In a panning shot, the subject that the photographer is tracking is pretty much going to be the only thing that APPEARS to be in sharp focus in the final shot. As such, it almost doesn't matter whether f/2.8 or f/22 was used to get the shot...as long as the SUBJECT was in focus when the shutter was opened. Of course, whether shooting panning shots or anything else, very small apertures will lead to visible sensor dust in the final image, so I recommend using larger apertures when possible, unless your camera has no sensor dust. (Hahahahahahaha!)

Manual exposure mode?
Here's one argument for using manual exposure mode in this situation: Since the camera doesn't know white from gray from black (it thinks every scene should be about 18% gray), if the composition suddenly includes a lot of bright sky, or a very dark area, and you're using Aperture-priority mode, the camera can select a shutter speed which is either too fast or too slow for a proper exposure of that scene (another topic for a future article). Manual exposure mode ensures that the exact values the photographer wants to use are, in fact, used.

Which shutter speeds are ideal for panning shots?
I find that shutter speeds anywhere between 1/90 sec. and 1/250 sec. to be acceptable for panning shots, but there are compromises. A shutter speed of 1/250 is almost too fast; since the shutter is only open for 1/250th of a second, not much 'action' happens while the shutter is open. And 1/90 is almost too slow. While you may get a few KILLER shots at such a slow shutter speed, you might also find that you have to take twenty shots before you get one "keeper". A shutter speed somewhere in the middle of this range (such as 1/160 or 1/180) is probably ideal for most motorsports panning shots.

What else do I need to know?
Here's something else to consider: Wide-angle or 'normal' lenses (i.e. below 70mm or so) will produce less visible motion blur than telephoto lenses. This is because as the camera is panning from side to side along with your subject, a telephoto lens will cause OTHER objects in the frame - such as the grass and background stuff - to move "faster" than if you were using a lens with a shorter focal length. You can easily see this phenomenon if you have a zoom lens; try panning right to left at the shortest focal length available on your lens, and then at the longest focal length. If you move the camera the same amount, you'll see that there is more relative "movement" (within the viewfinder's frame) of objects when viewed at longer focal lengths.

So here's how I would shoot it:
- Telephoto lens on the camera. The longer the lens, the greater the foreground and background blur effect...
- ISO sensitivity setting as low as possible. This will ensure the biggest possible aperture will be used (which will reduce visible sensor dust on the final image).
- Camera in either shutter priority or "Manual" mode
- Shutter speed at 1/180 (the camera will automatically select the aperture if you're using shutter priority mode, but you'll have to set the desired aperture if you're going full manual exposure.)
- Focus set to "AI Servo" (Canon) or "C" (Nikon), so the focus follows the subject you're tracking
- Stand with your feet at least shoulder-width apart, and square up to your target exposure area (where the subject will be when the shutter is OPEN).
- While keeping your feet planted, smoothly rotate the upper half of your body towards the direction the from which the subject is coming.
- As the subject comes into view, center the subject in your viewfinder, and depress the shutter button halfway in order to ask the camera to acquire and track focus on the subject. While you're doing this, smoothly rotate the upper part of your body as necessary to follow the subject's path of motion. Be smooth and try to match the subject's speed; keep it centered in the frame. The camera must be following the subject at the perfect speed BEFORE you trip the shutter. If the camera is moving too fast or too slow, the subject will be blurry in the final shot.
- When you're ready, squeeze the shutter button fully to trip the shutter and take the shot. You may find you can improve the shot by adjusting your feet, or changing your physical position in relation to the subject, or adding a little "tilt" to the camera, instead of having it level with the horizon.

If you did it right, you'll get both background blur and radial blur (in motorsports shots where there are wheels turning, for example), but the subject will be sharp.

Here are two examples:




- TAZ

nhfirefighter13

Good stuff, Taz.
Like I mentioned in the first article, there is no one proper way of doing things in photography. Different people prefer different methods. Try different ways and use what works best.

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bwhip

Great stuff. Thanks so much, nhfirefighter13 and TAZ!

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Purpdust

Thanks NH and Taz, These are Great.

ONEvcs

Bwhip, I think your camera has a setting, in my Nikon is the main dial, where while previewing the pictures on the camera screen, if you turn the dial, it will show you which settings the pictures where taken with.

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