Your camera thinks it’s smarter than you. As we speak at this very moment, it’s smirking in your bag, silently mocking you. It doesn’t have to be this way, it’s pretty easy to gain the upper hand and really take control, freeing your mind in the process.
In today’s post, I will explain the how’s and why’s of manual exposure and share a trade secret that will make shooting in manual so easy, you’ll wonder why they didn’t just explain it to you when they issued you your gear.
First, a word on automatic exposure. Modern SLR’s have several “Automatic” modes:
- Program Mode
- Aperture Priority
- Shutter Priority
- Full Auto
There are already more than enough blog posts out there that explain in detail what each of these modes do, so I won’t try to reinvent the wheel. Suffice to say there are substantial differences between the various automatic settings. For the purposes of this post, however, the only thing we need to know is that they all have one thing in common. In each of these modes, your camera is making decisions about what *it* thinks the exposure should be.
There are times when that’s exactly what you need. For example, if you are shooting a fast moving event with lots of different lighting conditions, an outdoor wedding reception, for example, you probably want to stay in AV mode. Otherwise you’re likely to miss too many shots, no matter how fast you are.
But if you’re in control of your environment and shooting a fairly static scene, a portrait session, for example, manual mode is the way to go. Here’s why: in any of the auto modes, you are at the mercy of wherever your lens happens to be pointing. The camera makes its decisions based on the light it’s reading through the lens (TTL). Tiny movements to the left or the right, up or down can cause dramatic differences in how your camera exposes the scene, especially in high contrast situations.
Another key reason to shoot in manual is flash photography. As I have mentioned in my High Speed Sync series, you need to kill your ambient light in order to get full effect of your off-camera lights. You can’t have your camera trying to override your ambient light decisions, you really have no choice but to shoot in manual.
Plus, in manual mode, you’ll get your shot much quicker because your exposure will be consistent and predictable. Luckily, learning to shoot in manual mode is pretty easy when you know the secret.
But before I get to the secret, here is some background on the settings involved.
The Three Variables
There are three, interlocking variables to consider here.
ISO is the number that represents how light sensitive your digital sensor will be. Most cameras start at ISO 100 (less light sensitive) and go up to 3200 or more (more light sensitive). You double the amount of light that is registered by your sensor by moving from ISO 100 to 200. You double it again by moving from 200 to 400. When you double the speed in this way, you have increased the exposure by “One Full Stop” of light. In photography, light is measured in “Stops”, each one letting in twice as much as the one before (or half as much, depending on which direction you’re moving).
The aperture is like a little iris that controls the amount light that passes through the lens. Apertures are measured in cryptic, counter-intuitive numbers that take some getting use to.
The smaller the number, the LARGER the aperture. For example, an aperture of 2.0 lets in twice as much light as an aperture of 2.8. Just like with ISO, a move from 2.0 to 2.8 would be considered “One Full Stop” of light, in this case you would be reducing the light by half. If that sounds backwards to you, remember that the larger the aperture number, the smaller the hole it makes, allowing less light to pass through. For example, the max (largest) aperture on my 70-200 is 2.8. The next full stop down (smaller hole) is 4.0, smaller still is 5.6, then 8, 16, 32 until you have a but a tiny hole through which all your light must pass.
Shutter speeds are measured in fractions of a second. A shutter speed of 1/60 lets in twice as much light as a shutter setting of 1/125. Just like with ISO and Aperture, shutter speeds are measured in “Stops”. As such, 1/60 is “One Full Stop” slower than 1/125, which means your shutter is open for twice as long, giving you twice the light.
The common thread here is that each of these three variables are measured in “Stops” and that each stop lets in twice as much light as the one before (or half as much, again, depending on which direction you’re going).
It’s important to understand that these values are all interlocking. Consider this scenario:
You’re shooting in manual with the following settings:
- ISO 200
- Apeture 5.6
- Shutter 1/30
You check out your histogram and you can see you have your scene all dialed in and exposed just the way you like it. But after taking a second look you realize that there is some camera shake, you need a faster shutter speed. No problem, you just increase the shutter speed from 1/30 to 1/60, a full stop, problem solved.
But because your shutter is now open for half as much time, your scene is going to be one full stop darker, and that’s not what you wanted. That stop of light needs to come from somewhere, you have two choices, you can increase your ISO a stop to 400, or open up your aperture a stop to 4.0.
One last thing before I reveal the key to making all of this easy, most digital SLR’s default to a 1/3 stop increment for ISO, aperture and shutter. That means that you have to dial three clicks to make one full stop of adjustment. So, using the example above, you can also do a combination of both ISO and aperture, doesn’t matter, so long as they add up to one full stop or three clicks.
Actually, what I am about to tell you is not a secret, it’s common sense once you think about it. I’m guessing it took me longer than average to figure this out, so it’s very possible that your reaction to my big secret will be something like, “Well duh”.
Here it is:
With not a huge investment of effort and time, you can shoot in manual without even thinking about it – Think of it this way, the ISO/Aperture/Shutter dials behave exactly the the same way the knobs on your kitchen sink do. Just like a water faucet, when you turn your ISO/Aperture/Shutter dial counter-clock-wise, you’re “opening it up”, letting more water/light in.
Conversely, if you turn your ISO/Aperture/Shutter clock-wise, you’re “closing it down”, letting less water/light in.
Knowing that they all interlock, and that a click to the right on one dial equals a click to the left on one of the other two is really easy to remember. And then practicing, practicing, practicing until your fingers know exactly where they are, what direction to turn to darken, which to lighten, increase depth of field, decrease depth of field, capture motion or create motion blur – you outsource all of that crap to your fingers the same way a top notch pianist would. You don’t have to think about numbers anymore, pretty soon you’ll get to the point where you can adjust the important settings on your camera by touch, without wasting brain cycles, without even having to look at it.
When I realized this, I spent two days practicing until four in the morning, walking around my kitchen taking photos with my Canon 5D (classic), exposing just by counting the numbers of clicks. I burned through so many batteries, filled up so many memory cards, shooting, shooting, with my eyes closed, like back when I was in basic and you had to put your rifle together blind folded.
In the end, my shutter fried, they make a nasty sound when they come apart. They know me pretty well at the repair counter at Looking Glass Photo in Berkeley, the best camera shop ever, catering to the serious photographer. Free advertising, we don’t have a relationship beyond the doctor/patient one.
It was two days and a about a three hundred dollar repair bill, but it was time and money well spent because that muscle memory is now etched deeply in my mind. I couldn’t forget it if I tried. It’s the reason why I will probably never move off of the 5D, too much invested in internalizing its controls and just the way it feels in my hands. I just hope they keep making parts for them.
Shooting manual in this way will free your mind to concentrate on more important things, like making your image match your vision.
The Napa Photographer