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Release your inner artist: Break the "P" barrier

Jon Nadelberg (jnadelberg)

Keywords: basics, modes, iso, shutter, aperture, exposure, depth_of_field, settings

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So you got a new DSLR, maybe for the holidays, and you’ve now been using it a couple of months. It’s got all sorts of knobs and buttons on it, and it looks a bit intimidating. Good for you, you’re using it! You have quickly learned that autofocus, auto-exposure and auto-ISO gives you very nice photos.

You will soon realize that DSLR can do so much more than just act as a bigger and heavier point and shoot camera. It is a machine that, in conjunction with your use of it, creates art. It can create beauty. But where do you start?

How do you go about learning to use your camera and understanding the concepts that are the foundation of photography? The answer is, as with everything, one step at a time

In this article we will discuss a way, by changing the exposure mode, which will make the camera less completely automatic. It will still do most things on its own, but this will begin to give you more control over how your images look, and send you on your way towards releasing your inner artist.

Exposure Mode dial on Nikon D3100

Figure 1. Exposure Mode dial on Nikon D3100. Most of these modes are not standard. The only ones that are important are M, A, S, and P. Note that they are separated off. Those four are the only ones you need to learn, and they are universal. More advanced cameras have only a mode button instead of a dial, and only let you select from these four basic modes.



Before we can talk about how to change exposure controls, we need to talk a little about what exposure is. Exposure is the amount of light reaching your digital sensor. It is determined by:


  • Shutter speed, which is the amount of time that light is allowed to hit the sensor. It’s like your eyelid. You open and shut your eyelid and let in light. Cameras typically have shutter speed that can range from as short as 1/8000 of a second to many seconds long.
  • Aperture, which is the size of the opening inside your lens that lets in light through to your sensor or film. It works like the pupil (or really, the iris) of your eye. The larger the opening, the more light is let in.


The combination of the shutter speed and aperture is called an “Exposure Value,” or EV. EVs work in conjunction with one other part of exposure, the ISO setting. The ISO setting is a measure of light sensitivity of your sensor. The higher the number, the more sensitive it is to light For any particular ISO setting, there will be an appropriate amount (aperture) and duration (shutter speed) of light for a certain exposure.

Another thing to remember is that there is not just one setting for any particular exposure, but an entire range of equivalent shutter speeds and apertures. All combinations that yield the same exposure amount have the same EV.

It works like this: If you open up your aperture bigger, you need less time for the light to hit the sensor. If you make the aperture smaller (also called stopping down), you need more time. While each of these combinations give an equivalent exposure and EV, they also can give a different appearance to your final image. We’ll explore these differences further on.



When a camera determines all or part of your exposure, it’s called auto-exposure. Cameras equipped with auto-exposure have the ability to measure the amount of light coming in through the lens and to compute an appropriate middle of the road aperture and shutter speed combination, based on your ISO setting. It doesn’t know what you are taking a picture of, or how you want it to look, so it will generally pick some average setting that will be acceptable for typical situations. Some cameras do this better than others, but this is what all auto-exposure features do. There are four main levels of auto-exposure mode:


  • Program mode. The camera chooses both the aperture and shutter speed for you.
  • Shutter Priority mode. You select the shutter speed; the camera chooses the aperture.
  • Aperture Priority mode. You select the aperture; the camera chooses the shutter speed.
  • Manual mode. You choose both the shutter speed and aperture. In this mode, the camera may give you some feedback as to whether it thinks you are exposing the image correctly, but it takes no other action.

Note how the names match the modes in the mode dial in figure 1 (P,S,A, and M). In addition to the above, your camera likely also has an Auto-ISO function, which will adjust the sensor’s sensitivity to light for a proper exposure based on the shutter speed, aperture, and light level.

Using your camera in Program mode (or one of the various automatic modes it might have) allows it to make all these decisions. What we are going to do is take your camera out of Program mode, and put it in Aperture Priority mode and examine what this control can do for your photos. The camera will still be selecting a shutter speed and ISO value, but you’ll be controlling this one aspect of previously automatic function.


Aperture and f/Stops

As mentioned before, aperture refers to the size of the opening within the lens that lets light through to the sensor. The various levels of light that lenses allow through are referred to as f/stops.

Nikon lens aperture ring

Figure 2. A Nikon lens with an aperture ring listing typical numbers representing f/stops. G type lenses do not have this ring. Above the ring, you can see the depth of field gauge for the lens. At f/16, and at the current focus, the depth of field will go from about 21 feet to 6 feet.

An f/stop represents the ratio of the focal length of the lens, (for example 50mm or 200mm) and the opening required for a certain amount of light to be let into that lens. The light levels are represented by progressive powers of the square root of 2. By taking a power of the square root of 2, and dividing it by the focal length of the lens, you determine how large the internal opening must be to let in the appropriate light level.

The chart below shows approximate values for a typical range of f/stops and the opening required on a 50mm lens.


f/Stop Derivation

x  2 x or f/Stop Aperture Opening Required On 50mm Lens (50/f-stop)
1 1.4 35mm
2 2 25mm
3 2.8 18mm
4 4 12mm
5 5.6 9mm
6 8 6mm
7 11 4mm
8 16 3mm



You may recognize the numbers in the center column from the f/stops in figure 2. These are whole f/stops. The formula provides that each number in this column either doubles or halves the amount of light from the next or previous f/stop. For example, f/1.4 lets in double the light as f/2, while f/8 lets in half the light as f/5.6. Doubling and halving like this makes calculating exposure simpler. You may also note that shutter speeds and ISO values also do the same sort of doubling and halving.

Numbers that are not in the above table usually represent either 1/3 or 1/2 stops that a lens or camera is capable of using. For example, f/1.8 (which is often seen as the maximum aperture of some lenses) is about 1/3 a stop smaller than f/1.4. You will always see lenses rated by their maximum f/stop value. (Some lenses have a variable maximum f/stop value due to the way they were constructed. In that case you’ll see lenses rated as something like f/3.5-5.6). The other thing to note is that because you divide the focal length of the lens by the f/stop value, as the f/stop increases in value, the opening actually gets smaller.

Do you need to ever know the actual opening size of the lens? No. Do you need to know which power of the square root of 2 you are using? No, although you can use the relationship between those numbers when saying something like “two stops lighter.” Otherwise there is almost no reason to talk about either. What you do need is the f/stop number. All cameras and lenses use this system. This means that f/5.6 on any lens is going to allow through the same level of light to the sensor regardless of its focal length. This is how the light meter in your camera is able to work, and how it can compute proper exposure regardless of lens focal length or manufacturer.

Remember: The lower the f/stop, the bigger the opening, and the more light it lets in, which is called a faster lens. The higher the f/stop number on a lens, the smaller the opening, and the less light it can let it, which is called a slower lens.  Faster lenses are harder to make well, and are generally more expensive to purchase than slower lenses.

(24 Votes )
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Originally written on April 30, 2015

Last updated on July 9, 2015

Jon Nadelberg Jon Nadelberg (jnadelberg)

Ribbon awarded for his multiple contributions to the Articles section

Foster City, USA
Silver, 205 posts


David H Dennis (davidhdennis) on May 21, 2016

If lighting conditions are changing, aperture or shutter priority mode may not be the best way to proceed, because the camera may need to adjust exposure past the boundaries you have set. I almost always take pictures of things happening in front of me for which I may not have time to precisely prepare. The bird is about to take off! The girl gives me an enchanting smile! Those moments may be over if I have to hesitate to correct exposure. So I like using program mode with creative control. Nikon DSLRs have a rotary control in back of the camera on the top right side. If you are in program mode, you can rotate that control left to increase the aperture and decrease the shutter speed, or right for the reverse. So if I want to maximize depth of field, as when I am shooting butterflies or other insects, I rotate the knob left. If I want to increase depth of field, as in separating out people or tree branches from the background, I move the knob right. In the mean time, if I'm suddenly shooting in a bright place form a dim one or vice versa, the camera will automatically override me if my settings would make things totally out of whack. Of course there are times when you absolutely need to force aperture or shutter speed to a specific value. For example, I use f/2.8 lenses. When shooting video, I need a wide depth of field range so I can shoot with manual focus. Otherwise the autofocus constantly switches, making horrible looking video. So I force aperture to f/5.6-8 using Aperture Priority. The really important thing, I believe, is to understand your camera and the impacts of various apertures and shutter speeds on focus. I really like the pictures the writer of this article took that show those effects very well. Hope that was of interest.

Jon Nadelberg (jnadelberg) on October 19, 2015

Ribbon awarded for his multiple contributions to the Articles section

Art is in the eye of the beholder. I can't really speak to how to make something more artistic.

victor benedicto (benedicto) on August 11, 2015

HI. nice technical informative article. Maybe to get to the artistic side of photography, can you add some tips on how to make a foto artistic. Thanks. ( just signed up.)

Jon Nadelberg (jnadelberg) on May 13, 2015

Ribbon awarded for his multiple contributions to the Articles section

That is all this is about. When I got my first camera, it was pretty much all manual. Manual focus, you had to set shutter speed and aperture. It was a Minolta SRT 202 (long since stolen, but I have a SRT 101 now. Fifty years old and still works!). You can't understand what to do in photography unless you turn off program mode, or worse some of these automatic modes, and set the camera yourself. The problem is the cameras are becoming so good, that they really know how to take pictures. Other than changing lenses, there is little difference between an SLR and a point and shoot. The simplest DSLR, say a D3100, can do so very much more. And people are always asking about "Why does my picture not look right." Of course most people reading this are going to know, but a lot, even those looking at this site and others, aren't going to know. I think it is important that articles like this, while very basic, are put out there so that people can understand the things that at one time were part and parcel of just using a camera. If I got a new camera today, I would have no clue how to move forward, nor would I understand what is going on with it. That is simply not any good. We have automated ourselves into helplessness. We should never forget that everyone has to learn, and that no one comes by photography with an innate understanding of how it works. It is not intuitive, but on the other hand it doesn't take a college class to learn. Just a few pointers and a bit of thought.

Mindaugas Pangonis (Hugatree) on May 12, 2015

Great simple article! Back to basics and encourages to think instead of leaving it all to robot within the camera :)

Jan Timmons (Jan Timmons) on May 10, 2015

Thank you, Jon. You've made this very clear. I appreciate your time. Not sure how I got off-course, but you've helped immensely. (I had used spot to meter various areas. Perhaps I should let the camera have a go at it, and compare the mode using aperture or shutter priority.) Thanks again. You write very clearly and concisely. –Jan

Jon Nadelberg (jnadelberg) on May 9, 2015

Ribbon awarded for his multiple contributions to the Articles section

If you put your camera in manual mode then the camera does not set the exposure, you do. However, the camera still has a light meter on it, and will recommend what it thinks is the proper exposure based on the metering type. It will report back this information in the meter display in the viewfinder and other displays for your camera. So, yes, it has no direct effect because in manual mode it is not setting your exposure. However, it is telling you what it thinks is the proper exposure, which is information you can either use or ignore. What it is going to tell you is based on whether you have chosen spot, center-weighted, or matrix metering modes. If you want to expose your image, you can do one of three things, use the camera light meter, an off camera light meter, or take a guess based on things like the sunny 16 rule. From that information, you can then make whatever changes you want based on the conditions at the time, and what you wish your photograph to look like. None of these metering types affect your image in manual mode, because the camera is not setting your exposure. The only effect these modes then have is in telling you what it thinks would be the proper exposure. I hope that makes sense.

Jan Timmons (Jan Timmons) on May 9, 2015

Sorry. You answer my query here: "Manual mode. You choose both the shutter speed and aperture. In this mode, the camera may give you some feedback as to whether it thinks you are exposing the image correctly, but it takes no other action."

Jan Timmons (Jan Timmons) on May 9, 2015

Aha. I think I've lost the dispute. Darrell Young, in his "Master the Nikon D810” book, refers to manual mode in Chapter 8. Thanks.

Jan Timmons (Jan Timmons) on May 9, 2015

Thank you for your article. Perhaps you could help to settle a dispute? I shoot in RAW manual mode —now using a D810. An older and more experienced photographer than I, by several decades, states that using matrix, center-weighted, spot, or the highlight-weighted metering has no effect when shooting in manual mode. Is he correct? (If you referred to this in your article, I missed it. I apologize.)

User on May 7, 2015

Very good article. I typically shoot in manual mode (Nikon D5100), but I have experimented with the Aperture and Shutter priority settings on occasions. I get some awesome results in any of these modes. This article will encourage me to experiment more with A and P modes.

Owen De (rjpg) on May 4, 2015

As a new "Nikonian" I thought this article was very helpful. Will be using all of these techniques.

User on May 3, 2015

Easy information to understand and useful no matter what level of photographer you are.

User on May 3, 2015

Great information. I just got a D3300 a few months ago and have been experimenting with the modes other than auto. This article will help to transition beyond auto

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