Camera Basics

It’s become a fairly regular thing now that I get asked for advice from people interested in starting photography. I’m only too happy to give it, but as it’s such a detailed topic, I tend to find myself writing what is basically a hand book on the subject. Rather then attempting to rephrase this every time I get asked, I’ve decided to do it properly.

Disclaimer: I appreciate people’s methods will vary, this is what I found works for me!

So what better place to share this knowledge then on my website. If you have any love, or interest, in photography I encourage you to pick up a camera and give it a try. You can use anything, even the most basic cameras can produce beautiful photographs. As you gain experience you’ll find you want to push you camera further, in light and speed, and this is usually when people eye up a higher end camera.


Camera basics

One of the trickiest things about learning camera control is that all the elements play off, depend on and influence in each highly. I find the best way of getting to grips with how all these controls play off against one another is to learn how they’d react under one condition type first.

But first let’s get some basics down. Like what are all these settings about?


Quite simply, the speed at which the shutter opens and closes to let light into the camera sensor. If you want to freeze the motion of a fast moving object, you want a fast shutter speed. If your subject is moving slowly, or not at all, a lower shutter speed will do.

  • For stationary subjects on dark evenings: 1/60 – of a second
  • For slow moving subjects/dull days: 1/125 – of a second
  • For fast subjects/bright days: 1/2000 – of a second

Once you know the basic rules of shutter speed you can experiment. A favorite experiment is to create swishing movement lines/light paintings with slow exposure settings.


Aperture refers to the width of the opening in the lens to let the light in.

  • Wide aperture – shallow depth of field (fuzzy background, subject stands out)
    Lets in lots of light, suitable for dark environments.
  • Narrow aperture – deep depth of field (most/all of the image will be sharp and in focus)
    Lets in less light, suitable for bright, sunny days.

The way aperture is written tends to confuse people. But if you think of it as a fraction, I find it makes a lot more sense.

Aperture is generally written as f1.8, f5.6, f8 etc. The maxium width the aperture can open depends on the lens. The lower the number, the wider the opening.

  • f2 – wide, lots of light, shallow depth of field. (fraction 1/2 = big)
  • f16 – narrow, less light, deep depth of field. (fraction 1/16 = small)


When we used film this was fixed, it’s the speed at which the chemicals on the film react to the light and produce an image. Now that we use DSLRs (digital single lens reflex) and mirrorless cameras (but that’s a whole other story) we can alter the ISO as we please (and the camera allows).

If the number is higher, the image develops faster but the take away is that this will result in higher levels of grain (noise). Higher ISO is suitable for high speed subjects and a fast shutter speed, OR dark conditions, when you want the camera to soak up as much light as possible, as quickly as possible. It’s all about speed.

Generally for images you want the ISO as low as possible, to avoid grainy (noisy) images.

  • ISO 100 – no noisy grain, suitable for bright, well lit situations
  • ISO 1600 – noisy and grainy, suitable for darker situations and fast moving subjects.




This is the distance between the lens and the image sensor when the subject is in focus. Eg. 18mm, 50mm, 200mm.

The real life application of this is that:

  • 10mm lens will be wide angle, seeing a wide range of nearby objects, used to create an almost fish eye view.
  • 18mm lens relatively standard, seeing similar to the human eye.
  • 50mm lens is zoomed in, getting closer to the subject, commonly used for portraits.
  • 200mm lens is also zoomed in, getting much closer to subjects, used for wildlife and sport photography.

The focal length can dramatically affect the appearance of an object in the frame. This is demostrated here.

There are also lenses with fixed focal lengths. These are called Prime Lenses and generally create sharper, high quality images than their flexible cousins, the zoom lenses.

The focal length will also depend on the sensor size in the camera. Most beginner DSLRs will have a cropped sensor, eg. My Canon 7D has a 1.6 cropped sensor, meaning that a 50mm lens becomes 75mm. Illustrated very well here.

  • 50mm lens on a Canon 7D. 50 ÷ 2 = 25. 50 + 25 = 75mm


Camera Modes

On a camera there are various modes. On my Canon for example the main ones I deal with are:

P – Program

Av – Aperture priority

Tv – Shutter priority

M- Manual

I’m usually on Manual. I like to have full control of what’s going on. I can make better decisions about the situation than my camera but leave this until you know what all the settings are about. It’s fun to experiment in M mode.

Av and Tv are both excellent modes to get to know the settings in.

Aperture priority (Av) allows you to only control the aperture, with the twiddly dial by the index finger. The shutter speed with compensate to whichever aperture you’ve selected in order to create a balanced image. If you select your desired aperture, and keep an eye on what the shutter speed is doing, you will quickly get to know which settings play well against each other, and which produce good results that you’re happy with.

The same goes for using shutter priority (Tv). This time the twiddly dial is in control of the shutter speed and the aperture will compensate.

Program (P) is a handy setting if you want a little control but the camera to still do most of the work. For example, if Auto keeps forcing the flash to pop up, head for program, where you can still twiddle the dials and affect the settings, and control whether or not the flash comes into the equation.

*It sounds clichéd but once you have an idea of what the various numbers do, the best way to get to know how the camera really works is to go out there and practise.*

Once you feel you have a good idea of how the aperture and shutter speed play against each other, set the ISO to a fixed number to bring ISO into the equation. If it’s bright, try keep it low, if it’s dark, you’ll need to raise it (push it) a bit. You will find as you push the ISO up, the image quality will go down. That’s the price we pay if we want to shoot in dark conditions.


Time for some examples

Smashed by Gandini at the Dublin Dance Festival 2014

1) Outside, light shade, bright day, fast moving juggling subjects
Perfect for:
Shutter speed: Fast – to freeze the action
Aperture: Wide – for attention focused on subject OR Medium – for focus on multiple subjects in group
ISO: Low – 400 – fast enough to catch detail, low due to perfect light conditions

Bob Dylan Fest 2014

2) Very low light, dark background, generally slow-mid speed subjects
Perfect for:
Shutter speed: Slow – 1/80. To pick up as much light as possible
Aperture: Wide – let in as much of the low light as psossible
ISO: High – 2000. Keeping the shutter speed and aperture set so that ISO can be as low as possible.

President Michael D. Higgins at Gasice 2014 Gold Awards

3) Low light, indoor situation, slow subjects
Perfect for:
Shutter Speed: Slow – 1/125. Subject moving slowly so shutter speed can be slow to capture as much light as possible, while still freezing the slower movement
Aperture: Wide – f2.8. Clear focus on the subject, plesantly blurred background to keep viewer’s focus. Take in as much light as possible in low light environment.
ISO: Mid – 600/800. The low light needs a slightly higher ISO to develop the image, but as the subjects are moving slowly the aperture and shutter speed can handle much of the compensation.

Incoming Owls

4) Dull day, fast moving subjects
Shutter Speed: Fast – 1/3000. These are fast moving animals and the shutter speed must keep up to freeze their action
Aperture: Wide – f2.8. With a dull day and a fast shutter speed, the aperture must be wide open to allow enough light in. When shooting fast animals this can make it tricky to focus and shoot in time, but it will pay off! The wide aperture also focuses detail on the animal itself, not a busy background.
ISO: High – 1600/3000. Depending on the light conditions the ISO will need to be fast, or very fast. If you close down the aperture to make catching the animal in focus easier, you will need to push the ISO more to still get a balanced light photo.

Scouting Ireland Vision 2020 Launch Minister2

4) Bright day, group shot, slow moving subjects
Perfect for:
Shutter Speed: Slow to mid – 1/125. Allowing for narrower aperture and a low ISO
Aperture: Mid – f8. An aperture of f8 is recomended for most group shots as this is the aperture most lenses shoot optimally at. For press photographs such as this one it is good to have a narrower aperture for definite clear subjects.
ISO: Low – 100/200. As low as possible for a clean, grain free photo. The subjects are not fast moving so you can saely use a low ISO.


5) Bright sun streaing through the canopy, shadey areas of contrast.
Perfect for:
Shutter Speed: Low – Mid – 1/200 or 1/500. Here I wanted to expose for the bright leaf and have the rest of the image darker in contrast. The branch was moving gently so a slightly quicker shutter speed was needed.
Aperture: Wide – f2.8/f1.8. The focus just on the leaf, everything else in the frame out of focus. This may require a faster shutter speed to expose correctly.
ISO: Low as possible – 200. Depending on how highlighted the leaf is by the sun, the ISO will vary. But try to keep is below 600.


So hopefully this has given you a good basic understanding of camera controls. There are endless possibilities with cameras, always new methods and ideas being put forward. Go out and give them a try.


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