Thursday , September 21 2017
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DSLR Tips and Tricks

CAMERA TECHNIQUES AND JARGON

There’s one sure way to improve your photography and that’s to get a grip on basic photographic techniques; don’t let the camera take all the credit for a great shot!

Aperture and Shutter Relationship

This is the essential first lesson of photography, understanding the relationship between the camera’s shutter and apertures. Control of shutter and apertures will:

  1. Determine correct exposure
  2. Determine the depth of field effect on a picture
  3. Determine whether motion appears blurred or crisp

That’s quite a lot to take in, stay with me, all will be revealed.

Lesson 1

How a camera works

From its early beginnings a camera was a light tight box that housed light sensitive film, the film has since been replaced by a light reactive sensor; as my grandad used to say, same thing only completely different.

We’ll stick to referring just to the new-fangled digital sensor, although everything that follows nevertheless applies to the operation and use of film cameras.

The sensor requires the correct factor of light to create a perfectly exposed picture. In simple terms the sensor is kept in the dark, protected by a shutter obstacle (shutter blind) that blocks the hole (aperture) within the lens.

Press the shutter release button and the shutter blind moves out the way allowing light to pass through the aperture and strike the sensor. If you’ve got the right amount of light then no doubt another Rembrandt has been created.

OK now we’re starting to unravel some of the mystique shared only by a handful of wizards.

Correct exposure

Your camera’s sensor requires a certain factor of light in order to produce a correctly exposed picture. Let’s call that factor ‘X’, the ‘X’ factor; I like it, sounds catchy.

If you let the sensor have too much light, the picture will be over-exposed, that’s not good. If the sensor receives too little light then the result is and under-exposed image, that’s bad.

There are a combination of ways to give your sensor that correct amount of light aka the ‘X’ factor.

Cameras now work with apertures (holes) that can be adjusted i.e. made smaller or larger.

Likewise the shutters can move through a range of speeds; for example a slow shutter speed will unblock the aperture and allow lots of light in before it closes. Conversely a fast shutter will snap back in an instant allowing only minimal time for exposure.

Here we have it:

  • Variable aperture sizes
  • Variable shutter speeds

These two variables work hand in glove, they are inseparable and essential to the understanding of photography!

Let’s go back to the ‘X’ factor; the required ‘X’ volume of light entering your camera can be achieved in two ways:

  1. By using a large aperture and a fast shutter speed. The large aperture will let loads of light in, the fast shutter will react swiftly to restrict light and close when ‘X’ has been achieved.
  2. By using a small aperture, which will restrict the amount of light, and a slow shutter to compensate, to leisurely open a close to allow the required light factor to hit the sensor.

So in general terms a large aperture is complimented by a fast shutter and a small aperture is accompanied by a slow shutter. Either combination will give a correct exposure; but with different results!

Now I’m aware that some of you have questions, especially concerning the vague references to ‘X’. Don’t worry we will return to this in a moment.

You’ve been very attentive, so let’s take a break.

Lesson 2

DEPTH OF FIELD

Depth of field is at the top of my list of techniques; once you’ve cracked this one your photography will improve by leaps and bounds. Once it sinks in you’ll never forget it; but you may need to re-read this passage and practice.

Where to start? I suppose with a basic definition, never easy but here goes.

Depth of field (DOF) refers to how much of your photograph appears in focus in front and behind your subject. For example a photograph with the foreground, subject and horizon in sharp focus is said to have a deep or large depth of field; (Image 1 –currently unavailable).

Conversely the same photo with only the subject in sharp focus would be described as having a shallow or small depth of field: (image 2 – currently unavailable).

  1. Large depth of field – most of the photo in focus from front to back.
  2. Shallow depth of field – usually only the subject in sharp focus

The depth of field effect is determined by the size of the lens’ aperture!

How does aperture control depth of field?

Apertures allow the sensor access to light, via the lens. The size of aperture (the diameter of the hole through which light enters the camera) controls the amount of light striking the sensor. By manipulating the aperture (f-stop) of your camera lens you can determine the depth of field effect in your photo.

Large aperture = Small f-number = Shallow (small) depth of field
Small aperture = Larger f-number = Deeper (larger) depth of field

Try and remember this; Large f number = small aperture. Small f number = large aperture.

All seems the wrong way round somehow! But that’s the way it is.

Now let’s pretend; below are a series of circles, these circles represent apertures within a camera lens. The smallest aperture lets in the least amount of light, the largest aperture will let in the most light.

APPERTURES & f NUMBERS

 

fnumbers1

f numbers ; the rule is, the smaller the f number the larger the hole (aperture); or, the larger the number the smaller the aperture. Take some time to get your head around this one because it’s important.

So to reiterate, an aperture at the f1.8 setting will let in much more light than the tiny f22 setting.

The f number setting on a camera are typically found on the lens as a turn dial operation or, now more common, as a digital, controllable display on the top or back of the camera. Check out the settings on your camera.

Lesson 3

SHUTTER SPEEDS

Shutter speeds likewise determine the amount of light that enters the camera. Press the shutter release button and the shutter blind moves out the way allowing light to pass through the aperture and strike the sensor. The shutter may be fast, letting little light in or slow allowing more light in.

As I highlighted earlier we have the option to vary:

  • aperture sizes and
  • shutter speeds

Do you recall how the two variables combine to allow the correct X factor of light to expose the sensor?

I’ll reiterate:

  • By using a large aperture and a fast shutter speed. The large aperture will let loads of light in, the fast shutter will react swiftly to restrict light and close when ‘X’ has been achieved.
  • By using a small aperture, which will restrict the amount of light, and a slow shutter to compensate, to leisurely open a close to allow the required light factor to hit the sensor.

fnumbers2

 

The diagram represents possible combinations of shutter speeds and aperture settings, if the aperture is small the shutter speed has to be slow to allow that X factor of light in!

So in general terms a large aperture is complimented by a fast shutter and a small aperture is accompanied by a slow shutter. Either combination will give a correct exposure; but with different results!

The effects created by shutter speed

We’ve had quite an in-depth look at the relationship between the aperture and the shutter; we’ve already established that different size apertures give different effects and that there is an intrinsic relationship between apertures and shutters; changing one affects/alters the other in order to maintain correct ‘X’ exposure.

Now let’s look at what happens when we start to play with shutter speeds.

Let’s get right in there:

  • A fast shutter speed, say 1/1000th, will freeze action; the sprinter out of the blocks, Superman in flight and our neighbour’s cat being chased by my Rottweiler.
  • A slow shutter speed, say 1/15th, will cause action to blur, running water, running people, running dogs chasing running cats.

Simples.

OK, time to think; answer the following questions before you proceed;

  1. If you set a slow shutter speed, what happens to the aperture? Is it likely to be large or small?
  2. When you set a fast shutter will the aperture more than likely be large or small?

Slow shutter will necessitate a smaller aperture.

Fast shutter will necessitate a larger aperture.

Now there’s no need to stress if it’s not quite sunk in because, the camera will help you out … usually.

You can tell the camera, via the AV setting, which aperture you would like; maybe a large aperture for that portrait photo of your girlfriend, she stays in focus, the background is blurred and just a wash of colour.

Maybe a small aperture to get your girlfriend and a thunderous wife stood arms folded in the distance.

Time to run, in which case a fast aperture (TV setting) will freeze your spindly little legs; whereas a slow shutter will cause you to blur and hopefully become unrecognisable. Deny everything!

  • YOU SET THE APERTURE AND THE CAMERA WILL WORK OUT AND SET THE SHUTTER SPEED!
  • YOU SET THE SHUTTER SPEED AND THE CAMERA WILL WORK OUT AND SET THE APERTURE!

Glory be. That’s how wonderful the technology is.

You can see how all this fits together by fiddling with your camera’s settings; try setting an aperture, note what shutter speed the camera sets then change the aperture and hey presto! The shutter speed has change.

Then get onto the TV setting and have a play with shutter speeds noting the change in aperture.

REMEMBER AS A GENERAL RULE YOU CAN’T HAND HOLD A CAMERA IF THE SHUTTER DROPS UNDER 1/60TH – CAMERA SHAKE KICKS IN (tripod required).

Well done if you’ve gotten this far, now you really understand the essential basics. Get out there and practice, practice, practice!