The Main Digital SLR Camera Advantages Part 3/3

Advantages of Digital SLR Cameras

This is the third part of the three part series on Everything you need to know About DSLR Cameras. The following are the main digital SLR camera advantages.

Ability to change Aperture

We are already familiar with the term Aperture. One of the main digital SLR camera advantages is the ability to change Aperture on demand. What happens when you mount a lens on your DSLR? A set of mechanical coupling at the lens mount form an electronic connection between the lens and the camera.

Now when you dial in the Aperture number from the menu or by turning the command dial, the corresponding aperture is set on the lens. Smaller Aperture will capture less light, but you get a larger DoF. Therefore by controlling Aperture you also control how much of the frame is going to be in sharp focus.

Your camera has a shooting mode labelled ‘A’ or ‘Av’. When you set the mode dial to this you are able to control the Aperture of your lens. We have already learned that exposure is a product of aperture and shutter speed. Therefore, when you set aperture manually, Shutter Speed is auto selected to ensure a balanced exposure.

Ability to change shutter speed

Similarly, another of the major digital SLR camera advantages is the ability to control Shutter Speed. Controlling Shutter Speed is all about controlling the length of time for which the Shutter remains open for light to pass through.

A longer Shutter Speed allows you to collect lot more light. There is yet another advantage. The longer the Shutter remains open the more movement it is likely going to achieve. This has some creative implications which we shall learn about later.

Your camera has a shooting mode labelled ‘S’ or ‘Tv’ when you set the mode dial to this you are able to control the shutter speed of your lens. Just as in Aperture priority mode, in Shutter priority mode as well, when you select Shutter Speed, Aperture value is auto selected by the camera to ensure a balanced exposure.

The Manual Shooting Mode

The Manual shooting mode is considered as the expert photographers preferred choice. This is the mode that allows you to change both parameters of an exposure. It is also one of the major digital SLR camera advantages. However, these days most mid-range point and shoots also provide manual shooting capabilities. So, it is no longer the bastion of DSLR systems.

As a beginner photographer you may find this mode a bit difficult to use. This is because it involves controlling both aperture and shutter speed in order to balance the exposure. You are better off shooting either in aperture priority or shutter priority modes to begin with. This is till you are confident about framing, focusing and the use of both aperture value and shutter speed in their individual capacities.

Manually focus an image

manual and auto-focusing

We have learned about focusing earlier. It refers to bringing a subject in sharp contrast from its surroundings in a frame. In DSLRs this is done automatically, when you depress the shutter release button half-way. Alternatively, you can manually acquire focus by turning the manual focus ring.

Review an image instantly after it has been taken

Another advantage of DSLR camera systems is you can immediately review and image after it is made. Thanks to the advent of digital technology.

The Optical Viewfinder

The Optical Viewfinder at the back of the camera is something that no other camera systems with a smaller sensor has. This is the best tool to compose and frame your images. This is provided of course that you have camera that gives you 100% of the frame coverage of what the lens sees.

Change lenses to change perspective

DSLR allows changing of lenses

No doubt the most important of all digital SLR camera advantages – the ability to change lenses. DSLRs have the largest collection of OEM and third-party lens systems. All manufacturers like Canon, Nikon and Sony have their own line of high quality lenses. Plus, third party manufacturers such as Tamron, Tokina, Rokinon and Sigma also produce excellent quality lenses for most of the camera mounts.

Though mirrorless systems have come off age, and now there is a good collection of lenses for MILC systems as well, DSLRs are still miles ahead in terms of the sheer number of options.

Plus, some DSLR systems work with legacy lenses; and without the need for adapters. For some this is probably the greatest of all digital SLR camera advantages. Lenses that were designed originally for film SLRs, can be mounted on some DSLRs and used with manual focusing.

How to use a DSLR camera

Now for some practical tips on how to work your DSLR camera.

The fundamental theory of a DSLR

You DSLR camera is essentially a light tight box. This box has a small opening at one end to allow light to enter the camera on demand. This opening is the Aperture. The surface on which light falls and the image is recorded is the sensor. The length of time this hole will remain open is decided manually or automatically. This is known as Shutter Speed. This is fundamental to all DSLR cameras.

Looking through the viewfinder

Turn on your camera. Look through the viewfinder at the back. You can immediately see a lot of information. Depending on the camera make you will information like this 250, 5.6, a number of small points strewn across the frame and A red dot. You would also have something that appears like a scale.

250 denotes the shutter speed that has been preset. 5.6 is the aperture. The scale is actually an indication of the exposure you are likely to get based on the aperture value and shutter speed.  There is a built-in light meter inside your camera and that is what meters the light reflected off of a scene and determines whether your exposure details (aperture and shutter speed) is going to produce a balanced exposure or the image is going to be over or under exposed.

Over and under-exposed image

An overexposed image is the result of an excessive amount of light collected, beyond what is required to produce a balanced exposure. On the other hand an under exposed image denotes an exposure where less amount of light is captured than what is required to make a balanced exposure.

What Happens When you half-depress the shutter release?

Half depress the shutter button. You will notice a few things. Chief among them is one of the tiny dots on the viewfinder lighting up (turn bright green or red depending on the camera make and model). These tiny points are actually auto-focusing points. They correspond to tiny line sensors on the focusing sensor.

When one or more of these lights up it means that the focusing mechanism of your camera has locked focus on the points corresponding to the AF points. It is pertinent to note here that the active AF point denotes the point which is in focus and would appear the sharpest in the image.

If at this point you fully depress the shutter release the reflex mirror will move away from path of the sensor an image will be recorded.

Working with the Aperture priority mode

This mode, as we have already learnt, is labelled as A or Av. When the main shooting mode dial is on A r Av turning the main (or sub) command dial will change the Aperture value in 1/3rd stop increments. We are already aware that the smaller the Aperture is (larger f-number) more of the image is in focus. Plus, it also means less is the amount of light that is captured.

On the other hand Larger the Aperture (smaller f-number), the less of the image will be in focus. But on the bright side the larger is the amount of light that you will capture.

aperture priority mode

When do you need to use a small aperture? Landscapes are one genre of photography when you need to use a small aperture (large f-number).


When do you need to use a larger aperture? A large aperture is necessary for portraiture. This helps to blur out the background or anything else in the frame that might not be adding to it or just be plain distracting.

Working with the Shutter Priority Mode

Much like the Aperture Priority mode simply turn your camera’s main shooting mode dial to read S or Tv. Now, turn the main or the sub command dial in order to change the shutter speed.

Shutter priority mode is a creative mode as it helps to capture light over a period of time. That has some advantages. Using shutter priority you can create beautiful results which is not possible using standard exposure techniques.


The next step is to learn about the technique of manual exposure. However, before you swim to the deep end of the pool let’s get a couple of things sorted.

Metering denotes taking a reading of the ambient light quantity in a scene. This is done automatically by the camera’s built-in light meter.  But you still have to select the appropriate metering mode.

Introducing the Built in light meter

The job of the light meter is to measure the average reflectance of the scene. Meaning it measures the amount of light that is reflected off of the scene. The interesting thing is the built-in light meter of all DSLRs systems assume that every time you click the scene is of average reflectance. In other words it is assumed that everything is about 18% grey.

This theory comes from the world of printing where 18% grey is the shade that have average reflectance. The problem, however, is that in real life that approach rarely ever works. If you are photographing someone standing in front of a white wall (or a snowy scene), your camera’s metering system will go haywire looking all that white.


It is programmed to see everything 18% grey and in this case the scene is dominated with white color. It would therefore assume that the scene is overexposed and try to compensate for that by pulling down the exposure.

metering tips

The same way if you have a black wall behind your subject, the camera’s metering will think that the scene is dark and therefore will try to compensate.

The three different types of metering modes

There are three different types of metering modes on all cameras. Some cameras, like Canon’s systems come with four. These three metering modes are center weighted, matrix or evaluative and spot metering. Each of these metering modes are important in specific shooting situations.

Center weighted metering mode is ideal for small subjects or subjects that occupy a small area of the frame. This mode takes into consideration only the center area of the frame and ignores everything else. Flower photography or a subject that is further into the frame are examples where this metering mode is useful.

Spot metering mode

Spot metering mode will consider only the area immediately around the active AF point and disregard everything around it. This mode is perfect for shooting subjects like a wedding ring, for macro photography where you are trying to meter on something as small as a pollen, or a petal, or even a drop of dew.

spot metering techniques

Matrix metering mode

Matrix metering mode is a very popular metering mode and one that takes into consideration the entire frame in order to meter. This mode is a very generalist way of metering and is only suitable when you are shooting landscapes or a scene which has average lighting across the frame.

matrix metering

Exposure compensation

When the camera’s metering mode suggests that the scene is either under over exposed you have do a few adjustments. First, check the metering mode to see that you are using the correct one for the shot you have set-up. Let’s say that you are photographing a flower and have set the metering mode to matrix. This is obviously the incorrect metering mode for the shot.

Second thing you have to do is manually adjust the exposure. In aperture priority, shutter priority and program mode you can use something known as Exposure Compensation. There should be buttons labelled +/-. Press it and then dial the sub-command dial to either underexpose or overexpose the scene.

In full manual mode Exposure Compensation will not work. You will have to dial in the right aperture value and shutter speed to ensure that the exposure is correct.

Here are some guidelines. Let’s say you are shooting a scene that is essentially too bright, a subject standing against a white wall, or a snowy landscape. You will need to over compensate by at least one stop or even two to ensure that the exposure is correct.

The same way when shooting a predominantly dark scene you will need to underexpose by about one to even two stops to ensure that the exposure is right.

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Rajib's love for the road is second only to his love for photography. Wanderlust at heart and a shutterbug who loves to document his travels via his lenses; his two passions compliment each other perfectly. He has been writing for over 6 years now, which unsurprisingly, revolve mostly around his two favourite pursuits.

Author: Rajib

Rajib's love for the road is second only to his love for photography. Wanderlust at heart and a shutterbug who loves to document his travels via his lenses; his two passions compliment each other perfectly. He has been writing for over 6 years now, which unsurprisingly, revolve mostly around his two favourite pursuits.

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