Choosing a camera

I believe the most common question that comes to mind when choosing a camera is
"Compact, Prosumer or DSLR?

My usual reply will be "What do you need?"

Each of the class of camera serves a different need, although the DSLR clearly outclass the rest in terms of image quality, there are several questions you should ask yourself before going in for the best.

The compact camera is light and easy to carry out compared to the bulky DSLR, and it performs reasonably well provided there is sufficient light. Furthermore, you dont really need a DSLR to take group photos or self pics. And then again, there's Photoshop.

"Do we need a good photographer or a good photo-editor?"
I never knew how to answer that.

The prosumer is somewhere in between consumer and DSLR, for those who want a little more functionality and performance, but not the bulk of DSLR. Personally, and I REALLY mean personally, I feel why settle for something nowhere here nor there? For a few hundred dollars more you can get a DSLR that not only performs better but has the prospect of interchangable lens.

The DSLR comes with a wide range of functions and image quality as well.
Firstly, there is minimal shutter lag (how long do you have to wait after clicking on a consumer).
Secondly, the availability of a wide range of lens (kit lens is never enough).
Thirdly, "what you see is what you get" looking through the viewfinder (I must admit I cant really compose will on a compact for some reason).
In addition, the noise control is significantly better than compact cameras.


I can go on and on why DSLR is better, but the more important question you should ask yourself is
"How often do I shoot?"

There is no point buying a DSLR that cost $1,500 and leaving it to collect dust in the cabinet (not even DRY CABINET) and using it 5 times a year.

If it is your first camera, I would strongly recommend trying out with a compact first to determine if you are going to shoot frequently. After you have decided, you should ask yourself

"Do I mind lugging that heavy black box down Orchard Road?"

And are you going to try it out on everything you see and can lay your hands on? Nature, Macro, Night, Day, Portraits, Architecture, Products, an evening sunset, a morning sunrise, a full moon.... the list goes on.

If yes, then I believe you are ready for the DSLR. The passion for photography is much more than merely owning a DSLR.

Budget should be the LAST issue that comes to your mind. There are 2nd hand cameras at Clubsnap going for as cheap as $350, and some are seldom used at all. Check the shutter count. Trust me, 2nd hands aren't that bad.

:)

Camera Function

The two basic parameters that affect the image taken from a camera are the shutter speed and the aperture size. Although both affect the amount of light incident on the image sensor of a camera, shutter speed and aperture size have a different impact on the resulting image.


The shutter speed and aperture size are indicated on the viewfinder of a DSLR as shown below.

From the figure, the shutter speed is set at 1/60s and an aperture size of F/5.6
The exposure meter indicates whether the setting is appropriate to produce a well exposed image. The brackets indicated the autofocus area of the viewfinder.


"But I'm using a compact camera!!"



The shutter speed and aperture value are also indicated on the LCD screen of compact cameras when the shutter trigger is depressed, just that no one ever notices them.


Most compact cameras use auto exposure function that decides the appropriate shutter speed and aperture value for the user. Whether these parameters can be changed by the user depends on the model of the camera. Normally cameras with manual function allows user to set the shutter speed and aperture size to their preference.


"Ok... So I can adjust the shutter speed and aperture size as I desire. How?"

"MASP" is your answer.


On the command dial (that round thing) of all DSLRs and some compact cameras (Canon's Powershot series), are the various settings that allow users to select the shutter speed and/or aperture size they desire. For Canon users, the command dial is similar.




A brief overview of the various functions:


Manual : Allows you to have the full control over the functions of the camera. Shutter speed and Aperture size, ISO, Flash, Exposure Compensation etc etc. can be adjusted by the user.


Aperture Priority : Allows you to have partial control over the functions of the camera. You set the desired aperture size, and the camera selects the appropriate shutter speed for you. Other functions such as ISO, Flash, Exposure Compensation can be adjusted by the user as well.


Shutter Priority : Similar to Aperture Priority, allows you to set the desired shutter speed and the camera selects the appropriate aperture size for you. Other functions such as ISO, Flash, Exposure Compensation can be adjusted by the user as well.


Programmed Auto : The user have limited control over the functions of the camera. The camera selects the appropriate shutter speed and aperture size for you. Other functions such as ISO, Flash, Exposure Compensation can be adjusted by the user.


Full Auto : The camera selects every single setting for you. Basically, point and shoot.


The mode you wish to use may depend on the situation in which the scene requires. Ideally, using manual allows you full control over the imaging parameters if the situation allows time for you to adjust. (Frankly speaking I seldom use M mode now coz I'm too lazy)

Most situations do not give you the luxury of time to adjust your settings, such as taking fireworks or during a fast-paced dance performance etc. Therefore it would be more efficient to set the shutter speed and allow the camera to decide on the appropriate aperture setting with shutter priority.

Lastly, you may wish to practice switching the dial to Programmed Auto whenever you are not using the camera. You never know when a good "moment" will come about, only to miss it when you are fumbling with your settings.

Shutter Speed Aperture and ISO

Shutter Speed

We now know that the shutter speed of a camera influence the amount of light able to reach the sensor of the camera, affecting how bright or dark the resulting image will be. The shutter speed of a camera is usually measured in seconds, as shown earlier. Most cameras typically are able to operate up to shutter speeds of 1/4000 of a second. The effects of varying the shutter speed of a camera can be seen in the photo below.




Starting from 1/20 of a second, the resulting image is overexposed, with the background being blown out. As the shutter speed is increased to 1/50 of a second, the image gets more well exposed, with the background being more visible. At 1/100 second, a balanced exposure is achieved. Increasing the shutter speed progressively causes the image to get underexposed as in the case of 1/400 second.


Aperture Size


The aperture size of the lens also affects the amount of light incident on the image sensor. The aperture size of a lens is measured in terms of the focal length divided by the diameter of the lens, known as f-stop values.

The common f-stop values are typically f/1.4 , f/2 , f/2.8, f/4, f/5.6, f/8, and so on. Hence, a LARGE aperture size will correspond to a SMALL f-stop value (f/1.4), and a SMALL aperture size will correspond to a LARGE f-stop value (f/22).

Its just maths, go think about it, assuming a constant focal length of 50mm, dividing by a small value (f/1.4) gives u a large result (aperture size). The opposite applies.

The image below shows the different aperture sizes with f-stop values.


The aperture size affects the image brightness in the same manner as the shutter speed. Using a large aperture allows more light to pass through and thus result in a brighter image. In addition to that, the aperture size influences the depth of field (DOF) of the resulting image.

Depth of Field (DOF)

The depth of field refers to the area of a photo that is in focus which is affected by the aperture size. A large aperture size would result in an image with a low DOF, while a small aperture size would result in an image with a high DOF. The image below shows how the DOF changes with decreasing aperture size.



At f/1.4 (wide open), only the front portion of the truck is in focus and everywhere else is out of focus (OOF). This is referred to as a shallow DOF. Decreasing the aperture size gradually increases the DOF of the photo, till at f/16 the entire photo including the background is in focus.

ISO

Lastly, the ISO setting of the camera affects the exposure of the image as well. ISO is defined as the sensitivity of the image sensor to light. The higher the ISO, the brighter the image will be, assuming shutter speed and aperture size are kept constant. However, increasing the ISO setting results in a trade-off of image quality for sensitivity. The resulting image will have a grainy feel as seen in the example below.



Increasing the ISO from 200 all the up till ISO 3200 results in an increasingly grainy image as shown in the enlarged portion on the right.

Getting the Right Exposure

How brightness of a photo is determined by the Exposure Value (EV) of the camera. The process of evaluating the amount of light and shutter speed / aperture size required by the camera is known as metering. The appropriate setting is then defined as 0 Exposure Value. Increasing or decreasing the Exposure Value thus alters the brightness of the photo by changing the shutter speed or aperture size. The process of altering the EV value of a camera is known as Exposure Compensation.

Each unit advancement in EV value is known as a "stop". Usually EV values are adjustable in stops of 1/3 EV. Increasing the EV value by a full stop doubles the amount of light entering the sensor. Therefore the shutter speed halves or aperture size and ISO doubles, or any combination to give a +1 EV.

In short, ISO 200 1/60s f/5.6 and ISO 100 1/30s f/5.6 has the same EV value. So does ISO 200 1/120s f/2.8 and ISO 400 /120s f/5.6




For compact cameras, the exposure compensation setting can easily be accessed by the menu button. With the initial EV value of 0, the shutter speed was 1/52s. Increasing the EV compensation to +2/3 EV results in a slower shutter speed of 1/30s, and the image is brighter assuming aperture size is kept constant at f/3.5 . The reverse applies.


As for DSLR, the exposure compensation can be accessed via the +/- button and seen through the viewfinder. It will be reflected in the exposure bar in the viewfinder in steps of 1/3 EV. As shown in the photo below.



Intially at 0 EV, the shutter speed was 1/40s. Increasing the exposure value by 1 stop indicated by the exposure bar results in the shutter speed being halved. Decreasing the exposure value by 1 stop doubles the shutter speed.

Getting a sharp image

In order to obtain a sharp image, proper focusing has to be carried out to ensure that the image converge on the plane of the sensor. Improper focusing would lead to out of focus (OOF) images as shown below.



A well focused image is shown with the words clear and sharp. A slight deviation off the focus point results in a slightly OOF image as shown above. A clearly OOF image is presented with everything out of focus. As most camera has an autofocus function nowadays, depressing the shutter trigger halfway allows the camera time to focus, before taking the shot.

Take note that the out of focus image in this case is DIFFERENT from the out of focus area due to aperture size. In this case, the desired point of interest is not focused, as opposed to that of DOF, where only the background is out of focus. Also take note of the handshake warning sign that indicates a slow shutter speed which will be addressed later.

As for DSLR, the focus dot indicates whether the focus area in the viewfinder is in focus. Look out for the GREEN dot (for Nikon) to determine whether your focusing is appropriate.




Composing a Shot

Although most camera has an autofocus function, they are not quite as smart as to know which is the area of interest we want to be in focus. (Although they ARE getting smarter with multi detection and all) Therefore I advocate "telling" the camera specifically where is the point of interest before composing the shot.

This can be done by first pressing the shutter button halfway over the area of interest to focus on the point, and then composing the shot with the shutter button still held down halfway.



For the example above, the camera was "told" to focus on the head of Wimpey the truck, and with the shutter button still held the shot was then composed before depressing the button fully to take the shot. This results in the head of the truck being in focus, and the rear being out of focus, as shown in the resulting image below.

Out of Focus vs Handshake

Out of Focus vs Handshake Blurring

"Why is my photo always blur?"

I get that question asked all the time. We need to first differentiate between out of focus and handshake blurring before being able to rectify the problem. Out of focus is primarily due to the image not converging well on the image sensor, while handshake blurring is due to hand movement while the image is taken.



As seen above, the distinction between a OOF image and a handshake blurring image is quite visible. Out of focus images creates a softness on the overall photo, like what you see when you have short-sightedness. Whereas in handshake blurring, the images seems to overlap, due to movements when the image is taken.

With the cause of the blurring known, we are then able to rectify the problem. For images that are out of focus, simply get the focus point right before taking another shot.

Majority of the time, image blurring is due to handshake caused by insufficient shutter speed. As a rule of thumb, the shutter speed has to be at least 1/focal length in order to avoid blurring due to handshake. What does this mean? If your focal length is 50mm, then the appropriate shutter speed should be 1/50s or faster. If you're shooting at 200mm, the appropriate shutter speed will then be 1/200s.

Especially in low lighting conditions (restaurants, night shot), the shutter speed may be too slow for handheld images to be taken.



The obvious solution would be to increase the shutter speed, or increasing the EV value in exposure compensation. However, this might lead to an underexposed image. Increasing the aperture size will compensate for the shutter speed. However, in most cases the aperture is already wide open.

Therefore the last option will be to increase the ISO at the expense of image quality. If the image quality degrades too much due to noise to the extent it is unacceptable, use a tripod or the camera flash.

Focal Length

The focal length of a lens refers to the distance from the image sensor required from the image to be focused. In simple terms, people refer it as "zoom in" or "zoom out". A short focal length is regarded as a wide angle or "zoomed out", while a long focal length refers to being "zoomed in".


For example, the lens above has a focal length range of 18 - 55mm. This means that the focal length when it is "zoomed out" is 18mm, while the focal length when it is "zoomed in" is 55mm.

A short focal length would be known as wide angle
A long focal length would be known as telephoto


Focal Length vs How many x Optical Zoom


Most compact camera on the market nowadays boast of 5 x optical zoom, some even 8 x optical zoom. How is optical zoom related to focal length?

Optical Zoom is given by :
(Longest Focal Length - Shortest Focal Length) / Shortest Focal Length.

For example , the 18 - 55mm lens above has an optical zoom of (55 - 18) / 18 = 2 times

However, that is where the common misconception arises. Many sales promoter market their camera based on the amount of optical zoom they have, 5 times ... 8 times... 10 times...

However, it is the focal length range we are really interested in, not the amount of optical zoom.

An example to demonstrate my point. A Sony Cybershot T90 claims to have a 4 times optical zoom, and so does a Casio Exilim Z280. Which is better? Or are they the same? If we compare the focal length range, the T90 has a range of 35 - 140mm, while the Z280 has a range of 26 - 104mm.

Clearly the Z280 features a wider angle lens compared to the T90. Most compact cameras are used for group photos, and a wide angle setup would come in handy in order to squeeze everyone into the photo.

An extreme case to point, the Sony Cybershot H10 boast a 10x optical zoom, with focal length range of 38 - 380mm. Not wide angle compared to most compact, and too telephoto for the camera to handle.

Focal Length vs Aperture Size

The focal length of the lens affects the maximum aperture size available.
In simple terms, the f-number of the lens increases as the lens is "zoomed in", resulting in a smaller relative aperture. While the physical aperture size does not change, the relative aperture size gets smaller as the focal length increases.


As the f-number = focal length / diameter of the lens,
increasing the focal length (zooming in) results in a larger f-number as the diameter of the lens remains constant.


Referring to Image 1 above, the specification of the lens states 18 - 55mm 1:3.5 - 5.6 This means that the aperture size is f/3.5 at 18mm, and f/5.6 at 55mm. The rest of the images shows the change in aperture size as the lens is "zoomed in". The camera was set to Aperture Priority with the widest aperture setting selected.

As the camera "zooms in", notice the aperture size increasing from f/3.5 to f/5.6


How important is this?

Hell it IS important. It signifies how good your lens construction is, especially at telephoto range.
Remember the rule of thumb for shutter speed requires at least 1/focal length to minimize blurring due to handshake.

For a standard Nikon AF 100 - 300mm f3.5 - 5.6 lens. At 300mm telephoto, the required shutter speed would be 1/300s. The fast shutter speed would mean that the camera needs to compensate it by either opening up the aperture or by increasing the ISO. With the above point mentioned, the widest available setting is f/5.6 , which could pose a problem in low light conditions. The only option left is to boost the ISO at the expense of noise, or use a tripod.


That is why lens which are capable of having small f-number (f/2.8, f/1.8, f/1.4 etc) are known as "fast" lens. Prime lens (fixed focus) lens are superior to zoom lens for the same reason, although they lack the versatility of zoom lens.


Still dont understand?

The bottom line. When the lighting condition is poor, try not to zoom in. Take most of your shots wide angled, so as to maximise the aperture size and shutter speed. If you noticed most of my shots are night are wide angled for the 2 reasons.

At 18mm, the minimum shutter speed required is 1/20s (easily achievable), and the widest aperture at f/3.5 allows sufficient light to enter for a reasonable image to be taken. ISO can be kept at 400 or 800 depending on the situation.

Otherwise, use a 50mm f/1.8 prime lens.