Task 8- Effective Use of Focal Length (4.1, 4.2, 4.3)

When it comes to photography, lenses are an integral and important factor in creating the perfect photo for your intention. Even if you have the just the right exposure and have composed the perfect shot, if you are using the wrong focal length it could drastically change the desired out come of your photo.

Lens Types

Wide Angle

Image Source

Lenses that have a short focal length are referred to as ‘wide angle’, they normally range from 18 – 35mm and are typically used for landscapes and interiors. They capture almost

everything your eye see before you, however because of this they are not suitable for portraits as they can distort facial features.


A standard lens ranges from 45- 50mm, they can be used for a wide range of photographic subjects as they are not at either end of focal range. Although they can capture nice landscapes, their strength is portraits as they produce flattering  more natural looking photographs.

Telephoto Lens

A telephoto lens have long focal lengths normally starting at 70mm ranging all the way to 600mm and you can either buy them as prime or zoom lenses. Due to their range you can shoot subjects at a great distance away, making it excellent for wildlife photography and the lens of choice for paparazzi. Telephoto lenses can also occur the same limitations as zoom lenses, the longer the focal distance the narrower the aperture will be.

(image source)


50mm Prime Lens(photo source)
35mm prime wide angle lens (photo source)

Prime lenses have one fixed focal length or one viewing length, but just because you can’t zoom in or out doesn’t make prime lenses inferior to other lens types. Prime lenses are more likely to produce higher quality images, their design is simple and less likely to be prone to visual distortion like barreling and will produce a technically more correct image. Prime lenses are more likely to be faster and have a wide aperture, allowing for better quality images. Prime lenses are a great starter lens and an excellent way to learn photography, despite it’s lack of range. A standard prime lens is 50mm, roughly the same distance the human eye can see in focus but you can get a range of other focal length including prime wide angle lenses.

Zoom Lens

18-55mm Zoom Lens (image source)

A zoom lens has a range of focal lengths, allowing more versatility than a prime lens and saves you from having to switch between different lenses while shooting. A standard zoom lens can either be wide angle (18-55mm) or short telephoto (28-135mm), these are often referred to as kit lenses. A disadvantage to a zoom lens is that they can often be more expensive as they can be very large pieces of equipment. They are also more likely to be slower lenses, as the aperture might not be able to go wider than f5.6 on some of the focal lengths.

Fast Lens vs Slow Lens

Lenses tend to fall into two categories either fast or slow, depending on their maximum aperture openings. Fast lenses will have wide apertures up to f1.8 and usually achieved when using a prime lens, a slow lens typically can only achieve an aperture up to f4. With a wider aperture a faster shutter speed is needed and is why we call them ‘fast. lenses. A fast lens will be better at shooting in low light conditions or when you need to capture fast action. Photographers also prefer fast lenses as wider apertures allows for shallower depth of field which is excellent for making subjects  standout against backgrounds, for example in portrait photography. However, fast lenses can be very expensive especially fast zoom lenses as they tend to be very large and heavy.
You are able to identify a fast or slow lens by the maximum aperture which is normally printed on the outside rim of the lens.

Lens Distortion

Lens distortion happens when the lens produces curved lines where straight lines should be and this can happen for a few different reasons, the most common distortions are barrel and pinchusion.
Barrel distortion is where lines will bend outwards from the centre of the image. Very wide angle lenses can produce the barrel effect and is very noticeable in architectural photography as buildings will appear slanted or bowed. Distortion can also happen if you’re standing too close to subject which is why wide angle lenses are not suitable for portraiture as it can distort and emphasise facial features.

Pincushion distortion is where the lines will bend inwards, creating the impression that things have been pinched, this most commonly occurs with telephoto lenses.
However, lens distortion can be used creatively, to create interesting looking perspectives or create impression of size, or you can use additional equipment like a fish eye lens to exaggerate distortion further.
Distortion can generally be avoided by correctly choosing the right focal length for the subject you are photographing and standing the correct distance away, it can also be corrected in postproduction.


Lens Filters

Lens filters have a few different purposes, they protect lenses, help shoot in difficult lighting conditions, reduce reflections and even enhance colours.

Lens Filter Photography Type Purpose
UV/Clear/Haze Filter Any Protects the front element of a lens from dust, dirt, moisture and potential scratches. High quality UV filters can be permanently mounted on lenses with a minimum impact on image quality.
Polarizing Filter Any Filters out polarized light, dramatically reducing reflections, enhancing colors and increasing contrast. Can be used for any type of photography. Polarizing filters are typically circular, allowing for easy control of the effect of polarization.
Neutral Density (ND) Filter Landscape, Flash Photography Reduces the amount of light entering the lens, thus decreasing camera shutter speed. Useful for situations where motion blur needs to be created (rivers, waterfalls, moving people) or large apertures must be used with flash to avoid overexposure.
Hard-Edge Graduated Neutral Density (GND) Filter Landscape Photography Hard-edge GND filters are primarily used in high contrast situations, where the sky is much brighter than the foreground and the horizon is flat. These filters are always rectangular (giving the ability to move them in all directions) and are typically used with filter holders.
Soft-Edge Graduated Neutral Density (GND) Filter Landscape Photography Soft-edge GND filters are also used in high contrast situations, but where the horizon is not necessarily flat. The soft edge allows for smoother transitions, making the use of a filter less evident. Soft-edge GND filters are also rectangular and are normally used with filter holders.
Reverse Graduated Neutral Density (GND) Filter Landscape Photography The reverse GND is a specialized filter used by landscape photographers when shooting against the sun while it is setting close to the horizon. While a regular GND filter gradually transitions from dark to clear towards the center, a reverse GND filter transitions from dark to less dark from the center to the edge.
Color/Warming/Cooling Filter Any Corrects colors, resulting in a change in camera white balance. Some color filters can subtract colors, blocking one type of color and allowing other colors through. These types of filters were popular for film. They are rarely used in digital photography, since their effects can be easily applied in post-processing.
Close-Up Filter Macro Photography Also known as “diopter”, a close-up filter allows a lens to focus closer on subjects. These filters are only used for macro photography.
Special Effects Filter Any There are a few different types of special effects filters. Star filters make bright objects look star-like; softening/diffusion filters create a “dreamy” look used for portraits, multivision filters create multiple copies of a subject; infrared filters block infrared and pass visible light; bokeh filters have a certain shape cut in the middle of the filter that makes bokeh highlights have the same shape, etc

Graph Source : https://photographylife.com/lens-filters-explained 



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