Camera Lenses and Flash

Lenses
Key points:
• Good quality lenses are essential for captivating photos.
• Consider the types of subject you intend to shoot.
• No single lens is perfect for every situation.
• A ‘prime’ lens is one with a fixed focal length (see below) while a ‘zoom’ lens is one that can be zoomed in and out to provide a wider range of focal lengths.
• Prime lenses tend to have better optical quality than zooms, and can usually achieve a wider aperture, giving them better low-light performance.
• The range of focal lengths offered by a zoom lens can provide more flexibility, making them suitable for a wider range of subjects.

Focal length
Definition: The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimetres (e.g., 28 mm, 50 mm, or 100 mm). In the case of zoom lenses, both the minimum and maximum focal lengths are stated, for example 18–55 mm.
So, what’s all that about?
Instead of wasting your precious time on unravelling this, it’s much simpler to remember:
• With a short focal length, you have to be close to your subject for a close-up.
• With a long focal length, you can be far away and still get a close-up.
• A zoom lens has a variable focal length
• A prime lens has a fixed focal length
• The focal length tells us the angle of view: how much of the scene will be captured, and the magnification: how large individual elements will be.
• The longer the focal length, the narrower the angle of view and the higher the magnification.
• The shorter the focal length, the wider the angle of view and the lower the magnification.

Types of lenses
Here we will major on the most common types.
Q: How do you decide which focal length lens you need?
A: It all comes down to what you want to photograph.
Standard Lenses

Standard lenses have a mid-range focal length, typically around 50mm.
They have an angle of view which is roughly the same as the angle that the human eye can comfortably view.
They usually have a fixed focal length and wide aperture, giving them excellent performance in low light.
They are popular for a wide range of subjects, including landscapes, portraits, and candid shots.

Macro Lenses

Macro lenses are designed specifically for close-ups.
They are useful for detailed photographing of any subject at very close range, e.g. insects, animals, and plants.

Telephoto Lenses

Telephoto lenses have a long focal length and provide a high level of magnification.
This allows you to photograph subjects at a moderate to far distance.
They tend to be a bit bigger and heavier than other types of lens.
They are popular for any type of photography where you can't get near to the subject, including wildlife and sports events.
They are also commonly used in portrait photography.

Wide - Angle Lenses
Wide - angle lenses have a short focal length.
They have a greater angle of view than a standard lens, allowing them to capture more of the scene in the image.
They are useful for photographing panoramas, cramped interiors, and other subjects which won't fit into a normal lens's field of view.

Here's a rough guide to lenses’ focal lengths, types and uses:
Lens focal lengths, types, and uses
Focal Length Lens Type Common Subjects
8mm - 24mm Ultra wide - angle Panoramas and skyscapes, artistic
24mm - 35mm Wide - angle Interiors, architecture, landscapes
35mm - 85mm (50mm common) Standard General purpose
85mm - 135mm Short telephoto Portraits
110mm or so Macro Close-up
135mm - 300mm Medium telephoto Close sports, action
300mm+ Super telephoto Distant sports, wildlife, nature, astronomy

Flash
Key points:

1. Even with increasing ISO settings appearing, reducing the need for flash in some situations, flash is still popular.
2. Most DSLRs have a built-in on-camera flash.
3. Most built-in flashes are only bright enough to illuminate subjects about 6-12 feet (1-3 metres) from the camera but, as you know, this also depends on the ISO setting and F stop you are using.
4. For most purposes the on-camera flash is suitable for indoor and outdoor photographs when your subjects are close to the camera.
5. There may be times where you want to use a separate flash unit fitted to your camera or an off-camera flash (flashgun), i.e. a separate, standalone flash unit. It will depend on your needs and the situation. If you use flash often then you might want to invest in a more powerful flash.
6. Most cameras today use TTL (Through The Lens) metering which automatically provides correct exposure, most of the time.
7. Some cameras also permit you to alter the flash output with a +- compensation button.
8. Some cameras also offer slow-sync flash which simply means the camera shutter stays open for a while even after the flash fires to allow some of the ambient room light to become part of the exposure. Slow-synch often requires the use of a tripod for best results.
9. Most cameras offer red-eye reduction. Another way to reduce the 'red eye' effect is to have the flash head above or to the side of the lens.

Flash Tips
We all know that flash provides additional light when conditions become too dark. So, we can dispense with this and explore other uses of flash.

Use fill flash for outdoor portraits
Reduce or eliminate shadows on your subject by using your camera’s flash to fill the shadow areas.
If the flash is overpowering the subject, reduce it.

Get your subject to face away from the sun
To save them squinting in the sun, get them to face in the opposite direction. With the sun now behind them, simply use a burst of flash to brighten up their face.

Try an off-camera flash: a flashgun
They come in all different shapes and sizes but stick to a well-respected maker.
*Flash Gun Image - Insert
In fact, this Canon Speedlite can be used both off and on the camera. So, two options for the price of one.
Positioning the flashgun in different places - to the side, above or below the subject - can create very interesting shots.
Use a remote off-shoe flash cord, which screws onto both the camera hot shoe and the base of the flashgun.
A wireless flash trigger will give you more freedom for flash placement. These are two-piece units based around a transmitter and a receiver.

Diffuse!
Diffusing is softening the light emitted by a flash.
Fit a flash diffuser on the flash head. A wide range of commercial flash diffusers are available.
There are less options for diffusing a pop-up on-camera flash. A no-cost plastic milk carton will do the trick!

Bounce the flash
For a softer, less-harsh and more even illumination, bounce the flash from a neutral-coloured wall or ceiling.
You can angle the flashgun or use a piece of white card to direct the flash when using the pop-up flash.

Use coloured gels in warm light
When you're carrying out flash photography in areas lit predominantly by warm light, the cool 'blue' light from a flash will intrude.
One way to mitigate this is to use coloured gels in front of the flash head. An orange gel will add warmth, helping you blend the flash light with the ambient light. The result should then be interesting rather than obvious.See the article below
amateurphotographer.co.uk

Use TTL flash compensation
Use the flash exposure compensation control on your camera or compatible flashgun to subtly blend a flash exposure with an ambient light exposure. Take a test shot and increase or decrease the amount to suit.

Practice makes perfect
It's best to master your technique in your own time, rather than trying it out on location when it's essential you get your shot first time.