Letting in the light
Without it there would be no
photography!
The picture that your camera produces is a
product of three things, which form a triangle. One is the sensitivity of the
digital sensor, one is the amount of time that sensor is exposed to the light,
and the third is the size of the hole used to let that light in. they’re called
ISO (a largely-defunct film term), shutter speed and aperture, and are measured
in stops. Each stop represents a doubling of the light reaching the sensor, or
its sensitivity. So a shutter speed of 1/500 of a second lets in twice as much
light as 1/1000, an aperture of F/4 lets in twice as much light as F/5.6, and
ISO 800 is twice as sensitive as ISO 400.
Shooting
in the golden hours will flatter faces and give a warm drama to landscapes.
Got all that? Unless you’re planning on
using full manual mode, you don’t really need to. Knowing that as you open the
aperture (lowering the F number) your shutter speed will need to rise to avoid
overexposed photos; or that as the light falls off in the evening a higher ISO
or wider aperture will be needed to avoid camera shake is enough.
F numbers and depth of field
Aperture is measured in F numbers – the
ratio of the lens’s focal length to its aperture. What’s important is that the
F number you set will determine both the amount of light the lens lets in, and
the depth of field (DOF) in the image – the distance between the nearest and
farthest objects or areas in your photo that are in focus.
Smaller
apertures have higher F numbers. F/22 lets in less light than F/1.4 but more of
the image is in focus.
It’s a tricky concept, as it depends on
lens focal length (longer lenses have narrower DOF), aperture (wider apertures
have narrower DOF) and subject distance (the closer your subject is to your
lens, the narrower the DOF). A portrait photographer may use a shallow DOF to
throw a background out of focus to concentrate attention on the subject; while
a devotee of landscapes will want his DOF wide to keep near and far objects in
focus. The size of your sensor can also have an effect – the tiny sensors in
iPhones (a 4.28mm lens) produce an image that’s almost completely in focus from
back to front, despite their relatively wide F/2.4 maximum apertures.
Why shoot in raw?
If your camera capable of saving pictures
as raw files (file extensions vary, but CR2 or NEF are common) instead of or as
well as JPGs, then this opens up a whole new world of photo editing. Modern
digital cameras produce JPEG is mages that are bright, contrast and appealing,
but this doesn’t always reflect the scene you saw when you tool the picture.
Also, some of the picture information is thrown away in the JPEG compression
process so that it can produce a small file.
Think of a raw file as a digital negative,
with no processing or compression applied. This means the final look of the
image is entirely in your hands, and is where programs such as Apple’s Aperture
or Adobe Lightroom come into their own. When viewed on your Mac, your raw files
may look dull – they almost always need some sort of work done to them – but
your labors will produce an image that more closely matches what you saw when
you tool the picture. Raw files also allow exposure, brightness and color balance
to be adjusted easily once the picture has been copied onto your Mac, as well
as noise reduction and other post-processing effects to be applied.
Pros & cons
·
No picture information is lost – everything the
sensor sees is recorded: Yes
·
Having more data makes post-processing easier
and more effective: Yes
·
Post-processing is mandatory. Unprocessed raw
files are often dull: No
·
Larger files mean more space taken up on memory
cards and hard drives: No
Get snaps on your Mac
For editing or just for storage, get
those photos transferred
When it comes to digital photography,
taking the picture is just the start. You’ll want to store photos somewhere
other than the memory card, but myriad post-processing options and digital art
tools await you too. To get there you need to transfer the pictures to your
Mac. There are several ways to achieve this. Programs such as iPhoto or
Aperture allow you to import directly into their libraries.
Card reader
A small USB device with slots in it for
many different kinds of cards, a card reader allow you to download form one
card while still taking pictures on another, and many new Macs have a slot for
the common SD cards build in. Really new Macs can take advantage of the faster
transfer speeds of USB3 with the right reader. As your card will mount on the
desktop as an external drive, this method allows you to store your images
wherever you like just by dragging and dropping them.
Direct USB connection
Many cameras have a USB socket on them, so
they can be simply connected to a Mac with a cable, which is often supplied in
the box. iPhoto, Aperture and Image Capture can be set to open automatically
when the OS detects that a camera has been attached, but photos can be added to
iPhoto or Aperture libraries later if you’d rather not import them directly.
Wireless
Wireless connectivity is an emerging
feature of digital cameras, and tends to be tailored toward transferring
pictures to an iPhone or iPad rather than a Mac. Canon, for example, offers a
free iOS app to enable direct Wi-Fi transfer of pictures form its Ixus compacts
and 6D SLR, while Sony Cyber-shot models and the Samsung Galaxy camera allow
you to upload images directly to Facebook. This is an area that will grow and
develop over the next few years.
They
very latest card readers take advantage of the superior speeds of the USB3 port
standard found on never Macs.
Image Capture
You might have missed this app entirely on
your hard disk, but it’s not only handy for importing all or some of the images
from your camera, iOS device or mounted flash card, but it’s also here that you
can set per-camera preferences about what app – if any launches when you
connect it to your Mac. It saves you a lot of frustration!
