Prepared by George Holt Digital Photography Digital Image Capture Essentials.

Prepared by George Holt

Digital Photography

Digital Image Capture Essentials


Module Content• Identify the features of a digital camera

and capture an image.

• Download photographs from a digital camera and store on disk.

• Features of a scanner and to scan an image.

• Import a digital image into a basicdocument.

• View and print a digital image.


Camera Types

• Point and Shoot – eg Canon Powershot A300, Olympus C60

• Mid Range – eg Fujifilm S5000, Canon Powershot A75, Olympus C770

• Pro-sumer – Digital SLReg Nikon E1, Canon Powershot PRO1 , Olympus E1


Typical Specs – Mid Range- Olympus C750 Ultra Zoom

• 4.1 million pixel CCD

• 10 x optical zoom lens (38-380 mm, 35 mm equivalent)

• Auto, Red-Eye, Forced, Off, Slow 1&2, External Flash Modes

• Movie capture (320 x 240 pixel)

• 1.5 " LCD screen

• Powered by 4 x AA Batteries

• xD-Picture Card compatible

• Scene Modes + Manual Settings


Standard Controls

• Diopter

• Viewfinder

• LCD

• Menu Navigation


Camera Features

• Lens.• Aperture.• Shutter.• Sensor.• Storage.• Flash


Advantages• What was that shot like?

Instant viewing of photos

• No more film! Take as many pictures as you want without having to pay for printing ‘dud’ photos.

• Editing Photos can easily be cropped, rotated, spots removed, fix the colour and lighten, darken and sharpen images.

• Taking Notes Take digital photos of things you need to remember or prove eg. Wiring inside your computer, condition of a road, damage from a storm, valuables in your house..

• It will last forever If carefully stored digital images will last forever and if a printout gets ripped, torn or coffee spilt on it, just reprint. Only cost is paper and ink/toner.

• ITS FUN!! Experiment, experiment, experiment!!!


Disadvantages• Shutterlag – Delay between pressing the button and getting the photo.

• Set up Costs $300-$1200 for camera + Accessories eg memory cards, cables, software, batteries, computer etc.

• Light Digital cameras are not as sensitive to light but you can change the ISO setting on most better cameras.

• Camera shake Some of the ultra compact cameras are too light in your hand and can be a bit “shaky”.

• Power Digital cameras are power hogs you can be forever recharging batteries.

• New Skills Getting the image out of the camera, processing it and getting a great looking print are not as easy as they were before at first.


Why convert documents to digital images?

Advantages DisadvantagesCan be easily transported on a disk, across the network or by email

Have to gain new skills to capture images

Cheap to reproduce – No printing costs. – SAVE MONEY$$$

Not everyone likes working on a computer

Puts the responsibility of managing handouts and missed work onto the user

What happens when the computer crashes

Users can’t loose their handouts and pages.

Can’t highlight or take notes on the page

Documents can be backed up and made safe

Can’t take it to bed. Yet?

You can edit the document Some documents can’t be edited

Can be used for lots of other courses etc.


CompromiseHow can we keep the advantages and deal with the

disadvantages?• Do short courses to gain skills or hire someone to do the

scanning and manage the documents.• The trend to electronic work is continuing and growing.

People will have to get on board or get left behind.• You can’t easily take notes on scanned pages yet but

soon we will plus we can takes notes on other pages or type our own text into some documents.

• Electronic books that are truly portable and comfortable to read in bed are coming.

• Computers can be reloaded and files recovered from backup copies on disk. It’s pretty hard to reconstruct a burnt page from a house fire.


Terminology• Megapixel – approx 1 million pixels. 1024x1024 pixels• CCD – Charge Coupled Device. An electronic sensor

that converts light into electrical signals that are stored as a digital image.

• Lens - A ground or molded piece of glass, plastic that focuses an image onto a CCD. Zooms and focuses the image onto the CCD

• Aperture - adjustable opening(iris) in an optical instrument, such as a camera or telescope, that limits the amount of light passing through a lens. often expressed as an f-number. Eg F2 or F8

• Shutter - A mechanical device of a camera that controls the duration of a photographic exposure, by opening and closing to allow light coming through the lens to expose film or CCD.


Terminology continued.• Memory card – an electronic device that

stores digital images.

• Interpolation – A mathematical process that Changes the resolution images by estimating pixel colours based on surrounding pixels.

• Depth of Field – The distance along the cameras axis that the image is acceptably in focus.


SensorsSensors are the digital equivalent of film.

Further Reading


Types of Sensors•Charge Coupled Device (CCD)The most common of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the camera’s lens. Each of the thousands or millions of tiny pixels that make up the CCD convert this light into electrons.

•Complimentary Metal Oxide Semiconductor (CMOS)One of the two main types of image sensors used in digital cameras. Its basic function is the same as that of a CCD. CMOS sensors are currently found in only a handful of digital cameras.


Aperture

F Stop Number Effect

F8 Small aperture, Long depth of field, Landscape mode

F2 Large aperture, Short depth of field, Portrait mode.

http://www.andrewmacbeth.com/articles/camera_basics.htm

http://www.photonhead.com/beginners/shutterandaperture.php


Shutter Speed• The shutter speed is simply the amount of time

that the lens opens the aperture and exposes the film. This is usually measured as fractions of seconds, such as 1/60th or 1/500th.

• The longer the shutter is open, the more light enters through the aperture and hits your film.

• If you have a shutter open for too long, it may "blur" the picture if the subject (or the camera) moves. This is particularly troublesome in sports photography, where you usually have to select a shutter speed of 1/500 or faster.

http://www.andrewmacbeth.com/articles/camera_basics.htm

http://www.photonhead.com/beginners/shutterandaperture.php


Storage cont…

Memory Card Size

CA

ME

RA

16 MB

32 MB

64 MB

128 MB

256 MB

512 MB

2 MP 17 35 71 142 284 570

3 MP 13 26 52 106 213 425

4 MP 8 16 32 64 128 256

5 MP 6 12 25 50 100 200


Interpolation – What is it?

• When software (camera, scanner, or photo editing) adds new pixels to an image based on the colour values of the surrounding pixels.

• Digital Zoom uses interpolation


Resolution and Print Size• How much resolution do I need?

Megapixels Print Size

1MP 6 x 4 inch

2 MP 5 x 7 Inch

3 MP 8 x 10 inch

4 MP 11 x 14 inch

In between A4 Size

5 MP 12 x 18 inch


Memory StorageGet the biggest memory card you

can afford

• Memory Card Types:Smart Media, Compact Flash, Memory Stick, Secure Digital

• Capacity:8Mb, 16Mb, 32Mb,128 Mb, 256 Mb

• Cost:$$$

Having a Spare card can keep you going when you fill your main card up and are away from your PC without having to delete any pics


Lenses

• Short (Wide Angle) (38 mm) –

• Long (Telephoto) (380 mm – 10 x)

• Zoom (Short to Long) (38-380mm)

•Fish eye lenses are extremely short and have lots of distortion.

The longer the lens the more camera shake will affect your images.


Optical vs. Digital ZoomDigital Isn't Always Better

• Always use optical zoom. Optical is what the lens sees.

• Digital zoom enlarges a portion of the image, thus 'simulating' optical zoom

• Digital Zoom or Photo Editing Software

• Always compare optical zoom on camerasThere is no point in comparing digital zoom with digital zoom or optical zoom with total zoom. Always compare optical zoom with optical zoom


Viewfinders and LCD’s

Optical Viewfinder Same as regular cameraNot always exactly what camera sees

TTL (Through-the-Lens) Sees what the lens sees

Digital Viewfinder LCD - reproduces exactly what camera sees but it is a

power hog!!LCD is low resolution and hard to see if the image is

focused correctly.LCD is very poor in bright light.


Transfer MechanismHow easy/hard is it to get your

photos from camera to PC?• USB Cable – most common• Cradle with USB for some cameras• Firewire for video cameras• Multi Card Reader• Printer with Memory port

• AV(composite RCA plugs)cables for connecting to a TV

• DVD player with card slots.• We also need software eg. Windows XP or the

software that came with your camera to interface between the computer and the memory card.


Shooting ModesMost digital cameras have a range of shooting modes to

help you take photos in a number of common conditions.• Automatic (AE)• Portrait• Landscape• Macro• Sport or action• Aperture Priority- The user sets the aperture, controlling depth-of-field.

The camera automatically selects the appropriate shutter speed. • Shutter priority - The user selects the shutter speed, and the camera

automatically selects the appropriate aperture.

• Night• Manual• Panoramic

Canon site

http://www.photonhead.com/beginners/cameramodes.php


Flash

• Flash Equipment.

• Flash Modes

• When should we use flash?

• Advantages and limitations.


Flash Equipment

• Built in flash.– Available on almost all digital cameras.– Can be very limited in range.– May have different modes of flash

• Flashguns.– Connects to some cameras by a “hot shoe” mount.– May have a separate power supply to the camera.– Often has a better range than built in flash.

• Flash heads.– Used for studio lighting.– Can be very expensive and bulky.


Flash Modes• Front Curtain Sync.

– Most common mode of flash

• Red Eye Reduction.

– Uses a double flash to cause the eye to

contract before the main flash.

• Slow Sync.

– Flash plus a slow shutter speed for dim

backgrounds.

• Slow Sync + Red eye.

– Combination of the above 2 modes.

• Rear Curtain Sync.

– Fires before shutter to create a trail on

moving subjects.

http://www.photonhead.com/beginners/controllingflash.php


When should we use flash?

• So we can take photos in dark conditions.

• Try using flash in the day time to light up shadowed areas. Eg faces.

• So we can use a faster shutter speed for fast moving objects.

• It can enhance the brightness and intensity of colours.


Flash limitations• Experiment to discover the range of your

flash unit. Typically flash is effective up to about 3-5m depending on the type.

• Flash can be very harsh and “wash out” photos.

• Choose the flash mode for the job don’t just leave it on auto.


Shopping – What you Need

• A camera• An adequate PC• Batteries• Memory/Storage• Image Editing Software• Printer• Tripod• Cleaning Kit


Accessories• Image Editing Software

Some with camera Try out a few: Photoshop Elements, Photoshop, Paint Shop Pro

• Printer Good inkjet colour printer Premium photo paper – don’t skimp Try a few out to see what works with your printer Why have good camera and use budget printer with lousy paper

• Tripod Close ups or long range telephoto (digital zoom) Night scene/slow shutter speeds

• Lenses and Filters Wide angle, close ups and telephotos may become out of the range of the lens

your camera came with. Not straight away but consideration for later on. Can they be add ons

• Camera Bag For camera and accessories but easy to use


Maintenance• Keep it packed up and clean!!

• Lint free cloths for wiping down the body.• Lens cleaning wipes for the lens – Wipe in

one direction once only and then discard and use another wipe.

• Brushes and air puffers.

• Reformat you memory card occasionally.

• Battery charging.


ISO Settings

• A digital camera's ISO rating corresponds to the speed ratings for 35mm film: A low number, such as ISO 100, is "slow," or relatively insensitive to light; a high number, such as ISO 400, is fairly sensitive. Every time you double the ISO, you halve the amount of light needed to properly expose a picture--and vice versa. The bigger the number of the ISO the more sensitive the sensor or film.

• Digital cameras amplify the signal from the CCD to simulate the effects of a faster(higher ISO) film.


Types of Scanners• Flatbed scanners, also called desktop scanners, are the

most versatile and commonly used scanners. Many flatbed scanners also do negatives or transparencies.

• Sheet-fed scanners are similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner looks a lot like a small portable printer.

• Handheld scanners use the same basic technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. This type of scanner typically does not provide good image quality. However, it can be useful for quickly capturing text.

• Drum scanners are used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams. Each beam is sent through a color filter into a photomultiplier tube where the light is changed into an electrical signal.

• Transparency Scanners can be used to scan slides or negatives.

http://computer.howstuffworks.com/scanner.htm


How scanners work.

• The entire mechanism (mirrors, lens, filter and CCD array) make up the scan head. The scan head is moved slowly across the document by a belt that is attached to a stepper motor. The scan head is attached to a stabilizer bar to ensure that there is no wobble or deviation in the pass. Pass means that the scan head has completed a single complete scan of the document.


Power Systems

Digital cameras are power hogs

• AA, Lithium Ion, NiMH, AC Power

Recommend • Two sets NiMH or Lithion Ion rechargeable

batteries• AC Adapter for use when transferring images or

displaying on TV; or a CARD READER!!• Card Reader. Cheap and very versatile.


Links

• http://www.photonhead.com/


Mastering LightLight has a colour and is measured in degrees Kelvin. White Balance can be set for:

•Cloudy

•Daylight

•Fluorescent

•Tungsten – light globes.

•Flash.

•Custom.