GSFC Photography ClubIntroduction to Digital Photography Class

Session 2 – Camera Mechanics

Scott Hull2/6/2012

Agenda Terms Exposure Review Camera Types Camera Parts Memory Cards Camera Settings Shooting Modes and Scene Modes Lenses Filters Flash Gadgets

Terms ISO (ISO = ASA) (adjustable)

The sensitivity of the CCD sensor chip Aperture (adjustable)

The amount of the lens diameter that you use White Balance (adjustable)

The color correction for the light you are in Optical vs. Digital Zoom

Optical zoom is when the lens moves to expand or contract the image

Digital zoom is a marketing tool – basically just cropping Live View

The ability to view the image on the display while you compose the shot

Stops A whole ‘stop’ is a change in the amount of

light by half or double 1/250 sec 1/125 sec 1/60 sec 400 ISO 200 ISO 100 ISO

Aperture numbers change by a factor of 1.4 Square root of 2, since double the light is 2x

area Area of a circle is π r2 f/4 f/2.8 f/2

Most cameras also show partial stops

Exposure ReviewSunny 16 Rule

On a sunny day, at f/16, the shutter speed is 1/ISOStop Action Tripod Zone

11/21/41/81/151/301/601/1251/2501/5001/10001/20001/4000

ISO 100

f /22

f /11

f/ 16

f /4

f /5.6

f/ 8

f /2

f/ 2.8

f/ 1.4

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Exposure ReviewSunny 16 Rule

On a sunny day, at f/16, the shutter speed is 1/ISOThese ISOs are one stop apart.

Stop Action Tripod Zone 11/21/41/81/151/301/601/1251/2501/5001/10001/20001/4000

ISO 50ISO 100ISO 200ISO 400ISO 800ISO 1600ISO 3200ISO 6400

f /22

f /11

f/ 16

f /4

f /5.6

f/ 8

f /2

f/ 2.8

f/ 1.4

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Exposure ReviewSunny 16 Rule – in the shade (-2 stops)

At f/16, the shutter speed is 1/ISO + 2 stops1/100 sec + 2 stops more light is 1/25 sec

Stop Action Tripod Zone 11/21/41/81/151/301/601/1251/2501/5001/10001/20001/4000

ISO 50ISO 100ISO 200ISO 400ISO 800ISO 1600ISO 3200ISO 6400

f /22

f /11

f/ 16

f /4

f /5.6

f/ 8

f /2

f/ 2.8

f/ 1.4

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Exposure ReviewSunny 16 Rule – indoors (-4 stops)

At f/16, the shutter speed is 1/ISO + 4 stops1/100 sec + 4 stops more light is 1/6 sec

Stop Action Tripod Zone 11/21/41/81/151/301/601/1251/2501/5001/10001/20001/4000

ISO 50ISO 100ISO 200ISO 400ISO 800ISO 1600ISO 3200ISO 6400

f /22

f /11

f/ 16

f /4

f /5.6

f/ 8

f /2

f/ 2.8

f/ 1.4

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Camera Types“Pocket” Camera“Point

and Shoot”

DSLRDigital SingleLens Reflex

“Bridge” Camera

Brands Which is better, Canon or Nikon?

My answer: Olympus Differences can be subtle

“Feel” – try several, and you’ll know Layout/ operations tends to follow a pattern New innovations in one vs. another Performance vs. image quality

Photographers tend to develop brand loyalty Lenses are expensive Easier to shoot in the ‘language’ you know Choose well, young shutterbug

Differences Between Camera Types(in a very general sense)

Point and Shoots + phones

Bridge Cameras DSLRs

Small – shirt pocket Medium – purse Large – carry or camera bag

Snapshots Good snapshots Documentation to artistry

Very weak flash (~10’) Stronger flash (~20’) Internal (~20’) + external

View the display only Electronic viewfinder Look through the lensShort range zoom Short to very long

zoomInterchangeable lenses

Very small sensor chip Small sensor chip Medium to 35mm frameAuto focus only Manual focus

difficultManual or autofocus

Very lightweight Noticeable weight Noticeable to heavy weight

Images OK for 5x7 prints

Images OK for 8x10 prints

Images OK for BIG prints

Very inexpensive Reasonably priced Can get very expensiveOften keep it with you Grab and go Requires preparation

Camera Parts

All digital cameras have: Lens Shutter Shutter release Sensor Computer Display screen Battery Memory card(s)

Most also have: Viewfinder Built-in flash ¼ - 20 tripod mount

Some Have: Hot shoe Mirror / prism Grip Selection dial(s) Beam splitter

What’s inside a DSLR?

Sensors(size does matter)

• Blue box is 35 mm film frame

• The difference (white area) is the crop factor

Pixel Size determines light gathering ability

Camera Pixels

(MP)

Sensor Size (mm)

Sensor Size (pixels)

Pixel Size (µm)

Crop Factor

Nikon D40 6.0 23.7 x 15.5

3008 x 2000

7.9 1.5X

Nikon D200

10.0 23.6 x 15.8

3872 x 2592

6.1 1.5X

Nikon D90 12.3 23.6 x 15.8

4288 x 2848

5.5 1.5X

Canon 450D

12.2 22.2 x 14.8

4272 x 2848

5.2 1.6X

Canon Rebel T2i

18.0 22.3 x 14.9

5184 x 3456

4.3 1.6X

Canon 60D

18.0 22.3 x 14.9

5184 x 3456

4.3 1.6X

Olympus E-5

12.3 17.3 x 13.0

4032 x 3024

4.3 2X

Canon A95

5.0 7.14 x 5.36

2592 x 1944

2.8 -----

Canon PowerShot SX150 IS

14.1 6.17 x 4.55

4320 x 3240

1.4 -----

Smaller pixels mean less light, and more noise, especially in low light

Crop Factor

Reported relative to 35 mm film Same focal length lens that was used

on film camera now focuses onto a smaller sensor

The sensor image area becomes expanded when viewing, so it is effectively magnified

Because of this, a 100 mm lens on a Canon APS-C camera gives the same magnification image as a 160 mm lens would on 35 mm film

Most have two types of memory Internal – holds the picture right after you shoot Removable cards– for downloading to a computer

Card formats Limited by the camera Compact Flash – bigger, faster, often cheaper Secure Digital – SD, mini SD, micro SD, SDHC,

SDXC Memory Stick, xD, Smart Media are far less

common Make sure you don’t over-buy

Memory

Memory Card Speed CF usually faster than SD SD Classes

Snapshots: Class 4 Enthusiast: Class 6 Professional: Class 10 Write speed slower than read speed

CF “X” Ratings Buy what you can afford Capacity vs. speed▪ Video▪ Fast subject▪ RAW vs. JPEG

Camera Settings Exposure Modes Shooting Modes Scene Modes Focus Modes Metering/ Exposure Compensation File Type/ Image Quality White Balance Playback A whole book full of others – read that book!

(the User’s Manual)

ChecklistOlympus E-5 Checklist

Mode Prog Aper Shut Man Bulb My 1 My 2 My 3 Card CF SD

Exp. Comp. -5 -4 -3 -2 -1 -0.7 -0.3 0 +0.3 +0.7 +1 +2 +3 +4 +5

HDR No +/- 1 +/- 2 Noise Red. On Off File Format JPEG RAW Both

White Balance Auto Daylight Shadows Cloudy Tungsten Fluor. Flash

IS Off Auto Vert Horiz ISO Auto 100 200 400 800 1600 3200 6400

Focus Manual S-AF C-AF Manual S-AF + Manual Center Auto Off-center

Drive Single High Low 12 Sec 2 Sec IR IR 2sec Face Detect On Off

Flash Auto Red Eye Fill Off Long Red Eye Long Full 1/4 1/16 1/64

Exposure Modes Auto

Camera selects everything: aperture, shutter speed, focus, ISO, flash - all of it, with no overrides

Usually works, often doesn’t Program

Camera picks aperture & shutter speed; focus can be overridden Aperture Priority

User picks the aperture, camera picks the shutter speed to match Often the preferred go-to mode for experienced photographers

Shutter Priority User picks the shutter speed, camera picks the aperture to match

Manual User gets to/ has to pick all settings

Shooting Modes

Single shot Self-timer Burst Short delay Remote control Bulb Bracketing for HDR

Scene Modes

Portrait Landscape Night

Scene Night

Portrait Sports Indoor Candle

Self Portrait Sunset Fireworks Food Documents Beach/

Snow Underwater

(4 options)

Snow Close-up Museum Backlight Panorama Probably

many more…

A Few Common Scene Modes Sports

Increases ISO, for faster shutter speed Landscape

Chooses narrower aperture, for longer depth of field Portrait

Chooses wider aperture, for short depth of field Night Portrait

Long exposure for background, plus flash for faces Fireworks

VERY long exposure (seconds) – must use a tripod Beach/Snow

Compensates for bright reflections by increasing exposure Night Scene

Increases ISO, for greater light collection, no flash

Focus Modes Autofocus on most new cameras is pretty

darned good Still not always perfectly crisp Doesn’t work for all situations

Very dependent on having high contrast areas and lots of light

Focus point can usually be defined on DSLRs Might still need to tweak the ‘sweet spot’ Single vs. continuous autofocus Manual focus on point and shoot and bridge

cameras is difficult, if possible

Metering Average

Original film approach, not used much anymore Spot

~1-5% of the field Location is usually definable, often in the center

Center-weighted average Central portion represents most of the input

Multi-zone metering (aka Matrix, ESP, others) Most commonly used default mode Mysterious algorithms consider many factors

including focus point, light distribution, etc. Use exposure compensation (+/-) to make small

adjustments

Files/ Image Quality RAW vs. JPEG

RAW is all of the data, straight from the sensor▪ Largest files, most flexibility later, and highest resolution

JPEG is processed and compressed before saving▪ Losses occur each time it is saved▪ Usually several levels of compression available

Why not just maximize everything with RAW? E-5 Example (12.3 MP camera)▪ RAW file: 12.4 MB, High quality JPEG: 5.3 MB▪ Little discernible loss in image quality▪ In fact, unprocessed RAW looks noisier at high magnification

Memory cards are big, but not infinite capacity RAW is also not as portable between viewers

RAW vs. JPEG

RAW: 12.4 MB JPEG: 5.3 MB

Olympus E-5; 12.3 MP camera(MD Renaissance Festival, 2011)

White Balance Colors change based on the source of the light

Light brown shirt in incandescent light can look green in fluorescent light

Even sunlight vs. shade makes a difference Image is interpreted differently based on settings Auto white balance is pretty good ~98% of the time Check your display frequently, and change the WB if

necessary RAW images are not corrected, so you can change it

later if it was off Can also be set WB manually for unusual situations

Lenses Built-in vs. interchangeable

Depends on the camera type Fixed vs. zoom

Fixed is typically lighter and higher image quality Zoom is more flexible

Cheap vs. expensive More expensive lenses have more elements, better

coatings, wider apertures, heavier weight Macro capability

Highly detailed close-up images Teleconverters

Goes between camera and lens to produce 1.4, 1.6, or even 2.0 x the focal length

Zoom Lens Cautions A ‘wobble’ of only 0.03° will cause the image to move by

1/8” at 20 feet With a 50 mm lens, you may not see that With a 400 mm lens, it is 8 times bigger, and very noticeable

Zoom lenses are also usually unbalanced when hand held More likely to get that 0.03° - or more

They also tend to have smaller apertures, so longer exposure times

Tripods help, but faster shutter speeds are more practical Tripod pointing is awkward and slow Usually means higher ISO, though more noise

Thus, the driver for more expensive, “faster” zoom lenses

Macro Traditionally, image on negative larger than

life Today, 4x6 print larger than life Options

Macro lens▪ Many lenses have macro capability built-in

Extension tubes▪ Moves the lens further from the sensor

Add-on adapters – cheap and poor image quality Reversing adapters

Focus and depth of field are very difficult Lighting can be a real challenge

Short working distance – can be less than an inch!

Image Stabilization Uses tiny gyroscopes to detect movement Optical Image Stabilization

Lens shifts the optical path, to stabilize the image Unique to the lens; extra $ for each lens Canon, Nikon, some Sony, Panasonic

Sensor shift Sensor is moved to stabilize image Works with all lenses, even old film lenses Olympus, Pentax, some Sony, Konica-Minolta

Digital Image Stabilization Used in some video cameras Computer changes the pixel region from frame to frame

Performance is rated in equivalent stops improvement Turn image stabilization OFF when using a tripod

Filters Ultraviolet

Mostly to protect the lens Cheap, and nearly invisible in the image

Polarizer Reduces glare Rotate for best effectiveness

Infrared Sees heat, for an ‘other-worldly’ effect

Neutral Density Reduces light, without shifting colors

Color Highlights individual colors

Gradient Neutral density on one end to clear on the other Great for darkening skies

Flash Obviously used to brighten a scene Flash power is determined by the Guide

Number GN = distance x aperture, at a specific ISO Example: 18m at ISO 200 (Olympus E-5 internal) Means that at f/5.6 and 200 ISO, anything beyond

3.2 m (~11 ft) will not be fully illuminated External flash

GN is typically about 30 to 50 Can be moved off-axis, to control shadows Many are remote triggered; can use multiple units

Gadgets Tripod Shutter release/ Remote control Monopod Ballhead Quick release Camera Bag Lens caps Spare batteries Screen protector Spare memory cards Reflectors/ diffusers GPS data tagger The list goes on and on…

What next?Now that I figured out my camera and I’m taking great pictures, I have a bunch of pretty files. What can I do with them? Photoshop Elements

If you think they look great now, just wait… Elements has the same basic tools at ~1/10 the price

Prints Costco, Target, Wal-Mart, etc. Probably not worth using your own printer▪ Usually clog up if you don’t print a lot of pictures

Create a photo book about a subject (cheaper than you think) Online software and Elements both make it pretty easy

Post them online Recommend a Flickr free account Photo Club Flickr site – we want to see what you’ve done! Facebook, other social media

Digital photo frame display

Recommended References Your camera User’s Manual – read it!

Download it for easy searching at home Carry it in your camera bag for reference

Web sites www.penncamera.com www.DPReview.com www.learnmyshot.com www.photoextremist.com Wikipedia

TV show Wild Photo Adventures Magazines

Digital Photo Popular Photography

Exercises (mostly for DSLRs) Depth of Field

Select a subject separated from a detailed background, or an inclined floor (grass or carpet)

Use manual focus on the subject and aperture priority mode Shoot a set of images at each of the whole stops (2.8, 4, 5.6, 8,…) Compare the area in focus in each

Repeat, but changing ISO by full stops and keep constant f/8 Notice where the image starts to get grainy for your camera

Repeat, but changing only the white balance Which image matches reality? Did Auto WB pick correctly?

Speed Use manual focus and shutter priority mode Focusing on the street, hold your camera steady, and shoot images of

moving cars at 1 sec, ½ sec, ¼ sec,… to the fastest your camera will go Compare the ability to stop the action vs. shutter speed Also notice what happens to the steady background in each shot Do the same thing while panning

More Exercises Minimum focusing distance

Take a picture straight-on of a newspaper page, at your lowest zoom focal length▪ Move closer, until the auto focus won’t focus any more▪ Repeat at the highest zoom focal length▪ Compare the highest magnification and the working distance

Image stabilization Hand-hold, without IS, in shutter priority, and take

longer and longer exposures of the same sharp subject▪ Where does the image get soft?▪ Repeat with IS on, if you have it▪ Repeat at different zoom focal lengths