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Principles Principles of Digital of Digital

PhotographyPhotographyUsing Digital Cameras to Using Digital Cameras to Enhance Mine TrainingEnhance Mine Training

Ted FarrishTraining SpecialistMine Safety and Health Administration

Evolution of Digital Evolution of Digital CamerasCameras

1960s-70s - digital imaging for space, military 1986 - 1.4 megapixel CCD sensor 1986 - commercial camera - 180K pixels, $3000 1993 - webcam pointed at Cambridge coffee pot 1994 - 1.5 megapixel for $8000 1995 - LCD preview screen 1996 - 300K pixels for $300

Sony Mavica 1-2 MegapixelsMedia: 1.5 floppy discSet a new standard for storage, use and distribution

Evolution of Digital Evolution of Digital CamerasCameras

Camera sales for digital surpassed film in 2000

18 million sold worldwide in 2001 ($8 billion)

2 million sold in the US in Q2 of 2002

300K pixel webcam for $30

1.3 megapixel for $80

14 megapixel for $3000

Digital Digital PhotographsPhotographs

Digital photographs are actually mosaics of millions of tiny Digital photographs are actually mosaics of millions of tiny squares called pixels. squares called pixels.



Your computer and printer use these tiny pixels to display Your computer and printer use these tiny pixels to display or print photographsor print photographs.



Your computer and printer use these tiny pixels to display Your computer and printer use these tiny pixels to display or print photographsor print photographs like ike

This process is comparable to the impressionist painters This process is comparable to the impressionist painters who painted scenes with small dabs of paint.who painted scenes with small dabs of paint.

Georges-Pierre Georges-Pierre Seurat Seurat

(December 2, 1859 – March (December 2, 1859 – March 29, 1891) was a French 29, 1891) was a French

painter and the founder of painter and the founder of

Neo-impressionism.Neo-impressionism.

Seurat created this scene using tiny dots of different colors. Similarly, a digital camera’s imaging device uses pixels to create a photo.

Digital CamerasDigital CamerasPixels and ResolutionPixels and Resolution

PixelPixel - A - A pixelpixel (short for (short for picpicture ture elelement, using the ement, using the common abbreviation "pix" for "pictures") is a single point in a common abbreviation "pix" for "pictures") is a single point in a graphic image.graphic image.

PixelizationPixelization - The stair-stepped appearance of a curved - The stair-stepped appearance of a curved or angled line in digital imaging. The smaller the pixels, and or angled line in digital imaging. The smaller the pixels, and the greater their number, the less apparent the "pixelization" the greater their number, the less apparent the "pixelization" of the image. Also known as the "jaggies".of the image. Also known as the "jaggies".

The quality of a digital image depends in part on the The quality of a digital image depends in part on the number of pixelsnumber of pixels it contains referred to as resolution. it contains referred to as resolution.

ResolutionResolution Resolution is the number of pixels used to capture an Resolution is the number of pixels used to capture an image. image.

Excellent Excellent imageimage resolution is achieved by a combination of resolution is achieved by a combination of pixel count pixel count andand lens resolutionlens resolution..

Digital camera resolution is measured in Megapixels. Digital camera resolution is measured in Megapixels.

One Megapixel is made of one million pixels/dots. One Megapixel is made of one million pixels/dots.

ResolutionResolution The more Megapixels - the higher the resolution the better The more Megapixels - the higher the resolution the better quality of the photograph.quality of the photograph.

ResolutionResolution The more Megapixels - the higher the resolution the better The more Megapixels - the higher the resolution the better quality of the photograph.quality of the photograph.

If the image sensor resolution is expressed as numbers such as 2048x1536, just multiply them out and divide by 1 million to get the resolution in megapixels.

In this case, we get 3+ megapixels.

2400 x 1800

= 4.3 mp

Megapixels and Megapixels and ResolutionResolution

1600 x 1200

= 1.9 mp

640 x 480

= .3 mp

The smaller the pixels, and the greater their number,The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the image.the less apparent the "pixelization" of the image. Also known as the "jaggies".Also known as the "jaggies".

Image Sensors Affect Image Sensors Affect ResolutionResolution

Image Sensors Affect Image Sensors Affect ResolutionResolution

Two types of image sensors:Two types of image sensors:

CCDCCD - Charge-Coupled Device sensors. - Charge-Coupled Device sensors.Well-developedWell-developedUsed in high-end digital camerasUsed in high-end digital camerasSome users say quality is higher than CMOS Some users say quality is higher than CMOS

CMOSCMOS - Complementary Metal Oxide Semiconductor - Complementary Metal Oxide Semiconductor Less cost than CCDSmaller sizeSome users say quality not as good as CCD

Image Sensors SummaryImage Sensors SummaryImage Sensors SummaryImage Sensors Summary

Different image sensors render colors differently, have different amounts of "grain," different sensitivities to light, and so on. The only ways to evaluate these aspects are to examine some sample photographs from the camera or read reviews written by people you trust.

Despite their differences, both types of sensors are capable of giving very good results and both types are used by major camera companies in both consumer and professional. Canon even uses CMOS sensors in their high-end digital SLRs.

Choosing a digital camera that fits Choosing a digital camera that fits youryour needs needs

Types of Digital Types of Digital CamerasCameras

Professional - 10 + megapixel, SLR design, Professional - 10 + megapixel, SLR design, interchangeable lenses.interchangeable lenses.

High end consumer - 3-6 megapixel, High end consumer - 3-6 megapixel, manual override, powerful zoom.manual override, powerful zoom.

Point-and-shoot - 1-3 megapixel, easy to Point-and-shoot - 1-3 megapixel, easy to use, compact.use, compact.


Professional - 10 + megapixel, SLR design, Professional - 10 + megapixel, SLR design, interchangeable lenses.interchangeable lenses.

Nikon D200Sensor: 23.6 x 15.8 mm CCD 10.2 million effective pixelsImage size can be changed.Media: SD CardUSB Connectivity to computer


High end consumer - 3-6 megapixel, High end consumer - 3-6 megapixel, manual override, powerful zoom.manual override, powerful zoom.

Canon Powershot A95Sensor: CCD 5 Megapixels Image size can be changedMultiple shooting modesMedia: CF CardShoots video clips


Point-and-shoot - 1-3 megapixel, easy to use, Point-and-shoot - 1-3 megapixel, easy to use, compact.compact.

Vivitar ViviCam 3720 Sensor: CMOSImage size 3 Megapixel Standard point and shoot8X digital zoomShoots video clips

LensesLenses

Aperture is expressed as Aperture is expressed as F-stopF-stop, e.g. F2.8 or f/2.8. , e.g. F2.8 or f/2.8.

The smaller the F-stop number (or f/value), the larger the The smaller the F-stop number (or f/value), the larger the lens (aperture).lens (aperture).

A "fast" lens is one that has a large maximum aperture A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras; F1.4, F1.2 for (F2.4, F2.0 for current digital cameras; F1.4, F1.2 for 35mm film cameras).35mm film cameras).

[Note: Many camera user manuals today will refer to the [Note: Many camera user manuals today will refer to the aperture in terms of "aperture value" instead of f/value)aperture in terms of "aperture value" instead of f/value)

ApertureAperture

Quick Quiz

Which lens has a larger opening (aperture): one with an aperture of F1.8 or one with an aperture of F2.8?

Quick Quiz

Which lens has a larger opening (aperture): one with an aperture of F1.8 or one with an aperture of F2.8?

ANSWER: F1.8

A Good Aperture RangeF1.8 - F16

F1.8F2.8 F4 F5.6 F8 F11 F16

This tells us that the camera has an aperture range of F1.8 to F16; the maximum aperture is F1.8, and the minimum aperture is F16.There are 5 f-stops between the max and min aperture. If your camera's lens is currently set at an aperture of F5.6, closing it by 1 f-stop would mean selecting F8; opening it up by 1 f-stop would mean selecting F4.

F1.8 F2.8 F4 F5.6 F8 F11 F16

1/250 1/1251/60

1/30 1/15 1/8 1/4

Aperture Settings and Shutter Speed

Tips for Shooting

Rule of Thirds

Wide Angle -- Depth