Transcript From Pixels to Projects

From Pixels to Projects
Understanding and Using Digital Photography
by Jessica Heldman and George Privateer
What you’ll learn today
• The basics of how a digital camera works
• What to look for in a digital camera and
how to choose the right one for you
• How to take the best possible picture
• The basics of digital photo adjustment
• How to set up your photos for laser
engraving
Digital Camera 101
How digital cameras work
• At the most basic level, a digital camera works much
the same as a film-camera
– The camera captures images through a series of lenses that
bounce light off a subject.
• Where digital cameras differ is in the image processing
– Film cameras process images chemically…heck, you don’t
even need electricity to operate a camera!
– Digital cameras convert images into a series of 0’s and 1’s that
represent the tiny colored dots, or pixels, that make up the
image.
– The number of pixels a digital camera can copy makes up the
cameras resolution.
“Learning the lingo”
Here are some of the basic digital camera terms we’ll be
using throughout the presentation:
• Resolution: Refers to the number of pixels a digital camera
can capture. Can be stated as either 3 mega pixel, 3 MP, or
2048 x 1536. Resolution is the most common term used to
differentiate digital cameras.
• Aperture: Refers to the size of the opening of the lens and
how much light gets to the digital camera sensor.
• Shutterspeed: Refers to how long the sensor is exposed to
light.
• Memory: How a camera stores images. Can be internal and
external. Also referred to as storage.
“Learning the lingo”
• Zoom: How the camera “zooms” in on an object. Can be
either digital or optical.
• White balance: Tells the camera what elements of a photo
should look white, and, in turn, what should look black and
all colors in between. Can be automatic or manual.
• LCD: Short for Liquid Crystal Display. It is the screen on the
back of most digital cameras that allows you to preview
photos.
• File format (type): Refers to the type of digital file the
camera will save images as. Most common are .jpeg, .tiff
and RAW.
• File size: Refers to the size of each photo taken. This will
vary based on resolution and file format.
Picking the right camera for you
What do I want?
There are literally thousands of options available in digital
cameras. When choosing a camera, you should focus on
what I call The Big Three:
Resolution
Zoom
“Feel”
Resolution
• When choosing a camera, here is an easy way to
determine what resolution you should be looking for:
– 2-mega pixel (2 million pixels) cameras can create prints up to
4” x 5” that are similar in quality to a photo lab print. This
camera would be fine for small sublimation jobs.
– 3-mega pixel cameras can make decent 8” x 10” prints. This
would be a good camera for sublimation and some photo
lasering.
– 4-mega pixel cameras can make very nice 11” x 17” prints, and
still hold good quality up to 16” x 20”. 4-mega pixel is the
current standard resolution, and would suit all sublimation and
most photo lasering jobs. Also allows for better image quality
after cropping in a photo-editing software package.
– 5-mega pixel and up cameras will produce very large 20” x 24”
prints with no loss of quality.
Zoom
• As stated earlier, there are two types of zoom in digital
cameras: optical and digital.
– Optical zoom means the lens does the work.
– Digital zoom means the computer processor does the work.
• Optical zoom will produce better results, as the zoom
happens before the image is captured.
• Digital zoom simply magnifies the pixels of the zoom
area after the image has been captured.
• Buyer beware! Cameras often list Optical and Digital
zoom together for a total camera zoom. The more
optical zoom, the better.
“Feel”
• This is the totally subjective part of the evaluation
process.
• If possible, use the camera before you buy.
–
–
–
–
How does it feel in your hand?
How easy is it to access the camera settings?
Is the LCD screen bright enough?
Is the camera menu intuitive?
• While a camera might have all the features you are
looking for, if it’s not comfortable to use, don’t buy it!
Being happy with the camera is the most important
“user feature”!
Other considerations
• Battery type
– Digital cameras are battery hogs. If possible, buy one with a
rechargeable battery or buy rechargeable batteries separately.
And always buy extras!
• Exposure controls
– If you want to adjust the aperture and white balance manually,
look for manual controls. Most cameras offer some level of
control, with the more expensive models offering more control.
• Memory
– Your camera should come with some sort of removable
memory, such as SmartMedia or Compact Flash cards. You’ll
want to add additional memory to store photos, so make sure
you know what kind of memory your camera takes.
Things to avoid
• “Digital zoom only” cameras
– Digital zoom doesn’t give you enough flexibility and decreases image
resolution and quality.
• Cameras that use floppy disks or CD’s
– Believe it or not, there are still cameras that use floppy disks and CDROMS for storage. They are often bulky and slow. Avoid these if at all
possible.
• Memory card readers
– They sound like a good idea, but memory card readers can be
unstable and accidentally erase your memory card, particularly multiformat memory card readers. It’s best to just hook your camera up
directly to your PC.
• Basing your decision on video capability
– Most digital cameras today offer the ability to capture video. While this
sounds like a nice feature, video files take up A LOT of memory card
space, and the video files themselves are often poor quality. Get a
dedicated video camera for video projects.
Our recommendations
• A camera with 4-mega pixels.
• A camera with at least 2x optical
zoom.
• A camera with an easy-to-navigate
menu system.
• A camera with removable memory
(SmartDisk or Compact Flash).
Ready…set…shoot!
Taking the best picture possible
• Besides your camera, the most
important element to the success of
your photo is….
LIGHTING, LIGHTING,
LIGHTING!
Taking the best picture possible
• Remember: a photo is really an image of the
light reflected through the lens of the camera.
• While the built-in flash for your camera provides
some illumination, you may want to consider an
external flash.
• At the very least, add some of your own
artificial light through additional lamps.
• Not only does poor lighting cause shadows, but
it will also throw off your cameras white
balance, giving you inconsistent color.
Some helpful lighting tips
• When taking pictures of people outdoors, try to take the
photo between 11am and 2pm, with the subject facing
the sun. The sun is high enough in the sky to
adequately light the subject and will minimize squinting.
• In low-light situations, increasing the aperture on your
camera will increase the amount of light the lens lets in,
and will help your picture quality.
• Even small work lamps will help light a subject indoors.
Have the subject face the light, and tilt the lamp either
toward the ceiling or toward the floor to avoid “washing
out” your subject.
• If you do a lot of product photography for catalogs or
mailings, consider purchasing a light box.
Other tips for great photos
• Stabilize your image with a tripod. Tripods with built-in
levels can cost less than $50, and will improve the
quality of your photos.
• Keep a lens cloth handy. There are cloths made
especially for digital cameras, although a lint-free
eyeglasses cloth will do fine and probably cost less.
• Is your background too dark out? Try increasing the
ISO speed. This will increase the sensitivity of the
image sensor in your camera, and will bring the
background into better focus. However, your camera
will be more sensitive to movement, so this would be a
good time to use a tripod.
Other tips for great photos
• When you are shooting a subject that is far away, such
as a performer on stage, don’t use your flash. A typical
internal flash illuminates up to 6’. This means the
subjects in the foreground will be brightly lit, while the
subject on stage will be in the dark.
• While the LCD screen is a great tool on digital cameras,
don’t forget about the viewfinder. The viewfinder is a
true representation of what you are shooting, as it
looks directly through the lens. You’ll be able to detect
shadows and other minor imperfections better through
the viewfinder.
After you take the picture
Basic photo correcting on a PC
• For the purposes of this presentation, we will refer to features in
Corel Photo-Paint 11. All image editing software (like Adobe
Photoshop and Paint Shop Pro) has similarly named features that
will perform the same functions.
• Once your image is loaded on to your computer, you may still need
to make some adjustments.
• Corel Photo-Paint 11 is pretty smart. Seven times out of ten,
image imperfections can be fixed by using the “Auto Equalize”
function.
– This will automatically adjust the basic parameters of the photo based
on the white balance of the image.
– Remember, Photo-Paint is going to look for the color “white” in the
image and base all of its color corrections off of that measure.
Basic photo correcting on a PC
• When the Auto Equalize doesn’t quite do it:
– Start with adjusting Brightness/Contrast/Intensity
• Usually, making an image slightly brighter will help you determine
what colors need to be adjusted.
• Beware! Don’t make your image too bright or it will throw off the
rest of your colors.
• Once you’ve adjusted the Brightness/Contrast/Intensity, try the
Auto Equalize again. This time, you might get the results you
want.
– Adjusting the Color Balance
• If you take a photo with a predominate color in the background,
you may see other objects in the image taking on this colors
characteristics (I.e. – A person in a photo with a bright green
background might have a slight green tint to them).
• Use Color Balance to tame certain colors or make others more
prominent.
Laser engraving your photo
“Learning the lingo”
Here are some of the basic laser engraving terms we’ll be
using throughout the remainder of the presentation:
• Halftones: Refers to how the laser sees your photograph.
Halftones are the series of small black dots that simulate the gray
tones of a photograph. In order for a laser to read a photo, it must
be converted to grayscale.
• DPI: Dots Per Inch. How many small black dots (halftone dots)
there are per inch of a photo. The higher the DPI, the sharper the
image (as far as the laser is concerned).
• LPI: Lines Per Inch. A term that originated in newspaper printing, it
also affects the quality of the image. Halftone images have a
maximum LPI of 150.
• PPI (for your laser): Pulse Per Inch. How many times in an inch
that a laser will fire. A PPI of 1000 means the laser will fire 1000 in
an inch.
Halftones and you
• When you look at a photo in a magazine or newspaper,
you eyes see a continuous grey image.
• In reality, it is a series of black dots that get smaller or
bigger, depending on the shading of the image. When
printers make a “halftone screen”, they are creating the
illusion of shades of grey.
• Your laser, in raster mode, sees your photo as a series
of black dots, and engraves all of those little dots at
different sizes to recreate the image on your substrate.
• The key to achieving a good reproduction of the original
image is to render the halftone dots accurately!
Digital camera settings
• Set the image quality of your digital camera to the best image
quality available.
– You’ll probably be saving the picture at a higher resolution than your
laser needs, but it is better to resize the picture down then to try and
enlarge it. You will end up with better lasering results.
• Once you’ve downloaded the picture, import it in to the image
editing software of your choice.
– For the purposes of this presentation, we will refer to features in Corel
Photo-Paint 11. All image editing software (like Adobe Photoshop and
Paint Shop Pro) has similarly named features that will perform the
same functions.
• Under the Image/Resample menu, adjust the image to the size you
want. You can also adjust the DPI at this time.
– NOTE: Photo lasering can be done between 72 and 300 DPI (180 to
250 is recommended). An image DPI more than 300 will dramatically
increase the file size, but not improve the rendering of your halftone
screen.
Rotary engraving a photo
• A rotary engraving system uses three axis –
X, Y, and Z.
• The software that drives the engraver is designed to
move from one point to another along a “vector” or line.
• The engraver was not designed to recognize each pixel
of a gray scale image. If that were the case, it would
have to raise and lower for each pixel, and engraving
would take hours or days to complete.
• The laser was designed to pulsate at short intervals
very quickly, thereby re-creating the gray scale image.
Setting up your picture for the laser
• After resizing, convert your image to grayscale. Do this
under Image/Color Mode/Grayscale.
– Check the brightness of the image after conversion to
grayscale. If the image is too dark, your laser will have to
remove a lot of the cap layer of your substrate, which can
cause overheating, warping, and loss of image quality. If the
image is too light, your laser will not cut through enough of the
cap and the image will appear faint.
– Adjusting the contrast of the image may make the grayscale
image more defined. The best way to see if this helps is to play
with the contrast setting.
• The ultimate goal is to have the image on your screen
look as close as possible to the desired outcome.
Basic laser settings
• For the best possible engraving, use the smallest
available lens size.
– A 1.5” lens produces a beam that is .003” in diameter, meaning
it will be able to render extremely small dots in your halftone.
• In general, combining this small lens size with a laser
software setting of 1000 DPI and 1000 PPI will give you
the greatest potential for success and rendering a
detailed halftone screen.
• The more accurately the halftone dot is rendered, the
clearer and sharper the image will be.
Source and reference materials
Sources
• Howstuffworks:
– http://electronics.howstuffworks.com/digital-camera.htm
• Yahoo! Shopping
– http://shopping.yahoo.com
• CNET Reviews
– http://reviews.cnet.com/4520-10165_7-5512377-1.html?tag=txt
– http://reviews.cnet.com/4520-11244_7-5535981-5.html?tag=nav
• Olympus Cameras
– http://www.olympusamerica.com/cpg_section/cpg_tipstricks.asp
• Digital Camera HQ
– http://www.digitalcamera-hq.com/hqguides/top-ten.html
• Rowmark’s Laser Guide Online
– http://www.rowmark.com/MARK/laser_guide/start.asp
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