The Advancing World of Digital Imaging

Transcription

1 The Advancing World of Digital Imaging by Darren Bernaerdt September 28, 2006 The photographic industry continues on its path towards further integration with digital technology. Currently the massive Photokina trade show is underway in Germany. Almost every major player in the industry has taken the opportunity to present a range of new products. Expect to see improved image quality and the ability to manipulate your images in more ef ficient ways. Following is a summary of the information presented this evening along with a list of resources if you require additional information. Digital Camera Basics It s still a camera! (viewfinder, lens, recording, exposure controls) SLR (single lens reflex) versus point and shoot/fixed lens An electronic chip captures the image (CCD or CMOS) Megapixel = one million pixels (picture elements or squares) Pixels are arranged like a spreadsheet (rows & columns) Multiply the horizontal number of pixels by the vertical range. Since a CCD or CMOS sensor can only sense light, multiply the megapixel value by three to get the RGB filesize. ie, a 6 megapixel camera will produce 18 megabyte RGB files. (Sufficient for 8x10 or 11x14 prints.) 2MP = 4x6 print, 3MP = 5x7 print, 6MP = 8x10 print, 10MP = 11x14 print (best quality) Memory cards most common formats are CF and SD Using Your Digital Camera JPEG versus RAW files JPEG is a compressed (space saving) format that can be read by a wide variety of sof tware. RAW is non-processed format that requires further work post capture. Flexibility in color and exposure plus a host of other options is gained. Resolution Measured in pixels per inch. 200 to 300ppi at the physical image size is required for printing. Most monitors are set to a resolution between 800 x 600 or 1024 x 768 pixels. When ing images, ensure the resolution is less than 800 x 600 pixels. White Balance Various light sources appear neutral to our eyes. If you photograph a neutral subject (white, grey) will it actually turn out neutral? This adjust is crucial to achieving realistic color. ISO How sensitive is your camera to light? Higher numbers yield a longer distance for your f lash or action stopping shutter speeds, however quality decreases as the settings increase. Sharpness, Saturation & Contrast It s usually best to leave these set to normal unless a specific subject requires them to be adjusted. Use your image editing software to make adjustments.

2 Basic Image Adjustments Cropping Most images have too much background. Get closer and eliminate the distracting elements that detract from your subject. Brightness The Histogram shows the range of tone from light to dark. For maximum impact, your image should have a full range of tone. Eyedroppers in Levels can be set to a 5 and 250 range. Once the 5 and 250 range is set for the eyedroppers, click on the area of the photo that should have a white highlight with the highlight eyedropper. Use the black eyedropper to click on the darkest or shadow area of your image. Double-click on the eyedropper and set the white (highlight) eyedropper to 250 for Red, Green and Blue. Double-click the black eyedropper (to the lef t) and set the shadow to 5 for Red, Green and Blue. The grey slider adjusts midtones brightness. Color If the image has areas that are known to be neutral, then use the eyedroppers in Levels to ensure there is no color cast. If you are unsure about color correction, try the Auto Fix option. If you need more control, try Quick Fix, Auto Levels, Auto Contrast or Auto Color Correction in the Editing Mode. Undo History A line by line log is maintained of the changes to your image. You can back up one step or many. Retouching Besides eliminating red-eye, inspect your image for other defects or distracting elements. Remember that your viewer s eye will go to areas of contrast or the brightest part of the photo. If it is an unwanted ref lection, try eliminating it. The Healing Brush clones with blending around the edges. The Clone Stamp Tool just copies the sampled area.

3 Backup More and more images are being captured every year. You must guard against eventual disaster by having a backup plan in place. Your hard disk will fail at some point. Although there are no firm practices in place, the National Archive is planning around a lifespan of no more than 5 to 10 years for optical media (CD or DVD). Don t leave your disks forgotten in a closet! Consider an external hard disk as a basic plan if you have none in place. 300GB drives retail for $200 and include automated backup sof tware. More complex systems are certainly available and I would advise further investigation if the quantity and importance of your data warrants it. For high volume photographers, consider The DAM Book: Digital Asset Management for Photographers by Peter Krogh ISBN Photography and Digital Post-Processing Techniques Aperture (Apple) and Photoshop Lightroom (Adobe) represent a the next generation sof tware for dealing with images. Although Aperture has been shipping since the beginning of 2006, Lightroom is still in beta (final release is expected in early 2007). This is a public beta with the sof tware currently at beta release 4. The underlying concept to both pieces of sof tware is to provide photographers with a better suite of tools and workflow for dealing with large quantities of images. I do not recommend committing important images to Lightroom as it is not feature complete until the final version ships. Based on my testing, it appears to be a very promising application for serious photographers. Lightroom is built around a database and will manage your files. You do not need to be concerned about the actual location of the images. If you prefer to reference an existing location, Lightroom can do that instead of moving the images into the central library. Photo binders or groups of images can be exported to another location or even burned to optical media. The power of metadata can be harnessed upon import by including keywords and populating the available fields with information about the photos. This could include descriptions, the photographer s contact information and other such data. Images can be sorted, edited and organized in the Library module. The Develop module is where adjustments to the appearance of the image can be made. These can be applied to one or many images at a time. Lightroom has some wonderful options for adding saturation, creating greyscales and adjusting individual colors. The Slideshow, Print and Web modules are rather self-explanatory. Lightroom will possibly have one more beta release before the final shipping version. It is available for Mac and Windows (see the link in the Resources section). Aperture is Mac only and requires a relatively recent computer to run it.

4 Example Images Telling a Story - wide establishing photo - look for details (the photo within the photo ) - investigate alternative points of view - silhouette (shoot directly into the sun with the subject blocking it), emphasize the contrast in Photoshop/Lightroom - use a compressed perspective (telephoto) Snow Geese - many cameras now have multi-point autofocus systems - Closest Subject Priority and continuous autofocus used with these images - the camera focuses on the closest object and continually tracks it - Image Stabilization or Vibration Reduction realigns the sensor (if in the camera body) or lenses to compensate for movement by the photographer - cropping and/or retouching would improve the composition - shutter priority and increased ISO to freeze the action - zoom to 100% on the camera s display to check if the action is being frozen with a high enough shutter speed Field Hockey - very similar situation as the snow geese - increase the ISO and use a high shutter speed to freeze the action - Group Dynamic AF to track subject (camera selects a point where it can best focus based upon an initial point chosen by the photographer) - Dynamic Area AF to track the subject as it falls upon the user selected point. Will shift to adjacent sensors

5 Heli - although it s an action subject like the snow geese and field hockey, some movement is desirable - shutter speed to be high enough for the body of the heli, but slow enough to blur the rotors - VR used in Active mode since the photographer is moving and the heli is vibrating - color balance adjustment is selectively applied via a layer mask (paint with black to hide the adjustment, white to show) - the vibrancy slider in Lightroom can be used to increase the saturation or purity of colors that are not currently very saturated. It avoids adjusting skin tones (so they remain natural). Merry-Go-Round - a static photo taken with f lash does not capture the warmth of the lights or the movement - experiment with deliberate camera movement and long shutter speeds (greater than 1/15 second) - f lash was used to capture some detail in amongst the blur - the dust on this image appears as a sof t dark grey blob. This dust is on the sensor, not the lens. It will appear in every photo in the same location. Take your camera to the repair depot to be cleaned (approx. $80) or investigate sensor cleaning options. For the do-it-yourselfer, look to micro-tools.com for the necessary supplies. More expensive options are certainly available at a retail level. Morning Heli - noise (similar to film grain) increases with temperature and longer exposures - most cameras have long exposure noise reduction. Enabling it reduces the buf fer and it only gets used with exposures longer than one second. - Dramatically brighter sky requires the use of a graduated neutral density filter - Overexposure can not be fixed in digital capture - Noise reduction sof tware such as Noise Ninja can be very useful. It uses profiles for each camera that is tailored to the particular characteristics of the noise. It can also adapt on the f ly. Ghosttown - carry your camera everywhere and try photos even if conditions don t appear favorable - 1/focal length is a good guide for the slowest shutter speed you can normally hand hold the camera at. ie, a 200mm lens, 1/200 second or shorter - Don t forget about subject movement - ISO was increased to 800 for the first image, then 1600 for the second - noise reduction exists in-camera, Lightroom/Photoshop and Noise Ninja - natural light can be better than on-camera flash

6 Conservatory - time of day can be a very important factor with your images - in this case, the night photo is much more dramatic - noise reduction (in-camera) was enabled and a 25 second exposure used - allowed time to flash a hand-held electronic flash two times from the right - daytime image is far less dramatic - note that the sky still has some color in it - use low ISO for less noise Food Still Life - shallow depth of field used to isolate the subject - easier to accomplish with a telephoto (100mm or longer) - use a low f/stop such as f/2.8 or f/4 - aperture priority exposure mode is useful to force a setting - diagonal lines to create a more dynamic composition Bears - continuous autofocus and Group Dynamic AF so the camera switches autofocus points if the subject moves - increase ISO to get higher shutter speed and more depth of field - your tolerance for noise will determine how high an ISO to use - Shadow/Highlight command will aid in getting more detail in the fur Shadow/Highlight summary: - makes shadows lighter without af fecting light tones and makes highlight darker without affecting dark tones - top section is for shadows, middle for highlights (we ll disregard the bottom section for now) - radius changes the halo around areas of local contrast - tonal width alters the range of af fected tones. ie, with Shadows, if the tonal width is set low, only the darkest tones will be made lighter - amount will alter the intensity of the adjustment - there is no formula to use this command evaluate the results on-screen (ensure your monitor is profiled!) Smart Sharpen summary: - sharpening adds artificial light and dark halos (or lines) along areas of contrast

7 - amount varies how intense the halos are - radius adjusts the thickness of the halos - lens blur is usually a superior algorithm compared to gaussian blur - it is possible to fade the sharpening effect from the highlights and/or the shadows - sharpen at 100% view and ensure the appearance is slightly too sharp if printing to an inkjet printer - for output at a photolab, keep your sharpening conservative Pharmacists & Conservatory - cloning is always difficult when the subject has hard lines and perspective - the Vanishing Point command overcomes having to manually work around the perspective when cloning - use the create plane tool to lay out a grid that matches the perspective in the image - a yellow grid indicates the drawn perspective is unlikely to be accurate, while a red grid indicates an impossible perspective - clone/heal as normal Image Processor is a script available in Photoshop (File>Scripts>) or Adobe Bridge (Tools>Photoshop>) that allows batch conversion of file type and resizing. It is very handy for processing large quantities of images. Resources adobe.com free 30 day trial of Photoshop, free copy of Photoshop Album picturecode.com noise reduction software megapixel.net digital camera reviews, forums & techniques (based in Vancouver, BC) dpreview.com extensive camera reviews, news, forums, glossary of terms & forums imaging-resource.com digital camera, printer & accessory reviews plus tutorials steves-digicams.com digital camera, printer & accessory reviews letsgodigital.org digital camera & accessory reviews computer-darkroom.com tutorials on inkjet printing and color settings photoshopelementsuser.com tips and tutorials for using Photoshop Elements photoshopsupport.com more tips and tutorials for Photoshop and Elements studio.adobe.com tips and tools hosted by Adobe adobe.com/support/forums/main.html support forums for Adobe products micro-tools.com DSLR sensor cleaning supplies luminous-landscape.com photography and digital capture information

8 robgalbraith.com digital capture information geared towards pros photoshopnews.com all things Photoshop damuseful.com digital asset management for photographers - Adobe Photoshop Lightroom Notes