Sam Wormley's Digital Photography

Digital Photography - Advanced dSLR http://edu-observatory.org/cfs/DP2/Week2.html LOW LIGHT PHOTOGRAPHY Suppose you were asked to photograph performers and patrons attending ISU's Madrigal Dinners in the Great Hall of the Memorial Union. The setting is early 1600s England and the lighting is mostly from candles. Being a professional and not wanting to call attention to yourself, flash photography is not a possibility. How would you approach this challenge? I captured this image of Dee Dreeszen of Musica Antiqua, playing a period recorder with a hand-held dSLR using an 85mm telephoto lens at ISO 1600, Aperture: f/1.2 and Exposure time: 0.077 (1/13) s. Click on the image above to see the full original. The inertial mass of the camera body and lens coupled with careful "squeezing" the shutter release helped to minimize motion blur due to camera shake. Look at the specular reflection in the eyes--you can discern slight camera shake in the 8-2 clock direction. Note that the large aperture isolates the subject from background and that the background "bokeh" is pleasing and compliments the subject. I chose not to fiddle with the color balance settings on the camera as I wanted to retain the "warm" effect of candle illumination. Large aperture lens are essential for working in really low light environments where longer exposures will only blur subject movement. Looking at the Depth-of-Field Data for this particular lens at http://edu-observatory.org/cfs/DP2/depthoffield.html one can see that for, say, a subject distance of 1.5 meters (5 feet) at f/1.2, the depth of field (region of critical focus) is only ą1 cm! Therefore, focusing becomes critical at large apertures. For this reason, lenses with very large aperture capabilities may be thought of as "artist's lenses" because of the artistic imagery that can be produced with a razor thin depth of field at maximum aperture. However, they come with a steep learning curve--mainly in the form of learning critical focus. Studies show that we most often look at human (and animal) eyes and are pleased to find them in critical focus... In portrature concentrate of the eyes. ASSIGNMENT No.2-1 - Photograph another person focusing on his or her eyes. In some of the images ask your subject to look into the camera lens. Note that there is implied communications with the viewer. In some of the images ask your subject to not look at the camera. Note that the resulting images take on the characteristic of looking in a scene--an unobtrusive observer. This is what you achieve with candid photography. Now purposely focus on some part of your subject in front or behind the eyes. How do the resultant images "feel to you"? Note that if your aperture is small, say f/8 or smaller, you may not see much out of focus. Digital Noise Last week, we noted that Nikon and Canon compete so heavily against each other that they are really about equal. From year to year one usually has an edge on the other and they tend to leapfrog each other back and forth. As of this writing Canon barely has the edge in sensor noise. If you look at the original image in great detail http://edu-observatory.org/cfs/DP2/IMG_5813.JPG, you will find the noise level just perceptible--finer that you would expect for film grain of the same sensitivity (ASA 1600). Digital Noise Tests http://www.kenrockwell.com/tech/dslr-comparison/index.htm http://www.kenrockwell.com/nikon/d200/d200-hi-iso-nr.htm http://www.kenrockwell.com/nikon/d200/d200-noise.htm http://www.kenrockwell.com/tech/noise.htm This chart, adapted from "Film versus Digital My Summary", Roger N. Clark, http://clarkvision.com/imagedetail/film.vs.digital.summary1.html provides a comparison between digital and film in terms of spatial resolution of film in units equivalent to digital camera megapixels. "Better" refers to spatial resolution only. Signal to noise is similarly important to image quality and is discussed in the reference. Common Obstacles in Night Photography http://www.cambridgeincolour.com/tutorials/night-photography.htm "Night photography is subject to the same set of constraints as daylight photography--namely aperture, shutter speed and light sensitivity--although these are all often pushed to their extremes. For this reason, the abundance and diversity of night photography has been closely tied to the advance of photographic technology. Early film photographers shied away from capturing night scenes because these require prohibitively long exposures to maintain adequate depth of field, or produced unacceptable amounts of image noise. Furthermore, a problem with film called "reciprocity failure" means that progressively more light has to reach the film as the exposure time increases--leading to diminishing returns compared to shorter exposures". ASSIGNMENT No.2-2 - Photograph another person with the only light source being a single candle. Experiment with different color balance settings. Suggest that your subject have some white in the clothing to help you analyse the results of your color balance settings. ASSIGNMENT No.2-3 - Photograph a watch with a luminous dial such that there is a balance of ambient light illuminating the watch, yet low enough to capture the light of the luminous hands. Pretend you are doing a product shoot for a magazine advertisement. The editor will be picky! Hint--You will likely need a tripod for your camera (or at least some means of holding it steady). How much depth of focus will you need to satisfy your editor? Low Light Photography http://www.sederquist.com/clanight.html http://www.picturecorrect.com/articles/low_light_night_photography_tips.htm PHOTOGRAPHY TUTORIALS http://www.cambridgeincolour.com/tutorials.htm http://www.geofflawrence.com/photography_tutorials.htm Basic Photography: A Set of Exercises http://teeksaphoto.org/Writing/BasicPhotoExercises.html BOOK RECOMMENDATIONS Stephen Johnson "Stephen Johnson on Digital Photography" O'Reilly Media, Inc. (August 1, 2006) ISBN: 059652370X Tim Daly "The Digital Photography Handbook" Amphoto Books (2003) ISBN: 0-8174-3793-2 David D Busch "Mastering Digital SLR Photography" Course Technology PTR (2004) ISBN: 1-59200-605-1 Jon Canfield "Print Like a Pro: A Digital Photographer's Guide" Peachpit Press (2006) ISBN: 0-321-38554-3 Harald Johnson "Mastering Digital Printing, Second Edition" Course Technology PTR (2004) ISBN: 1-59200-431-8 swormley1@mchsi.com