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Tuesday, July 1, 2008

More Depth Of Field


Using A Tilt/Shift Lens • Intensify Now Or Later? • Protecting You From Yourself • Patience • Super Scans

This Article Features Photo Zoom

Protecting You From Yourself
I’m 60, and my husband bought me a digital camera. I love it, but it seems more particular than the film one. I don’t understand why, on certain items (flowers) and when I have a certain lens on, it won’t let me take a picture, or I can’t get it to focus.
Marty
Via the Internet

With your film camera, you could take any picture regardless of the consequences. The fully automatic shooting mode on digital SLRs tends to be designed to protect you from making bad photographic decisions. This can be frustrating if you don’t know what they’re trying to tell you. If the lens isn’t in focus, the camera won’t take a picture. If the lens won’t focus, you may be using the wrong one for the job. For example, for flower close-ups, you need a close-focusing lens or maybe even a macro lens.

Also, be sure to calibrate the viewfinder for your vision. If the viewfinder isn’t focused for your eyesight, you’ll have problems focusing your images properly. If you’re using autofocus lenses, be sure that feature is activated on the lens and camera body.

These automatic features aren’t a bad thing. Some, like auto ISO, will ensure that you get a photograph even when the lighting is minimal. Experiment with your camera’s semiautomatic functions, such as aperture priority and shutter priority, to attain greater versatility in your photography with your new camera.

Patience

In your May 2008 column, you showed an image where you took six exposures and applied the Helicon Focus software. I understand your preference for the longer lens, and I understand the need for the focusing rail to keep the frame constant while changing focusing points, but how on earth did you get the flower to hold still for six exposures?
J. Weber
Via the Internet

You’ve identified one of the few limitations of the Helicon Focus technique: The subject must not move while you’re capturing the images. But there’s some forgiveness in the Helicon Focus Professional version. It enables you to “clone” segments from one image to another, and this can help to overcome flaws caused by subject movement. Otherwise, you just have to plan for the best time of the day to shoot, and be patient. Shooting in the morning, when wind is likely to be calmer, is one strategy. Usually, wind comes in gusts, and working quickly, during lulls, is sometimes necessary. This is how I accomplished the image in this column. [Editor’s Note: Read George Lepp’s article on using Helicon Focus in this issue, “Unlimited Depth Of Field.”]

Super Scans
If I use a scanner with 4000 dpi or better resolution and a dynamic range of 4.2 to 4.8, can I produce a digital file that’s equal to the results from a drum scan done by a professional print lab? I’m interested in data size, image quality and the potential for large prints. I want to produce extremely large prints from 35mm Fujichrome Velvia slides, 6x12cm and 6x17cm negatives and transparencies, 4x5 negatives and transparencies, and 5x7 negatives.
J. McGrew
Carmel, California

Excellent scans can be accomplished from 35mm to 6x9cm negatives or transparencies with reasonably inexpensive desktop scanners. The results will come very close to the quality achieved by the expensive drum scanners used by professional labs. For all but the most demanding uses, these desktop scanners, such as the Nikon Super Coolscan 9000 ED, should give you more than adequate results. Assuming that you have very sharp and well-exposed images, you should be able to make prints of up to 40 x 60 inches from these scans.

For the larger negatives and transparencies, you’ll need a completely different type of scanner. You may need to research several flatbed scanners that have recently come onto the market that may give you good results with a transparency adapter up to 8x10 inches in size. The ultimate non-drum scanners come from Hasselblad. The Flextight X1 has a resolution of 2400 dpi for 4x5, up to 6300 dpi for 35mm; the Flextight X5 has a resolution of up to 8000 dpi for 35mm. The price of the X5, about $20,000, is still far less than a drum scanner.

For information about upcoming seminars and digital-imaging workshops, visit www.geolepp.com. If you have any tips or questions, address them to: OUTDOOR PHOTOGRAPHER, Dept. TT, George Lepp, 12121 Wilshire Blvd., Suite 1200, Los Angeles, CA 90025-1176 or online at www.geolepp.com.

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