Tuesday, January 27, 2009
Don’t Take My Kodachrome Away
Scanning Kodachrome • Choosing Quality Lenses • Best ƒ-Stop Revisited • Large-Format Printing
Q I’m using a Nikon Coolscan V to digitize some of my film images into versions I can display or market online. I choose good, technically correct slides to convert. Typically, E-6 images (Velvia, Ektachrome VS, Ektachrome G) look fine as .jpg or .tif files with little extra work. But I’m often disappointed with the results of scanned K25 or K64 Kodachrome slides. What should I do?
Marshall, North Carolina
A You can achieve very good scans of Kodachrome slides on the Nikon V, but you must turn off the Digital ICE option (the function that automatically removes dust spots and scratches). Unfortunately, this means you’ll need to do more corrective work to manually clean these scans. You might also check the Nikon website to be sure your scanner is working with the latest software. The Nikon 5000 scanner is a better option for Kodachrome slides.
Choosing Quality Lenses
Q If quality (not cost, weight or size) was the only criterion, which Canon lenses (L series or EF-S series) are best for use on a camera with a 1.6x (APS-C) sensor?
Orange Park, Florida
A Canon’s L series lenses are the manufacturer’s best professional-level optics. The EF-S series includes many consumer-level lenses and can be used only on the smaller-sensored cameras (the Rebel, D30, D40 and D50). Each series offers excellent lens choices for D-SLRs with smaller sensors. In my opinion, to achieve optimum quality, you’d choose lenses from the L series, with one exception. The EF-S 10-22mm wide-angle lens, which gives the smaller-sensored cameras the equivalent wide-angle effect of a 16-35mm zoom mounted to a full-frame camera, has no counterpart in the L series. If quality is your primary concern, another reason to purchase the superior L-series lenses is in preparation for your future acquisition of a D-SLR with a full-frame sensor. Nikon’s D-SLR cameras have full-frame or 1.5x sensors. Their best optics are designated ED. Nikon’s AF-S DX Nikkor 12-24mm ƒ/4G IF ED is the wide-angle lens of choice for the 1.5x sensors.
Best ƒ-Stop Revisited
Q In your article “The Best ƒ-Stop” in “Tech Tips” in the November issue of Outdoor Photographer, you state, “We often use ƒ/16 when we need maximum depth of field and are willing to compromise a little bit on sharpness. But if you stop down even further, to stops such as ƒ/22 and, if possible ƒ/32, you’ll see degradation of the image that’s far worse than photographing wide open. Yes, you’ll get more depth of field, but the overall image will become soft due to diffraction.”
I’ve been told by a very knowledgeable landscape photographer friend that the effects of diffraction connected with ƒ/22 or smaller only become noticeable with 40-inch prints. If this is true, diffraction may be a problem in theory but not in practice (at least for my work). I’m wondering if you accept this view or not.
Via the Internet
A Your friend has a point. All image degradation, including that caused by diffraction, becomes more evident at larger print sizes. But in my opinion, with 35mm film or full-frame digital capture, degradation caused by diffraction will be apparent in prints as small as 81⁄2x11. This may be less of a problem for landscape photographers who shoot with a wide-angle focal length because the magnification on the film or sensor is minimal at wide angles. Diffraction is greatly increased by magnification in the camera. If you want to test this out for yourself, try shooting a macro shot at 2x or more with a variety of ƒ-stops. You’ll get excellent sharpness at ƒ/8 and a very unsharp image at ƒ/16. Finally, if you shoot a landscape image at ƒ/22 and ƒ/32 with a medium- or large-format camera, you’ll have less diffraction due to the large lens openings. There are many variables associated with the issue of diffraction, but I always consider this factor when making my exposure settings in any given situation. I always want to get the sharpest possible image and never want to unnecessarily limit my print or publication options in advance. There are better ways to achieve the necessary depth of field, from landscape to macro, without resorting to small apertures. See our article, “Unlimited Depth Of Field” in the July issue of Outdoor Photographer.
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