Feb. 2003
President's
Message
Photo FAQs
Photo FAQs
Eric Kissa
Q: I am going to buy a scanner. What are the options?
A:
The selection of a scanner depends entirely on your needs. For small prints
(up to 8 x 10) a flatbed scanner with a 2400 x 4800 dpi resolution is
adequate for scanning 35mm film or slides. The highest rated Epson Perfection
2450 costs about $400, the Epson Perfection 2400 about $250. Flatbed scanners
are useful also for scanning prints and negatives larger than 35mm, as
well as for copying documents. Most digital darkrooms have a flatbed scanner,
in addition to a film scanner.
Large prints or slide modifications necessitate a film scanner. The price
range of a scanner with 2900 dpi resolution is about $700-800 but more
resolution is needed for extensive cropping and professional quality 16
x 20 prints. The price of a film scanner with 4000 dpi resolution is in
the $11001600 range. The quality of the Nikon Super Coolscan 4000 ED approaches
that of a drum scanner costing over $5000.
I use the 4000 dpi resolution routinely. Even at the 4000 dpi resolution
extensive cropping of a 35mm negative may yield a scan with a barely sufficient
20MB file size.
The quality of a scan is not determined by the resolution of the scanner
alone, the quality of the optical system is important as well. The ICE3
software for removing scratches, the GEM for grain equalization management,
and the ROC software for color restoration are useful features of some
higher end film scanners.
Q: I have heard that Kodak has improved the scanning characteristics of a color negative film. What is the name of the improved film?
A:Color negative films have a wide exposure latitude but are more difficult to scan than the transparency films. The base color of color negative films varies from brand to brand and relative to the image density even from frame to frame. Kodak has claimed that the Supra films (ISO 100, 400, 800) have been formulated for improved scanning. Tests (Shutterbug, November 2000) have supported this claim. The Supra films have been discontinued, however. Kodak has introduced at the Photokina exhibition Royal Supra films (ISO 200, 400, and 800), said to have improved scanning characteristics. The Royal Supra 200 and 400 are new emulsions, the Royal Supra 800 is the old Supra 800 repacked under a different name. No resurrection of the Supra 100.
Q: How can I adjust the lighting ratio of two electronic flashes?
A:The
lighting ratio is the ratio of the light intensities provided by two light
sources. The lighting ratio of two identical electronic flash units can
be changed by (a) reducing the light output of one of the flashes, (b)
using a neutral gray filter or a diffuser on one of the flashes, (c) changing
the distance of the flashes, or (d) the angle of the flashes.
In portrait photography the main light is usually twice as strong as the
fill light. However, the actual exposure on the film is not determined
solely by the light falling on the subject but by the light reflected
by the different areas of the object. This is what you and the film can
see. Portrait photographers measure lighting ratios of flood lights by
using an incident light meter, or more accurately, measure the reflectance
of the lighter and the darker side with a spot meter. This technique is
not usable for electronic flashes.
In a studio, the modeling lights (small lights with a light bulb) on top
of the electronic flash units can approximately predict the illumination
by the flashes. The distance and the angle of the lights (and the attached
flashes) can be adjusted until the desired lighting has been achieved.
On location this may not possible. The lighting technique must be simple
to be practical. One of the flashes should be stronger than the other
flash but the lighting ratio does not need to be exactly a typical 1:2
or 1:3 ratio. When photographing flowers with two flash units one of the
flashes is usually aimed at the flower in the 45o position and the weaker
one from the other side or from above. A good guess is needed to decide
where the shadows are going to be in order to avoid double shadows.
Q: Which mail order stores are reliable?
A:I have ordered from B&H and Adorama for many years without any problems. New York has several other reliable mail-order stores, as well as some unreliable ones. For specialty items Porter, in Iowa, is very satisfactory. However, we should not forget our local camera stores, we need them. In a local camera store we can buy an item we can see and get something we need immediately instead of having to wait for a few days. Beginners especially are better off buying locally. A mail ordered item may not be what they really wanted. Some attractively priced cameras and lenses are „gray market‰ imports sold without a warranty. Do not forget the shipping charges and if the equipment is faulty, you have to pay return postage and insurance.
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Send questions concerning photographic
equipment (cameras, lenses, accessories, filters), photographic techniques
(other than digital), and film, as well as information on international
photographic exhibitions, to: ekissa @aol.com.