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Date: | Mon, 21 Feb 2000 21:13:27 -0500 |
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Dear Ross;-
You bet yer boody I'm interested in a photography session at the COA. I
did all the photos for the Wentletrap Book. The most important thing was the
lens; a 55mm Micro-Nicor. I used a bellows as it was more adjustable than
"rings". I used two flashes, one a slave. I could a probably done better. But
the law of diminishing returns set in.
Art
Ross W. Gundersen wrote:
> Dear Shell Photographers:
>
> I have read the last series on photography with interest, since I am the
> Photographic editor for American Conchologist. Producing good
> photographs of shells depends upon many factors, but primarily upon what
> type of pictures you want to produce. Price tag is also of importance
> (35mm as well as digital).
>
> Lenses: Taking pictures of shells falls into the realm of macro- and
> micro-photography. This means pushing lenses to the limits of their
> design. Generally speaking you should use lenses that are designated as
> "macro". This designation means that they are highly corrected lenses
> which produce excellent quality images with the use of extension tubes.
> Using a general lens with extension tube will produce an image which is
> slightly blurred, with much less resolution. The drawback of most
> digital cameras is their lens (usually low quality). Excellent lenses
> are found only on the higher models of Nikon, Olympus, and Sony digital
> cameras. These lenses are up to the demands of macro- and
> micro-photography.
>
> Depth of Field: Depth of field is also associated with lenses. It
> refers to the depth or thickness of an object which is in focus to our
> eyes. To increase depth of field, or the amount of the image apparrently
> in focus, increase the F-stop. However, as magnification increases your
> depth of field decreases. Eventually, all of the shell will not be in
> focus. Then multiple pictures are necessary (covered latter.
>
> Lighting: Adequate lighting is necessary for both resolution and color
> rendition. Low levels of light produce grainy images of incorrect
> color rendition. The general rule is the brighter the better for both
> resolution and color. This becomes a necessity in macro- and micro-
> photography when using higher F-stpos to increase your depth of field.
> As the F-stop increases the level of light delivered to you film or CCD
> decreases.
>
> Color balance or color rentition is also affected by lighting. Film
> and CCD react to different sources of light producung different color
> renditions. Tungste/halogen are richer in reds. Fluorescent is richer
> in blues. Flash produces a narrow window of both reds and blues. With
> a digital camera you are stuck with one CCD and its reaction to light
> of different wavelengths. However, with filn you can use a film
> produced for different sources of light (e.g tunsten). To achieve
> proper lighting you may end up using tungsten, flourescent and flash
> all at the same time (I do).
>
> Compositing: Tis term refers to assembling parts of different images
> into one image. In extreme macro-photography and micro-photography
> eventually magnification become so high that not all of the image is in
> focus. Take multiple images so that all of the shell is in focus in at
> least one of the images. To accomplish seamless compositing you have
> to convert the image into digital format using either a flat bed
> scanner or a slide scanner. Scan each image. Using a graphic imaging
> program, such as Adobe Photoshop, you select the parts of the image
> that are in focus and reassemble them into one image. Now the entire
> shell is in focus.
>
> Cost: You cannot produce superb images of shells with inexpensive
> equipment. Good quality macro lenses run from $200 - $600. Generally
> speaking the higher the price tag, the greater the lens correction to
> produce sharp images. Extension tubes are less expensive $50-$175.
> Digital cameras capable of producing high resolution images are now
> available from $800. No comment is being made here about "hidden costs".
>
> These comments are the tip of the iceberg and not meant to be exhaustive.
>
> Is anyone interested in a photographic clinic at the COA meeting in
> Houston??
>
> Best, Ross
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