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From: Ed Uthman <[email protected]> Newsgroups:, Subject: Gross Specimen Photography (monthly posting, 34K, v. 2.03) Date: 4 Mar 1998 19:46:45 GMT Message-ID: <[email protected]> Summary: This paper is an introduction to photography in general and  gross specimen photography in particular. It is aimed at pathology  residents who have suddenly found themselves in the position of  taking pictures of specimens on a copy stand using a camera unlike  any they are familiar with. X-XXMessage-ID: <[email protected]> X-XXDate: Wed, 4 Mar 1998 19:52:26 GMT  Version: 2.03 Last-modified: September 2, 1996 Archive-name: pathology/gross-specimen-photography Posting-Frequency: monthly (first Wednesday) URL: Maintainer: Ed Uthman <[email protected]>          AN INTRODUCTION TO PHOTOGRAPHY IN GENERAL...                                        AND GROSS SPECIMEN PHOTOGRAPHY IN PARTICULAR                                 A Guide for Residents Who Have Had This Unwelcome Chore                      Dumped Upon Them                                            Ed Uthman, MD <[email protected]>           Diplomate, American Board of Pathology                                  At its birth about 1824, photography as practiced by its first devotee, Joseph Nicephore Niepce, was a messy, all- consuming pursuit that made use of such substances as bitumen of Judaea, lavender oil, and pewter. Today, chemical, mechanical, and electronic technology has made photography a neat, transparent, facile technique which we may easily apply to another messy, all-consuming pursuit: gross anatomic pathology. Despite the amount of automation available in photography, it is important to grasp a few general principles, so that we may use to our advantage a few powerful controls we have over the photographic environment.  The main considerations in gross photography are exposure, focus, image size, composition, color balance, and film selection.  I. EXPOSURE  This is essentially the problem of balancing the amount of light coming through the lens with the sensitivity of the film. We seek the ideal exposure and eschew the underexposure (slide too dark) or overexposure (slide too light). The determinants of exposure are:  A. FILM SPEED, measured as arbitrary standardized units    ("ISO" or, formerly, "ASA"). ISO and ASA are numerically    equivalent units. The film speed depends on film    manufacturing process and type of development used on the    exposed film. Although films are packaged with a stated    ISO rating, some may be "pushed" to higher speeds by    special processing techniques. This should be kept in    mind before throwing away valuable film you have    mistakenly underexposed. The faster the film, the less    the resolution (causing increased "graininess"); also    colors are more subdued in fast film (such as Kodacolor    1000) than in "slow" film (such as Kodacolor 25). The    graininess and subdued colors of very fast films can be    used for artistic effect but are of no value in technical    photography. Therefore, we tend to choose slower films    for our gross lab cameras, so that we may produce    pictures with the greatest resolution and most accurate    color rendition. A film faster than ISO 160 should    probably not be used.    B. APERTURE, the setting of the iris diaphragm in the lens,    determining how much light is allowed through the lens    into the camera. Aperture measured as "f/ stops" (f/2.8,    f/4, f/16, etc). The f/ ratio is calculated by dividing    the focal length of the lens (see below) by the diameter    of the iris diaphragm opening through which light passes.    Therefore, the greater the diameter, the more light is    let in, and the smaller is the f/ ratio. Each f/ stop is    1.4 (the square root of 2) times the preceding f/ stop.    Each "stop" multiplies the amount of light by 2X. As an    example, f/1 lets in twice as much light as f/1.4 and    four times as much as f/2. The "speed" of the lens is its    f/ ratio at its widest aperture setting. An f/1.2 lens is    considered very "fast," while an f/5.6 lens is "slow."    Generally, fast lenses are more expensive than slow ones    and in fact do not have as good corner-to-corner    resolution as slower lenses. Because we generally have    plenty of light at our disposal in gross photography, we    opt for excellent resolution over lens speed. Most lenses    for our purposes are f/2.8 to f/4 at their widest    aperture settings. We typically choose to "stop down" our    diaphragms in most cases, because almost all lenses have    optimal resolution when not used at their maximum    aperture. The "ideal" f/ stop is generally taken as 2 to    2-1/2 stops "down" from the maximum aperture. For an    f/2.8 lens, therefore, the optimal aperture setting would    between f/5.6 and f/6.7. The other reason to stop down    from maximum aperture is to improve "depth of field" (see    "Focus," below). I personally shoot almost all my    specimen photos at f/8.    C. EXPOSURE TIME, or "shutter speed," measured in seconds or    fractions of seconds (1/30 s, 1/1000 s, etc) represents    the total time the film is exposed to the focused image.    It is determined by setting the camera shutter to open    for a specified length of time.       Effects of various shutter speeds:       1/1000 sec - 1/60 sec: These are OK for hand held camera    in existing light.       1/60 sec : Always use this with electronic flash, since    just about all flashes are specifically synchronized for    this speed. Using a slower speed (e.g., 1/30 sec) will    also work, but a faster speed (e.g., 1/125 sec) will ruin    the picture by failing to expose part of the frame. Note:    Some of the more modern and/or expensive cameras allow    flash synching at 1/125 second or faster speeds, but make    sure this is true of your camera before trying it.       1/30 sec - 1/2 sec : We tend to use this range for tripod    or copy-stand work, including gross photography. This    range is generally not acceptable for hand-held cameras,    because most people cannot hold the camera still enough    for this length of time. By using these slower speeds for    gross photography, we allow ourselves the luxury of    smaller apertures (giving us good depth of field and    maximum resolution from the lens) and slower films    (giving us maximum film resolution and best color    rendition).       For example, each of the following exposure parameter set-    ups give the same exposure. Which would you choose for a    gross photograph taken on your copy stand, assuming you    have a camera with an f/4 lens?         A. ASA 50 film; f/4; 1/30 sec            B. ASA 50 film; f/8; 1/8 sec            C. ASA 200 film; f/16; 1/8 sec         I would choose set-up 'B.' Set-up 'A' involves shooting   at maximum lens aperture, at which lens resolution is not   the best. Set-up 'C' lets us stop down the aperture for   good lens resolution but requires us to use faster film   with poorer resolution than the ASA 50. Therefore, 'B'   looks like the best compromise.      Even though a good copy stand will keep the camera   motionless and allow long exposure times, there is a   theoretical problem, called "reciprocity failure," which   may interfere with color balance in very long exposures.   But this is never a problem as long as you don't allow   the exposure time to exceed 1/2 second, and you'd   probably not notice it even if you shot a 2-second   exposure (which may occasionally be necessary when using   bellows at maximum extension; see below).      How do you determine exposure? There are two ways to do   this:      1. Most cameras have a built-in light meter that monitors      the amount of light coming through the lens. This meter      attempts to optimize the exposure either by averaging      the total light hitting the film plane (an "averaging      meter") or using a small sample area (usually the      center of the field) to measure the amount of light      focused on that particular spot (a "spot meter"). In an      "aperture priority" system, the meter then looks at the      aperture you have set on the lens and automatically      adjusts the shutter speed to give the desired exposure.      In an "shutter priority" system, you set the shutter      speed and the light meter automatically adjusts the      aperture. These functions are available in what is      referred to generally as the "auto" mode. In addition,      most modern cameras have a "program" mode, which      completely automates exposure determination by choosing      both the aperture and the shutter speed for you. This      means all you have to do is compose the picture, focus,      and push the button.            Program mode has been a boon for photography in      general, because it allows you to concentrate on      composition and not have to worry about fiddling with      aperture rings and shutter speed knobs. There is,      however, a price to pay, especially in technical      photography. The main problem is that automatic      exposure systems (except in high-end cameras) are      standardized for snapshot type photography, where there      is no striking difference between background and      subject illumination. Also, an automatic exposure      system will attempt to make the subject have a      "neutral" brightness. In technical photography, we do      not necessarily want this; we want brain to look light      and spleen to look dark, just like these respective      subjects appear to us in real-time. Therefore, I do not      use the camera's automatic exposure system for routine      specimen photography.         2. Because of the above considerations, I recommend that      you take advantage of the rigidly standardized exposure      environment of the copy stand and virtually always use      manual exposures. Determine the ideal exposure by      shooting a roll of film at various settings and then      stick with this exposure when shooting specimens. You      can still use the light meter when faced with an      unstandardized situation, such as having one of your      four floodlights burn out on Saturday and not being      able to find a replacement.            Parenthetically, I have found through experience that      when shooting documents of black printing on white      paper, you should use an exposure one stop brighter      than your standard setting for specimens. For instance,      if you normally shoot specimens at f/8 and 1/8 sec, you      should choose f/8 and 1/4 sec when shooting a document.      Never, never let the camera shoot black-on-white      printed documents on "Auto" or "Program," because the      camera will think you want the white paper to appear      neutral and will force a bad underexposure.            Another hint: When forced with shooting pictures on a      set-up you are unfamiliar with, you may have no idea      what settings to use. A good solution is to meter on      the palm of your hand (believe it or not, it makes no      difference what color you are; the palm of everyone's      hand looks about the same to a light meter) and note      what settings the camera's light meter indicates.      Simply switch over to manual and enter these settings.      Then you can shoot away and always get at least      acceptable results.       II. FOCUS  There are two things to consider here, methods of focusing and depth of focus.  A. Methods of focusing.      1. Autofocus. Most manufacturers today produce autofocus      cameras aimed at various markets. The most popular of      these, aimed at the advanced amateur and the      professional, are probably the Minolta Maxxum series      and the Canon EOS. These cameras are packed with      automation which allow automatic film advance and      rewind, automatic and program exposure modes, and      autofocus. Automatic focusing uses a system whereby a      computer in the camera uses vertical lines in the      subject and focuses the lens by analyzing these lines.      I have not used autofocus systems in specimen      photography but have experience with them for snap      shooting. The problem is that if there are insufficient      vertical lines in the picture, the focusing system with      be fooled and can leave you with a terribly out-of-      focus picture. I have stuck with manual focusing for      specimen photography but would love to hear what the      autofocus aficionados have to say about its use.         2. Manual focus. In this method you simply view the      subject through the viewfinder and turn a focusing ring      until the subject sharpens. If you have a choice, I      recommend a viewfinder with a split-field focusing      prism to help with critical focusing, but others prefer      a focusing grid, which, as far as I know, is only      available on high-end cameras, like the Nikon F series.       B. Depth of field      It is easy to focus on a flat object, such as a slice of   brain, but things get stickier when photographing objects   with depth, such as a windowed pediatric heart specimen.   Shooting these subjects requires a knowledge of the   concept of depth of field. It turns out that the zone of   depth at which the camera is in focus is greater at   smaller apertures (larger f/ numbers) than at larger   apertures. Therefore focusing is very critical when the   lens is "wide open" but much less so when "stopped down."   Let's say you are shooting an opened colon to   demonstrate, en face, a large villous adenoma. If you   focused on the "top" of the tumor (the part nearest the   camera) and shot the picture with the lens aperture at   f/2, the tip of the adenoma would be in focus, but the   sides would be slightly out of focus, and the surrounding   colonic mucosa would be totally out of focus and probably   not recognizable. However, if you stop down to f/16, the   entire specimen would be in focus. Since this results in   decreasing the exposure by six stops, you would have to   compensate by increasing the exposure time by a factor of   two to the sixth power, or 64. For good depth of field   and optimal lens resolution, I use f/8 routinely and   reserve f/16 and f/22 for subjects like the windowed   heart. Most cameras have a "depth-of-field preview   button" that lets you stop down the lens to its preset   aperture, so you can view how much depth-of-field you'll   end up with in the resulting picture (normally the   aperture diaphragm stays wide open until the instant the   picture is taken, so you have a nice, bright viewfinder   in which to compose the shot).  III. IMAGE SIZE  The size of the image in the camera depends on 1) the size of the subject (of course), 2) the distance of the subject from the camera, and 3) the focal length of the lens. The focal length is the distance from the lens to the image when the lens is focused on infinity. The effects of lens focal length are as follows:  The greater the focal length,    1. The larger the image appears for a given distance.   2. The farther away from the subject you can be for a      given image size.   3. The more critical the damping of camera motion to      prevent blurring.   4. The slower and more expensive the lens.   5. The less the sense of depth and perspective.   6. The less the curvilinear distortion of straight lines.   7. The _more_ flattering to the face in portrait      photography (makes face less moony and nose less      prominent).   8. The _less_ flattering to the body in figure      photography (makes subject look stouter).       Depth of field (see section II.B, above) is independent of focal length in the world of close-up photography [this is not true in landscape photography, where lenses with shorter focal lengths have greater depths of field].  Lenses are classified in groups based on their focal lengths and other properties:    16 - 35 MM (WIDE-ANGLE LENSES). Rarely used in medical   photography, these are best for landscape and   architectural photography. They make landscapes look more   expansive and buildings more imposing. They tend to be   extremely sharp lenses that have excellent contrast.      50 - 58 MM ("NORMAL" LENSES). These are used for most   routine work, including gross photography. It is rarely   necessary to use anything other than a normal lens for   our purposes except when shooting close-ups so extreme   that the bulk of the lens shadows the subject, so that it   cannot be illuminated sufficiently. In this case you   need:      80 - 135 MM (MEDIUM TELEPHOTO LENSES).These are used for   high-magnification macrophotography to increase working   distance, and for "over the shoulder" intraoperative   photography. For instance, you can be twice as far away   from the subject with a 100 mm focal length telephoto   than with a 50 mm normal lens and still get the same   image size on film.      200 - 2000 MM (LONG TELEPHOTO LENSES). These are usually   not used in medical photography but are indispensable in   sports, nature, and journalistic photography.      MACRO LENSES. Operationally, the only thing special about   these is that they have an extra long focusing extension   to allow you to focus on very close objects. They are   generally available in the "normal" focal length and the   medium telephoto ranges. For instance, Nikon makes two   excellent macros, a 60 mm and a 105 mm. Since they are   aimed at the technical market, macro lenses tend to have   excellent optics, are very durable, and are several times   more expensive than normal lenses of corresponding focal   lengths. Most macros in the normal lens category allow   you to focus down to objects close enough to give you a   "3:1" or "2:1" ratio; that is, the image size is one-   third or one-half, respectively, the size of the subject.   Most macro lenses can be used with an inexpensive   extension ring, which allows focusing down to 1:1 or   "life size," i.e., the image size is the same as the   subject size (Sigma makes a very nice, not-too-expensive   macro lens that focuses down to 1:1 without an extension   ring, and Nikon's  much pricier 105 mm AF macro lens    allows a 1:1 focus). This allows you to take some    breathtaking shots of otherwise unimpressive subjects,   such as pituitary adenomas. You can even make a corpus   luteum look spectacular.      VARIABLE FOCAL LENGTH (ZOOM LENSES). These are very   convenient for general photography, since you don't have   to move the camera so much. I am still waiting for   someone to come up with an affordable zoom lens that is   macro at all focal lengths and can focus on close   objects. Many of the lenses advertised as "macro-zooms"   are really just zoom lenses that allow close-up   photography only at a fixed focal length. When in "zoom"   mode, such lenses are not macro. Other zooms supposedly   have "continuous close focusing" throughout their range   of focal length, but the specs I have seen on these show   that they all have a minimal focusing distance that is   too long for practical use on a copy stand. My advice is   too stay away from zooms unless you are really up on the   capabilities of the individual models and know exactly   what you need. If are absolutely set on using a zoom   lens, you could try this: get a regular (non-macro) zoom   lens which zooms by turning a ring rather than sliding a   slide (i.e., a zoom lens which is not a "one-touch" zoom).   Then put extension rings between the zoom lens and the   camera. Extension rings are simply a set of tubes which   extend the lens forward from the body of the camera.   This will give you a zoom lens which focuses close-up   but not far away. Extension rings can usually be had   for less than $100. Appropriate zoom lens focal lengths   would include 28 - 85mm and 35 - 105mm.      BELLOWS. This is not a lens at all but simply a shade   that extends the lens very far away from the body of the   camera. This allows you to take true photomacrographs,   producing an image size up to three times that of the   subject. For instance, when shooting a 105 mm lens on a   bellows at full extension, the Lincoln Memorial on the   reverse side of a U.S. penny fills a 35mm frame. Multiply   this magnification by the amount you get when projecting   a slide in a lecture hall and you get some idea of how   Brobdingnagian a world you can present to an awed   audience. The only problem with the bellows is that light   intensity fall-off (as per the inverse square law) at   maximum extension requires you increase the exposure   accordingly. Also you have to be extremely careful about   camera motion, which is magnified correspondingly.    IV. COMPOSITION  If you consider yourself more of a technical type than an artiste, you are probably intimidated by this aspect of photography. Although Ernst Haases and Edward Steichens are probably born and not made, much technique of composition can be easily learned by the average eye. In gross photography, first step is good specimen preparation. This is what separates the excellent from the mediocre; the inspired pathologist from the drudge; art from mere visual documentation. After you get comfortable with the camera, you should spend almost all your time preparing the specimen, with the actual photography being a brief anticlimax. Here are some tips I find useful:  A. Cut away tissue that is of no interest, or that obscures    the interesting features.    B. Use props to position the specimen when necessary. A    slice of liver needs no props, but a gallbladder looks    better when you shove a few wads of paper under the    periphery to make it look like the saccular structure    that it is. Modeling clay is also a good material from    which to devise custom props.    C. Watch out for the obtrusive ruler. A lot of pathologists    remonstrate incredulously when I tell them I almost never    shoot a specimen with a ruler in the field. For one    thing, no one has made a ruler yet that is as unobtrusive    as I would like. Most specimens need no ruler, especially    full organs or full organ slices. We all know how big a    lung is; if not, we're only there for the free lunch    anyway. If you really want to know how big the lesion    was, just read the gross; it even gives all three    dimensions! If you really want to impress the conference    attendees with how big a goiter is, take a picture of it    with an everyday object, such as set of keys. Or, better    yet, bring the gross specimen to the conference and    ceremoniously drop it on the table with a loud thud.       I quit using rulers when I realized I never looked at    them except to marvel at how distracting they were. I    really don't think any one else looks at them either.    But if you're so anal that I can never convince you to    lose the ruler, do me a favor and shoot just one of your    frames on each specimen without it. I'll guarantee you    that nine times out of ten, that's the pic that you're    going to want to show at the conference.    D. Keep the background clean. This is a real pain, but to do    otherwise really compromises the photograph. It is much    easier to keep things clean when dealing with a fixed    specimen than a fresh, bloody one. On a related note, try    to keep the camera clean. Layers of dried gore    accumulating on the body of a tough Nikon F3 probably    won't hurt the camera, but it tends to gross out certain    people, particularly OSHA inspectors.    E. When photographing lungs or hollow viscera, use inflation-    fixed specimens when possible. You have to resist all    sorts of pressure from various circles to cut up the    specimen when it is in the fresh state, but, then again,    all great artists suffer for their work. I have yet to    see a gross photograph of uninflated, unfixed lung that    was any good. Inflation fixation of gut segments delays    your diagnosis a day but rewards you with gross    photographs that would bring tears to the eyes of any    radiologist.    F. Try to get rid of as much blood as possible. Otherwise,    the specimen ends up being just varying shades of red and    pink.    G. Watch out for distracting highlights. Fresh specimens    usually have very shiny surfaces that produce glare.    There are several things you can do to cut the glare on a    fresh specimen:      1. Formalin dip for just a few minutes; this preserves      color but dulls the surface; in overnight-fixed      specimens which have lost their color, soak in 70% EtOH      to partially recover color.         2. Turn off room lights.         3. Consider changing the lighting situation of your set-      up. Nice copy stands are usually set up with four big      floodlights. You may consider turning off the two on      the front of the stand and leave the two on the rear      on. Remember to adjust your exposure to accomodate the      loss of these lights.         4. Polarizer/analyzer filters do a great job, but the big      polarizers that go between the floodlights and the      subject are very expensive and fade out fairly rapidly.       H. Photographic backdrops. The choice of a proper backdrop    is essential for a professional looking photograph. The    best background is the one no one knows is there. Several    options are available:      1. Transilluminated light board with non-glare glass -      expensive; klutzes drop things on the glass and break      it; departmental business manager is incredulous at      expense of replacement and usually stalls its purchase.         2. Wet black velvet - less expensive ($12/yard); reusable      for a long time if you're careful; keep fresh, bloody      tissue off! Give each resident his/her own piece. Of      course, if you shoot anything that may have infectious      agents on it, you can't re-use the velvet, unless you      can find a way to sterilize it (another argument in      favor of shooting only fixed tissue).         3. Water immersion tray - Incredible shots of delicate,      "three-dimensional" objects make you into an amateur      Lennart Nilsson; solves problems of gravity and glare      simultaneously for such objects as villous adenomas,      chorionic villi, emphysematous lungs, etc. In my      experience, it takes quite a bit of patience to get a      good shot, as undesirable bits of grunge tend to float      into the field of view just as you are releasing the      shutter.         4. Towel from surgery - sure sign of an amateur; an      embarrassment to say the least. However, if that's all      you've got, ask for a clean towel to replace the bloody      one they handed you the specimen on.       V. COLOR BALANCE  We perceive a sheet of paper illuminated by an incandescent bulb to be just as white as if it were illuminated by direct sunlight. This goes along with our concept that "white" light is composed of light of all colors. This is true to an extent, but various "white" light sources produce their component colors in varying proportions. For instance, the surface of the sun has a temperature of about 6000 Kelvins and has much more blue light in it than the radiating surface of a tungsten filament glowing at 3200 Kelvins, which has more red light. This relation between temperature of a glowing object and its color is well known to most people (although not by its scientific name - Wien's First Law), since we are taught from the fifth grade that a blue flame is hotter than a red one.  Although the neurological visual processing system behind our eyes compensates for this variability, the film in a camera cannot. The solution is to make film where sensitivity to the colors of the spectrum is specifically balanced for the color distribution of the light source. When shooting in daylight or with an electronic flash, we need to use "daylight" film. Alternatively, when using incandescent lights (such as the floods on the copy stand), we need to use "tungsten" film. This is not some theoretical consideration. If you try to use daylight film with the floodlights you will get an unacceptably orange picture; conversely, shooting tungsten film with a flash will produce a picture that looks like it was painted by Picasso during his "blue" period.  VI. FILM SELECTION  You will select film based on your need for good resolution, your budget, the necessity of rapid processing turnaround time, and the format in which your photographic work is to be presented.  A. Color transparency film. These yield the 2" x 2" mounted    transparencies known affectionately as "kodachromes" (in    the way that facial tissue is known as "kleenex"). The    actual frame size of the transparency is 24 x 36 mm.      1. E-6 process color reversal film (Ektachrome,      Fujichrome). Compared with Kodachrome (see below),      these are expensive; they have quirky color response      (being notoriously poor in rendition of eosinophil      granules, which look kind of dull purple rather than      vivid orange), and the slides fade with time (although      this may not be true of newer films in this category).      Nevertheless, the E-6 films are by far the most popular      in med center settings because of the ready      availability of the E-6 process. Most professionally      oriented processors can routinely turn around the film      in four hours. With a readily-available kit, you can      even process these films at home for about US$3 per 24-      exposure roll (plus a one-time US$30 investment for a      developing tank and reel).         2. Dye injection film (Kodachrome). Kodachrome is      superior in every way to the E-6 films, except that the      processing is slow and is usually done in large      reference centers where the film must be sent.      Eosinophils look great, and the slides last essentially      forever if stored properly. It is difficult to find      tungsten versions of Kodachrome, but the daylight      versions can be shot under tungsten illumination if a      special filter is used.       B. Color negative film (Kodacolor, Ektar). Also generally    available only in daylight versions, these films yield    color negatives which must be printed. It is preferable    to use color negative film for posters, rather than    having color prints made from your transparencies. This    is because color prints from transparencies usually    suffer from enhanced contrast that compromises the    accuracy of the rendition. When having color prints    processed, you must work closely with a skilled print    processor for good, publication-quality prints. The    automated printing machines used in "one-hour" facilities    are not capable of producing an accurate print from a    color negative of scientific subject (unless, perhaps, it    is a portrait of the scientist).    C. Polachrome film. This abomination of a transparency film    develops in a few minutes in a processor you can keep in    your desk drawer. It is extremely expensive, and the    dense emulsion makes slides too dark on projection; the    colors are less than impressive. It is best not to let    the clinicians know you have a Polachrome processor. They    will start giving you the conference cases even later and    will not realize how lousy the pictures are, while you    are grinding your teeth trying to find that audience-    pleasing mitosis somewhere on the screen.    D. Black-and-white film. Not to go into this at any length,    but you should use this for originals to be used for    publication. Black-and-whites made from color negatives    or transparencies are generally second-rate. Also you can    experiment with color contrast filters, which can really    improve results.     NOTES ON PURCHASING PHOTOGRAPHIC EQUIPMENT  1. Only a fool or the government pays retail for photographic    equipment. 2. The best prices are available via mailorder. You can find    ads for these companies in any photography-oriented    magazine. 3. The only drawback to mailorder is that you have to know    exactly what you want when you order it. Mailorder outfits    are notorious for bait-and-switch. Decide what you want    by reading and talking with other photographers before    calling to make the order; otherwise, you _will_ be taken    to the cleaners by these extremely effective salespeople. 4. Don't pay any attention to brand-specific chauvinism.    Many photographers are quick to look down their noses at    any brands other than Nikon, Canon, Hasselblad, and Leica.    I think you will be very pleased with other brands, for    which you will pay a _lot_ less money. The major factor    which determines the quality of photographs is the skill    of the photographer, not the brand of the equipment.                          ACKNOWLEDGEMENTS                                Dr. Donald McGavin, Professor of Pathobiology, Univ. of Tennessee College of Veterinary Medicine, generously provided many fine suggestions from detailed review of the first version of this paper, and I have incorporated most of them into the current version.   Lisbeth Kuehn provided some helpful information concerning depth of field, which I was previously unaware of.  Norbert Fuerst sent me some good information on macro and zoom lenses.  I also wish to posthumously thank my father, G. O. Uthman,  who taught me, among many other things, the basics of photography.  All opinions given here are ultimately mine, as are any errors.   _______________________________________________________________  An HTML version of this FAQ is available through the author's home page at:                                              IMPORTANT                                Please send any constructive comments about this paper to Ed Uthman, <[email protected]>. I am especially interested in  correcting any errors that may have crept in.                        COPYRIGHT NOTICE                                Copyright (c) 1995, Edward O. Uthman. This document may be freely distributed. It may be reformatted for purposes of compatibility. It may be freely used for personal and educational purposes, but it may not be used for commercial purposes without prior written consent of the author. It may be included in toto or in part as components of other documents with proper attribution.                           DISCLAIMER                                While I have made every reasonable attempt to include only accurate information, it is possible that some of the information is wrong and may result in inadequate photos. Photography is an empirical technique, so experiment liberally with test rolls before "shooting for keeps." 
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