Usenet 1994 January

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Newsgroups: rec.photo,news.answers,rec.answers Path: senator-bedfellow.mit.edu!bloom-beacon.mit.edu!gatech!swrinde!sgiblab!pacbell.com!iggy.GW.Vitalink.COM!ns!news From: amolitor@network.com (Andrew Molitor) Subject: rec.photo FAQ and answers Message-ID: <1993Dec20.043346.13956@ns.network.com> Followup-To: rec.photo Summary: Some of the questions asked frequently in rec.photo, and their answers. Or at least, a good try at them. Sender: news@ns.network.com Nntp-Posting-Host: blefscu Organization: Department of Mathematical Sciences Date: Mon, 20 Dec 93 04:33:46 GMT Approved: news-answers-request@MIT.Edu Lines: 628 Xref: senator-bedfellow.mit.edu rec.photo:78379 news.answers:15994 rec.answers:3409 Archive-name: rec-photo-faq Version: 1.0, 5/1/93 ------------------------------------------------------------------------ >>>> Contents ------------------------------------------------------------------------ Some rec.photo generalities Other photo informational sheets, and mailing lists A short lexicon of terms Some useful phone numbers Some miscellaneous questions Equipment - brands, purchasing and quality ------------------------------------------------------------------------ >>>> Some rec.photo generalities ------------------------------------------------------------------------ Kodak Publications These are recommended so often that the fact of their existence is worthy of a spot here. Kodak publishes a large set of pamphlets on various subjects photographic, from how to dispose of darkroom chemistry to how to take pictures of monitors and TV screens. Some are free, the rest are cheap. All may be obtained from 1-800-242-2424, easily. The catalogue of publications is designated L-1, and may be obtained free. How to ask a question in rec.photo This may seem silly, but a surprising percentage of questions asked in this newsgroup are ill-phrased. In an effort to help this problem go away, I suggest: 1) specify make and model of equipment 2) specify exact film type (read it off the box!) 3) specify exact camera settings 4) be as detailed as possible about the circumstances and failure mode/problem. Try to get the terminology right -- look it up if you're not sure! In short, provide as much detail as possible. Is it OK to flame in rec.photo? No ;) We don't flame in this newsgroup. Really! This is one of the very few unmoderated newsgroups with almost no flame content. Hey! Let's split rec.photo up in to several groups! Periodically, people suggest that rec.photo get split up. The consensus generally arrived at is 'no', and the reasons given are many. The big ones seem to be: Too many different ways to split the group, everyone would have to read all the groups anyways, there'd be a *lot* of crossposting, and the group doesn't get that much traffic anyways. If you're feeling snowed under, poke around your site, and figure out how to use kill files, if you have them, to filter out articles on subjects you're not interested in. ------------------------------------------------------------------------ >>>> Other photo informational sheets, and mailing lists ------------------------------------------------------------------------ These are posted to rec.photo by the indicated people (when I know 'em -- please let me know of any mistakes or missing info). This should not be taken as license to mail these people for copies! Please wait a while for a copy to be posted before trying other routes. - Nikon FAQ sheet (monthly posting) -- (tredysvr!ubbpc!kjm@gvls1.gvl.unisys.com) - Camera Feature List(s) -- glporter@zeus.calpoly.edu (Glen Porter) - Mail-order house review list -- blondin@rockies.ATT.COM (BlondinDJ) - The "FAQ regarding lenses" and the "Lens Tuturial" (monthly posting) -- jacobson@cello.hpl.hp.com (David Jacobson) - The EOS FAQ posted occasionally, and available for FTP on moink.nmsu.edu (128.123.1.46) -- rma@clockwise.att.com (Bob Atkins) These are the photographic mailing lists I know of: Brian Reid runs a mailing list of people who use Leicas and other rangefinder cameras. If you'd like to be on it, send mail to: leica-users-request@mejac.palo-alto.ca.us or decwrl!mejac!leica-users-request, if you can't do "@" addressing. Medium Format Digest. Moderated. Rather variable frequency, a a digest once a week, or more. Send mail to hamish@netcom.com, to subscribe, or submit items. Mailing list for Bronica S, EC, and EC/TL users. This list is dedicated to these models since many of the parts are interchangeable. The purpose is to create a forum that is the most likely place to get answers to your questions about these cameras. Subscribe by sending a note to: bronysaur-request@post.royalroads.ca There is a mailing list for a variety of topics surrounding stereo photography, handled by a list server at LBL. To subscribe, send a message to listserv@csg.lbl.gov with 'subscribe photo-3d <your name>' in the text (NOT the subject line!) of the message. Contact bercov@csg.lbl.gov for more help or information. Photo-CD information is distributed via the photo CD mailing list. Those who wish to subscribe to it should send mail to the following address: listserv@info.kodak.com with the command SUBSCRIBE PHOTO-CD <first-name> <last-name> on a line by itself in the body (and no other text). Substitute your first name and last name where indicated; these will be used to identify you when you submit a message to the list. Your electronic mail address will be derived from this subscription request message. ------------------------------------------------------------------------ >>>> A short lexicon of terms ------------------------------------------------------------------------ f-stop The ratio of focal length to aperture diameter (actually, 'entrance pupil' diameter, which is not quite the same). Any two lenses set at the same f-stop will allow the same amount of light to pass through them (aside from minor differences in light losses in the lens). Smaller numbers mean more light. ISO/ASA, Film speed The rated speed of the film, as determined by a published and somewhat technical standard. Higher numbers indicate that the film in question requires less exposure. Some films seem to perform better when used at speeds different from the manufacturer recommendation, however. EI, Exposure index The film speed at which the photographer chooses to shoot the film. Often the same as the ISO/ASA of the film. EV, Exposure Value A measure of total exposure given the film. 1 sec at f/1.0 is EV 0, as is any other equivalent f-stop/shutter speed combination (2 sec at f/1.4, 4 sec at f/2.0). EV 1 is one stop *less* exposure (e.g. 1 sec at f/1.4), EV -1 is one stop more, and so on. GN, guide number Power rating for flash. Given a film speed (An EI, in fact), to compute the correct f-stop for exposure, divide the GN by the subject distance. NOTE: this implies that you need the correct units for subject distance, both feet and meters are commonly used. GN's for a flash are usually given as 'GN 140 in meters at ISO 100'. ------------------------------------------------------------------------ >>>> Some useful phone numbers ------------------------------------------------------------------------ [I've only tried some of these, and would especially welcome any additions and/or corrections! - Andrew] 800 number phone # directory system: 1-800-555-1212 Canon: 800-828-4040 NY 516-488-6700 (east coast) CA 714-769-6000 (west coast) Victor Hasselblad, Inc. 201-227-7320 Minolta Consumer Relations CA 714-895-6633 x101 Douglas Dodge or Bill Suarez NJ 201-825-4000 Minox: 516-437-7837 Nikon: 800-NIKON-US, 800-645-6687 (general info/customer support) 800-645-6635 (new product information) 213-516-7124 (parts depot) Olympus: NY 516-364-3000 NJ 800-221-3000 dealer listings, manuals, literature Europe: Germany (++49) -40-23773-0 Fax: -649 Sigma: 516-585-1144 Tokina: 310-537-9380 Tamron: 516-484-8880 Tamrac ( camera carrying supplies ): 800-662-0717 Vivitar: 800-352-7481 Yashica (Contax/Kyocera as well?): 201-560-0060 (USA main office) 908-560-0060 (apparently works as well?) 312-250-0591 (midwest USA office) 818-247-2140 (western USA office) 416-671-4300 (Kyocera Canada) (040)25 15 07 0 (Yashica Kyocera Germany) (01)720 34 34 (Yashica Switzerland) 283-4244 (Yashica do Brasil Industria e Comercio Ltda.) (03)797-4631 (Yashica Japan) Calumet: 800-CALUMET Kodak Information: 800-242-2424 800-465-6325 (In Canada) Ilford Information: 800-535-9205 Ilford technical support: 201-265-6000 Pentax: 303-799-8000 Fuji Customer Service: East Coast: 800-279-4419 (??) West Coast: 800-326-0800 ext. 4223 Polaroid Customer Service: 800-225-1618 (technical literature?) 800-343-5000 (also customer service?) Light Impressions (dealer in archival products) 800-828-6216 University Products (dealer in archival products) 800-336-4847 Photographers' Formulary 800-922-5255 406-754-2896 (Fax) Lightworks (source of photographic chemistry) 800-776-9678 Bostick & Sullivan (platinum printing and other exotic chemistry) 818-785-4130 A Photographer's Place (excellent source of photographic books) 133 Mercer St. P.O. Box 274, Prince St. Station, New York, NY 10012-0005 212-431-9358 or 212-966-2356 (one or the other is current) ------------------------------------------------------------------------ >>>> Some miscellaneous questions ------------------------------------------------------------------------ Will airport X-ray machines damage my film? Reports vary. Some machines will, others won't. High speed film (ISO 1000, up) is certainly at risk. Ask for a hand search, but you may not get one. Lead bags may help. Don't worry overmuch about ordinary film. Is Kodalux the same as Kodak? Nope. Kodalux is the name of a chain of labs, some or all of which were previously owned by Kodak. Kodak sold these labs to Qualex, which owns and operates the Kodalux labs. To make things more interesting, Kodak does own a large share of Qualex, but does not control it. Further, there has been some suggestion that the Kodalux name applies to only those Qualex labs that were, in fact, formerly owned by Kodak. What can I do about people's eye's turning red in my photos? This is red-eye, caused by light from your flash bouncing off the subject's retina, back through the camera lens. Red-eye reducing flashes emit a series of low-level flashes before the shutter fires, to cause the subject's iris to close a little, reducing the effect. Increasing the ambient light, even if only for a moment (with a flashlight, say, pointed at the subject's eyes) will accomplish a similar effect. Turning up the room lights, if possible, should help in the same way. These methods work, but to a limited extent. A better solution is to move the flash away from the lens, so the bouncing light misses the lens. This can only be accomplished with detachable flash units, and one usually does so by putting the flash on a bracket, mounting it some distance from the lens. Lastly, if you can bounce the flash off the ceiling, or even diffuse it to some extent, red-eye will be reduced. Note that in these cases, you must adjust your exposure, as less light from the flash will actually reach the subject. How do I take pictures of TV screens/monitors? Use a tripod and slow shutter speeds. Use a shutter speed of 1/30 of a second or slower (i.e. 1/15, 1/8 etc..) The longer you can make the exposure, the better. Bracket exposures a stop or two each way. Longer lenses will help compensate for curvature of the screen. Darken the room to help eliminate glare from the screen. Do everything you can to align your camera with the screen. It is very easy to take crooked pictures! See Kodak publication AC-10, as well. What about this 'movie film' I see advertised here and there (Seattle Film Works, for example)? There are several labs that sell this film, and processing. Usually they offer to process it into prints and slides, as well as give you a free roll. This film is indeed movie film, the unused parts of long rolls from the movie industry. As such, the age and condition of the film is unknown. Also, only a few labs can process the stuff, your local one-hour lab cannot. In general, it's probably not a very good deal. How do I take pictures of fireworks? You will need a tripod. The idea is to leave the shutter open long enough to catch a few bursts. As with flash photography, exposure is determined only by aperture. Try F-stop = square- root of film speed, as a guideline. With ISO 100 film, try an f-stop around f/11, and an exposure of 3-6 seconds, for example. Use the widest angle lens you have, 50mm is a little too narrow on 35mm camera. Ask your photofinisher to print the sky black, lest the print be 'compensated' and come out gray. Help! I over/under exposed a roll of film! Color print film overexposed by 1 or 2 stops can be processed normally. It's somewhat more sensitive to underexposure. Slide film is not nearly as easy-going. Films can be push or pull processed, to compensate (to some extent) for under or over exposure. Prices for this service vary from a couple bucks a roll on up. Shop around. My prints look all funny! What can I do? Look at the negatives, to see if they're the problem. If a huge blotch appears on the print but not on the neg, or if there's no detail in grandma's dress in the print, but you can clearly see it in the neg, then get a reprint (and ask for it to be done free!). Printing problems are common, and can be corrected by re-doing the print right. How do I get film leaders out of film cans? If your camera doesn't let you rewind film in such a way as to leave the leader out, your best bet seems to be to stop by your local photo store and get the little tool they sell for extracting leaders from cans. These apparently work really well. Some people can fool an power-rewind by popping the back open as they hear the film snap off the takeup spool. The <X> in/on my camera is dirty, how do I clean it? If it's the mirror, or something in the viewfinder, don't worry about it (it doesn't effect image quality). If it's the lens, get some lens cleaner and tissue, and follow the instructions. Don't worry about minor smudges or specks of dust on or inside the lens, they won't have any serious impact. Think before scrubbing! Do I need a 'circular' polarizer, and what is one, anyway? Circular polarizers are just like regular polarizers, but have an additional optical element to stir the light up after the filter has done its thing. This stirring keeps autofocus mechanisms and some light-metering mechanisms from getting confused by polarised light. If the manual says you need to use one, you likely do. Do I need a UV/skylight filter on my lens? This is a tough call. Such a filter will protect the lens, and will alter your images slightly in the positive ways advertised. They will also degrade image sharpness slightly, and contribute to flare (you get two more air-glass surfaces in the light path). What about teleconverters? They degrade image quality noticeably, yes. The best image quality is obtained from a lens of the appropriate length. Next is a lens + *matched* teleconverter (i.e. a teleconverter designed especially for the lens, or lens family), followed by a fixed focal length lens with a non-matched teleconverter. Using that $90 teleconverter on your 3rd party 70-200mm zoom lens will make rotten pictures. Using that Nikon 300mm lens with the matched 1.4X teleconverter will make nice pictures, you'll probably need a loupe to see degradation from a real 400mm lens. What about mirror lenses? Mirror lenses are small and cheap and have long focal lengths. They also tend to have fixed-size apertures (and slow, typically f8 or worse), so you can adjust exposure only with shutter speed or filters to reduce light. Finally, they render out-of-focus highlights as fuzzy donuts rather than fuzzy dots, which some find objectionable. What's the Zone System? It's a system of light-metering combined with development tailored to each exposure, to produce as good a negative as possible. It was developed by the famous photographer Ansel Adams, and Fred Archer. Is there a Zone System for color photography? Not really. You can use the ideas to get your exposures 'right', but development controls are out, since altering development makes nasty color shifts. There are various unsatisfactory systems published, but this is the short form. What's the sunny 16 rule? For taking pictures of objects brightly lit by the sun, in the absence of a better guess, expose the film at f/16, with a shutter speed of 1/<film ISO> (or equivalent). I.E. ISO 400 film yields 1/400 sec at f/16, 1/800 sec at f/11 etc.. Choose the nearest shutter speed your camera has (1/500 and 1/1000 in the example, for many cameras). How do I take a picture of the moon? Well, the moon is brightly lit by the sun, so use the sunny 16 rule! Before you say this is crazy, note that it doesn't matter how far away Aunt Martha is, as long as she's well lit by the sun, right? The moon's a bit farther out.. Often, you want the moon a little overexposed (it's a bright white thing, you know) so the 'looney 11' rule has been suggested. Use f/11 and 1/ISO shutter speed. Also, you really will want a very long lens, lest you wind up with a small white dot. The longer the better, really. For reference, the moon is around 1/2 a degree wide, while a 50mm lens has angle of view around 40 degrees, 300mm has 7 degrees, and a 500mm has about 4 degrees. So with a 500mm lens, the moon will be about 1/8 of the width of your frame (the long way). How do I take a picture of a moonlit landscape? From Jeff MacDonald (jmacdon@cg-atla.UUCP) comes the Loony f/4 rule: Set the aperture to f/4 and open the shutter for 1/EI days. That is, if you are shooting film at a speed of 100, at aperture f/4, use a shutter speed of 1/100 day or around 15 minutes. This is, of course, purely a starting point, and is based on the illumination of the full moon. How about some general guesstimated exposure guidelines? Ok! This is a table of compensations, in stops, from the sunny 16 rule. E.G. For heavy rain, use 4 stops more exposure, for a backlit subject in hazy sun, use 1 + 1.5 to 2 stops more. I stole this table verbatim from (faust@bagels.enet.dec.com): Sunny 16 variations Lighting correction Bright sun 0 Backlit subject +1-1/2 to +2 Hazy sun +1 Sidelight Subject +1/2 to +1 Light clouds +2 (-1/2 under hazy conditions, -0 Overcast +3 under overcast or shade conditions) Heavy rain +4 Dense Shade +6 One more thing: A rule of thumb for the slowest shutter speed you should use, hand-holding your camera, is 1/focal length of lens. That is 1/50 sec or so for the standard 50mm lens, 1/300 sec or so for the long 300mm lens. This is purely a rule of thumb, steadier people may get away with slower shutter speeds. What's a grey card, and what's it good for? A grey card is, well, a grey cardboard card. It's a specific shade of grey, 18% reflectance that's visually about the middle between black and white. More usefully, it's also the 'average' tone camera meters aim at. Taking a meter reading off of a grey card held next to your subject gives you the exposure that will render the grey card the right tone on film -- and as a corollary, should render a black subject black and a white subject white. Metering off the white subject will render it 18% grey, you see, which isn't always what you want. Is there an FTP archive for rec.photo? Yes! moink.nmsu.edu (128.123.1.46) has a number of possibly useful files. Log in as 'ftp' or 'anonymous', with your FTP client, please do send your real email address as the password, and look around. ------------------------------------------------------------------------ >>>> Equipment - brands, purchasing and quality ------------------------------------------------------------------------ This section is full of probably unfair generalisations, and exceptions to the things said abound. The author has tried to write short rules of thumb to be taken with a grain of salt, the most important of which is that you tend to get what you pay for. Expensive things tend to be better than cheaper things. Do not expect the $30 Pakina special to perform as well as the Canon! The term 'Big Name Manufacturers' is used below to avoid writing long lists of manufacturers of things photographic. By way of example only, Nikon and Canon are Big Name makers of cameras, Kodak and Fuji are Big Name film manufacturers. What's a good cheap camera? There are lots of them. Go to your local dealer, and spend some time talking and trying things out. Find out what features *you* want. Be prepared to take some time to handle equipment. Are the New York mailorder places good? If you know exactly what you want before you order, they're generally ok. Don't let them pressure you into buying extra stuff. B&H, Camera World of Oregon, and Adorama are places with good reputations. Avoid Cambridge Camera Exchange at all costs. Who makes the best lenses? The Big Name manufacturers all make marvelous lenses. Arguing about lens quality is a waste of time, since the actual differences are not really great. If you want sharper images, use a monopod or tripod, or go to a larger film format. Are Sigma/Vivitar/Tokina/etc lenses any good? In general, they are not as good as those made by the Big Name Manufacturers -- this should not be surprising, since they are in general cheaper. The modestly priced zoom lenses are likely fine for snapshots. Durability of these lenses is reputed to be lower than the Big Name lenses. However, some of these lenses are excellent. Use the price as your guide, it's reasonable to guess that an expensive Sigma is about as good as a similarly priced Nikon, and it may well be worth further investigation. Who makes the best cameras? See 'Who makes the best lenses'! Who makes the best film? That depends on your application. The standard color print films are probably fine for most normal applications. Is there a problem with the film(s) you have used in the past? If not, stick with them. All the Big Name manufacturers make decent films, and there are very few bad films. Some color print films: Under lights of mixed color or fluorescents - Fuji Reala. High resolution - Ektar 25. High speed - Ektapress 1600 (and other Ektapresses) Low contrast - Kodak VPS VPH Wide exposure latitude - Gold 100. Some slide films: Good archival qualities - Kodachrome. Saturated (bright) colors - Fuji Velvia. Black & White Slide Film: TMax from Kodak, processed in their reversal kit (at home) Kodak Duplicating Film (process in Dektol, at home, ISO .5! Available from Freestyle in California) Agfa DiaDirect. Slow speed direct positive film. Hard to find? I have a chance to buy <X> for $<Y>, is it a good deal? Get a copy of Shutterbug, and look around in the various advertisements for an idea of current prices. If it might be a 'classic' of some sort, look at McKeown's or McBroom's guides (my local photo shop has a copy they let me look at, your local library may well have copies as well). What should I look for when purchasing used camera equipment? (the following is a slight rework originally written by liang@saul.cis.upenn.edu, forwarded to me by Bruce_Barrett@qm.genmagic.com) Used lenses: Fugus or mold. hold it up against strong light and put you eye close to the rear element. Turn the lens from side to side so see if there are any uniform patterns in the lens. Dust will not appear uniform. Lenses with one or two hairline scratches will not affect image quality, but you should bargain for a lower price. In general, scratches on the front are less severe as ones on the rear of the lens. Aperture coupling. If the camera has depth fo field preview, use it and see that each successive aperture setting is smaller (or larger), and make sure that the maximum aperture is indeed maximum when the camera is fired. If there is no DOF preview, use a slow shutter speed. Iris diaphram speed. On worn lenses, sometimes the diaphram blades can not close fast enough, so if you use a fast shutter speed, the lens will not be able to fully close down to a small aperture before the shutter opens. Open the back of the camera and make sure the smallest aperture is the same size at maximum speed as at a slow speed when fired. Also check for oil on the diaphram blades. Security of mounting. Make sure the lens mounts tightly. Even the very slightest wobble could affect focus. Used cameras: <This is from me, and could use some work> Check for obvious damage, overall wear. Heavy wear does not mean it won't work, but probably indicates heavy usage. Check the shutter -- for focal plane shutters, open the back, for in-lens shutters, peer through the lens. Fire the shutter at a variety of speeds to verify that it, at least, opens and closes repliably. Check the meter, if any. Pointing it at a northern sky during the day ought to indicate 1/film-speed shutter speed at f/16 as a more or less correct exposure, with the lenscap on, it ought to indicate (of course) a very long exposure. Try various equivalent aperture/shutter-speed combinations (see above) to ensure that the meter reads more or less the same for all.