From: mario@cs.man.ac.uk (Mario Wolczko) Subject: Cameras for astrophotography -- SUMMARY Date: 9 Jan 92 17:36:37 GMT How well matched is your camera to the demands of astrophotography? The aim ~~~~~~~ This is the result of a USENET survey to find out which cameras have particular features useful for astrophotography. The features listed are of a rather unusual nature, and not the sort of thing you can easily find out by looking at published listings of camera features. However, it should not be assumed that you must possess a camera with all these features before actually trying to take pictures of the night sky! Most are just convenience features; some are only useful in very specific circumstances, of for a particular style of working (e.g., your preferred focussing technique). Many other important things are not addressed, such as: - price and availability (many of the models listed below are no longer in production, and can only be obtained secondhand) - price & quality of available optics - quality of build, completeness of "system", type of lens mount, etc. Answers to these questions can be obtained from more general sources of information. The questions: ~~~~~~~~~~~~~~ Does the camera have: 1. The ability to lock the mirror up before opening the shutter; this can reduce vibration for non-B exposures (if you're using the B setting you should use the "hat trick" to begin and end the exposure). 2. A mechanical `B' speed (and possibly other shutter speeds), not requiring batteries; batteries have a habit of flaking out in the cold of the night. Also, some cameras continuously drain the battery while the shutter is open -- this is bad news for long exposures. 3. A self-timer (mechanical or electronic?); useful in some situations to avoid camera shake, also nice if not dependent on batteries. 4. A `T' speed (obviates cable release in some situations); this cause the shutter to open when the release is depressed once, and close when depressed again. 5. Interchangeable screens, either all-matte and/or clear screens (possibly with crosshairs); the usual focussing aids (split-image rangefinder and/or microprism grid) do not work well at night and/or with slow optics. Some people prefer matte screens; others use clear screen and crosshairs for a knife-edge test. 6. A removable pentaprism (possibly with an additional magnifier for viewing the focussing screen directly); as most telescopes point up, it may be useful to look directly at the focussing screen from above the camera rather than from the normal position. Sometimes a right-angle attachment does this, but extra optics means less light to the eye. Also, some like to use knife edge focussing on the bare screen. A magnifier can also help in this respect. 7. The ability to take well-registered multiple exposures (I'm not counting the old trick of disengaging the film advance as if rewinding); this is useful for pictures showing, e.g., the moon passing through eclipse. 8. An optional data back; if you don't want to write down exposure details. Note that the information is not completely regular -- e.g., in some cases I have details of mechanical non-B shutter speeds, in some cases not. It's not safe to make any assumptions in the absence of such information. A question mark means nobody provided an answer. The Answers: ~~~~~~~~~~~~ Camera\Question 1 2 3 4 5 6 7 8 -------------------------------------------------------------------------- Canon FTb y y y n n n y n Canon F-1 y y(all) y(m) n y y y y Canon F-1n n y y(m) n y y y y Canon T90 n y y n y n y y Fujica ST-701 n y(all) y(m) n n n n n (screw mount) Minolta SRT-202 y y y(m) n n n y n Nikkormat FTn/ y y(all) y(m) ? n n n n FT2/FT3 Nikon F y(*7) y(all) y(m) y y y n n Nikon F2 y y+10s y(m) y y y y y -1/2000 Nikon FE ? y y ? y n ? ? (others electronic) Nikon FE2 ? y y ? y n ? ? (others electronic) Nikon FM n y(all) y(m) n n n y y Nikon FM2n n y+1s- y(m) n y n y y 1/4000 (w/o x-hairs) Nikon F3 y y(*6) y(e) y y y y y Olympus OM-1 y y+1s- y(m) n y n(*5) n y(*3) -1/1000 (matte+clear,w/x-hairs) Olympus OM-2S n(*4) y y(e) n y n(*5) n y(*3) (as OM-1) Olympus OM-3 ? y ? n y n(*5) n y(*3) (as OM-1) Olympus OM-4 n(*4) y y(e) n y n(*5) n y(*3) and OM-4T (as OM-1) Pentax K1000 n y(all) y(m) ? n n ? ? Pentax ME n y y(m) n n n n y and ME super +1/125 Pentax MX y(*2) y y(m) n y n n ? (all) Pentax LX y y+ y(m) n y y y(*1) y 1/75-1/2000 (w/x-hairs) Zenit 11 n y+T+V y(m) y n n n n Zenit E,EM n y+ y(m) n n n n n 1/30-500 Notes ~~~~~ (*1) You can even rewind to any previous frame with a very small tolerance. (!) (*2) The MX _does_ have mirror lock-up, but it's not an advertised feature. You need to acquire the knack, but once learnt it's quite easy - just a light tap on the shutter release button. (due to Stephen Mounsey) (*3) An additional internal contact for more databacks was introduced with the OM-1n. (*4) No manual mirror lock-up is avilable, but the use of the 12-second self-timer locks up the mirror at the start of the 12 seconds. (*5) Numerous correspondents praised the Varimagni right-angle finder which provides switch-selectable 1.2x and 2.5x views of the screen. (*6) Via auxiliary body release only: set speed dial to "B" (or maybe "T" as well?). Cannot use in conjunction with cable release. (*7) One correspondent claimed not; several said yes. The majority gets the decision! Errors and omissions ~~~~~~~~~~~~~~~~~~~~ With the exception listed in Note 7, I received no conflicting information. However, if you believe that an entry in the table is wrong, please mail me (address below). If you would like to add an entry for some camera not listed, that's fine too. A complete list of responses (lots of assorted interesting facts) can be obtained from mario@cs.man.ac.uk. If any of the contributors would not like their contribution so distributed, please let me know. The Good Guys: ~~~~~~~~~~~~~~ David Smith, Rich Casto, Bob Lombardi, Doug McDonald, Stephen Mounsey, Phil Herring, Steve Hix, Jan Isley, Markus Buchhorn, Mike Chuang, Drew W. Saunders, Tim Conrow, Aldo G. Cugnini, Bill Jones, Markus Wandel, Taku So, Joel Jacobsen, Tony Arnerich. Mario Wolczko 9 Jan 1992 ______ Dept. of Computer Science Internet: mario@cs.man.ac.uk /~ ~\ The University uucp: mcsun!uknet!man.cs!mario ( __ ) Manchester M13 9PL JANET: mario@uk.ac.man.cs `-': :`-' U.K. Tel: +44-61-275 6146 (FAX: 6236) ____; ;_____________the mushroom project___________________________________