Archived posting to the Leica Users Group, 1998/06/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The difference between between 1/250 and 1/236(which is 0.331038 ms off 4ms, thus 8.275934%). See the table below,(HTML). I don't think it's a big deal either. I used Excel on a WinChip 200 machine to calculate. 1/s (dial) 1/s actual diff in ms off by (%) 1000 952 -0.0504 -5.04% 500 483 -0.0704 -3.52% 250 236 -0.2373 -5.93% 125 124 -0.0645 -0.81% 60 65 1.2821 7.69% 50 53 1.1321 5.66% 30 32 2.0833 6.25% 15 16 4.1667 6.25% 8 8.7 10.0575 8.05% 4 4.4 22.7273 9.09% 2 2.3 65.2174 13.04% 1 1.02 19.6078 1.96% Tom K. - ---------- From: Mark [SMTP:mark@steinberg.net] Sent: Sunday, June 28, 1998 0:50 To: leica-users@mejac.palo-alto.ca.us Subject: [Leica] Shutter Speed Inaccuracy TEAShea@aol.com wrote: > > << M6 n$B!<(J 1666706, control of the shutter speed with a spectron:(J > nominal speed (measured speed) : 1000(952),500(483),250(236), > 125(124),60(65),flash (53),30(32),15(16),8(8.7),4(4.4),2(2.3),1(1.02). >> > > Dominique, this is quite an impressive performance. > is it ? actually it's overexposed, overexposed, overexposed, exposed, underexposed, underexposed, underexposed, underexposed, underexposed, underexposed, underexposed, exposed. !!! if we assume that they calibrated the light meter correctly, and it actually reads the light correctly at whatever fstop, and indicates a correct exposure, then the shutter will confound that correctness at all but two shutter speeds (1/125 and 1/1). at 1/4 and 1/2 that confoundedness has become quite dramatic, noticeably so ? what's interesting is that for all the talk of incredible glass (and i have seen the results for myself and am a believer) the notion of even accurate light metering is thrown out the window by inaccurate shutter speed. i'd be interested to see the accuracy of the R8 shutter speed. i guess the point i am trying to make, the question i am asking, regards how critical accurate exposure is to a photograph, given the latitude one has when printing the final result ? i'm sure to a fuji or kodak emulsion scientist these errors are horrendous ? or does the same "messiness" exist in the emulsion production process ? (i.e. what kind of quality control is there in terms of ISO rating between batches of film ? take three rolls of 3200 ASA film, how close are they to that 3200 rating ?). (the scientists are horrified because they work hard on consistency no doubt and here we ae throwing darts at their ISO ratings). how about the paper scientist ? is that messiness reproduced there ? chemicals ? temperature ? i guess this message has become an exploration of all the various reasons why shutter speed inaccuracy might be but a piss in the ocean of inaccuracy in terms of creating final print. current technology won't let us fix focus (no doubt someone is working on the photoshop filter to fix it) but everything else is pretty elastic ? m