Archived posting to the Leica Users Group, 1997/06/11
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]User Surachai V. at UNESCAP4 is not defined Original text follows ---------------------------------------------- Received: from gatekeeper5.un.org by mail-in.un.org (SMTPLINK V2.11.01) ; Wed, 11 Jun 97 09:38:27 EST Return-Path: <owner-leica-users@mejac.palo-alto.ca.us> Received: by gatekeeper5.un.org; id AA125605587; Wed, 11 Jun 1997 09:26:27 -0400 Received: from mejac.palo-alto.ca.us(192.147.236.1) by gatekeeper5.un.org via smap (V3.1) id xma010137; Wed, 11 Jun 97 09:15:30 -0400 Received: by mejac.palo-alto.ca.us id AA20579; Wed, 11 Jun 97 03:55:35 -0700 Received: by mejac.palo-alto.ca.us id AA20573; Wed, 11 Jun 97 03:55:17 -0700 Received: from default (saturn.bnla.baynet.de [194.95.218.131]) by uranus.planet (8.7.5/8.7.3/FF-Nr3) with SMTP id MAA28800; Wed, 11 Jun 1997 12:56:06 +0200 Date: Wed, 11 Jun 1997 12:53:27 +0300 X-Mailer: Virtual Access by Ashmount Research Ltd, http://www.ashmount.com Message-Id: <VA.00000033.0100f9e2@default> To: leica-users@mejac.palo-alto.ca.us Cc: leica-users-digest@mejac.palo-alto.ca.us Subject: Re: Leica-Users List Digest V1 #503 From: Otto Braasch <otto.braasch@bnla.baynet.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit In-Reply-To: <9706100701.AA09430@mejac.palo-alto.ca.us> Sender: owner-leica-users@mejac.palo-alto.ca.us Precedence: bulk Reply-To: leica-users@mejac.palo-alto.ca.us Eng-Suan wrote: >>> You are correct to quote the MRBF of 322.6 rolls for your 4 bodies. What I meant was if you take ANY RTS III randomly and use it *under the same coditions* as you used for your 4 bodies, then the MRBF will be some what more conservative. My calculation suggests it is at least 222 rolls. (based on one-sided Chi-square distribution at 95% confidence level.) If I have the data for R8 I could use what the reliability engineer called time-truncated (without failure) to estimate the MRBF. But for the two sets of data to have any meaningful comparison, the cameras must worked under the same condition (the way you handled them and the environment they were subjected to.) And so far we are assuming the failure rates of the cameras are constant, that is to say the MRBF of first 2 years is the same as that of the subsequent 2 years. It is theoretically acceptable to consider electronic circuits and equipment to have constant failure rate, but rarely so for mechanical parts. You have been using RTS III for 3.25 years but the R8's are less that a year in the market....the discrepancies are there. <<< Eng-Suan, Thank you very much for commenting on the MRBF approach. The objective I had in mind when posting the figures was to encourage other users to come up with their data - if they have any. Once users of Leica-R models post their figures, there might be some chance for a ROUGH comparison of body endurance between different R-models and other camera brands. Unfortunately photo magazines (for multiple reasons?) do not run any tests on durability of cameras, which, when done professionally under the same conditions, could supply users reasonable information. I am fully aware of the many variables that will prevent a professional comparison when data are collected by different people under various conditions at different times. However at present it seems to be the only way to get rid of pure guesswork and hearsay when it comes to the question: "how long can I expect this camera to function under what conditions"? Wonder, when we will see new MRBF figures here? Regards, Otto