Archived posting to the Leica Users Group, 1999/01/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Guido Ridoli wrote: > > Is it possible to measure the brightness and focal lenght of an > external finder for example, there is a great difference in > brightness between a 35mm finder SBLOO and a 35 mm WEISU; > and if it is, can we measure a "kind of f/stop" for an external > finder? Shine a light of known strength through the finder and measure the strength of the light (lux? lumen? something else?) on the other side. Would that work for an absolute rating? Illuminate the white side of a grey-card (90% reflectance) with uniform diffuse light. Use a spot meter to measure through the view- finder to get a reading. Use same spot meter to measure through another viewfinder. Provide a relative rating. Feasible? M. - -- Martin V. Howard, Application Systems Laboratory, | Dept. of Comp. & Info. Sci., Linkoping University, | Just "DOHH" it! SE-581 83 Linkoping, Sweden. Tel +46 13 282 421, +----------------+ Fax +46 13 142 231; marho@ida.liu.se; www.ida.liu.se/~marho