Archived posting to the Leica Users Group, 2003/12/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]And... what were the effects of the simultaneous Laphroig versus Lagavullin testing? :-) Jim - http://www.hemenway.com animal wrote: > Sorry for the earlier empty post. > Here goes. > A collegue and myself wanted to find out if we could get 80 line pairs per > millimeter using a Leica and a Kenyon gyro stabiliser. > We could not find those data in literature so last night, while also doing a > test of Laphroig versus Lagavullin, > we decided to give it a try ourselves. > > We scribbled some lines on a piece of paper with a group of line pairs one 1 > cm per pair and the other 5 mm per pair. > With a Noctilux 18 meters away we calculated the image on the film to be 36 > and 72 line pairs per millimeter. > We suspended the camera and running gyro from a bungee cord and started. > First exposure was at 1/250 second and f1.0 going in stops to 1 second and > f16.0. > > Then we tried the same sequence while handholding the camera and bracing > ourselves in a doorway. > > By then we became to doubt the ability of a 4000 dpi scanner to resolve our > results. > While one would assume that 4000 dpi translates to 80 line pairs per > millimeter,some knowledgeable people we asked suggested that 60lp/mm is > about the best such a scanner can do. > So we had to aim a little lower and did the same test with an aasummicron90 > mm and the stabiliser starting at 1/60 and f2.0 . > > Although our test was hastily done it still yielded some suprises to us. > The biggest being that the stabiliser clearly is able to permit shots at 1 > second. > Others were that the noctilux was still giving good results at f 4.0 and 5.6 > and stayed that way until f16.(we realise that the focus shift of the lens > could have been to our advantage at those apertures if we started out with a > focus error). > Also suprising was that at f 8.0 and smaller the summicron image is starting > to fade. > Lastly it shows that it is hard to find the testcard when handholding the > camera. > On the page the first column is the stabilised noctilux the second is the > same handheld(stopping at 1/8th) > and the last is the summicron. > The film used was Kodak E100 GX . > The question is to get rid of focusing errors .can one set the lens > accurately at infinity just by putting the index on thatmarkingAnd if so at > what distance would one have to put the target? > http://www.leica-gallery.net/apekop/folder-6004.html > best regards > simon jessurun > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html > - -- Jim - http://www.hemenway.com - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html