emillu Posted November 22, 2009 Share #1 Posted November 22, 2009 Advertisement (gone after registration) Hi there, I figured as a rookie M8 user, i should understand exactly how it work scientifically/optically. I have look through the web regarding a complete knowledge specifically to Leica M8. but, no luck! even on Leica's official web site. Regarding how each parts work together, Distance meter viewing window, Brightness sensor, Bright line illumination window, Viewfinder window (with diagram the best). How lights come in from the lens and pass through the image to the viewfinder? Please help! Link to post Share on other sites More sharing options...
Advertisement Posted November 22, 2009 Posted November 22, 2009 Hi emillu, Take a look here How M8 RF work? general knowldege. I'm sure you'll find what you were looking for!
Nicoleica Posted November 22, 2009 Share #2 Posted November 22, 2009 Wow! That's a lot to try and explain simply. But...here goes. 1) Distance measurement. This is performed through a cam transmitting the lens setting to the camera, and this moves a mirror/prism array inside the rangefinder assembly so that the image seen in the centre patch indicates the focus point once this is aligned with the image seen through the viewfinfder. The rangefinder centre image is taken from the small window on the other side of the lens to that of the main viewfinder window and the distance is calculated using the difference in angle between the images seen through the two windows. 2) The 'brightness' measurement. This is calculated from the amount of light falling upon a sensor inside the camera body, and is reflected off of the shutter curtains after traveling through the lens. Hence the term 'TTL' for 'Through The Lens' metering. The M8 has an additional sensor in the little round window on the camera body, and this is used for calculating the approximate aperture used, and for other calculations within the camera's internal processing. 3) The 'bright line' frame. This is selected by the lens in use, or via the preview lever, and moves a frame mask into the path of light collected through the big window to the side of the main viewfinder window. This image is then projected into the viewfinder display. 4) The viewfinder window. This is the big window on the front of the camera that provides your main view of the scene, The Leica M8 manual, and the M brochure provide quite a lot of information about these various systems, together with illustrations. I'm sure that other members will dive in with more detail if needed. Link to post Share on other sites More sharing options...
emillu Posted November 22, 2009 Author Share #3 Posted November 22, 2009 Wow! That's a lot to try and explain simply. But...here goes. 1) Distance measurement. This is performed through a cam transmitting the lens setting to the camera, and this moves a mirror/prism array inside the rangefinder assembly so that the image seen in the centre patch indicates the focus point once this is aligned with the image seen through the viewfinfder. The rangefinder centre image is taken from the small window on the other side of the lens to that of the main viewfinder window and the distance is calculated using the difference in angle between the images seen through the two windows. 2) The 'brightness' measurement. This is calculated from the amount of light falling upon a sensor inside the camera body, and is reflected off of the shutter curtains after traveling through the lens. Hence the term 'TTL' for 'Through The Lens' metering. The M8 has an additional sensor in the little round window on the camera body, and this is used for calculating the approximate aperture used, and for other calculations within the camera's internal processing. 3) The 'bright line' frame. This is selected by the lens in use, or via the preview lever, and moves a frame mask into the path of light collected through the big window to the side of the main viewfinder window. This image is then projected into the viewfinder display. 4) The viewfinder window. This is the big window on the front of the camera that provides your main view of the scene, The Leica M8 manual, and the M brochure provide quite a lot of information about these various systems, together with illustrations. I'm sure that other members will dive in with more detail if needed. Hi, Thanks for your quick response! I came across this diagram (attached), I guess my real question was how these parts (Distance meter viewing window, Brightness sensor, Bright line illumination window) play the role while the light travel through the lens to the Mirror of pentaprism Thanks again! All the best! Link to post Share on other sites More sharing options...
Nicoleica Posted November 22, 2009 Share #4 Posted November 22, 2009 Now I understand the reason for your questions. The diagram you have been looking at is a side view of an SLR camera. (Even though it seems to be labelled as a 'Top view'.) A rangefinder camera doesn't have most of those parts. In a rangefinder, there is no mirror or pentaprism assembly. Instead you view the scene directly through the viewfinder window, and focussing is achieved by use of the rangefinder system as described above. You don't actually see through the lens. This is one reason why rangefinders are normally smaller than SLR's, and have brighter viewfinders. I you look at the Leica 'M' system brochure, there are a few good illustrations and explanations of the various parts, and how they work. (Look under the M7/MP too, as most of these parts are common across the whole range.) Here's an example. Link to post Share on other sites More sharing options...
lars_bergquist Posted November 22, 2009 Share #5 Posted November 22, 2009 Hi, Thanks for your quick response! I came across this diagram (attached), I guess my real question was how these parts (Distance meter viewing window, Brightness sensor, Bright line illumination window) play the role while the light travel through the lens to the Mirror of pentaprism Thanks again! All the best! Emilly, that is a Single Lens Reflex camera (SLR), NOT a rangefinder camera. With a SLR, you see the subject trough the taking lens, projected on a matte screen. Before the shutter is tripped, the mirror swings up. With a RF camera like a Leica M, viewing and focusing are done upstairs, and photographs are taken downstairs, and the little lever that transmits the lense's (downstairs) distance setting to the rangefinder mechanism (upstairs) is the only traffic between them. Just like a well-ordered English upper-class home ... Consequently, no screen, no pentaprism, no finder blackout. It is an entirely different game. But it is the best game in town. Go find a photo dealer that can demonstrate a Leica M to you. Any Leica M -- in this respect, they all work the same, and have done so since 1954. For I cannot think that you do have an M. But if you do, have a SLR camera demonstrated to you instead. The old man from the Age of the Leica M3 Link to post Share on other sites More sharing options...
roydonian Posted November 22, 2009 Share #6 Posted November 22, 2009 Hi there, I figured as a rookie M8 user, i should understand exactly how it work scientifically/optically. I have look through the web regarding a complete knowledge specifically to Leica M8. but, no luck! even on Leica's official web site. Regarding how each parts work together, Distance meter viewing window, Brightness sensor, Bright line illumination window, Viewfinder window (with diagram the best). How lights come in from the lens and pass through the image to the viewfinder? Please help! The following is a good starting point on how viewfinders and rangefinders work: Looking Forward: Link to post Share on other sites More sharing options...
Guest mc_k Posted November 22, 2009 Share #7 Posted November 22, 2009 Advertisement (gone after registration) thanks for the article. Are there any books, in or out of print, on the technical side of rangefinder cameras (optics and mechanical construction)? Thanks. Link to post Share on other sites More sharing options...
luigi bertolotti Posted November 22, 2009 Share #8 Posted November 22, 2009 There is a classic book from Theo Kisselbach that expalins a lot on RF Leica technology; about M8, if you serach in the forum, there has been a superb series of threads from a respectable member of us (Mark Norton) who completely DISMANTLED his M8 taking,and posting, a lot of pictures, with deep and detailed explanations... for instance, you can see in detail how the framelines of the finder are made and projected; search for "anatomy"... or in "Mark Norton" threads... (it's rather old... I'd say 2007) you'll find it: is an astonishing work. Link to post Share on other sites More sharing options...
Guest mc_k Posted November 22, 2009 Share #9 Posted November 22, 2009 thank you !! Link to post Share on other sites More sharing options...
jaapv Posted November 22, 2009 Share #10 Posted November 22, 2009 This thread is a joke -right? Link to post Share on other sites More sharing options...
darkspark Posted November 23, 2009 Share #11 Posted November 23, 2009 There is a classic book from Theo Kisselbach that expalins a lot on RF Leica technology; about M8, if you serach in the forum, there has been a superb series of threads from a respectable member of us (Mark Norton) who completely DISMANTLED his M8 taking,and posting, a lot of pictures, with deep and detailed explanations... for instance, you can see in detail how the framelines of the finder are made and projected; search for "anatomy"... or in "Mark Norton" threads... (it's rather old... I'd say 2007) you'll find it: is an astonishing work. I looked it up because it does sound very interesting. Here's the link so that you don't have to do the search again:http://www.l-camera-forum.com/leica-forum/leica-m8-forum/21331-anatomy-leica-m8.html Link to post Share on other sites More sharing options...
luigi bertolotti Posted November 23, 2009 Share #12 Posted November 23, 2009 This thread is a joke -right? Not at all sure... there are people who, even if passionate photogs, know the good reputation of Leica but haven't a clear idea of what is a RF... the husband of a friend of my wife, who I discovered was a Nikon+TLR Rolleiflex experienced user and darkroom amateur, one day looked at me - with M8 - and said "wow, a Leica ! Sometimes I thought to have one... let me see... so what ? Is not a reflex viewfinder ? How do you focus ?..." etc... Link to post Share on other sites More sharing options...
lars_bergquist Posted November 23, 2009 Share #13 Posted November 23, 2009 How not to focus a M. The old man from the Age of the SLR Link to post Share on other sites More sharing options...
Bo_Lorentzen Posted November 23, 2009 Share #14 Posted November 23, 2009 Lars, you realize naturally that SOME users will not find this picture instructional at all, only wonder what the point is..? One of my very good friends borrowed my M6 for a outing. shooting away, kept saying that he had a great problem seeing the focusing field some times.... until I realized that on and off he would cover the rangefinder window. Guess Im more upset with myself for not pointing this out first thing. . Link to post Share on other sites More sharing options...
shaunmadden Posted November 23, 2009 Share #15 Posted November 23, 2009 The following is a good starting point on how viewfinders and rangefinders work: Looking Forward: Roy, thanks for the link to an informative article, Regards Shaun Link to post Share on other sites More sharing options...
jaapv Posted November 23, 2009 Share #16 Posted November 23, 2009 This thread holds some information as well: http://www.l-camera-forum.com/leica-forum/leica-m8-forum/72598-slow-shutter-camera-holding.html Link to post Share on other sites More sharing options...
lars_bergquist Posted November 24, 2009 Share #17 Posted November 24, 2009 Lars, you realize naturally that SOME users will not find this picture instructional at all, only wonder what the point is..? One of my very good friends borrowed my M6 for a outing. shooting away, kept saying that he had a great problem seeing the focusing field some times.... until I realized that on and off he would cover the rangefinder window. Guess Im more upset with myself for not pointing this out first thing. . Bo, I admit that this was a most un-Christian thing to do. My first impulse was not to tell him to move his second finger off the rangefinder window, but to get the picture to gloat over. On the other hand, I have seen people using a focusing grip that completely blocked the finder, and then wondering about the peculiar finder picture. A SLR does tolerate some bad habits the M does not ... and that is its virtue. The old man from the Age of Non-Focusing Box Cameras Link to post Share on other sites More sharing options...
elgenper Posted November 24, 2009 Share #18 Posted November 24, 2009 Bo, I admit that this was a most un-Christian thing to do. ... Wow.... Unusually large crowd in the Leica booth at this year´s Fotomässa, so no wonder some totally unfamiliar with RF´s. This fellow must have walked away more convinced than ever that Leicas are overrated..... At least, it isn´t me, regardless of the beards..... Link to post Share on other sites More sharing options...
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