Guest mc_k Posted August 26, 2010 Share #41 Posted August 26, 2010 Advertisement (gone after registration) sure, exept the following equation is more convenient to remember obviously: [1 - {(cos x) / (cos (x+-y)}] X 100 = [{tan(x)sin(y)+cos(y)-1}/{cos(y) + tan(x)sin(y)}] X 100 The formula (in #29) with " + - " is an abbreviation for two formulas--to highlight the difference between sloping the target in the two ways. So there is no "equality" in your equality. Really, this is less welcome than constructive criticism. Testing the rangefinder seems natural enough. How do you think the rangefinder is designed and linked to everything in the first place--without any geometry? How do you think it gets adjusted at the factory--without any attention to the errors in testing it? Link to post Share on other sites More sharing options...
Advertisement Posted August 26, 2010 Posted August 26, 2010 Hi Guest mc_k, Take a look here Focusing Issues. I'm sure you'll find what you were looking for!
bill Posted August 26, 2010 Share #42 Posted August 26, 2010 I cannot speak for anyone else but my incredulity stems from why anyone would bother. I would no more remap the CPU in my car than go through all this rigmarole. To each their own. Regards, Bill Link to post Share on other sites More sharing options...
Guest mc_k Posted August 27, 2010 Share #43 Posted August 27, 2010 I cannot speak for anyone else but my incredulity stems from why anyone would bother. I would no more remap the CPU in my car than go through all this rigmarole. To each their own. Regards, Bill well I think some people bother because the equipment is not accurate enough out of the box for their kind of photography. Your kind of photography is not necessarily my kind of photography. Link to post Share on other sites More sharing options...
DOUG66 Posted September 5, 2010 Share #44 Posted September 5, 2010 Hi, I mentioned in a previous post that I was working on reducing the error in setting accurately the angle of the chart. The solution consist of two components. (1) A laser mounted on the camera which aligns with the front of the camera body and shines a beam of light parallel to the lens axis. (2) A mirror mounted at 30 deg to and attached to the chart such that when the camera and chart are in the desired alignment, the laser beam is reflected back along its path to a small screen mounted on the laser. The mirror is mounted on a precision angular aluminium block which is accurate to +/-0.02 degs. The laser mount is clamped to the top of the camera with a single nylon screw so as not to mark the camera and has an accurately machined reference face to mate with the front of the camera. Accurate lateral positioning is not required. The system works very well and gives very precise angular alignment of the testing set up. It should enable testing over greater distances than before, but this has to be checked out. The attached photos show the components. Doug. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/128700-focusing-issues/?do=findComment&comment=1429093'>More sharing options...
Onley Posted September 7, 2010 Share #45 Posted September 7, 2010 I find this very interesting for say calibrating lenses. Could I ask a question more related to actual focusing in the field? The only lens I have a problem with at the moment with my M8 is the 90mm wide open when focused at say between 07m and 2.5m. My lens focuses slightly long so I can adjust very carefully to compensate. However it is hit and miss whether the two images in my original focus were completely spot on. This means if I am taking a portrait focusing on the eyes I may be a cm or so out. Or recently taking some red berries I had the same problem. My max aperture is f2.8 on this lens and I genuinely wonder what technique people with for example a 50mm f1.4 Summilux wide open use to ensure that their focus is really accurate. I do wear glasses and although I have tried the 1.25 magnifier I find it both uncomfortable to use and that it adds little to the accuracy. I would dearly love to hear techniques and tips for very precise focusing during practical picture taking; I would love to invest in a 50mm Summilux for the very reason that it can be used to make a subject stand out at full aperture but there is little point if I can't focus it spot on! Link to post Share on other sites More sharing options...
Onley Posted September 7, 2010 Share #46 Posted September 7, 2010 I find this very interesting for say calibrating lenses. Could I ask a question more related to actual focusing in the field? The only lens I have a problem with at the moment with my M8 is the 90mm wide open when focused at say between 07m and 2.5m. My lens focuses slightly long so I can adjust very carefully to compensate. However it is hit and miss whether the two images in my original focus were completely spot on. This means if I am taking a portrait focusing on the eyes I may be a cm or so out. Or recently taking some red berries I had the same problem. My max aperture is f2.8 on this lens and I genuinely wonder what technique people with for example a 50mm f1.4 Summilux wide open use to ensure that their focus is really accurate. I do wear glasses and although I have tried the 1.25 magnifier I find it both uncomfortable to use and that it adds little to the accuracy. I would dearly love to hear techniques and tips for very precise focusing during practical picture taking; I would love to invest in a 50mm Summilux for the very reason that it can be used to make a subject stand out at full aperture but there is little point if I can't focus it spot on! Link to post Share on other sites More sharing options...
jaapv Posted September 7, 2010 Share #47 Posted September 7, 2010 Advertisement (gone after registration) well it all depends on what you are shooting and what you are trying to accomplish, doesn't it.Which is exactly my point - if your images are not focussed correctly send it in to somebody who can adjust the thing to the correct tolerances. It is a pointless to go through all this testing yourself. The attempted precision leads to nothing. Unless your hobby is testing instead of photographing. I find this very interesting for say calibrating lenses. Could I ask a question more related to actual focusing in the field? The only lens I have a problem with at the moment with my M8 is the 90mm wide open when focused at say between 07m and 2.5m. My lens focuses slightly long so I can adjust very carefully to compensate. However it is hit and miss whether the two images in my original focus were completely spot on. This means if I am taking a portrait focusing on the eyes I may be a cm or so out. Or recently taking some red berries I had the same problem. My max aperture is f2.8 on this lens and I genuinely wonder what technique people with for example a 50mm f1.4 Summilux wide open use to ensure that their focus is really accurate. I do wear glasses and although I have tried the 1.25 magnifier I find it both uncomfortable to use and that it adds little to the accuracy. I would dearly love to hear techniques and tips for very precise focusing during practical picture taking; I would love to invest in a 50mm Summilux for the very reason that it can be used to make a subject stand out at full aperture but there is little point if I can't focus it spot on! If the lens is calibrated correctly you can focus spot on. If your Elmarit 90 misfocusses,which is not unusual as this is a lens from the film era, you need to have it adjusted. There are third party services that do this, and Leica adjusts to "M8/9 standard" nowadays. Link to post Share on other sites More sharing options...
Guest mc_k Posted September 7, 2010 Share #48 Posted September 7, 2010 ...if your images are not focussed correctly send it in to somebody who can adjust the thing to the correct tolerances... Well you can do two things. You can discourage people from checking their equipment, hoping that most of the equipment is already satisfactory. In a recent post Jaap suggested "98%" of the lenses come perfect from the factory; I have no idea if this is true, but I doubt it. The other thing you can do is encourage people to check their own equipment, hoping that most of the testing will be done in a reliable and responsible manner. That last part sounds like wishful thinking to me, too. I think when the M8 came out the non-stop focus testing threads on the forum drove the return of much equipment that probably had nothing wrong with it; this is a cost that gets passed on to everyone, and it may be very high. When the M9 came out it was more of same. People were returning lenses they had measured to the "millimeter," or returning cameras (by themselves) that had tested positive for focus shifting. Link to post Share on other sites More sharing options...
Guest mc_k Posted September 8, 2010 Share #49 Posted September 8, 2010 ...It is a pointless to go through all this testing yourself. The attempted precision leads to nothing... not sure where in the thread anybody recommends doing anything. The poster shared what he made for focus testing. Do you really want to say checking your equipment by focus testing is pointless? If it's not pointless, what's wrong with doing something to make it better. If you don't have a laser, make it better with something else--tripod, plumb bob, magnifier, piece of string, whatever you have. What is the hang up? The example above (wide open and close up) is enough to justify any added attention; so is wide open and moving. If your photography doesn't involve this then, sure, maybe you don't have the interest or the need. Link to post Share on other sites More sharing options...
bill Posted September 8, 2010 Share #50 Posted September 8, 2010 This appears to be a separate pastime, with little connection to photography. It leaves me cold, but whatever floats your boat. One thing I would say though - I would not be happy to find I had bought a Leica lens or body that had been tinkered with or "calibrated" by a well-meaning amateur in his shed. Regards, Bill Link to post Share on other sites More sharing options...
Guest mc_k Posted September 8, 2010 Share #51 Posted September 8, 2010 This appears to be a separate pastime, with little connection to photography. It leaves me cold, but whatever floats your boat. One thing I would say though - I would not be happy to find I had bought a Leica lens or body that had been tinkered with or "calibrated" by a well-meaning amateur in his shed. Regards, Bill I think you're kidding, but this is a thread on cameras--craft not art. Checking the camera has always been part of the craft of photography--19th century, this century, whenever. Link to post Share on other sites More sharing options...
bill Posted September 8, 2010 Share #52 Posted September 8, 2010 Actually, I was deadly serious. I would not want to buy a lens or camera that had been "calibrated" by an amateur with home-made equipment, however well intended. Have a look at this thread and try to understand what I mean... Regards, Bill Link to post Share on other sites More sharing options...
jaapv Posted September 8, 2010 Share #53 Posted September 8, 2010 Well you can do two things. You can discourage people from checking their equipment, hoping that most of the equipment is already satisfactory. In a recent post Jaap suggested "98%" of the lenses come perfect from the factory; I have no idea if this is true, but I doubt it. Please link to that post..... Link to post Share on other sites More sharing options...
jaapv Posted September 8, 2010 Share #54 Posted September 8, 2010 not sure where in the thread anybody recommends doing anything. The poster shared what he made for focus testing. Do you really want to say checking your equipment by focus testing is pointless? If it's not pointless, what's wrong with doing something to make it better. If you don't have a laser, make it better with something else--tripod, plumb bob, magnifier, piece of string, whatever you have. What is the hang up? Yes - your photographs will show whether you need to have your gear adjusted. Tinkering around with " testing" is not going to change anything. Instead of agonizing, have it attended to. Link to post Share on other sites More sharing options...
ldhrads Posted September 9, 2010 Author Share #55 Posted September 9, 2010 OP here! Lenses and camera came back late last week from Leica US. Before the date I had asked for. Great communication. No charge except for the 90 summicron. Happy to report that photos from all of them are improved and I am quite happy. Unless I see an issue, I don't expect to set up the scale and test them again. I'm pleased with how the photos look and as many have said. That's really what matters. I did the tests because I could tell from my photos that they were off. What a discussion!!!! Link to post Share on other sites More sharing options...
Guest mc_k Posted September 9, 2010 Share #56 Posted September 9, 2010 thanks for the update Link to post Share on other sites More sharing options...
Guest mc_k Posted September 9, 2010 Share #57 Posted September 9, 2010 Please link to that post..... http://www.l-camera-forum.com/leica-forum/customer-forum/133349-how-long-calibrate-m9.html#post1396834 ...It seems a bit overdone to have a new lens adjusted sight unseen. There is a 98% chance that it is fine as it is. Link to post Share on other sites More sharing options...
Guest mc_k Posted September 9, 2010 Share #58 Posted September 9, 2010 Actually, I was deadly serious. I would not want to buy a lens or camera that had been "calibrated" by an amateur with home-made equipment, however well intended. Have a look at this thread and try to understand what I mean... Regards, Bill Well I'm the same way, but I don't think checking things for yourself implies you will adjust the camera/lens yourself, and there was no mention of that. Link to post Share on other sites More sharing options...
Guest mc_k Posted September 9, 2010 Share #59 Posted September 9, 2010 Yes - your photographs will show whether you need to have your gear adjusted. Tinkering around with " testing" is not going to change anything. Instead of agonizing, have it attended to. The point of a ruler test, or shooting wine bottles, or whatever is that just taking pictures is misleading, there are too many additional variables involved. I have no problem with "don't bother testing," it probably leads to less equipment sent back that is o.k. to begin with. But "don't bother testing, and send back anything doubtful" is something else. Link to post Share on other sites More sharing options...
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