derder Posted May 6, 2011 Share #1 Posted May 6, 2011 Advertisement (gone after registration) hi all, got my M8.2 for 1 month now, been enjoying it heaps. being my first RF camera, takes a bit of time getting used to my its so much fun!! i have a question. tonight I was just playing with it at home. and I noticed when I try to focus on, say a wall paining with lots of letters/words on it, not ALL letters in the VF focus patch is in perfect focus??? i can focus "word" on the painting perfectly, but then the letters on the edge of the VF patch its slightly out?? the same phenomenon happened when I focus on say the corner of the photo frame, holding the camera at 45 angle. the point of the corner is in perfect focus, then I can see the ghost image of the photo frame being out near the edge of the focus patch.... its almost as tho the focus patch is say 5 degrees rotated clockwise. I have never noticed it when I was out shooting, and i havent dropped the camera or anything..... i only have one lens so cant test out other lenses. is there something wrong with my cam/lens? or is it normal for RF focus patch to be not edge to edge mm perfect?? any other tests I can try?? cheers Link to post Share on other sites More sharing options...
Advertisement Posted May 6, 2011 Posted May 6, 2011 Hi derder, Take a look here do I have an alignment problem???. I'm sure you'll find what you were looking for!
george + Posted May 6, 2011 Share #2 Posted May 6, 2011 If you hold the camera at an angle to a flat subject it is possible that one side of the viewfinder patch will show a noticeably different distance from the subject than the other. Consequently there can be unalignment on one side of the patch or the other. Try to draw a plan view sketch of this and you will see the cause. Hope this is what you are finding. Enjoy your camera. Link to post Share on other sites More sharing options...
bpalme Posted May 8, 2011 Share #3 Posted May 8, 2011 Mine does this but I thought it was normal since parts of what you see in the patch are further apart at angles... I'm a newb so interested in answers here. Link to post Share on other sites More sharing options...
lct Posted May 8, 2011 Share #4 Posted May 8, 2011 If you hold the camera at an angle to a flat subject it is possible that one side of the viewfinder patch will show a noticeably different distance from the subject than the other. Consequently there can be unalignment on one side of the patch or the other... ...I thought it was normal since parts of what you see in the patch are further apart at angles... +1 Link to post Share on other sites More sharing options...
george + Posted May 9, 2011 Share #5 Posted May 9, 2011 Yes, normal. Not just possible. Sorry for the confusion, if any. But the good news is, your camera seems to behave normally. Link to post Share on other sites More sharing options...
jaapv Posted May 9, 2011 Share #6 Posted May 9, 2011 Note that you need to keep your eye in the optical axis to read the rangefinder correctly. If you hold the camera skewed and angle your eye off that axis you will get inaccurate results Link to post Share on other sites More sharing options...
ho_co Posted May 9, 2011 Share #7 Posted May 9, 2011 Advertisement (gone after registration) That's why Leica people are such straight shooters. Link to post Share on other sites More sharing options...
Guest #12 Posted May 20, 2011 Share #8 Posted May 20, 2011 Note that you need to keep your eye in the optical axis to read the rangefinder correctly. If you hold the camera skewed and angle your eye off that axis you will get inaccurate results source/explanation? thanks Link to post Share on other sites More sharing options...
Guest #12 Posted May 21, 2011 Share #9 Posted May 21, 2011 I have asked you several times in the past for a justification/source for this; if you don't have one, you shouldn't keep posting this. You can see if there is a significant error for yourself--with a tripod and naked eye. Link to post Share on other sites More sharing options...
lct Posted May 21, 2011 Share #10 Posted May 21, 2011 Off-axis viewing can affect coincidence RF accuracy perhaps (?) but i doubt it might have significant effect on split-image rangefinders. Link to post Share on other sites More sharing options...
chris_livsey Posted May 21, 2011 Share #11 Posted May 21, 2011 hi all, tonight I was just playing with it at home. and I noticed when I try to focus on, say a wall paining with lots of letters/words on it, not ALL letters in the VF focus patch is in perfect focus??? cheers I am not clear what you are saying here. Are you focussing on a flat painting on a wall but viewing at a 45 degree angle not straight on ? If you are straight on and the camera and wall are parallel then all the patch should be in focus at the same time. Note: the frame edge and painting may be sufficiently far apart (in depth) that if you focus on the frame edge which sticks out from the wall then the words on the painting itself which are further back may be out of focus and show a double image on the patch. If you are, as I read your post, looking at the wall from a 45 degree angle then if you focus on the nearest point of the painting with the left hand side of the patch the far end of the patch, right hand side, will show two images, out of focus. It is further away from your camera than the area you are focussed on. If you remain perfectly still and move (yes I know a contradiction but move the camera NOT you) the patch so the furthest area (RHS) is now over the area previously in focus with the LHS it should now show perfect focus. The patch is very, very sensitive, as is the point of focus in digital. The slightest misalignment will show. With the body/lens/sensor alignment we are talking of microns being significant. I am sure mathematically it can be shown how much difference in depth the rangefinder is sensitive to at a given distance. Just not by me I hope this helps, or if someone can phrase it better, and shorter please do so. Link to post Share on other sites More sharing options...
Guest #12 Posted May 21, 2011 Share #12 Posted May 21, 2011 sorry, maybe one of my posts above was not so diplomatic Link to post Share on other sites More sharing options...
Guest #12 Posted May 21, 2011 Share #13 Posted May 21, 2011 ...I am sure mathematically it can be shown how much difference in depth the rangefinder is sensitive to at a given distance. Just not by me ... ...we just did this one, actually. So, for example, at 0.7m, best viewing conditions, stock 0.68X magnification: +-4.5mm. (In theory.) Link to post Share on other sites More sharing options...
Guest #12 Posted May 22, 2011 Share #14 Posted May 22, 2011 I was also interested in the difference between using one edge of the patch or the other for focusing a perpendicular target...I didn't think it amounted to anything. I used approx. 0.7mm for the width of the cutout, which I got from the frameline anatomy thread, and found the discrepancy is always smaller than the rf accuracy; in other words, you would never notice the difference. 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/151078-do-i-have-an-alignment-problem/?do=findComment&comment=1678960'>More sharing options...
jaapv Posted May 22, 2011 Share #15 Posted May 22, 2011 I have asked you several times in the past for a justification/source for this; if you don't have one, you shouldn't keep posting this. You can see if there is a significant error for yourself--with a tripod and naked eye. Is forty years of experience not good enough? I have time nor inclination to delve into ancient books for you edification. For instand Jan Zwarts, het Leica Systeem, Haarlem 1967. If your look in skewed, you create a secondary angled optical axis, which coincides with the optical axis of the camera at the point you are focussing on. This will create a parallax error in the RF patches, which are virtually at 2.0 m. This parallax error will be zero at two meters only, of course. Draw your diagrams. Link to post Share on other sites More sharing options...
Guest #12 Posted May 22, 2011 Share #16 Posted May 22, 2011 Is forty years of experience not good enough? I have time nor inclination to delve into ancient books for you edification. For instand Jan Zwarts, het Leica Systeem, Haarlem 1967.If your look in skewed, you create a secondary angled optical axis, which coincides with the optical axis of the camera at the point you are focussing on. This will create a parallax error in the RF patches, which are virtually at 2.0 m. This parallax error will be zero at two meters only, of course. Draw your diagrams. thanks for the reply. I would expect anyone who focuses a rangefinder would also be interested in this topic; maybe they will back me up on this. Since the book is unavailable and in Dutch, maybe you would translate the relevant passage? Are you describing a diagram in the book? Link to post Share on other sites More sharing options...
jaapv Posted May 22, 2011 Share #17 Posted May 22, 2011 No it is just a user tip. However, it is quite easy to do your own test. Focus exactly on a clearly defined (for ease of seeing, you are not testing your focussing ability here) object about 15 m away. Now move your eye to the side of the ocular. You need to twist the camera to keep the subject in the middle of the Rf patch. Now you will see double contours appearing. Link to post Share on other sites More sharing options...
Guest #12 Posted May 23, 2011 Share #18 Posted May 23, 2011 1. I couldn't confirm the test, but it may just be me. There is a washout in the patch if the eye is much off center, that makes it hard to tell. I am just looking from a tripod. If you look at a frameline in front of a white piece of paper and move your eye around you see a "double image" of the frameline, but I don't think that is a true double image. Also, if you do some test where you "twist" the camera, you may get a double image because you have not maintained the distance. 2. Regarding the diagram, take the simplest case where a target is two points on the viewfinder axis separated by a distance. If you look down the vf axis and focus on the closest point A, you will then see one point in the patch. If you now look down another axis through point A you will see two points in the patch, but.... that is not a double image, that is two single images. A double image would have been more than two points. So there is no focusing error. Having said all that, it may turn out that you are right for some other reason, but so far I don't know. Thank you for getting the reference, I appreciate it. Link to post Share on other sites More sharing options...
lct Posted May 23, 2011 Share #19 Posted May 23, 2011 Off-axis viewings have never affected my RFs accuracy in 30+ years of practice i must say. Link to post Share on other sites More sharing options...
chris_livsey Posted May 23, 2011 Share #20 Posted May 23, 2011 No it is just a user tip. However, it is quite easy to do your own test. Focus exactly on a clearly defined (for ease of seeing, you are not testing your focussing ability here) object about 15 m away. Now move your eye to the side of the ocular. You need to twist the camera to keep the subject in the middle of the Rf patch. Now you will see double contours appearing. I am not doubting the optical effect you have described nor questioning the source but I will dispute that "it is quite easy to do your own test" I have tried and failed after twisting myself, my camera, glasses on/off, magnifier on/off. I am giving up now but as it was a problem I didn't know I had I can retreat back into my ignorance happy. I do hope we hear back from the OP, perhaps he (assumed) is measuring the frame and wall or has twisted his back trying all our recommended contortions. Link to post Share on other sites More sharing options...
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