rpsawin Posted June 4, 2020 Share #1 Â Posted June 4, 2020 Advertisement (gone after registration) I have three Konica Hexanon M lenses (28/2.8. 35/2 Â 50/2). and would appreciate any info on how to detect back focusing. IÂ would like to use these lenses on both a digital and various film Leica bodies. Thanks in advance for your help. Best regards, Â Bob Link to post Share on other sites More sharing options...
Advertisement Posted June 4, 2020 Posted June 4, 2020 Hi rpsawin, Take a look here How to detect back focus. I'm sure you'll find what you were looking for!
jdlaing Posted June 4, 2020 Share #2  Posted June 4, 2020 The Simple Way to Check Backfocus Place a Siemen's Star Chart on a Wall. ... Position the camera at level height about 10 feet away. ... Mount a zoom lens or mid-range prime lens. ... Open up the iris of the lens all the way. ... Focus by eye using a viewfinder or monitor. ... Check to see if your eye focus matches the lens marking.   Link to post Share on other sites More sharing options...
jankap Posted June 4, 2020 Share #3 Â Posted June 4, 2020 And look if the range finder "agrees". Naturally with your M8! Â Link to post Share on other sites More sharing options...
Alberti Posted June 4, 2020 Share #4  Posted June 4, 2020 How I do it? Take a picture wide open such as a portrait, at close range (i.e. 70cm) and keep the RF spot in the center. In digital you get feedback, but focus should be the same, in digital you can see it. I film you have a thicker emulsion, so focus is more forgiving, specially in e.g. Tri-X. For me the M-8 was very critical; the M240 is easier but it's apparent precision much tighter. The M9 is handsome in use. never used film next to digital though. To test focus I tried in the past using rulers and edges but it always made me nervous - what am I doing? Once I want to Will van Manen Kamera-Service in Zoetermeer with a Canon 1.4. I told him one shot is heaven, the next one hell. Oh he said, typical old grease. The lens then jumps. He relubed it and secured the focus and it is marvelous, spot on. So. Best thing to do is send your set of lenses to such a repair sevice! He adjusted various of my older lenses. To check focus myself, I take a picture, and then check with a tool like Capture One if the focus is right spot on. C1 is very good for this, specially if you still happen to have an older low res monitor. In this example I focussed on the eye brows. It is a Jupiter-3 known for haphazard focus, but this one has been adjusted at F1.5 for close focus. 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! It came out quit well. Soft like a Sonnar, very practical plane of focus. Some lenses have an uneven plane of focus, for example my M-Rokkor 40mm. The edges focus to the back (towards infinity) , wide open. Some Leica designs do that too. Don't try a Siemens chart because it will make you crazy. No lenses are equal all over (or go for the new Leica designs, I have one that has the same quality all over at all diafragms . . . you only use the diaphragm for effect, not sharpness, and then a chart is OK. Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! It came out quit well. Soft like a Sonnar, very practical plane of focus. Some lenses have an uneven plane of focus, for example my M-Rokkor 40mm. The edges focus to the back (towards infinity) , wide open. Some Leica designs do that too. Don't try a Siemens chart because it will make you crazy. No lenses are equal all over (or go for the new Leica designs, I have one that has the same quality all over at all diafragms . . . you only use the diaphragm for effect, not sharpness, and then a chart is OK. ' data-webShareUrl='https://www.l-camera-forum.com/topic/310276-how-to-detect-back-focus/?do=findComment&comment=3986998'>More sharing options...
Alberti Posted June 4, 2020 Share #5  Posted June 4, 2020 And with an EVF you can check and the two forms of focussing, but use a tripod! Millimeters count. Even with a wide angle. But it is not half as good as Capture one. Link to post Share on other sites More sharing options...
J.Nordvik Posted June 4, 2020 Share #6  Posted June 4, 2020 Print this: https://www.fotosav.ru/articles/faq/back_focus/back_focus_testing.aspx 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/310276-how-to-detect-back-focus/?do=findComment&comment=3987111'>More sharing options...
jaeger Posted June 4, 2020 Share #7  Posted June 4, 2020 Advertisement (gone after registration) aim one of the keys on your keyboard at 45 degrees. Link to post Share on other sites More sharing options...
jaapv Posted June 4, 2020 Share #8 Â Posted June 4, 2020 I think that the best test is to judge the focusing on a larger number of your photographs. If they show a systematic back focus and you are sure that your focusing technique is correct, it is time to send your camera and lenses to a trusted repair shop. Messing about with rulers and targets is second-guessing the expert who has to correct the system anyway IMO. Link to post Share on other sites More sharing options...
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