finkaudio Posted February 23, 2007 Share #1 Posted February 23, 2007 Advertisement (gone after registration) Hi, I came across a very strange effect and I’m wondering if somebody got an idea what to do. On my last trip to LA, I took a CV 15mm with me to play with. ( together with a black M8 I had on loan from my dealer after I paid for mine already) After I came back, I noticed that all of those 15mm shots of landscapes have been out of focus/very soft. I used the typical hyperfocal distance setting method. Today - same lens, but new M8 – I tried again in my office. A newspaper in 2m distance was focused with the scale on the lens. 4.5 – no problem. 5.6 – also no problem. Nice and sharp. As a last experiment, I set the hyperfocal distance. I used F8, so I did set it to 5.6 to get one the safe side, following an article in Luminous Landscape. And as a result, the picture was soft/out of focus. Any idea what that could be? I have no problems with other lenses and the owner of the 15mm keeps telling me his pictures on a Bessa are very sharp. Here is a crop of one of those shots I did in January with F8 Best regards Karl-Heinz Fink Link to post Share on other sites More sharing options...
Advertisement Posted February 23, 2007 Posted February 23, 2007 Hi finkaudio, Take a look here Focus problems with CV15mm on M8. I'm sure you'll find what you were looking for!
stunsworth Posted February 23, 2007 Share #2 Posted February 23, 2007 Hi Karl, depth of field is so large with the 15mm that if your other lenses are ok I'd say it's either the lens or the screw to M adaptor that's the problem. I've used my M8 and Voigtlander 15mm quite a bit and had no problems. Link to post Share on other sites More sharing options...
finkaudio Posted February 23, 2007 Author Share #3 Posted February 23, 2007 Hi Steve, I tried several adapter, so that should not be the problem. Best regards Karl-Heinz Link to post Share on other sites More sharing options...
jaapv Posted February 23, 2007 Share #4 Posted February 23, 2007 There are some out-of spec adaptors being sold on e-bay. Could that be it? Link to post Share on other sites More sharing options...
thpeters Posted February 23, 2007 Share #5 Posted February 23, 2007 Hi Karl, I had in the beginning of this week the same problems as you, I brought the Voightlander back to the store and bought the ASPH 35 mm. 1:2 Now my pictures are sharp. Theo Link to post Share on other sites More sharing options...
stunsworth Posted February 23, 2007 Share #6 Posted February 23, 2007 Hi Karl, I picked a 15mm shot more or less at random. I've attached a full size image and 100% crop. Please don't judge the image, it's had no work done on it at all - and probably doesn't deserve any :-). I think the lens has acceptable sharpness considering the cost. 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/17022-focus-problems-with-cv15mm-on-m8/?do=findComment&comment=180715'>More sharing options...
finkaudio Posted February 23, 2007 Author Share #7 Posted February 23, 2007 Advertisement (gone after registration) Hi Steve, I think the lens design is OK, maybe just my copy is bad. Theo, did you have the problem also on the 15mm?? BTW, I only use original Leica adapter. I bought a few of the old ones early enough Best regards Karl-Heinz Link to post Share on other sites More sharing options...
robsteve Posted February 23, 2007 Share #8 Posted February 23, 2007 Karl: Try just putting the lens at infinity. Hyperfocal focusing doesn't work well on digital. You will also find the 15mm sharpest at f6.3. It shows this in the MTF curves and from my personal tests with the M8. In the closer ranges, I did some tests to find exacly where 2m is on the focus. Even shooting at f8, the difference between having the focus set to the middle of the 2m mark or slightly to one side or the other will creat soft pictures compared to having the focus right. There is an argument for rangefinder coupling even wide lenses like the 15mm VC. This is one reason I would not spend a lot of money on the new Zeiss 15mm. Since it too is not rangefinder coupled, half your pictures will not be critically sharp. Particularily if shooting people up close. Here is a scenic shot. I probably had it on infinity. The frost on the rocks in the foreground is still acceptably sharp. Robert Link to post Share on other sites More sharing options...
finkaudio Posted February 23, 2007 Author Share #9 Posted February 23, 2007 Hi Robert, I'll definately give it a try. Thanks! I also ordered another copy, as the one I tested was not mine anyway. Best regards KH Link to post Share on other sites More sharing options...
robertwright Posted February 24, 2007 Share #10 Posted February 24, 2007 So this is my question, I was hoping to use the cv15 for interior work, which would mean most of the field is not at infinty. but somewhere between 2 and 4 meters. Do you (robsteve) think that if I throw out some sharpness by shooting at 11 or 16 I can get acceptably sharp pics with zone focusing, or is it going to be hit and miss? Karl: Try just putting the lens at infinity. Hyperfocal focusing doesn't work well on digital. You will also find the 15mm sharpest at f6.3. It shows this in the MTF curves and from my personal tests with the M8. In the closer ranges, I did some tests to find exacly where 2m is on the focus. Even shooting at f8, the difference between having the focus set to the middle of the 2m mark or slightly to one side or the other will creat soft pictures compared to having the focus right. There is an argument for rangefinder coupling even wide lenses like the 15mm VC. This is one reason I would not spend a lot of money on the new Zeiss 15mm. Since it too is not rangefinder coupled, half your pictures will not be critically sharp. Particularily if shooting people up close. Here is a scenic shot. I probably had it on infinity. The frost on the rocks in the foreground is still acceptably sharp. Robert Link to post Share on other sites More sharing options...
robsteve Posted February 24, 2007 Share #11 Posted February 24, 2007 So this is my question, I was hoping to use the cv15 for interior work, which would mean most of the field is not at infinty. but somewhere between 2 and 4 meters. Do you (robsteve) think that if I throw out some sharpness by shooting at 11 or 16 I can get acceptably sharp pics with zone focusing, or is it going to be hit and miss? I used the 15mm for interiors and it worked fine. This was on film. If you practise a bit and figure out the depth of field, it should be no problem shooting at F8 and getting decent sharpness. You will just have to do some tests and figure out where the lens should be set. As I said earlier, the hyperfocal shooting is not accurate. I am on vacation now, but have the 15mm with me. If I get a chance tomorrow, I will try shooting the condo interior and see how it works. Robert Link to post Share on other sites More sharing options...
robertwright Posted February 24, 2007 Share #12 Posted February 24, 2007 thanks that would be tremendous. Buying the WATE is like buying another M8... Link to post Share on other sites More sharing options...
finkaudio Posted February 24, 2007 Author Share #13 Posted February 24, 2007 Hi, following the discussions from yesterday, I tried again and shot some tests also on infinty. Mmmh, looks like Robert was right. On infinity setting, I get much sharper results. F8, focus infinity Now F8, hyperfocal setting on F8 Now F8, hyperfocal setting on 5.6 And even 5.6 on infinity looks not bad But what does this mean? Hyperfocal setting does not work on M8 or my 15mm is a bad copy?? Best regards Karl-Heinz Link to post Share on other sites More sharing options...
finkaudio Posted February 24, 2007 Author Share #14 Posted February 24, 2007 ..........I tried the same with the CV21. F8, focus infinity Now F8, hyperfocal setting on F8 Now F8, hyperfocal setting on 5.6 Funny enough, it looks like I have the same result with the 21. Maybe somebody can make a test as well. Should be important to know if the hyperfocal thing still works or not on my M8. Or is there something wrong with my thinking?? Best regards Karl-Heinz Link to post Share on other sites More sharing options...
sergiolov Posted February 24, 2007 Share #15 Posted February 24, 2007 The CV 15, when working correctly, is a very sharp lens, and absolutely tolerant, due to the huge depth of field, of the position of the focusing ring. The examples you posted ,with thigs getting better if you set the lens to infinity,seem to suggest that the lens is farther from the focus plane than it should be. I suggest trying a shot( with the lens on infinity) of a scene including details from a pair of feet to infinity, to determine if there is a point in focus. If so, the lens is probably not totally set in the camera. Otherwise, bad copy. (did you use a different adapter with the 21?) Sergio Link to post Share on other sites More sharing options...
dkreithen Posted February 24, 2007 Share #16 Posted February 24, 2007 There is nothing wrong with the lens or body. What you are seeing is that you are violating the assumptions used in calculating the depth-of-field scale that is on the lens. Remember, a lens is perfectly focussed only at a single distance. Everything else that is assumed to be sharp (within the depth-of-field) relies on an assumption of a certain circle-of-confusion figure which is used in the calculations. By looking at the image at 100% (which is equivalent to some huge print size) you are demanding that, to be sharp, the circle of confusion must be much smaller than that assumed for the calculation of the depth of field scale on the lens. If you really want it to be sharp at such huge magnifications, then you must recalculate the depth-of-field scale and the "sharp" region of focus will be much smaller. Or, simply print the picture at reasonable sizes (for example, approximately that used in the assumption) and it will look sharp. Link to post Share on other sites More sharing options...
sergiolov Posted February 24, 2007 Share #17 Posted February 24, 2007 There is nothing wrong with the lens or body. What you are seeing is that you are violating the assumptions used in calculating the depth-of-field scale that is on the lens. Remember, a lens is perfectly focussed only at a single distance. Everything else that is assumed to be sharp (within the depth-of-field) relies on an assumption of a certain circle-of-confusion figure which is used in the calculations. By looking at the image at 100% (which is equivalent to some huge print size) you are demanding that, to be sharp, the circle of confusion must be much smaller than that assumed for the calculation of the depth of field scale on the lens. If you really want it to be sharp at such huge magnifications, then you must recalculate the depth-of-field scale and the "sharp" region of focus will be much smaller. Or, simply print the picture at reasonable sizes (for example, approximately that used in the assumption) and it will look sharp. What you say is correct, but generic. In this case, due to the great depth of field of the CV15, the usable depth of field extends from 3 feet to infinity. The following images are CV15 at 5,6 set to 2 meter mark. 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/17022-focus-problems-with-cv15mm-on-m8/?do=findComment&comment=181479'>More sharing options...
mwalker649 Posted February 24, 2007 Share #18 Posted February 24, 2007 I just recieved my cv 15 and the 21 mm view finder. The lense is very sharp at 5.6 at infinity. The 21mm view finder however has its frame lines at a 45 degree angle, not horizontal or vertical. I guess I need to send that back. Link to post Share on other sites More sharing options...
finkaudio Posted February 24, 2007 Author Share #19 Posted February 24, 2007 There is nothing wrong with the lens or body. What you are seeing is that you are violating the assumptions used in calculating the depth-of-field scale that is on the lens. Remember, a lens is perfectly focussed only at a single distance. Everything else that is assumed to be sharp (within the depth-of-field) relies on an assumption of a certain circle-of-confusion figure which is used in the calculations. By looking at the image at 100% (which is equivalent to some huge print size) you are demanding that, to be sharp, the circle of confusion must be much smaller than that assumed for the calculation of the depth of field scale on the lens. If you really want it to be sharp at such huge magnifications, then you must recalculate the depth-of-field scale and the "sharp" region of focus will be much smaller. Or, simply print the picture at reasonable sizes (for example, approximately that used in the assumption) and it will look sharp. Hi Daniel, I "discovered" the problem because I could see it on a 4x6 print Best regards KH Link to post Share on other sites More sharing options...
lct Posted February 24, 2007 Share #20 Posted February 24, 2007 ...As a last experiment, I set the hyperfocal distance. I used F8, so I did set it to 5.6 to get one the safe side, following an article in Luminous Landscape. And as a result, the picture was soft/out of focus... Forgive my question, but in front of which distance marking did you set it to f/5.6? Infinity? Link to post Share on other sites More sharing options...
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