Archived posting to the Leica Users Group, 2016/12/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks Frank, I'm familiar with the wide-open DOF, as I take most photos with the 90 'cron at f2. I've been using it for around a dozen years, and it's been spot-on all that time, till recently. My 50 'cron and 90 tele-elmarit are both focussing absolutely spot on in multiple focus tests, and they were calibrated two or three years ago by Leica in Germany. I'm afraid I can't borrow an M240 here in fairly rural Japan, andrenting from Tokyo would be too expensive. I'm now thinking that perhaps my best course is to send the repair man my M9 and ask if he can adjust the 90 'cron so that it focusses properly on my camera. Can you see any problem with this route? Peter Take some time to test it right.... First of all, you realize that the DOF for a 90mm lens at F2, at 5 feet away, is roughly an inch? Using the M9 in question, and a tripod, focus using the RF on the pencil. Shoot, Refocus and shoot again, several times. Move the focus ring from infinity to the correct focus,, and also from 3 feet to the correct focus point. Evaluate all the test shots on your computer in the center of the image, at 1:1. Try to mentally average the good ones. If the shot is out of focus, you have 2 possible problems: the lens or the camera is wrong. Beg, borrow, or steal (rent?) a M240. Repeat as above. In addition, use Live View to check your result. Live View represents the sensor. Use a magnifying glass ( loupe is preferred) to evaluate the LV output. If the result using the M240 is correctly focused, either in the Live View or the output file, the problem is with the M9 body. If it not correctly focused with the M240, and especially if the actually focus point is the same between the 2 cameras files shows the same WRONG focus plane for both bodies, then it probably is the lens. It is unlikely that 2 different camera bodies RF are both off. And especially off by the same amount. Now the wild card... some lenses have focus shift with changing Fstops or with distance. Is the 90 Summicron one of them????? DAG charged me $100 each or so to collimate a couple of lenses I had that were funky ( including a 75 f1.4, whose DOF is the same at 5 feet and F1.4) Frank Filippone Red735i at verizon.net My 90 Summicron is front-focussing on my M9. A colleague recommended an independent repair man proficient with Leica lenses (this is in Japan). The repair man emailed me back to say the lens is fine and his machine says the focus is fine too, so probably my camera is in error, perhaps the distance meter, rangefinder or the mount. Thing is, Leica replaced my sensor in July, and I haven't used it much in the four months since. The camera seems to be fine. Last night I took some focus test shots with my other lenses wide open and focusing on the 25cm mark of the ruler where the pencil tip is pointing: https://www.flickr.com/gp/geordiepete/5r3ce9 OK, I didn't use a tripod, and I could have made the test more rigorous, but it's still clear that those lenses are spot on wide open. I couldn't test the 90 Summicron at the same time, as it is in another city with the repair man. However, I made many tests with it before I sent it off, both in real-life situations, and with rulers. It wasn't the kind of error that only shows up with rulers. I'm not into that kind of photo. The lens was clearly front-focussing to a large degree, so that a portrait wide open would always be unusably out of focus. I'm thinking, the repair man must be wrong, so I'll ask him to send me the lens back, and I'll ship it out to Leica. But they might say the same thing! If my camera is at fault, it looks like Leica should repair it free, as they recently replaced the sensor. But my other Leica lenses (plus the 35/1.2 Voigtlander) are all spot-on. I'm beginning to worry that to get my 90 Cron working properly on my camera might be very expensive indeed, as I might have to send the camera and all lenses together to be examined. Does anyone have any good advice? Peter