john_pete Posted October 15, 2018 Share Posted October 15, 2018 hi there. I just got a pentax 67 with a 105 mm 2.4 version lll. Ive been taking 3 rolls of film and gottrn maybe 4 sharp images all taken close portrait from breast and up. But but..im more interested in shooting full body but when i fo that.. regardless of any aparture its not getting sharp at all. I aim for the face at sparture 2.4, 4, 5.6, 8 and non is in focus. I even use tripod. Only when i move up close i can get sharp images at 2.4 and so on. I use portra 160. As soon i move further away to get fullbody they becom unsharp/ out of focus. What the heck am i doing wrong? I attached images so you can see what i mean. Thanks for any good surgestions. The first is up close and ok sharp and in focus. The other i move away to get full body..and it gets unsharp. These are just test shots, i did some other yesterday i better light but the same result. Link to comment Share on other sites More sharing options...
john_pete Posted October 15, 2018 Author Share Posted October 15, 2018 First one shot at 2.4 , second one at 5.6 on trpod both Link to comment Share on other sites More sharing options...
tom_chow Posted October 15, 2018 Share Posted October 15, 2018 From the full length shot, the picture looks front focused. I perform a focus test using a setup like this: Wide open, clear flat object with contrast, and a pane to see where the lens is focusing (similar to the focus calibration tools you can buy). This screen was front focusing slightly, not really noticeable when using F4~F2.8, but obvious with an F2 lens. I would determine this first. If focus is good, then it's time to look at the lens. "Manfred, there is a design problem with that camera...every time you drop it that pin breaks" Link to comment Share on other sites More sharing options...
Silent Street Posted October 16, 2018 Share Posted October 16, 2018 (edited) There are a lot of things to come to grips with, and to understand with the Pentax 67. Has the focusing screen been removed at some time? When this has been done, the screen must be calibrated in three places around the central spot for focus at near and far distances. ? Possible broken meter coupling chain If the meter coupling chain has been repaired (breakage is common and requires disassembly of the front of the camera for access) , both the lens mount flange and the focusing screen will then require joint calibration with a collimator, again for accuracy of focus. Regarding this last item, read this sticky I prepared on the pentaxforums.com site re prevention of breaking the meter coupling chain: https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/372838-advisory-pentax-6x7-67-meter-coupling-chain-ttl-meter-prism.html The 105mm f2.4 lens is reasonably robust, but should be also be checked independently of the camera for any misalignment that may have been occasioned through eg dropping. Edited October 16, 2018 by Silent Street Garyh | AUS Pentax 67 w/ ME | Swiss ALPA SWA12 A/D | ZeroImage 69 multiformat pinhole | Canon EOS 1N+PDB E1 Kodachrome, Ektachrome, Fujichrome E6 user since 1977. Ilfochrome Classic Master print technician (2003-2010) | Hybridised RA-4 print production from Heidelberg Tango scans Link to comment Share on other sites More sharing options...
john_pete Posted October 16, 2018 Author Share Posted October 16, 2018 Thanks tom. Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted October 16, 2018 Share Posted October 16, 2018 (edited) Definitely a front focussing issue. From the description and pictures, it's due to a displacement of the focussing screen of around 0.25mm*, or an angular displacement of the mirror. Not sure it can be due to lens mount mis-assembly, because surely that would affect both the film-plane and viewing-plane equally? So first thing I'd check is the seating of the focussing screen. Maybe there are shims missing? To get front focussing, the viewing screen would need to be closer to the lens than the film-plane. So that rules out dirt under the screen, and makes it look more like user-meddling or incompetent 'repair'. You might also want to check if the lens apparently focuses 'beyond infinity'. I'm guessing it might. * A 0.25mm constant focussing error changes the plane-of-focus by almost 1 metre at 6 metres subject distance, but by less than 100mm when the subject is at 1.5 metres. Hence the better close-up than distant focussing. Edited October 16, 2018 by rodeo_joe|1 Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted October 16, 2018 Share Posted October 16, 2018 Another thought occurred to me, too late to edit. I've had lenses with a sloppy or jerky helicoid, that just wouldn't hold focus when the focussing grip was released. The lens would 'pop' out of focus when I took my hand away. This turned out to be simple lack of grease in the helicoid from normal wear and aging. Does the lens focus feel excessively loose or sloppy? Can you feel any play in the focus grip if you push or pull it? If so, then the lens needs a CLA. Link to comment Share on other sites More sharing options...
paul ron Posted October 16, 2018 Share Posted October 16, 2018 diopter? without a lens, look through the viewfinder. can you see the markings on your focusing screen? are they sharp? The more you say, the less people listen. Link to comment Share on other sites More sharing options...
john_pete Posted October 17, 2018 Author Share Posted October 17, 2018 Ok thanks guys! Link to comment Share on other sites More sharing options...
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