next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Printable Version +- Opticallimits (https://forum.opticallimits.com) +-- Forum: Forums (https://forum.opticallimits.com/forumdisplay.php?fid=4) +--- Forum: Micro-Four-Thirds (https://forum.opticallimits.com/forumdisplay.php?fid=16) +--- Thread: next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro (/showthread.php?tid=1006) |
next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Klaus - 11-04-2015 Quote:It matters because the measurement was at close focus, so the effect might seem worse there than in "reality"? See the sample images. The borders are softer than the MTFs suggest. I think you should get over the idea that the measurements are close focus. The object magnification is FAR beyond anything that you would consider to be a close focus scenario. Close focus ends a 1:10. At some stage I calculated this - was it 1:50 ? Something like this. The object magnification is the same across all tested lenses. In any case it just doesn't matter here - the field curvature is visible at infinity. If I didn't spot this in the sample images I wouldn't have reported it (plus/minus human error that can always occur even during measurements). The MTFs are the beginning of wisdom but not the end of it. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - davidmanze - 11-04-2015 I would assume there is touch screen AF in LV, it would probably be sufficient to tap focus at 1/3rd in from the edge of the screen to achieve hyperfocus @7mm AF without all the guess work scenarios for distant scenes. For my Sigma @ 10mm as the AF at inf. was totally variable I just put a point of paint on the barrel when I had established inf. (non window Pentax version) and focused manually. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Boby - 11-04-2015 Quote:The test chart is at around 51x the focal length distance. For 7mm that means around 7 x 51 = 35,7mm distance.Rather 36 cm, but thanx. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Klaus - 11-05-2015 Quote:Rather 36 cm, but thanx. Actually this is incorrect - it's about 50cm. Object size = 900mm Image size = 13mm Object distance = 500mm -> focal length 7mm for MFT Reference: http://www.giangrandi.ch/optics/focalcalc/focalcalc.shtml 0.5m is also the hyperfocal distance at 7mm @ f/5.6, BTW. The hyperfocal distance at 7mm @ f/2.8 is 1.1m. Hyperfocal distance = depth-of-field of half that distance to infinity - assuming a flat focus field that is. Reference: http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm And the hyperfocal has very little to do with macro photography. It is a guidance for landscape photography. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Brightcolours - 11-05-2015 Quote:Actually this is incorrect - it's about 50cm.You once wrote that the testing distance is 51x the focal length (that that is not the case apparently, is not on me). Besides that I forgot to take the crop factor into account, which was silly. Hyperfocal distance should be a thing of the past. Unless one dislikes getting the best results. It is a theory from when print size and resolution usually were limited. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Klaus - 11-05-2015 Quote:You once wrote that the testing distance is 51x the focal length (that that is not the case apparently, is not on me). Besides that I forgot to take the crop factor into account, which was silly. You still wouldn't go for infinity focus for best results either. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Brightcolours - 11-05-2015 Not taking any field curvature into account, indeed focussing at the horizon/infinity/main subject gives the best results. http://www.trenholm.org/hmmerk/DOFR.html next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Klaus - 11-05-2015 Quote:Not taking any field curvature into account, indeed focussing at the horizon/infinity/main subject gives the best results. He's talking about maximizing the depth-of-field which is a different discussion compared to critically sharp foreground corners. In an ultra-wide image I find sharp foreground corners to be paramount - thus where you see object details - whereas I can live with a somewhat less sharp infinity region which is blurred by the atmosphere anyway - thus where the details are reduced anyway. Your mileage may vary. next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Guest - 11-06-2015 Any comments on the purple fringing i mentioned in post #4 ? next PZ lens test report: Olympus M.Zuiko 7-14mm f/2.8 Pro - Boby - 11-06-2015 afaik there is a certain mismatch between Olympus and Panasonic regardings the transmisssion/detection of very short wavelengths (UV or near UV). Anecdotally, the PF appears therefore mainly when using a Panasonic lens on Olympus camera (or/and vice versa - I am not quite sure here). |