Well after shooting almost a year with my tamron 17-50 on my pentax camera, i do sometimes feel that my camera/lens is not focusing on the right target. So being a lazy person, i decided to do some calibration on this lens after a year. Did read up some guide in CS forum / youtube on how to calibrate. Although i do not have the optimum equipment (spyder calibration tools), i try to use a ruler on a white back grounded. Camera mounted on tripod adjusted to my so call 45 degree angle.
focus is on the 2inch on the ruler.
As per guide, people recommend to do a micro adjustment based on tele of the zoom lens (my case is 50mm) as DOF is more critical when focal length is at its tele range instead of wide. But i do find that on wide, it back focus too much when my tele is on focus. What do you guys think. Will making a trip to Tamron service Centre solved this problem or will they just blame it on camera issue and ,y way of testing?
50mm at default (front focus)
50mm at -10 micro adjustment ( spot on.. to my standard very happy almost going to celebrate)
switch to wide angle and test
17mm at -10 micro adjustment (alamak back focus.. WTH)
17mm at default (change to default.. oei not bad although still got a bit of back focus)