Originally posted by fulcrumx29 I used a chart that the focus is on a black-wight contrasty line, so I think the focus is on where it should be. But I observe the phenomenon that focus will get further back on smaller apertures on FA 50, DA 16-45, and Nikon AF50/1.4d. At wider apertures, the focus distance changes fast and slower ans slower when small apertures were taken. Mostlikely, smaller than 2.8 the item would be in focus. However, the focus error will enlarge when the subject is far away. For example, my 16-55 won't focus in infinity at f4. I got to do more test on smaller apertures to make a conclusion.
If you are interested, would you like to take a similar test? Just simply change aperture and you may find the focus center move backwards. It sould be interesting if you have spot on focus in most apertures, which still means I got a lemon lens or body.
Many thanks,
Tony
Somewhat unlikely it's the body since it focuses wide open, then
stops down the lens. Sounds like focus plain shifting with the aperture.
diglloyd: A Brief Introduction to Focus Shift Focus shift is a displacement of the sharp plane of focus when the lens is focused wide open, but the image is made with the lens stopped down.
Quite literally, the optimal plane of focus moves, depending on aperture! With every lens I’ve tested to date, the focus moves farther away.