This is in the manual focus mode.
If I focus my lens so that a certain object is clear and crisp, and then do one of the following, will I have to focus again?
- Change the aperture
- Switch to a different lens that has the same focal length (such as switching from a 19mm prime to a 18-105 and zooming to 19mm)
- Change the focal length by zooming
- Change the focal length by switching to another lens
Will I need to re-focus? Am I correct in understanding that I have to re-focus in cases (3) and (4)?
Let's assume that the focal point is beyond the minimum focusing distance of the lens.
This is with reference to a Sony NEX-5R, with three lenses (in case it matters): a 19mm f/2.8 prime, a 35mm f/1.8 prime, and an 18-105 f/4 constant aperture zoom. I usually shoot in aperture priority mode.