@anyone
When I get a chance I will attempt to measure this myself, but until then, does anyone know th reference plane for the focus distance reporting?
That is the sensor or the lens principal plane?
I know it won't make that much difference in calculating depth of field etc, but I'm being picky ;-)
Cheers
Garry
Sensor plane!
:-)
Thanks
There is usually a marking on the camera for that. I see them on my AE1, 5D3 and 7D2. It is a circle with a horizontal line through the middle.
@rpt
I needed to confirm that ML Lua reporting was referenced to the sensor ;-)
I needed to do this as the DoF equations I use are referenced to the lens principal plane, i.e. about a focal length difference, which for macro becomes important.
Cheers
Garry
Oh dear! So you will need a table of lens and the distance of the principal plane from the sensor. But then you knew that already :)
@rpt
Yes, an 'impossible' task, so I'm simply going to use the focal length as an approximation.
After all, the distance between the sensor and the principal plane of the lens, for non-macro work, is insignificant compared to the principal plane of the lens to the focus distance; especially for wide angle work.
Also, the depth of field equations are already an approximation, i.e. assuming a simple, thin lens and ignoring the pupil magnification.
Cheers
Garry