Minimum focus distance - Tamron 70-300

[flippedgazelle]

How is the minimum focus distance of a lens calculated? From the edge of the barrel? The mounting point? The back of the camera?

Anyhoo, according to the manual, the minimum focus distance of my Tamron 70-300mm is 37.4", when using "macro" mode. However, I've been able to determine that when manually focusing, I can focus on an object 26" away from the end of the barrel. This equates to about 32.5" away from the mounting point, and 34.5" from the eyecup.

This is at 300mm.

/shrug

[axl]

As far as I know, the minimal focusing distance is calculated from the medium (in your case the sensor of the camera). This should (used to) be marked at the bottom of the camera but I haven't seen this mark on any recent Pentax body. Usualy the tripod mount is in the line with this, but it's not necesary. But I'd say the tripod mount is the closest guestimate.

BR
Peter

PS: anybody, feel free to correct me if I'm wrong and given misleading info

[flippedgazelle]

Originally Posted by axl

As far as I know, the minimal focusing distance is calculated from the medium (in your case the sensor of the camera). This should (used to) be marked at the bottom of the camera but I haven't seen this mark on any recent Pentax body. Usualy the tripod mount is in the line with this, but it's not necesary. But I'd say the tripod mount is the closest guestimate.

BR
Peter

PS: anybody, feel free to correct me if I'm wrong and given misleading info

Good stuff - thanks for the info.