Correct.
Macro extension tubes are here to increase the distance between sensor and lens, so that lens could focus on objects that are closer.
There is formula:
1/FL = 1/A +1/B
where A and B are distances between optical centre of the lens and object and sensor.
If you work it out a bit, you will see how it works...
Last edited by bojan; 06-01-2009 at 09:33 PM.
|