>> K5-II +/- exposures have large errors, in AEB mode >>
Long exposures appear to have large errors, using AEB mode.
Also, even for the same starting point, two different photo
sets, can have actual +/- exposures that are different.
Strange but true.
Some examples for my Pentax K5 II with FW v1.04 follow.
The values are for a fixed aperture and ISO setting.
Ex1, Theoretical plus Actual exposure:
0EV = 1.0, 1.0
-1EV = 0.5, 0.8 (error=+60%)
+1EV = 2.0, 3.0 (error=+50%)
-2EV = 0.25, 0.30 (error=+20%)
+2EV = 4.0, 5.0 (error=+25%)
Ex2, Theoretical plus Actual exposure:
0EV = 1.0, 1.0
-1EV = 0.5, 0.8 (error=+60%)
+1EV = 2.0, 3.0 (error=+50%)
-2EV = 0.25, 0.40 (error=+60%)
+2EV = 4.0, 6.0 (error=+50%)
Ex3, Theoretical plus Actual exposure:
0EV = 2.0, 2.0
-1EV = 1.0, 0.8 (error=-20%)
+1EV = 4.0, 2.5 (error=-38%)
-2EV = 0.5, 0.4 (error=-20%)
+2EV = 8.0, 6.0 (error=-25%)
Ex4, Theoretical plus Actual exposure:
0EV = 1.0, 1.0
-1EV = 0.5, 0.6 (error=+20%)
+1EV = 2.0, 2.5 (error=+25%)
-2EV = 0.25, 0.25 (error= 0%)
+2EV = 4.0, 4.0 (error= 0%)
Ex5, Theoretical plus Actual exposure:
0EV = 1/400, 1/400
-1EV = 1/800, 1/800 (error=0%)
+1EV = 1/200, 1/200 (error=0%)
-2EV = 1/1600, 1/1600 (error=0%)
+2EV = 1/100, 1/100 (error=0%)
Ex6, Theoretical plus Actual exposure:
0EV = 1/400, 1/400
-2EV = 1/1600, 1/1600 (error=0%)
+2EV = 1/100, 1/100 (error=0%)
-4EV = 1/6400, 1/6400 (error=0%)
+4EV = 1/25, 1/25 (error=0%)
Any comments?
Thanks in advance