See also: http://chdk.setepontos.com/index.php?topic=12102.msg118725#msg118725I do not understand why we define a minimum and maximum for the subject distance.set_focus(0) returns the minimal subject distance und a too large value for set_focus() returns infinity (-1). There is no risk for wrong results without limits.There are a lot of cameras whose subject distance range is greater than 65,535 - most of the SX series. But not all of these cameras have a special definition for CAMERA_MAX_DIST.Also the setting of the hyperfocal distance is affected when the calculating a value greater than 65,535 gets. Probably all cameras, where the hyperfocal distance is greater than 65,535, have a larger range for the focus distance.msl
Cam FL F COC Hyp CAM_MAX_DISTSX1 100,0 5,7 0,005 350977 65535SX10 100,0 5,7 0,005 350977 65535SX20 100,0 5,7 0,005 350977 66490SX30 150,5 5,8 0,005 781194 9090910SX40 150,5 5,8 0,005 781194 9523810SX50 215,0 6,5 0,005 1422523 9523810SX60 247,0 6,5 0,005 1877447SX100 60,0 4,3 0,005 167502 65535SX110 60,0 4,3 0,005 167502 65535SX120 60,0 4,3 0,005 167502 65535SX130 60,0 5,6 0,005 128631 65535SX150 60,0 5,6 0,005 128631 65535SX160 80,0 5,9 0,005 217029 65535SX170 80,0 5,9 0,006 180871 65535SX200 60,0 5,3 0,005 135909 68447SX210 70,0 5,9 0,005 166172 65535SX220/230 70,0 5,9 0,005 166172 2000000SX240/260 90,0 6,8 0,005 238325 1550000SX270/280 90,0 6,8 0,005 238325 65535SX400 129,0 5,8 0,005 573957SX500 129,0 5,8 0,005 573957 65535SX510 129,0 5,8 0,006 478319 65535SX520 180,6 6,0 0,005 1087393
I think the correct setting of the hyperfocal distance is especially important for good landscape shots.
As regards the focussing, I have found that the focus override / subject distance varies from camera to camera (even new un-molested ones). To produce relevant Subject distance figures I simply produce a plank of wood with paper stickers at 25mm intervals to produce a chart of values that relate to focussed images at the 25mm intervals. Generally I have found that once the distance exceeds 500mm its pretty accurate. Its the smaller distances that need the attention. every camera I own except the older models such as a530 are all inaccurate regarding subject distance so I produce a true subject distance chart for each. I recently purchased 2 A4000's both new and both are different, but produce identical pictures once used with the true subject distance from my charts.
...Except that the last year of working with Canon's MF capability (especially in smaller cameras without built-in MF) has let me to believe this is an uncalibrated function. So supplying the set_focus() with a hyperfocal distance will not necessarily give you a shot focussed there. Canon AF looks for the sharpest image - it doesn't care about the actual distance. And that's what people use 99% (or more) of the time.
I dismantled the ixus 117 again, screwed in the 3 screws of the sensor (bringing the sensor plane nearer to the lens) and voilà, setting focus to infinity via script or menu now works fine on wide angle.
Not sure if i definitely will transform the ixus 117 into a cheap infrared camera
Canon AF looks for the sharpest image - it doesn't care about the actual distance. And that's what people use 99% (or more) of the time.
Still I think that the general limitation of the maximum subject distance (65535) is not quite correct
Started by Chris710
Hello, I'm a NEWBIE - HELP!! (Newbies assistance, User Guides and thank you notes)
Started by cppasm
Started by funnel
General Discussion and Assistance
Started by Geezer
General Help and Assistance on using CHDK stable releases
Started by l_d_allan