Override subject dist.value? - General Help and Assistance on using CHDK stable releases - CHDK Forum

Override subject dist.value?

  • 4 Replies
Override subject dist.value?
« on: 08 / April / 2008, 13:22:53 »
Am totally new so have been trying to read the forums and use a few new CHDK features each day.

Have been trying to make some copies of  ~14 x 22 cm drawings and have a dedicated Target and setup to minimize variation.    My present  setup for A570  is Manual, Zoom 10mm, f5.0, IS off, Custom Timer 5 sec and 10 shot RAW JPG,  Subj.distance bracket.value 5 and Value Factor 1  with - Bracketing type because my previous Macro tests showed a tendency for this camera to focus further away than I was aiming with default autofocus.  The DOF Calculator values for Near and Far Limit  and lens to subject are shown in Misc.

The AllBest section concerning  Subj.distance bracket.value seems understandable to me.

No so concerning  Override subject dist.value?  "There is a view that this way to use manual focus several convenient than through standard slider with incomprehensible behavior Test results show that for small distances (macro range) and perform substantial shifts for at least 1 cm on the average not less than 5 cm, if you wish, you can make more accurate verification)"
and "This new changing of SD Override on-the-fly works in real-time. Meaning as you change the Subject Distance value it will update the lens focusing mechanism just as if you were using your camera's manual focusing controls. Interestingly, at wide-angle you can enter or make use of Super-Macro Mode focusing distances, without having to engage the special Super-Macro Mode feature on your camera."  CHDK firmware usage/AllBest - CHDK Wiki

Seems very useful and would like to know how to use this feature.



Re: Override subject dist.value?
« Reply #1 on: 08 / April / 2008, 17:51:26 »
Clarification: "my previous Macro tests showed a tendency for this camera to focus further away than I was aiming with default autofocus."  Should have said I have the default Safety MF on (p47 Canon A570IS Advanced User Guide).


Re: Override subject dist.value?
« Reply #2 on: 09 / April / 2008, 01:31:49 »
« Last Edit: 22 / April / 2008, 16:58:28 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye

Re: Override subject dist.value?
« Reply #3 on: 09 / April / 2008, 02:45:58 »
I think it is very clear if you go through the "CHDK firmware usage/AllBest". It is a method to change focus distance with each step as low as 1mm. In s3is if you set the FL to 36mm, you can focus from inf (or something like 65m) right till 0mm without engaging super macro mode in 1mm steps, if you want so. After setting the basic focus, you can set "Bracketing in Continuous Mode" for some value for subject distance and shoot merrily through custom timer setting.

Take printout of "CHDK firmware usage/AllBest" and read at your leisure.

It is a great feature even for copying your slides and negatives, if you can bear the distortion at 36mm. (Yes I know that you can use a longer FL with closeup lens).

Re: Override subject dist.value?
« Reply #4 on: 19 / April / 2008, 11:37:34 »

Maybe part of my confusion with this is I have an A570IS and do not know if I can use all, part, or none of this option?

You seem to have some idea what it can do so would you please explain how to use it with an A570.




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