Entering ALT mode from ubasic? +other questions

viktorzk

« on: 03 / March / 2009, 19:02:39 »

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Hello,

I am unable to enter ALT mode from ubasic on my IXUS 850 IS (SD800), using CHDK version 0.9.6-714.
Here is what I have tried:
Edit: After looking through the code, I guess this was a stupid question. My problem is that some ubasic commands don't work, and the script cannot automate through simple button presses what one can do manually in ALT mode. Hence some of the following questions.

And several other questions:
- Is there a way to toggle MF mode and to check if the camera is in it?
- Why does the set_aflock 1 command produce a parsing error? Is there any other command that locks focus?
- When review mode is set to "hold", the shoot command takes 32 seconds, around 30 of them in review mode. I tried it with two get-and-print-time statements around it, and a click "shoot_half" does not help. When review mode is off, shoot works fine. Any ideas why? And is there a way to change the review mode?
- When I change the focus manually, the SD indicator (the white one in misc) shows that only certain SD values can be set. Until 136, any value can be set, after that the gaps become wider and wider, resulting in 181 possible values from 63 to inf. Is this normal? I recorded the values and went through them for a second time, and they had changed slightly. The next day, the last value before inf had changed from 7280 to 5352, and most of the other possible values were around the midpoints of the 'gaps' in my initial recording. Why does this happen? Is there any way to force a certain SD? Is there any way to get the next allowed SD value?

Thank you in advance!

« Last Edit: 13 / April / 2009, 17:10:11 by viktorzk »

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IXUS 850 (SD800) 1.00e

viktorzk

Re: Entering ALT mode from ubasic? +other questions

« Reply #1 on: 13 / April / 2009, 17:02:17 »

Hello again,

Did I say anything wrong or forbidden? I hoped to get at least an "I don't know" answer! I realize that CHDK is free and nobody is obliged to do anything, but most threads get answers, and I am wondering if this one just went unnoticed.

Please excuse my impudence

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IXUS 850 (SD800) 1.00e

Microfunguy

4037

Re: Entering ALT mode from ubasic? +other questions

« Reply #2 on: 13 / April / 2009, 17:17:37 »

Quote from: viktorzk on 13 / April / 2009, 17:02:17

Please excuse my impudence

Of course

The fact that you are running a script means that you are in ALT mode !
[you edited your post while I was writing this]
As far as setting a precise subject distance is concerned, the Canon firmware decides the nearest value to move to.
As you focus further away the steps become bigger because the depth-of-field region is rapidly increasing.
Very close up, you can move one millimetre at a time.

To set manual focus mode your script needs to 'press' whatever buttons are needed on your camera.
You will then set a variable to a non-zero value to indicate you are in manual-focus mode.

Cannot answer your set_aflock 1, I do not use CHDK.

David

« Last Edit: 13 / April / 2009, 17:19:42 by Microfunguy »

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viktorzk

Re: Entering ALT mode from ubasic? +other questions

« Reply #3 on: 13 / April / 2009, 19:07:15 »

Dear David,
Thank you for the reply.

Quote from: Microfunguy on 13 / April / 2009, 17:17:37

As far as setting a precise subject distance is concerned, the Canon firmware decides the nearest value to move to.
As you focus further away the steps become bigger because the depth-of-field region is rapidly increasing.
Very close up, you can move one millimetre at a time.

When I try to set the focus to (for example) 1500, Canon decides that the nearest value is (for example) 1510. However, tomorrow I try again to set the focus to 1500, and Canon decides that the nearest value is 1507. Why is this difference?

Quote from: Microfunguy on 13 / April / 2009, 17:17:37

To set manual focus mode your script needs to 'press' whatever buttons are needed on your camera.
You will then set a variable to a non-zero value to indicate you are in manual-focus mode.

My camera does not officially support manual focus. The only way to manually change the focus is through ALT mode in CHDK.

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IXUS 850 (SD800) 1.00e

Microfunguy

4037

Re: Entering ALT mode from ubasic? +other questions

« Reply #4 on: 15 / April / 2009, 10:22:30 »

Quote from: viktorzk on 13 / April / 2009, 19:07:15

When I try to set the focus to (for example) 1500, Canon decides that the nearest value is (for example) 1510. However, tomorrow I try again to set the focus to 1500, and Canon decides that the nearest value is 1507. Why is this difference?

Well, these cameras have very short focal length lenses.
That means a tiny movement of the focus stepper motor can change the focused distance quite a lot.
I guess the precision of the mechanical movement is as good as it needs to be for normal use.
You will never set an exact value every time, what difference does it make anyway ?

Quote

Is there a way to toggle MF mode and to check if the camera is in it?
My camera does not officially support manual focus. The only way to manually change the focus is through ALT mode in CHDK.

I do not really understand this.
You want to toggle manual-focus mode but you are saying the camera does not have that mode !

David

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whoever

280
IXUS950

Re: Entering ALT mode from ubasic? +other questions

« Reply #5 on: 15 / April / 2009, 13:42:27 »

Quote

Is there a way to toggle MF mode and to check if the camera is in it?
My camera does not officially support manual focus. The only way to manually change the focus is through ALT mode in CHDK.

The F/W of cameras without regular MF mode often contains functions MFOn() and MFOff() that do the job to some extent. Checking the mode is through PropCase 133 (see http://chdk.wikia.com/wiki/PropertyCase), or by calling shooting_get_focus_mode() from C-code (returns 1 for MF, 0 otherwise).

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