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hyperfocal distance and my SX100

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Offline shinnen

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hyperfocal distance and my SX100
« on: 26 / October / 2018, 09:58:02 »
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Hi,
      I'm reading an article now, about hyperfocal distance and how it relates to DOF. Does CHDK have any settings relating to hyperfocal distance, wrt to my SX100?
Thanks,
..... john
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Offline msl

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Re: hyperfocal distance and my SX100
« Reply #1 on: 26 / October / 2018, 13:04:07 »
=> http://chdk.wikia.com/wiki/CHDK_1.4.0_User_Manual#Camera_Key_Usage_with_CHDK

Use MF. Enable CHDK ALT mode. With the down key you get the hyperfocal distance.

msl
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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #2 on: 26 / October / 2018, 13:43:41 »
Quote from: shinnen on 26 / October / 2018, 09:58:02
Does CHDK have any settings relating to hyperfocal distance, wrt to my SX100?
CHDK scripts can query the current hyperfocal distance with get_dofinfo( ) (Lua) or get_hyp_dist( ) ] (uBASIC) and then call the set_focus( ) function to use that value.

You can also display the current hyperfocal distance via the CHDK OSD ( DOF Calculator )
« Last Edit: 26 / October / 2018, 13:47:28 by waterwingz »
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #3 on: 27 / October / 2018, 19:41:49 »
Great! I'll check those out.
Thanks,
.... john
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #4 on: 29 / October / 2018, 11:53:56 »
I think I'm doing something wrong. Do I just copy what's below, name it get_dofinfo.lua, and run it? If so, I'm not getting anything.
.... john
dof=get_dofinfo()
 
  • dof.hyp_valid [boolean] - Is hyperfocal distance valid?
  • dof.eff_focal_length [x 1000 mm] - 35mm equivalent focal length
  • dof.coc [x 1000 mm] - circle of confusion
  • dof.aperture [x 1000] - aperture
  • dof.near [mm] - near limit
  • dof.min_stack_dist [mm] - smallest meaningful stack distance
  • dof.dof [mm] - DOF
  • dof.focal_length [x 1000 mm] - focal length
  • dof.hyp_dist [mm] - hyperfocal distance
  • dof.far [mm] - far limit
  • dof.focus [mm] - focus distance
  • dof.focus_valid [boolean] - Is focus valid?
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #5 on: 29 / October / 2018, 19:35:42 »
Quote from: msl on 26 / October / 2018, 13:04:07
=> http://chdk.wikia.com/wiki/CHDK_1.4.0_User_Manual#Camera_Key_Usage_with_CHDK

Use MF. Enable CHDK ALT mode. With the down key you get the hyperfocal distance.

msl
Hi msi,
      Well, I managed to get the camera to display the 5 DOF values, with the help of your link.
When I rotate the adjustment wheel, in MF, all of the values change, except for the HYP value, which stays at 2.51. I assume that at some point one of the values will tell me when I have hit the hyperfocal length?
..... john
« Last Edit: 29 / October / 2018, 19:37:59 by shinnen »
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Offline waterwingz

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hyperfocal distance and my SX100
« Reply #6 on: 29 / October / 2018, 19:55:14 »
For a given f-stop, the hyper focal number is fixed. Unless you change the f-stop it won't change.  Note that changing the zoom position changes the f-stop.

So adjust the focus manually until the focus setpoint equals the displayed hyper focal distance.
« Last Edit: 29 / October / 2018, 19:56:54 by waterwingz »
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #7 on: 29 / October / 2018, 22:31:37 »
Hi,
      So, basically, I have to guess when the hyper focal distance is the same as the focus set point; because the focus readout is a bar, and doesn't give any numbers. In the case of 2.51, I would have to guess which of the 4 divisions between 2 and 5 is closest to 2.51. Am I missing something here?
.... john
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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #8 on: 29 / October / 2018, 22:37:31 »
I haven't looked at it in a while but you can get both the current focus setting and hyper focal distance displayed numerically.  In fact, I've never seen a bar unless you are talking about the Canon OSD widget and not something CHDK displays.

I'll find one of my cameras and take a look for you.

Incidentally, the depth of field on these little cameras is huge.  You're probably not going to find anything magical about the hyper focal distance value. 
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #9 on: 30 / October / 2018, 09:28:36 »
Hi waterwingz,
          "...but you can get both the current focus setting and hyper focal distance displayed numerically." Yes, I think I had that when I activated the DOFcalculator in CHDK, which showed S/NL/FL/DOF/HYP :.388/.336/.407/.099/2.51 for example (in MF); but I couldn't figure out how to set the HYP, except by guessing it's location on the bar.
           "In fact, I've never seen a bar unless you are talking about the Canon OSD widget and not something CHDK displays." Yes, you're right. When I deactivated CHDK the bar was still there.
           "Incidentally, the depth of field on these little cameras is huge.  You're probably not going to find anything magical about the hyper focal distance value." Well, perhaps I'm wasting my (and your) time then?
Thanks,
.... john 
« Last Edit: 30 / October / 2018, 09:30:43 by shinnen »
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