chdk manual focus override equivalents (sx50, sx40)

tonyb

« on: 07 / August / 2013, 17:36:49 »

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When using chdk manual focus override. How do I know what to enter for film equivalents: 24mm, 28mm, 35mm, 50mm, 100mm and 135mm. Is it possible to set the zoom at those steps from chdk's menu?

« Last Edit: 07 / August / 2013, 17:45:31 by tonyb »

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philmoz

3070

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #1 on: 07 / August / 2013, 18:23:04 »

You're confusing subject distance (focus) with field of view (zoom).

CHDK allows you to override subject distance in the Extra Operations menu; but there is no override for the zoom position.

Phil.

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CHDK ports:
sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
g12 (1.00c, 1.00e, 1.00f & 1.00g)
sx130is (1.01d & 1.01f)
ixus310hs (1.00a & 1.01a)
sx40hs (1.00d, 1.00g & 1.00i)
g1x (1.00e, 1.00f & 1.00g)

waterwingz

11478

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #2 on: 07 / August / 2013, 18:31:13 »

Quote from: tonyb on 07 / August / 2013, 17:36:49

When using chdk manual focus override. How do I know what to enter for film equivalents: 24mm, 28mm, 35mm, 50mm, 100mm and 135mm. Is it possible to set the zoom at those steps from chdk's menu?

If you go into the CHDK settings -> OSD settings -> Miscellaneous Values menu and then:
1) select Show Misc Values to [Always]
2) select Show Zoom [ * ]
3) set Zoom Value to [ EFL ]
you can have the CHDK OSD display the 35mm equivalent "Effective Focal Length" value of your zoom settings.

Then just use the camera's zoom lever to adjust zoom position like normal, using the OSD reading as a guide.

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Ported : A1200 SD940 G10 Powershot N G16

tonyb

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #3 on: 07 / August / 2013, 19:21:56 »

I guess there isn't a way to set field of view (zoom) steps from chdk's menu

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reyalp

11339

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #4 on: 07 / August / 2013, 21:57:17 »

Quote from: tonyb on 07 / August / 2013, 19:21:56

I guess there isn't a way to set field of view (zoom) steps from chdk's menu

No, but you can probably do it from a script using the set_zoom function http://chdk.wikia.com/wiki/CHDK_scripting#set_zoom_.2F_set_zoom_rel_.2F_get_zoom_.2F_set_zoom_speed

Out of curiosity, why would you want to set it from the CHDK menu rather than using the built in controls?

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tonyb

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #5 on: 07 / August / 2013, 23:38:14 »

Quote from: reyalp on 07 / August / 2013, 21:57:17

Quote from: tonyb on 07 / August / 2013, 19:21:56
I guess there isn't a way to set field of view (zoom) steps from chdk's menu

Out of curiosity, why would you want to set it from the CHDK menu rather than using the built in controls?

Just to start the camera at a certain zoom step which is always the same. And that I want the camera to keep. But, yes I can use the zoom buttons, although the steps aren't very precise.

What do I use with set_zoom(?) for 24mm, 28mm, 35mm, 50mm, 100mm and 135mm. Is there table somewhere?

Thanks all!

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waterwingz

11478

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #6 on: 07 / August / 2013, 23:44:35 »

Quote from: tonyb on 07 / August / 2013, 23:38:14

Just to start the camera at a certain zoom step which is always the same. And that I want the camera to keep. But, yes I can use the zoom buttons, although the steps aren't very precise.

You can tell CHDK to always run a script at startup - which would let you have the zoom go to your defined position each time the camera starts ( you'll need to have the script switch to shooting mode to do that)

Quote

What do I use with set_zoom(?) for 24mm, 28mm, 35mm, 50mm, 100mm and 135mm. Is there table somewhere?

You camera will have a fixed number of zoom steps. Most simple cameras have 8-12 steps from one end of the range to the other - the megazooms have a lot more. They are not tied to any 35mm camera equivalent - more just a division of the zoom lens mecha range into equal size chunks.

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Ported : A1200 SD940 G10 Powershot N G16

Fotoni

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #7 on: 08 / August / 2013, 05:31:32 »

You also could adjust zoom speed via script? So the steps won't be so fast when using the zoom lever. I have that same problem with IXUS 300 HS because the lever is just clumsy for precise adjusting and have to go forward and backward many times to get 50mm EFL. Slower zooming would be a problem though, if you want to reach maximum zoom as fast as possible.

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tonyb

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #8 on: 08 / August / 2013, 10:08:10 »

Quote from: Fotoni on 08 / August / 2013, 05:31:32

the lever is just clumsy for precise adjusting and have to go forward and backward many times to get 50mm EFL. Slower zooming would be a problem though, if you want to reach maximum zoom as fast as possible.

Fotoni, that is correct, the zoom lever is just clumsy and precise adjusting takes time.
May be this can be added to the chdk menu in the future. For now using Zoom Value to [ EFL ] somehow helps.

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waterwingz

11478

Re: chdk manual focus override equivalents (sx50, sx40)

« Reply #9 on: 08 / August / 2013, 10:09:17 »

Quote from: Fotoni on 08 / August / 2013, 05:31:32

You also could adjust zoom speed via script?

You can certainly write a script that will watch the zoom lever and move the lens at any speed you desire when the lever moves. However, you will still only get a finite defined number of discrete steps but you code things so that there is a longer delay between taking each step - allowing you more time to release the zoom lever.

Also, there currently there is no way to also activate a "half-press" or "full_press" using the shutter release button while a script is running, so you would have to assign other buttons to those functions in your script. Not very convenient if you are trying simply trying to change the zoom speed.

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Ported : A1200 SD940 G10 Powershot N G16