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Open Camera Controller >> OCC Developer Zone >> Software to control exposure length
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Message started by Trogdor420 on 03/11/09 at 18:19:29

Title: Software to control exposure length
Post by Trogdor420 on 03/11/09 at 18:19:29
Quite often I find myself taking nighttime photos using my camera's Bulb setting and shutter extension cable in the locked position.  I was wondering, how difficult it would be to write a program that would let you control the duration of an exposure when the camera is set at 'B"?  Would anyone else find a program like this useful?

JM

Title: Re: Software to control exposure length
Post by steve on 03/11/09 at 20:17:11
I think you are describing a control that acts as a single-function trigger?  I'd been thinking about implementing that but I currently just set a shutter speed on one of the test buttons of the bracketer and use that to trigger each shot. If you could confirm that you want just a shot length and a trigger, I can whip that up, or are you describing a trigger that must be held down for the duration of the shot? That is easily doable as well. (I should probably write both?)

Title: Re: Software to control exposure length
Post by Trogdor420 on 03/12/09 at 22:45:15
Basically, a simple program that will let me control the duration of an exposure with my camera set in 'B' mode.  For instance, say I am taking pictures of the night sky and I want a 4 minute long exposure.  I would like something that would essentially replace the need for me to lock my shutter release and manually time the exposure.  

JM

Title: Re: Software to control exposure length
Post by phoomp on 06/19/10 at 05:34:15
Did something like this ever get implemented?  I'd like to use OCC as a remote to shoot bulb shots (open shutter when shutter-release is pressed, close shutter when shutter-release is depressed).

If this is implemented, how do you do it?  I haven't been able to figure it out.

Title: Re: Software to control exposure length
Post by Martin Clark on 06/19/10 at 13:02:21
i was actually thinking about this the other night... when i was testing star trails exposure...

i exposed for 4mins. @ f4.0... using the hdr program "test" thing

this means clicking it every time it has done, and opening your ds in pitch black darkness might change your exposure (especialy if you have something  you want to dodge in the foreground)

your intervalometer works great for the re-exposing part but, but it doesnt control the exposure lenght... if it does it only does a minimum bulb exposure on my camera (issue? mmm yes)

so your intovalometer needs to be changed somewhat to adapt to this feature (or make a long night exposure version)

witch is an intervalometer with bulb exposure control

maybe a 90s-40mins(2400s)(max exposure you can do without sensorburn) in 10s increments?

Title: Re: Software to control exposure length
Post by Steve Chapman on 06/21/10 at 21:56:26
This must have been lost in the ether, but it should be easily implemented. I'm off to Arizona for a week of filming, I'll bring the dev system along to see if I can find the time to code this. I'm assuming you'll want an on-off toggle and a clock display? Should the gui be red for night vision?

Title: Re: Software to control exposure length
Post by Martin Clark on 06/21/10 at 23:30:26
yes, that might help, even if its only aesthetic value (and red takes longer for the eyes to adjust because its the darkest colour)

Title: Re: Software to control exposure length
Post by phoomp on 06/22/10 at 05:35:37
I could see a couple ways of doing it:
a) press button to open shutter, press button to close shutter.
b) press and hold button to open shutter, release button to close shutter

'b' replicates typical SLR behavior (and good for exposures under 5 seconds), but 'a' would be nicer for longer exposures.

Ideal might be for the application to be able to differentiate between a press and a press-and-hold and support both behaviors (ie: a press that lasts longer than 1.5 seconds = press-and-hold). But, recognizing that might be too much to ask for, I'd say 'a' (press to open, press to close).

As for the colour, red for night vision would be perfect (toggle to normal would be a nice-to-have, but there will be few times that long exposures would be used in good light).

This is awesome!  Thanks!

Title: Re: Software to control exposure length
Post by phoomp on 06/30/10 at 03:53:39

wrote on 06/22/10 at 05:35:37:
... blabber ...

Sorry ... the interface designer in me popping out
:-[

Title: Re: Software to control exposure length
Post by phoomp on 07/30/10 at 01:30:23
Is there any way that I can help with this?

(interface designer with some small knowledge of html and wpf)

Title: Re: Software to control exposure length
Post by Steve Chapman on 07/30/10 at 05:40:24
I should apologize, I should have coded this, I just can't find a free minute. I'll be spending a few days on the HMS Surprise next week, and I promise I'll find the time to write this during long nights on deck.

Title: Re: Software to control exposure length
Post by Steve Chapman on 07/30/10 at 05:41:55
Btw, Phoomp, you simply need to download the C source from the OCC link at the top of the page.

Title: Re: Software to control exposure length
Post by Steve Chapman on 08/10/10 at 22:33:20
Here's where it's at.



The executable:
http://PanoCamera.com/Releases/latch.nds

Title: Re: Software to control exposure length
Post by phoomp on 08/28/10 at 23:23:49
Awesome!  I really like the ability to set the delay length and the shot length.

Would it be possible to add the ability to open the shutter with a button press and close it with another button press? (I'm thinking specifically about photographing fireworks, where you may not know exactly how long you want the shutter to be open)

Title: Re: Software to control exposure length
Post by Yogie on 04/06/11 at 15:35:52
Hi,

I like the latch.nds homebrew but I wish it would be extended and adds behaviors like a common remote offer such features like the Canon RS-80N3 or TC80N3.

Not only for the bulb mode! As well for focusing and triggering the shutter release in any program and camera mode.

Cheers

Yogie

Title: Re: Software to control exposure length
Post by Yogie on 04/07/11 at 05:05:56
Another neat thing would be nice to have with latch would be an ND filter calculator to calculate the long term exposure.  :)

I think there are still more things to come ...  ;D

Cheers

Yogie

Title: Re: Software to control exposure length
Post by Yogie on 06/06/12 at 07:05:27
OK, meanwhile I wrote my own program for that :-)

Anyhow I still wonder if we only can trigger a full pressed release or if it would be possible to send a half way pressed trigger signal as well? But I think I will ask this anywhere else in the forum.

Cheers
Joerg

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