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Flashes, CHDK and Canon Powershot SX40 HS

Started Aug 2, 2013 | Discussions
gt13013 New Member • Posts: 8
Flashes, CHDK and Canon Powershot SX40 HS

Hello.

In brief: I have 3 external (non Canon) flashes that behave oddly with my SX40 HS. If you have a SX40 or SX50 and a Canon compatible flash, I would like to know how it behaves. I have explained the problem in detail on this page, and suggest to put the results on the same page:

http://www.editgrid.com/user/gt13013/Canon_SX40_HS_and_flashes

In detail: I want to use CHDK combined with a motion detection program and an external flash. The problem comes from the fact that this program simulates an halfway press on the shutter button, and with my 3 external flashes (Olympus, Vivitar, Nikon), the halfway press on the shutter button makes the screen completely dark, which prevents the motion detection from working. Since the internal flash of the SX40 does not behave the same way, perhaps a Canon compatible flash would behave as the internal flash, and in that case I will buy it.

Thanks for reading

Canon PowerShot SX40 HS
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reyalp Regular Member • Posts: 201
Re: Flashes, CHDK and Canon Powershot SX40 HS

gt13013 wrote:

Hello.

In brief: I have 3 external (non Canon) flashes that behave oddly with my SX40 HS. If you have a SX40 or SX50 and a Canon compatible flash, I would like to know how it behaves. I have explained the problem in detail on this page, and suggest to put the results on the same page:

I don't think your problem is directly related to this, but just FYI, there is a known problem where having an external flash (or anything that triggers the switch in the hot shoe) mounted prevents CHDK exposure overrides from working. This happens on sx40 and other recent cameras with external flash support.

PhilM oz Senior Member • Posts: 1,350
Re: Flashes, CHDK and Canon Powershot SX40 HS

gt13013 wrote:

Since the internal flash of the SX40 does not behave the same way, perhaps a Canon compatible flash would behave as the internal flash, and in that case I will buy it.

Both the 580EX and 90EX work correctly (same as internal flash).
I suspect any Canon flash that supports ETTL will work the way you want.

With the latest version of CHDK you can also enable ETTL flash mode when the camera is set to M mode. The Canon menu only allows manual flash power setting; but CHDK can override this to allow the flash power to be calculated during the shot.

Phil.

OP gt13013 New Member • Posts: 8
Re: Flashes, CHDK and Canon Powershot SX40 HS

reyalp wrote:

gt13013 wrote:

In brief: I have 3 external (non Canon) flashes that behave oddly with my SX40 HS. If you have a SX40 or SX50 and a Canon compatible flash, I would like to know how it behaves. I have explained the problem in detail on this page, and suggest to put the results on the same page:

I don't think your problem is directly related to this, but just FYI, there is a known problem where having an external flash (or anything that triggers the switch in the hot shoe) mounted prevents CHDK exposure overrides from working. This happens on sx40 and other recent cameras with external flash support.

OK. Thanks

OP gt13013 New Member • Posts: 8
Re: Flashes, CHDK and Canon Powershot SX40 HS

PhilM oz wrote:

gt13013 wrote:

Since the internal flash of the SX40 does not behave the same way, perhaps a Canon compatible flash would behave as the internal flash, and in that case I will buy it.

Both the 580EX and 90EX work correctly (same as internal flash).
I suspect any Canon flash that supports ETTL will work the way you want.

With the latest version of CHDK you can also enable ETTL flash mode when the camera is set to M mode. The Canon menu only allows manual flash power setting; but CHDK can override this to allow the flash power to be calculated during the shot.

Phil.

Thanks for the information. With this new information in mind, I reconsidered the problem and I have found a solution.

1) Probably one solution would be to get a recent Canon Compatible flash. I will perhaps do it when the editgrid tablewill receive some data

2) Staying with my old flashes, I realized that there is an option in the motion detection script that I use (the script is MDFB-080914-VideoButtonModels.bas ). This option allows to suppress the halfway shutter button pressing during the motion detection. With that option, the LCD display stays clear, and the motion detection works.

Regards. Gerard

OP gt13013 New Member • Posts: 8
Re: Flashes, CHDK and Canon Powershot SX40 HS

Since the editgrid website has closed, the interested people can now find the spreadsheet here . If you want to contribute, add your contribution and contact me. I will update the file.

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