A Impromptu/Cheap Luxmeter Alternative: Measuring Lux With a Canon Camera and CHDK

[electrothump]

Be sure that the file is in the root directory of the SD card and not in a sub directory.

Another thought is that you might want to try a new or reformatted card just in case.

Be sure there is a photo on the card and that the last image is not a video.

If that fails could you describe step by step what you did?

I'm not sure why, but with a new card it worked fine. Thanks for the help.

DN

 

[csshih]

what was the size of your card?

CDHK doesnot support over 4GB, and 4GB will have to formatted in FAT16.

 

[zcaiyb]

Very nice. I cannot wait to buy a Canon Camera

 

[electrothump]

what was the size of your card?

CDHK doesnot support over 4GB, and 4GB will have to formatted in FAT16.

If you are asking me the size of the card that didn't work, it's just a regular ole 2 gig Lexar Platinum 60X. I've tried it since I got the new one working, and that one just doesn't wanna do it. It still stores images okay. I did the format thing using CardTricks, and I didn't get any error messages. Dunno!

DN

 

[csshih]

huh.. strange.. I have no idea.

well, what measurements are you guys getting? I'm still curious on how accurate this method is.

 

[656nm]

A camera light meter is likely to be within a few percent of the value from a good dedicated light meter. If it was not, the cameras would be taking bad pictures and people would be returning them.

If anything, the camera is probably more accurate than many of the low end meters out there. The key thing to getting good numbers is reproducibility of the procedures used to get your results.

 

[jirik_cz]

I already use Canon camera with CHDK firmware for measuring runtimes. More info here. Posts #9 and #13.

 

[csshih]

Thanks for the info!

 

[Rexlion]

It was really interesting to come across this mention of CHDK being used to measure flashlight beam lux. Neat! I've been using SDM (Stereo Data Maker), which incorporates CHDK, on a pair of Canon cameras to take stereoscopic (3D) photo pairs for the last year or so. It's nice to know that I can put the software to an additional use.

 

[csshih]

always fun to play around with new stuff, but I've noticed a problem recently,
Seems with über high output lights, the reading is pretty innacurate, so I'll stick with single die lights for now

 

[Bonky]

wouldn't you have to shine the beam directly into the camera rather than bounce it?

 

[TITAN1833]

I'm not sure why, but with a new card it worked fine. Thanks for the help.

DN

thanks for the rip!,now I have got to get one of those canons ,and BTW MrGman already gave the best tip

 

[travelinman]

Does anyone know if this downloadable software will work for a SLR digital rebel? I've an older one that is running digic II software now.

 

[Justin Case]

http://chdk.wikia.com/wiki/CHDK

 

[csshih]

wouldn't you have to shine the beam directly into the camera rather than bounce it?

seems it doesn't work as well that way.

I appears that the camera isn't meant to be pointed directly at extremely bright light sources.


CHDK is not supported for any DSLR, as it was meant to expand on the software of point and shoot devices.

I think the developer didn't see a need to have more advanced features already on DSLRs..

 

[travelinman]

http://chdk.wikia.com/wiki/CHDK

Tnx ....It appears the firmware hasn't been "ported" yet, (whatever that means) for the Canon EOS 350D. :mecry:

 

[cue003]

This is a canon only capability? Do other cameras have something similar?

 

[Rexlion]

This is a canon only capability? Do other cameras have something similar?

AFAIK it's just certain Canons, those models that some enterprising people have been able to dump the firmware and figure out how to integrate this additional program that boots from the SD card. Search for the CHDK wiki for a list of supported models.

 

[elwood]

I can't seem to get the luminance value to display. I'm using an SD1000 with firmware 1.01A.

I've tried cycling power a few times and even messed with the OSD layout editor.

Any suggestions?

EDIT: I figured it out. You have to set "show misc values" to "always or shoot".

 

[js-lots]

Is canon the only camera that can do this. I have a sony T500 and was wondering if there are any of these firmware hacks for the sony. Thanks