Test - HDR with s90 and CHDK

Here's a quick test using my s90 and the CHDK exposure bracketing with the built-in timer. Just to see, I shot a 9 exposure bracket with RAW - merged and finished in PSCS5.

This is cool for a couple of reasons - 1) the s90 now has better built-in bracketing than my 5D. 2) the scene itself was not so remarkable, but the data captured from it allowed me to relight the scene. Originally this was an overcast gray sky outside - I tried to go for a golden, sundrenched look. I converted the RAWs in DXO to TIFF (DXO has s90 modules) then PSCS5 merge and finish.

Just another reason to love the mighty s90.

Kirk

Here is the 0EV JPEG, FYI.

Kirk

I just put CHDK on my SX100IS, though I haven't had time to play with it much yet. Nice to see some decent results with it. So am I hearing you right that you set it up to automatically shoot 9 bracketed shots with just one push of the shutter, set with your timer on?

Yes. The s90 has a timer function that permits the user to set the timer interval (countdown) and the number of shots to fire. This is a normal function of the s90. CHDK permitted me to specify bracketing based on shutter speed, at 1 ev intervals. If I set the s90 timer to wait 1 second and fire 9 shots, and I use CHDK to specify 1 ev bracketing, with increasing shutter speeds (increasing meaning higher denominator or shorter time) then I push the shutter release and the camera takes 9 exposures, starting at the brightest exposure (the one I set in Manual mode prior to initiating the capture) and taking progressively darker exposures until all 9 are shot. If you set the normal canon option to capture raw+jpeg, then you will end up with 9 raw (and jpeg) in order, from brightest to darkest exposure, which is also preferable to the 0,-,+ bracketing order.

Kirk

Interesting. I have to check my camera when I get home as to whether it has the capability to set the number of shots to fire, or if CHDK provides this as an option. I'm pretty sure that my original firmware does not provide this capability, so hopefully CHDK does as one of its many options. All other aspects of what you accomplished I can do with the aid of CHDK. Glad you got yours to work out. I'll post up if I get mine to.

Jon

Also - check to see if someone has written a script to perform the same thing. THen you can just load the script on our card, set up the script parameters and run it, hands off.

Hope to see the results! I am going to try another few tests - I'll post here. The really nice part is, I have a tiny tripod (about 10" tall) and the s90 with this bracketing ability - ultraportable portable compared to lugging around the 5D, a full size tripod and head, etc., etc. It is nice that DXO has s90 modules to remove distortion and lens artifacts - no luck on PSCS5, otherwise I would go start to finish in ACR-PS. Not that the distortion is a super big deal, I'm just saying....

It is also nice to have a camera that shoots RAW (as opposed to having to use CHDK 10bit RAW) that is supported by ACR, etc. I found that a CHDK RAW solution for me, being a mac user, was to shoot with the DNG option enabled and use Raw Developer to convert my RAWs to TIFFs for merging.

Kirk

I will check for the script, thanks. I have a small tripod too and agree when on the go this presents a great portable solution. Especially if I can get the camera to take multiple shots.

One snag I ran into was with my SD card. Are you using a SD card over 2 Gb? If so, how did you format and partition it? and did you make it bootable? I have a 4 gig card which is normally in this camera, but so far I can't get past this. I've been testing with an old 512 card, but it would be nice to get over this hurdle.

Jon

Update. I got my 4 GB card formatted, but now the RAW images are not being read by PS or LR.....damn, it's always something. BTW, jpg's off the card are fine, so I don't believe this has anything to do with the card formatting. Also was able to get my camera to shoot multiple shots at various shutter speeds.

The RAW format written by chdk is not compatible with ps, acr, lr. Go to the chdk wiki for suggested raw decoders. Dcraw will work, as well as variants of it. You might also try enabling save raw as dng. I assume that your camera does not shoot raw natively?

Good thing is, if you are intending to use the chdk raws for hdr, you can just use dcraw from the command line and make them linear 16 bit tiffs in a batch, a great starting point for feeding your favorite hdr app.

Keep at it, you're almost there.

Kirk

kirkt wrote in post #10779304
Yes. The s90 has a timer function that permits the user to set the timer interval (countdown) and the number of shots to fire. This is a normal function of the s90. CHDK permitted me to specify bracketing based on shutter speed, at 1 ev intervals. If I set the s90 timer to wait 1 second and fire 9 shots, and I use CHDK to specify 1 ev bracketing, with increasing shutter speeds (increasing meaning higher denominator or shorter time) then I push the shutter release and the camera takes 9 exposures, starting at the brightest exposure (the one I set in Manual mode prior to initiating the capture) and taking progressively darker exposures until all 9 are shot. If you set the normal canon option to capture raw+jpeg, then you will end up with 9 raw (and jpeg) in order, from brightest to darkest exposure, which is also preferable to the 0,-,+ bracketing order.

Kirk

hi Kirk
could you please explain where you get the native interval function on the S90? I only see a 3 pict-bracketing option. Is it with CHDK that you get that ?
thanks

The exposure stepping is from CHDK - the prescribed number of shots in your bracket (ie, 3, 5, 7 etc) is from the built-in s90 timer. On the rear of the camera, you push the directional pad down, i think (i don;t have the camera in front of me) to get to the timer menu. There is a timer mode that permits you to prescribe the countdown and the number of shots to fire once the countdown is reached. So, with the built-in timer/shot count feature you prescribe the number of shots in your bracket, with CHDK you prescribe the change in exposure between each shot. With the s90, you can shoot in the Canon RAW format (instead of the CHDK RAW format) so you can use all of your favorite RAW converters - now, with the Lightroom 3.2/ACR 6.2 update, s90 lens correction profiles are available as well. DXO has had these for a while, but now you can do your entire HDR in PSCS5 if you want.

Kirk

thanks kirkt