PowerShot SX220 HS - Porting Thread - page 9 - General Discussion and Assistance

vit40

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Re: PowerShot SX220 HS - Porting Thread

« Reply #80 on: 26 / May / 2011, 04:48:09 »

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Thanks, funnel. I don't need zebra / overlay anyway. I have 3 more questions:

- is autoloading of chdk working with this camera (with up to 4 GB card)
- is old style chdk raw saving working (I don't use dng as chdk raw is faster)
- is video compression adjustable (or any other differences versus older cameras saving mjpeg)

And 2 questions about out-of-the box video mode (without CHDK)

- is it possible to apply exposure shift without locking the exposure (it's not clear to me from page 119 of the manual) and is it also working during movie recording or has to be pre-set before starting recording
- is it possible to use manual focus (and what's about usage of Set button to do refocus when using CHDK)

Thanks

« Last Edit: 26 / May / 2011, 04:51:06 by vit40 »

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funnel

349

Re: PowerShot SX220 HS - Porting Thread

« Reply #81 on: 26 / May / 2011, 07:09:10 »

Quote

- is autoloading of chdk working with this camera (with up to 4 GB card)

Yes, bu only up to 4GB for now, for bigger cards you can use the firm update start method.

Quote

- is old style chdk raw saving working (I don't use dng as chdk raw is faster)

Yes, but I don't know how to view them normally. I will post a sample later.

Quote

- is video compression adjustable (or any other differences versus older cameras saving mjpeg)

Yes it can be adjusted. In 1080p mode and the highest quality setting want's to write at about 20MB/s, of course the card can't handle this.

Quote

- is it possible to apply exposure shift without locking the exposure (it's not clear to me from page 119 of the manual) and is it also working during movie recording or has to be pre-set before starting recording

Exposure in video can be set before starting the recording, not during video recording. I never tested this and I'm not sure how it works.

Quote

- is it possible to use manual focus (and what's about usage of Set button to do refocus when using CHDK)

During video recording you can use the Set button to autofocus lock on other subjects. Manual focus during video recording works when pressing slow zoom button. For now here's a bug and if you go from the slow zoom to fast zoom the camera crashes. It works but you must be careful when using this feature until I find how to fix that.

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vit40

276

Re: PowerShot SX220 HS - Porting Thread

« Reply #82 on: 26 / May / 2011, 11:32:09 »

Thanks. Yes, looking to manuals, it seems that only SX10, 20, 30 and older S3, S5 ... have option of adjusting video exposure during recording. Other cameras whether lack this feature (like my A620, A650) or have an option to set exposure prior to recording (like SX110)

However, CHDK ads this functionality to A620/650, but ist's of limited use - every zooming unlocks the exposure, causing abrupt change of brightness. And it affects only exposure time and not ISO (unless something changed in new versions - I didn't try)

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funnel

349

Re: PowerShot SX220 HS - Porting Thread

« Reply #83 on: 27 / May / 2011, 07:14:11 »

@vit40

I uploaded some sample shots of the color pallete in DNG, CRW and JPG, without zoom and full zoom
http://www.zshare.net/download/90656964b2bd9de5/

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vit40

276

Re: PowerShot SX220 HS - Porting Thread

« Reply #84 on: 27 / May / 2011, 08:58:05 »

hi, funnel

I downloaded the files. There is no geometry correction at full zoom, so I could generate a dng profile for this camera. If you or someone else is interested, read the instructions in mentioned topic "CHDK dng profile generator", because I have very specific procedure for this, as it's not based on shooting the real target but a kind of back engineering

Exif tag "Default Crop Origin" needs slight correction if we want that image on jpg from dng is at the same position as jpg from the camera. Correct value seems to be "60 28" (I'm not quite sure because image is not very sharp, but noise patterns seem to be at the same position with this setting). But it's not a big deal, error is only 10 pix horizontally and 3 pix vertically

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vit40

276

Re: PowerShot SX220 HS - Porting Thread

« Reply #85 on: 27 / May / 2011, 15:58:05 »

Here is also new color matrix

1.4458 -0.5704 -0.1562 -0.2520 1.1470 0.1388 -0.1336 0.2334 0.4387

I whitebalanced it so that ACR with img_6532.dng is showing color temperature 5500K and tint +5 (instead +6700 / -18 with previous matrix), assuming it was taken in lighing similar to typical daylight. Also moved red primary from position 0.71, 0.11 to 0.71 0.14 in CIExy diagram, because red hue was a bit too low (like on some other color matrices in dcraw). Probably it should be even higher, but I didn't want to overdo the corrections.

New color matrix can be applied to existing dngs using exiftool :

exiftool -ColorMatrix1="1.4458 -0.5704 -0.1562 -0.2520 1.1470 0.1388 -0.1336 0.2334 0.4387" <filename.dng>

It would be nice if someone try this color matrix with a bunch of different photos and see if displayed color temperature / tint is about correct

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funnel

349

Re: PowerShot SX220 HS - Porting Thread

« Reply #86 on: 29 / May / 2011, 05:44:05 »

Thank you. When I try to change the colormatrix with exiftool it displays "Sorry, ColorMatrix1 is not writable. Nothing to do."

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vit40

276

Re: PowerShot SX220 HS - Porting Thread

« Reply #87 on: 29 / May / 2011, 15:03:28 »

I asked Phil Harvey to enable writing of color matrices a while ago, he did it very quickly, so you have only to download the latest version of exiftool. Before that, I was using my program (DngMatrix) for that

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funnel

349

Re: PowerShot SX220 HS - Porting Thread

« Reply #88 on: 30 / May / 2011, 10:38:44 »

Ok, I tried your colormatrix and looks definitely better. I opened both images in PS with the old and new matrix and applied the daylight white balace to both and compared them. Is this the correct way to check it? The new one looks a lot better.

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vit40

276

Re: PowerShot SX220 HS - Porting Thread

« Reply #89 on: 31 / May / 2011, 04:43:20 »

What I did when I was calibrating WB of my cameras was that I applied a corrected color matrix to a bunch of daylight photos (taken in nice weather, outside shade etc). When set to WB as shot, ACR should show color temperature 5000-5500 on most photos (like my 400D, where Adobe is providing calibrated profiles). If it's still not the case, tell me what the average is and I can make another color matrix. Also, check is red hue on various photos ok (compare with jpeg from camera) - from my feeling red primary should be moved further up in CIExy diagram, because it's usually around position 0.70 0.25 on most cameras

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