SX160 RAW files are 4MP whereas JPG is 16MP, plus raw has len distortion

ShahJahan

30
King Of The World

SX160 RAW files are 4MP whereas JPG is 16MP, plus raw has len distortion

« on: 10 / March / 2014, 01:57:16 »

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Hello.

I am new to CHDK and am using Canon PowerShot SX160 IS Camera. I have two problems and I'm NOT sure if this is normal with CHDK?

1. When I shoot with RAW plus JPG, my RAW files are limited to a resolution of 2304 x 1730 pixels (4MP) whereas my JPGs of the same shot are of 4608 x 3456 pixels (16MP). That is my RAWs are of 1/4th resolution of my JPGs! Is there a way to shoot at 16MP RAW?

2. My RAWs have a severe lens distortion (barrel distortion) whereas my JPG doesn't. Plus my JPG of the same image is cropped, whereas my RAW isn't.

PS: I'm fine with the second problem as I can fix it in PhotoShop, although I'm really concerned about the quarter of a resolution in RAW as I'm losing a lot of data! Can someone kindly guide me on how to shoot RAW at full resolution?

Thank you very much.

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The name ShahJahan comes from Persian, where Shah means King and Jahan means World,
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reyalp

13392

Re: SX160 RAW files are 4MP whereas JPG is 16MP, plus raw has len distortion

« Reply #1 on: 10 / March / 2014, 02:26:34 »

Quote from: ShahJahan on 10 / March / 2014, 01:57:16

1. When I shoot with RAW plus JPG, my RAW files are limited to a resolution of 2304 x 1730 pixels (4MP) whereas my JPGs of the same shot are of 4608 x 3456 pixels (16MP). That is my RAWs are of 1/4th resolution of my JPGs! Is there a way to shoot at 16MP RAW?

Most likely the program you are using to view them is showing reduced resolution, CHDK isn't capable of saving a reduced resolution raw. irfanview (among others) does this for large raw files. There is usually an option to see full size. To make use of raw, using a dedicated raw processing program like raw therapee, lightroom etc is recommended.

Quote

2. My RAWs have a severe lens distortion (barrel distortion) whereas my JPG doesn't. Plus my JPG of the same image is cropped, whereas my RAW isn't.

This is what the camera actually sees, the Canon firmware does lots of correction. You can create a lens profile using Adobe's lens profile tool if desired. Some are posted in http://chdk.setepontos.com/index.php?topic=9268.0

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ShahJahan

30
King Of The World

Re: SX160 RAW files are 4MP whereas JPG is 16MP, plus raw has len distortion

« Reply #2 on: 12 / March / 2014, 14:16:15 »

Thanks a lot for your replies.

Quote from: reyalp on 10 / March / 2014, 02:26:34

Most likely the program you are using to view them is showing reduced resolution, CHDK isn't capable of saving a reduced resolution raw. irfanview (among others) does this for large raw files. There is usually an option to see full size. To make use of raw, using a dedicated raw processing program like raw therapee, lightroom etc is recommended.

Thanks, that was indeed the problem. IrfanView was showing the correct resolution of JPGs, but for some reason, it was reporting the incorrect resolution for the raw DNGs. Using PhotoShop, I found that both the JPGs and the DNGs are of 16MP.

Quote from: reyalp on 10 / March / 2014, 02:26:34

This is what the camera actually sees, the Canon firmware does lots of correction. You can create a lens profile using Adobe's lens profile tool if desired. Some are posted in http://chdk.setepontos.com/index.php?topic=9268.0

Unfortunately I cannot seem to find a Lens Profile for my SX160 IS. And since I'm new to all of this, I can't seem to be able to get it perfect in removing the lens distortion. Although I'm learning and hopefully I'd be able to accomplish it.

Thanks again, you have been very helpful.

Kind Regards.

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The name ShahJahan comes from Persian, where Shah means King and Jahan means World,
so the name ShahJahan in its literal sense means King of the World.