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Author Topic: Optimal G7 Setting - What is closest to RAW?  (Read 2864 times)

envision

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Optimal G7 Setting - What is closest to RAW?
« on: April 03, 2007, 09:17:05 pm »

As a long-time owner of Canon DSLRs and lenses and a user of RAW, I nonetheless reached the conclusion that the G7 is currently the best small carry-everywhere camera (given my own priorities) to replace my beloved but aging S50.  Lack of RAW is unfortunate, but that's the fact, and therefore I (and other G7 owners) can use some expert help.

Even using SuperFine, with normal settings there are some presumed JPEG-ed effects that can be seen in middle brightness areas.  Even at ISO 200 there is a hint of detail smearing seen in the Lumix series (grass and hair taking on that Lumix look), and there is chroma noise.  Blown highlights are also a problem at times.  My tentative solution has been to use the Custom Color option, and set both sharpness and contrast to -2 (lowest setting), and saturation to -1.  then I usually set exposure compensation anywhere from -1/3 to -2/3 stops.  

I am guessing that the DIGIC-III algorithm first does sharpening and tone curve adjustments, and then finally implements JPEG compression.  If so, my reasoning is that minimizing these adjustments will lead to a JPEG that retains as much dynamic range and detail as possible.  

But, I don't know if my assumptions are correct.  For example, is it possible that by reducing sharpening prior to JPEG compression, low-level detail is actually MORE likely to be smeared by the JPEG algorithm than if it had been pre-sharpened?  Etc.

If someone out there understands how DIGIC-III works, please advise how to achieve the goal of retention of maximum detail and dynamic range on the G7, so that post-processing of the JPEG in PS will give the greatest flexibility to retain dynamic range, enhance image quality, adjust sharpening and tone curves, etc.  In other words, what settings come the closest to delivering the benefits of RAW?

Otherwise without an understanding of how the algorithms work, in sequence, a great deal of laborious testing of all permutations would be the only way to be sure this amazing little camera can be used to its full potential.

Thanks !!
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Ray

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Optimal G7 Setting - What is closest to RAW?
« Reply #1 on: April 03, 2007, 09:35:41 pm »

What you are doing appears to me to be the right thing, but I can't help you regarding details of the DIGIC-III algorithm. There's no substitute for taking a few test shots, even if only to find out the degree of IQ difference resulting from different settings.

How is the 1280x720p video quality of the G7? 15 fps sounds a bit choppy. Have you found a way of doubling or quadrupling the frame rate in post processing?
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envision

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Optimal G7 Setting - What is closest to RAW?
« Reply #2 on: April 03, 2007, 10:16:12 pm »

I have not tried the video yet so I cannot comment.
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Broke

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Optimal G7 Setting - What is closest to RAW?
« Reply #3 on: April 05, 2007, 04:51:08 pm »

In my experience, reducing the contrast as you've done does relatively little to actually increase the dynamic range of the camera -- this is easy to demonstrate if you photograph a high contrast scene [with My Colors Off and Custom Color] and compare blown highlights.  There is a small difference in favour of the Custom Color setting at Contrast -2.  I have found that in trying to save highlights its often difficult to avoid posterization of shadow areas in post-processing, this has been a challenge.

It is unfortunate that Canon doesn't give the user the option to control in-camera noise reduction as Panasonic does -- this would leave the option of using more advanced noise reduction programs (ex. neat image).  I have had good success with local noise filtering in Photoshop using layer masks -- this camera affords lots of practice in noise reduction.
 
I have experimented between using the default in-camera sharpening and using Unsharp Mask in photoshop and can see little difference in artifact, noise etc., personally I don't think there's a lot in it.  I'm sure there will be those that disagree...

Regarding white balance, solutions like Lightroom afford the ability to edit JPEG like RAW, though probably the best option is custom white balance using a grey card/ expodisc or the like.

The G7 produces some wonderful images, especially if one takes care before exposure, minimizing post-processing after -- I've really enjoyed it.

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Quote
As a long-time owner of Canon DSLRs and lenses and a user of RAW, I nonetheless reached the conclusion that the G7 is currently the best small carry-everywhere camera (given my own priorities) to replace my beloved but aging S50.  Lack of RAW is unfortunate, but that's the fact, and therefore I (and other G7 owners) can use some expert help.

Even using SuperFine, with normal settings there are some presumed JPEG-ed effects that can be seen in middle brightness areas.  Even at ISO 200 there is a hint of detail smearing seen in the Lumix series (grass and hair taking on that Lumix look), and there is chroma noise.  Blown highlights are also a problem at times.  My tentative solution has been to use the Custom Color option, and set both sharpness and contrast to -2 (lowest setting), and saturation to -1.  then I usually set exposure compensation anywhere from -1/3 to -2/3 stops. 

I am guessing that the DIGIC-III algorithm first does sharpening and tone curve adjustments, and then finally implements JPEG compression.  If so, my reasoning is that minimizing these adjustments will lead to a JPEG that retains as much dynamic range and detail as possible. 

But, I don't know if my assumptions are correct.  For example, is it possible that by reducing sharpening prior to JPEG compression, low-level detail is actually MORE likely to be smeared by the JPEG algorithm than if it had been pre-sharpened?  Etc.

If someone out there understands how DIGIC-III works, please advise how to achieve the goal of retention of maximum detail and dynamic range on the G7, so that post-processing of the JPEG in PS will give the greatest flexibility to retain dynamic range, enhance image quality, adjust sharpening and tone curves, etc.  In other words, what settings come the closest to delivering the benefits of RAW?

Otherwise without an understanding of how the algorithms work, in sequence, a great deal of laborious testing of all permutations would be the only way to be sure this amazing little camera can be used to its full potential.

Thanks !!
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