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DNG has less detail than JPG for A4000

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Offline reyalp

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Re: DNG has less detail than JPG for A4000
« Reply #50 on: 22 / June / 2013, 16:49:45 »
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So, I opened the JPG in PSP and the DNG with IrfanView.
In my experience, Irfanview does not do a great job rendering DNGs and offers you very little control over how it does it. In particular, it appears to do an automatic levels adjustment and the demosaicing doesn't seem to be particularly good.

It's fine for a quick look but is not a reasonable starting point for a serious comparison.
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Offline reyalp

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Re: DNG has less detail than JPG for A4000
« Reply #51 on: 23 / June / 2013, 18:56:39 »
Here's an case where I found raw useful. The picture is a 60 second exposures of the ISS passing overhead.

Auto dark frame is disabled, because I don't want to wait an additional 60 sec between exposures. Because of this, the camera jpeg suffers severely from hot pixels and amp glow. Stacking is out because I don't want gaps in the trail.

After shooting, I created 5 dark frames with the same exposure settings (using CloseMechaShutter to shoot with the shutter closed) and averaged them using "raw average"

The DNG dark frame and various noise reduction and color adjustments were applied using raw therapee

I'm not sure what's up with the purple on the right, it isn't amp glow, as it doesn't show up in the darks. The moon is just out of the frame in that direction.

The attached comparison shows 100% crops of png made with raw therapee (top left), camera jpeg (top right), bottom left is irfanview default rendering of DNG (bottom left).

Original files https://www.box.com/s/mfvj6pn2iy4ndpjgy2gf
CRW_8751.DNG - original DNG
IMG_8751.JPG original camera JPEG
CRW_8751.PNG rendered from the DNG
CRW_8751.png.out.pp3 raw therapee settings used to create PNG
CRW_8751_compare.png comparison crops
edit to add
d10-64s-iso100.DNG - dark frame (raw average of 5 dark frames)

In the end it's not a great image anyway, but it would be difficult to get the same result from the camera jpeg.
« Last Edit: 05 / November / 2013, 18:27:50 by reyalp »
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Online blackhole

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Re: DNG has less detail than JPG for A4000
« Reply #52 on: 24 / June / 2013, 03:33:06 »
Good job, a good idea to do a master dark frame in camera  with a Raw average function.

 

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