February 21, 2018, 08:42:51 AM

Author Topic: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?  (Read 6823 times)

Canon Rumors

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FastRawViewer and RAWDigger have created a utility that will split the Dual Pixel RAW files from the Canon EOS 5D Mark IV do increase dynamic range of the highlights about +1EV in a single explosure.

FastRAWViewer explains how this works:

Canon 5D Mark IV’s sensor has a somewhat unusual pixel arrangement: each pixel is composed of two subpixels. If Dual Pixel RAW mode is enabled in the camera, the resulting CR2 file contains two images, or two frames: one composite, made from reading both subpixels, summed; and the other is made out of one set of subpixels.

The intended use of this arrangement is to enable some extra editing after the shot: because of the parallax between the subpixels, Canon Digital Photo Professional software allows one to preform microadjustment of focus, bokeh shift, and ghosting reduction.

However, there is one more possible use for a dual-pixel raw, which is not covered by the manufacturer: the second frame, the one that is made out of one set of subpixels, collects half of the light that the composite frame does, as if it was exposed one stop lower compared to the composite frame.

In essence, in Dual Pixel Raw mode, the camera records into one file some equivalent of two shots, bracketed by (approximately) 1 EV.

This tool will give the EOS 5D Mark IV about +1 EV of usable dynamic range, making it one of the best stills cameras on the market in that regard.. The advantage to this over bracketing your shots, is there’s no risk of motion blur as it happens in one exposure.

As Canon News notes, there will be a slight parallax error, which means a close and far element will appear at slightly different angles to each other.

Read more about and download the application here.

« Last Edit: February 13, 2018, 11:18:00 AM by Canon Rumors »
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BeenThere

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #1 on: February 10, 2018, 02:53:33 PM »
Would there be slightly more noise in the 1/2 pixel frame because some noise is canceled when adding two sub frames together (The composite frame)?  I don’t see any other downside to the technique other than the extra processing steps/time.

midluk

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #2 on: February 10, 2018, 03:16:32 PM »
The high ISO performance of this half pixel would likely be like that of a crop sensor with a crop factor of 1.4.
And out of focus highlights will very likely be only half visible in the half image.
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IglooEater

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #3 on: February 10, 2018, 03:41:17 PM »
I’d love to see this worked through.  There will be a parallax errors of course, but how much will that influence the output?  More than one stop more DR I’m guessing..?

BeenThere

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #4 on: February 10, 2018, 03:52:38 PM »
Parallax from two points 1/2 pixel apart would be negligible. Camera shake is at least that much.

3dit0r

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #5 on: February 10, 2018, 03:58:49 PM »
Intriguing. Would love to see some results if someone has a play. Just about to order my 5D mark IV so can’t try it myself right now.

rrcphoto

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #6 on: February 10, 2018, 03:59:05 PM »
And out of focus highlights will very likely be only half visible in the half image.

true. if it wasn't a bayer sensor.

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #6 on: February 10, 2018, 03:59:05 PM »

Mt Spokane Photography

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #7 on: February 10, 2018, 06:18:44 PM »
I decided to try this, its actually sunny out, so I took some photos with both white and dark objects in them, expecting that the white would be blown out.  It turns out that the 5D IV didblow out the whites in the final image, but not beyond recovery.


The Result of combining the extracted image with the CR2 was AWFUL!   The outline of the trees that is present in the extracted frame. YUK!


1.  The Image from Lightroom with no adjustments, white post blown out but not beyond recovery.





2.  The extracted Bright frame, not as blown out as the original.





3.  The composite frame using photomerge in Lightroom.  Notice the outline around the trees looks awful!






4.  A photo adjusted just clicking the autotone button in Lightroom.  Much Better.






rrcphoto

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #8 on: February 10, 2018, 06:30:16 PM »
I decided to try this, its actually sunny out, so I took some photos with both white and dark objects in them, expecting that the white would be blown out.  It turns out that the 5D IV didblow out the whites in the final image, but not beyond recovery.


The Result of combining the extracted image with the CR2 was AWFUL!   The outline of the trees that is present in the extracted frame.

well, your image would have been partially distorted by parallax.  were you trying to do that on purpose?

and it looks like LR didn't handle the blending well at all tbh.

IglooEater

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #9 on: February 10, 2018, 06:51:16 PM »
I decided to try this, its actually sunny out, so I took some photos with both white and dark objects in them, expecting that the white would be blown out.  It turns out that the 5D IV didblow out the whites in the final image, but not beyond recovery.


The Result of combining the extracted image with the CR2 was AWFUL!   The outline of the trees that is present in the extracted frame. YUK!


Huh, thanks for the comparison!

I’m curious- do you think it would be better if one was* to stop down to make the background was in focus?  Or would it not change because the difference distance between foreground and background remains the same?

*were or was correction possibly needed from Alan or Orangutan

Mt Spokane Photography

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #10 on: February 10, 2018, 07:49:47 PM »
I decided to try this, its actually sunny out, so I took some photos with both white and dark objects in them, expecting that the white would be blown out.  It turns out that the 5D IV didblow out the whites in the final image, but not beyond recovery.


The Result of combining the extracted image with the CR2 was AWFUL!   The outline of the trees that is present in the extracted frame.

well, your image would have been partially distorted by parallax.  were you trying to do that on purpose?

and it looks like LR didn't handle the blending well at all tbh.

If it was distorted by parallax, that's how it is going to be for users, I don't know how to prevent it, 10 ft away from the post.

Lr does not work well for combining images, but the result is awful, more than usual so something is going on.

The bottom line is that for reasonably over exposed images, just adjusting the raw 5D MK IV in Lightroom works better and is easier.  I did not attempt to purposely over expose a image, just like I don't take photos with a lens cap on or boost exposure 5 stops.


Because Lightroom is pretty bad at merging images, I downloaded a trial of Helicon.  Its much better, but still will need some tweaking.  Here is the file just as it came out.  No outline of the trees!

« Last Edit: February 10, 2018, 08:10:22 PM by Mt Spokane Photography »

Mt Spokane Photography

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #11 on: February 10, 2018, 08:16:24 PM »
I also tried zerene Stacker, but it could not handle the DNG files generated by DPRSplit.

rrcphoto

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #12 on: February 10, 2018, 09:45:33 PM »
do you have the dng's? could i get them - I'll try them through photomatix.

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #12 on: February 10, 2018, 09:45:33 PM »

EzDingo

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #13 on: February 10, 2018, 09:55:07 PM »
Quick test...

1. Original RAW unprocessed

2. Original RAW + 100% highlight recovery

3. Original RAW + 100% highlight recovery with window area masked from Frame 2 of dual pixel file with again 100% highlight recovery.

Note both frames were processed to match exposure. In other words the darker frames exposure was raised to match the lighter frame making masking the window in seamless and simple for this quick test.
« Last Edit: February 10, 2018, 10:00:14 PM by EzDingo »

Mt Spokane Photography

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #14 on: February 11, 2018, 01:12:21 AM »
do you have the dng's? could i get them - I'll try them through photomatix.
The original photo plus extracted dng is here.  I merged the cr2 original and the dng (both are basically tiff images).


https://www.dropbox.com/sh/jvh7khyc5xlcnv3/AACK0Rwh-rBKC8QFoXo4qRTua?dl=0

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Re: Want to Increase The Dynamic Range of Your EOS 5D Mark IV Raw Files?
« Reply #14 on: February 11, 2018, 01:12:21 AM »