Tag Archives: HDR

Adobe DNG HDR Format, Part 3

I’m  back once again with even more information from Lightroom developer Eric Chan, and best practices for creating HDR RAW files in Lightroom CC 2015 / 6.  Previously we reported that Adobe recommends just two exposures for creating an HDR DNG file, which was and is true, but now Eric expands on that idea, and explains under what conditions you might want to add more than two exposures.  Before we begin, if you haven’t caught up on this topic, check out Part 1 or Part 2 in this series.

Eric starts with some advice on merge speed:

More images in an HDR merge will take proportionally longer.  2 frames is [normal,] 3 frames is even longer, etc.

Whether or not a third (middle) frame will help will depend on a lot of things, including the tonal content of your scene, and the spread of your exposure bracket.  Keep in mind that a third frame increases the likelihood of misalignment between the frames.

If merging two frames, I generally recommend they be within 3 stops of each other.  For example, I’ll capture one shot for the highlights, then open up 3 stops and capture another frame, then blend those two.

I don’t recommend merging two frames that are super-spread apart.  Continuing the above example, I would NOT recommend shooting my second image by opening up 6 stops.  Why not?  Because I am likely to see some range of tones in the merged result that are visibly more noisy than other tones.  These are the pixels that are clipped in the 2nd (bright) shot, and therefore the HDR blending algorithm needs to grab those tones from the 1st (dark) shot, which is noisier for those pixels.

So it’s fine to use the in-camera HDR bracket facilities, including ones that allow you to take 3 shots quickly, like 0/+3/-3.

Some examples:

0/+1/-1:  I would just merge the +1 and -1 shots (they’re within 2 stops of each).
0/+2/-2:  I would merge either the 0/+2 shots or 0/-2 shots (depends on how I metered the scene).  For very high contrast scenes, I’d merge all three.
0/+3/-3:  Similar to the 0/+2/-2 case.

I would consider the +1,5/-1,5 case “3 stops apart”.
The +3/-3 case would be 6 stops apart.

So there you have a more detailed version of “best practices” for shooting Lightroom HDR.

If you’re a Canon 5d mk III user, you likely know that you have an in-camera HDR function.  The camera produces a merged JPEG for you, but it also keeps the RAW files.  You can use this and just ignore the JPEG.  I do not own a 6D or a 7D mk II, but since they’re also newer Canon bodies, I suspect they may have the HDR feature as well.

If you don’t have one of these bodies, or if you want more control over the bracketing, or if you’re on the 1DX, you can also use the AEB tools to create 2, 3, 5, or 7 shots bracketed at any difference from 1/3 to 3 stops each.  Check out the AEB section of your manual, or do a little Googling to learn how to use these features.

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Adobe DNG HDR Format, Part 2

This is a follow-up to my previous post about Adobe’s new HDR DNG format.

I had another conversation with Eric Chan, a developer on Adobe Lightroom CC / 6, and one of the key people involved in the new Photo Merge features.  It was mentioned that the data in an HDR DNG is demosaiced, linear data, so I had some questions as to how closely the file resembles a true RAW file, and how this stacked up against sRAW or mRAW formats which are also demosaiced. Continue reading Adobe DNG HDR Format, Part 2

Lightroom CC / 6 Photo Merge to HDR’s Deghosting

Here’s another quick video tutorial for you about the impact that deghosting has on the image quality of an HDR merged in Lightroom CC / 6.  The image noise shown in the video is a result of Lightroom depending on a single exposure for the image areas where deghosting was applied.  You can minimise this issue by being careful to hold the camera steady, and only photograph stationary subjects.

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Adobe DNG HDR Format, Part 1

With the launch of Adobe Lightroom CC 2015 / Lightroom 6 and it’s matching version of ACR, we now have the ability to create high dynamic range RAW files via DNG.  It’s pretty impressive that you’ll get all the benefits of RAW such as whitebalance, tint, highlight recovery, etc, in a single file that’s much smaller and significantly more editable than a 32-bit TIFF.

And yet you may have also heard that this new DNG capability is built on a 16-bit technology.  “Wait!”  You think… “doesn’t that mean I have more flexibility with a 32-bit TIFF file??”

Not quite.   Continue reading Adobe DNG HDR Format, Part 1