How to HDR from Bridge

Report · Jul 21, 2022

I haven't tried HDR before though I have shot sequences with that in mind. So in Bridge I found the menu item "Auto stack for HDR/panorama, and it made several groups, but now I don't know how to proceed. These are RAW images. If I go to Photoshop, I see no groups, but am asked to choose images, so how is this used? I see in the folder that it made some groups, maybe for panorama that were not really intended for such, but missed several series of identical scenes that were shot with HDR in mind.

Report · Jul 21, 2022

Hi Robirdman1,

I've been doing HDR for about 25 years; let's see if I can help.

For one thing, I've never been a fan of Photoshop's HDR; some like it, me — not so much. However, Adobe Camera Raw's HDR is a thing to behold.

Since you're taking raw images (GREAT!), this is easy: select the three* (or more) proto-HDR images in Bridge, right-click, and select "Open in ACR." After ACR opens, select the same three images, and right-click on them again, you'll see this option:

Notice also that you get the other options of "Merge to Panorama" and "Merge to HDR Panorama."

When the new window pops up, make sure that you have the "Align Images" checked. Also, see if "Apply Auto Settings" is checked. I prefer using the Auto as it gives me a leg up on operations.

After you OK this, you need to save the new DNG file into the folder where the proto-images are held. Then, finally, you can fine-tune the image in ACR.

If you choose to do some HDR Panoramas, tilt your camera to portrait position, and preview your intended scene through the lens to make sure that your vertical region is covered (you do not want partway to realize that you need to shift your angle up or down). Then, start from one end, take your shot, move about 2/3 of that shot to the right or left, take another three, rinse and repeat till done.

* Now, onto those three shots: each of the three shots should be two stops apart, typically -2, 0, +2 stops. If your camera is within 6-7 years old or newer, you can get by with two stops: -2 & +2. There is no need to go -2, -1, 0, +1, +2. Why these differences? First off, I did an experiment many years ago, set my camera up on a tripod (for this experiment), and too every 1/2 stop. When it came to processing I first processed every 1/2 stop. Then, using the same images, I selected the every stop. Then, using the same images I processed every two stops. There was essentially no difference in the result.

But again, why two versus three stops? When HDR using multiple shots changing only the exposure time started, most digital cameras didn't have raw capabilities and could only take JPGs. Now, let's pretend that the dynamic range of a scene is 36" wide (I'm converting dynamic range from light to distance to help explain my point.) The dynamic range of a jpg is about 14", but the dynamic range of a raw image is about 19". It takes three JPG images (42") to cover the dynamic range of the scene (36"). But only two are needed (38") for a raw image because they have a greater dynamic range.

So, when do you need more? Whenever the scene needs more. In my example above, there's plenty of light so two or three images are fine. But, let's say you're in a dark shed with an open window. Then you may need one or two more shots to capture the range: -4, -2, 0, +2, +4.

Lastly, why am I still taking the "unneeded, middle shot (either the "0" or the "-2, & +2" in either example). It's insurance. You may be in a position that you'll never ever be able to get back to that scene again. So take the shot, memory is cheap. If you later find you do not need the extra shot, toss them later. If you got the space, keep them.

If you have any other questions, just ask.

Report · Jul 22, 2022

thanks. this was useful. A little different from the direction, no "open in ACR" but "open in Camera Raw", so I assume that meant the same. Or if I just had the images selected, then they would open there. I tried with a number of images, and the exposure was usually improved, even when I did some that only had 2 images. Previously, I had let Bridge automatically stack images in the folder for HDR, figuring this chose the similar ones. However doing and opening the stack in camera raw would only show one non-mergable images so I had to unstack each group and then load. so I wonder what the use of stacking for HDR was. I think that the more modern shots I was doing just had poor light at the time, as they didn't seem to have the vibrance of the scanned slides I took more than a decade before, but glad to see how this all works.

Report · Jul 22, 2022

Yes, opening in ACR, Camera raw, or if all images are raw images, they will all get to the same place.

Because you can do the same process with JPG or TIF images, I was being specific to cover all bases.

THIS OPENS A WHOLE NEW BALLGAME IF YOU ARE USING IMAGES SCANNED FROM SLIDES. For reasons beyond my knowledge, the resultant digital image from a scan is inherently different than an image taken of things taken by a camera, even if you were taking photos of slides or negatives as I have done. For example, film has grain, but digital images do not. PS's noise removal does not know how to deal with photographs of grain. Electronic noise, yes, but not grain. (FWIW, I've found Topaz's DeNoise does an OK job dealing with grain. Not as good as it does with digital noise, but much better than PS's dealing with grain.)

Otherwise, I've no experience with images or scans of digital attempts to do HDR. However, the SilverFast scanning software does have an HDR mode where it scans images twice, once for a darker pass and once for a lighter pass, and assembles these during processing (you never see two images out of this process). The results do help the image, but they are time-consuming.

Stacking, in Bridge, is solely to help de-clutter your images. That is, rather than looking at 40 individual images, you could be looking at ten stacks with the HDR one on top of each. It solely makes it easier to peruse your images. If you ever start using Lightroom Classic, you can select an entire day shoot and tell it to Stack all images taken 1 second or less from the next. This will stack only the HDR-proto images. Then you can select just the stacked images and have LRC process these images while you look at your mail or something. Then you can go back and go to each Stack and do any fine-tuning on the images.

Report · Oct 18, 2022

As gary@flannerytrim.com points out "Stacking, in Bridge, is solely to help de-clutter your images."And it looks like what you need is to use LrC for this function to have meaning for what you seem to assume/want. I was wondering the same thing.