Lightroom: Provide exif indiction to destinguish between focus stack photos and the composite

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Recent firmware upgrades on some Olympus cameras has added an in-camera focus stacking feature. My guess is that this is going to take off with the other manufacturers as well. One issue I have is that in LR Library, there is no indication on either the image or the exif list that shows which image is one of the stacked images and which is the in-camera manufactured composite. OK, it should be clear by simply looking at the image but in practice this works only if everything has gone perfectly. I've been doing it by shooting in raw+jpeg mode only so that I know that the image without a raw twin must be the composite image, however, this is wasteful. I'm the Adobe geniuses could easily pop in an icon that shows the photo as a composite.
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Bob Trlin

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Posted 3 years ago

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Bob Trlin

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Of course I meant, "I'm sure the Adobe geniuses..." not as is written, "I'm the Adobe geniuses...". Apologies for my Freudian slip!
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John R. Ellis, Champion

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You could try running the free Exiftool to see if there is a metadata field that the camera inserted distinguishing the composites but that isn't being imported by LR. If there is such a field, then you could use the Data Explorer LR plugin to identify the composites by that metadata field: http://regex.info/blog/lightroom-good...
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Bob Trlin

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Good point! I've used the Jeffrey Friedl addons in the past but had some issues with getting them to work with LR6. Until I sort that out I went to my old favourite PhotoME. I had the exifs of one of the stack photos and the composite listed side by side. There were no obvious differences apart from "Focus step count", "Calculate Focus Distance" and some undefined fields but the data didn't say much at least not to me. I'm sure the manufacturers could agree to use one of the undefined fields for this purpose it they were so inclined.
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John R. Ellis, Champion

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If you upload a sample non-composite and its composite to Dropbox or similar and post the sharing links here, I can dig around with Exiftool, which might reveal a possibility.
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Bob Trlin

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John,
I did a quick and dirty stack of eight using the Oly in-camera focus stacking. This is the Dropbox link https://www.dropbox.com/sh/bkvzk0kqyi...
The 8 stack photos are numbered *91 to *98 and the composite numbered *99. There is no PP other than that inherent in the camera and LR.

A few observations:
1. The composite has been cropped slightly for some reason yet the pixel count is still the same. This implies slightly greater resolution but one would need to pixel peep to confirm this For comparison, I ran the same stack through Helicon but it didn't crop.
2. Curiously, the composite is given a time stamp somewhere between the first and last stack photo. This results in LR slotting the composite somewhere into the middle of the pack. I initially thought that perhaps the in-camera focus stacking might have began before the last few photos were taken and the date stamp on the composite represents the start of processing. However, when I ran the stack through Helicon, I was shocked to see that it did exactly the same thing. It must have some other significance.
3. On jpegs, the Helicon composite was slightly better than the Olympus one but when I used Helicon's feature of doing stacks off DGN's, Olympus had the edge.

Looking forward to what you come up with.
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John R. Ellis, Champion

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I examined each of the photos and the composite with "exiftool -a -G", and the only differences I found were the capture and modify dates, the LR label applied (green versus purple), the rating, and the file size.

The composite is 8.4 MB, while the photos range in size from 6.3 to 7.8 MB. You could conceivably try to use the file size as the indicator, but without examining a large number of stacks, it may not be a consistent indicator across different subjects and shooting conditions.

I read in a review that you can also shoot in raw, though the composite is always a JPEG. That would be one way to distinguish the composite.

It seems a silly omission on Olympus' part not to distinguish the composite with metadata.
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Bob Trlin

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Yes I agree, it is a silly omission. Actually, as I'm getting more familiar with it, I think one can rely on the composite being the highest file number even though it is not necessarily the latest capture time.

The green and purple labels and ratings were mine. Sorry about that.