Lightroom Classic: Honor 'Use Smart Previews instead of Originals' even when zooming to 1:1 in Develop tab

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tl;dr: Change LR so its handling of Smart Previews with "Use Smart Previews instead of
Originals" is identical to its handling of Smart Previews when the original raw file is
unavailable.

LR Classic (v8) has a preference setting named "Use Smart Previews instead of Originals" which allows users to specify that Smart Previews be used in place of the full-sized original (raws) even when the original files are available/accessible to LR. However, if you're in the Develop tab and zoom to 1:1, LR will ignore that setting (and the Smart Preview) and use the full-sized original instead, which defeats the performance benefit of Smart Previews since it incurs the time penalty of a full-quality demosaic. Can you please change LR to fully honor the ''Use Smart Previews instead of Originals'' for all Develop-tab operations, including when working at 1:1?

It's understood that the Smart Preview render (currently 4MP) is a smaller version of the original, and as such there are compromises on the amount of detail available to the user at 1:1 for Develop operations such as sharpening and noise-reduction. However, these are accepted compromises of the feature since that is the way LR's Smart Previews work when the original file is unavailable anyway.

Reference to thread: https://forums.adobe.com/thread/2280965
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Horshack

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Posted 1 month ago

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Photo of Victoria Bampton - Lightroom Queen

Victoria Bampton - Lightroom Queen, Champion

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The smart preview only workflow you want is already available by taking the originals offline (e.g. rename the folder). The preference setting you mention is a performance setting, designed to be half way between smart previews and originals, so you get the performance benefits of smart previews but the quality benefits of originals, without constantly having to take files offline and online. As a result, I could only support this request if it was for an additional smart preview only setting, rather than a prefer smart preview one.
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Horshack

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@Victoria, Yes, taking the media offline (or renaming the folder) is what I'm currently doing to work around this. As for "Use Smart Previews instead of Originals" being a halfway performance setting between smart previews and originals, my testing does not bear this out. I described my results here: https://forums.adobe.com/message/11039399#11039399.
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Victoria Bampton - Lightroom Queen, Champion

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I have read your thread. There are arguments both ways, and all sides were considered when the feature was being developed, with the current behavior being the one with the greatest support.

The feature request stays open for others to vote, but it'll get more traction as an additional feature rather than replacing one that other people have come to rely on.

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Johan Elzenga, Champion

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I agree. There is no harm in a preferences checkbox 'Use virtual copies also when zooming 1:1', but I would definitely vote against any suggestion to simply change the current behavior.

In the meantime, you could use a 1:3 to zoom into a zoom level that should still be covered by the virtual copy size and so should not require the rendering of the full image.


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Horshack

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@Johan, I'm fine with a separate 100% option as you and @Vixtoria suggested but that doesn't seem worthwhile because the current implementation of the option doesn't provide any performance benefit vs standard previews.

As for using 1:3 of the already reduced-image size presented by the Smart Preview, that is insufficient to do any brush masking or evaluation of sharpness/NR. And as stated it provides no performance benefit over a Standard Preview anyway.
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Victoria Bampton - Lightroom Queen, Champion

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> the current implementation of the option doesn't provide any performance benefit vs standard previews. 

Yes it does. Standard Previews aren't used in the Develop module because they're rendered files. If you're running through doing general tonal edits/crops without zooming in, then the current implementation can make a big difference. It's only when you zoom into 1:1 that it doesn't help.
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Johan Elzenga, Champion

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"As for using 1:3 of the already reduced-image size presented by the Smart Preview".

You misunderstand. You are not going to get a 1:3 view of the reduced image size if the original is online. You will get a 1:3 view of the original size. Just like zooming in to 1:1 will be 1:1 of the original image (but that is what you didn't want). And because 1:3 is normally still within the size of the smart preview, that zoom ratio should not cause the rendering of the full image.
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Horshack

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@Johan, When I view a Smart Preview at 1:3 for which the original is available and "Use Smart Previews instead of Originals" is enabled, I see the one-second demosaic delay, the same as when I zoom it to 1:1, and this is for a 45MP image on a 1080 display, so considering the Smart Preview is 4MP there is plenty of resolution available for LR to display it without the full demosaic yet it's still doing it anyway.
(Edited)
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Johan Elzenga, Champion

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No, it's not. A 45 MP image is a little over 8100 pixels wide. If you view this at 1:3, then the image will be about 2700 pixels wide. That is more than the width of a smart preview. So for those images try 1:4 zoom.
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Horshack

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@Victoria, I saw no difference in performance doing a wide variety of Develop tab adjustments on the Standard Preview vs Smart Preview at the default FIT sizing view of the image, and this included tonal adjustments. In contrast, I saw a 1+ second penalty doing the same at 1:1 since that entails a full-quality demosaic of the raw data and edits.


If a user is going out of his way to tell LR to use the Smart Preview even when the original file is available then that user is telling LR he wants to use the full conception of what a Smart Preview is. As it stands now the option denies the user access to a 1:1 zoomed view of his Smart Preview, which means he's getting even less functionally and flexibility than when the original raw file is unavailable, and for no perceivable benefit over a Standard Preview.
(Edited)
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Victoria Bampton - Lightroom Queen, Champion

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How noticeable the benefits are depends on your CPU, GPU, drive speed, photo resolution, whether the photo has been cached in the camera raw cache already, and more. 

To give an example, imagine you shoot with a 36MP camera, you store the photos on a NAS and you haven't viewed them recently, so they're not in the local camera raw cache, but you do have smart previews stored locally. The difference in that scenario is night and day. 

On the other hand, if you have a fast computer, fast local storage and the photos are already cached, you wouldn't see any benefit whatsoever.