Lightroom CC for mobile: Double tap for accurate 100% zoom on iPad Pro

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  • Updated 2 months ago
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Seems that double tapping to zoom in Lightroom Mobile on iPad Pro is inconsistent and never yields actual 100% image pixel to display pixel view. Initial zoom factor appears to depend on actual image file resolution and is about 75% zoom with image files from my D500, but closer to 50% zoom with files from my D850. Repeatedly double tapping eventually yields something closer to 200% zoom for image files from both cameras. I’ve seen a few posts dating back a year or more on this subject and none have been answered. Are there implementational issues with iOS and/or certain mobile devices with adding this functionality? Needless to say an accurate 100% pixel to pixel view is a very important feature to be able to consistently assess image sharpness/detail and noise.
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Roy McLaren

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Posted 5 months ago

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Roy McLaren

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Yeah, I've no interest in where we stand from a "legal" perspective ;-). Would just really like to get to the bottom of this and for the software to behave in an expected and predictable manner.

Also, just wanted to add that this has been a very fruitful discussion so far, and have now been able to highlight that Lightroom CC / Lightroom Mobile CC on Apple OS based HW platforms does not yield anything resembling a true 100% zoom functionality (per our 1:1 pixel relationship definition that is). Moreover the %-age zoom applied is inconsistent from device to device. Then to top it off we have the 200% "bug". Whilst we are clearly experiencing varying mileage in terms of repeatability of this specific behavior (for me it is very easy to induce with Apple Pencil) the 200% issue is a very interesting case because it is the one scenario that is actually providing a whole number relationship giving impression that whatever calculations are being applied have a built-in knowledge of device display resolution? This 200% statement being subject to the more careful measurement methodology you are applying, if you have the time and energy?

Maybe time for moderators of this forum the re-instate my original "feature request" wording in my thread title?
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Prasand J.

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Yeah, it'll be interesting to see if the 200% matter is a relative calculation based on the previous zoom (or just a programmatic slip / double-triggering), or actually calculating the 200% correctly. Also interesting to see if I can get the bug to trigger across devices, I only tested the iPad on that. Will check it tomorrow. Also I have an Apple Pencil 2, so I'll check to see if it's easier for me to trigger the bug using it also.

@ "feature request" ... I think the 200% bug is the issue, but can also see how the non-1:1 would be an issue for those whose style / livelihood relies on tack sharp focus. The fact that Photoshop's 100% zoom is incorrect on macOS, this might be an issue that goes back pretty far. I can see the headlines now, "in the world of Adobe you've only been seeing 98% of what you should've" or "1:0.92's the new 1:1"

Kidding of course; everything's probably fine on Windows & Android.
(Edited)
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Roy McLaren

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As monitor resolutions increase 1:1 zoom is not just for pixel peepers, but seems a very reasonable criteria for assessing sharpness and noise. It also has advantage of displaying the image at the monitor's native resolution removing whatever rendering tricks are necessary for a responsive full-screen fit view with risk for associated artifacts. Often I think rendered images in Lightroom Classic on my desktop (24" monitors) are soft in screen-fit view, but turn out to be perfectly sharp when viewed at true 1:1, so having the ability to review images at a true 100% magnification is the "only" way to make a proper assessment of the image (or re-phrasing that, at-least only way to make a standardized assessment). Let's not forget when we want to crop images which in my case is very often.

According to your calculations the headline should be:

"In the world of Adobe, 1:1 view is not really defined and moreover is dependent on image file resolution and for example in the case of a 24MP 6000x4000 image will be 68.3% zoom on an 11" iPad Pro and iPhone7, whereas it will be 88.97% on a MacBook Pro 13" and 128% on Apple TV 4k, and maybe something else around 70-75% on a 13" iPad Pro. Occasionally it may even be 200%, but you might need an Apple Pencil if you want to tap into that feature more regularly"! Just kidding around, but that seems to be the present deal with Apple OS based products.

Looking forward to your calcs for the 200% "bug"
(Edited)
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Prasand J.

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Pixel peeping is the act of viewing photos at 100% (or greater) to assess sharpness, noise, and defects. It's often used in a derogatory way due to the tendency to be obsessive about it. However, as a New Yorker its been my experience that we use it here in a non-derogatory / casual way. Then again, we do that for many words that others would consider "bad" elsewhere, lol.

Ultimately, I mean no ill will by it, but what you described is pixel peeping.
(Edited)
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Roy McLaren

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Ok, in that case I’m a pixel peeper :-). Personally didn’t know what zoom factor was required to be considered part of that esteemed family. 100% it is then :-)
(Edited)
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Roy McLaren

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Any updates on this subject? Thanks.
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Christopher Howell

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Hi - I would just like to add another voice requesting a 100% zoom implementation that is consistent, makes sense, and results in one file pixel=one display pixel. I’ve had the 200% bug occur too, but frankly I wouldn’t really care if there was a consistent way to zoom to 100% / 1:1 or whatever adobe wants to call it. A zoom indicator or numerical option would be nice too
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Roy McLaren

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The absolute best option would be to add a feature allowing a selectable range of consistent and accurate zoom factors, e.g., 1:1, 2:1, 4:1, etc., just like Lightroom Classic CC (or for that matter as implemented Lightroom CC desktop). Due to differences in display sizes and resolutions among devices it would be appropriate to allow a range of different standard zoom settings. However, just having access to a consistent and accurate 1:1 zoom would be a very nice feature to start with, especially given that this is "supposed" to be a currently supported feature!! Would be nice to get some feedback on this from Adobe.
(Edited)
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Michael Boldt

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After recognizing today, that Lr mobile fails to show 100% views of my D750 raw-files on my iPad Pro, google search leads me right to this thread. Has there been any feedback from Adobe to this issue after your last post? Are there any other news?
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Roy McLaren

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No, there hasn't. I am assuming it is not a priority item for Adobe, or there is some technical barrier to enable a resolution with iOS...