Keystone Not Working

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Keystone Not Working

Postby NNN636774544166320981 » Wed Dec 18, 2019 12:34 am

I can't seem to get the 4way keystone tool to straighten. I'm shooting rectangular paintings which should snap to perfectly straight but it's not. I have no problem doing this in ACR and Lightroom. Does anyone have any thoughts?

These are links to screenshots of the problem.

https://photos.google.com/photo/AF1QipPwsoTFEzVl2Vk2bOZNPH-RDa3eyIUP9LltLF_8
https://photos.google.com/photo/AF1QipOajzM7-uGDoJ1SbOaLjETuJxXzlX-aJ2cOc1FU
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Re: Keystone Not Working

Postby ClauS » Wed Dec 18, 2019 3:12 am

Your links don't work. They give me 404 error page. Probably they are private or I don't know, you're pasting the wrong url.

I'll try to help anyway. Check at 100% zoom that you're putting keystone tool points in the right places. Different zoom level could produce unwanted shifts that even if unnoticeable could result in wrong inclinations.
Also check the amount value. It should be 100% by default but you can even increase it further if 100 is not enough. Last but not least, CO is not able to correct an exaggerated perspective. Look both vertical and horizontal value to check you're not at full scale after keystone is applied.
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Re: Keystone Not Working

Postby NNN636774544166320981 » Wed Dec 18, 2019 2:10 pm

Thanks Claus.

Yeah, I have the points on all 4 corners, and have zoomed in to be accurate. Its just a painting on a white wall and the perspective is not exaggerated, rather just a little out of 'square'. I shoot over 2,000 paintings each year and in other software this correction accurate and simple.

I’m thinking the problem is that in Lightroom the tool is a ‘transform’ function as opposed to a Keystone function. I understand Keystone corrects perspective which can only act on the vertical and horizontal axis, while transform is more of a skew which can adjust all 4 sides in differing degrees on each side unrelated to the axis. For instance, in Photoshop if you attempt to correct this using "transform>perspective" it will adjust the both left and right or top and bottom in tandem, while if you were to use "transform>skew" you have the option to adjust each side independently from the others. Or in ACR/LR you can use the transform tool to just draw 4 lines around the image and it snaps into place. I'm guessing the C1 Keystone tool simply adjusts in a perspectival manner, then auto rotates to attempt to get straighter. It does not seem to work as a transform.

Perhaps I'm missing something?

I'm not sure how to make the photos work on this forum. They're hosted on Google Photos, are public and posted using the forums Img function.
Image
https://photos.app.goo.gl/KW9RC7VvSJLpi5XZ9
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Re: Keystone Not Working

Postby Ian3 » Wed Dec 18, 2019 4:32 pm

You should find that it can work on horizontal and vertical at the same time. There are three different options if you press and hold the button on the toolbar. The icon for the option you want looks like #. (A bit.) And if the picture is not too skewed it can work well, but it is very dependent on getting the nodes in the right place. It's perhaps not as easy for that kind of application as something like Photoshop or Affinity Photo.

Ian
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Re: Keystone Not Working

Postby ClauS » Wed Dec 18, 2019 4:49 pm

NNN636774544166320981 wrote:Thanks Claus.

Yeah, I have the points on all 4 corners, and have zoomed in to be accurate. Its just a painting on a white wall and the perspective is not exaggerated, rather just a little out of 'square'. I shoot over 2,000 paintings each year and in other software this correction accurate and simple.

I’m thinking the problem is that in Lightroom the tool is a ‘transform’ function as opposed to a Keystone function. I understand Keystone corrects perspective which can only act on the vertical and horizontal axis, while transform is more of a skew which can adjust all 4 sides in differing degrees on each side unrelated to the axis. For instance, in Photoshop if you attempt to correct this using "transform>perspective" it will adjust the both left and right or top and bottom in tandem, while if you were to use "transform>skew" you have the option to adjust each side independently from the others. Or in ACR/LR you can use the transform tool to just draw 4 lines around the image and it snaps into place. I'm guessing the C1 Keystone tool simply adjusts in a perspectival manner, then auto rotates to attempt to get straighter. It does not seem to work as a transform.

Perhaps I'm missing something?

I'm not sure how to make the photos work on this forum. They're hosted on Google Photos, are public and posted using the forums Img function.
Image
https://photos.app.goo.gl/KW9RC7VvSJLpi5XZ9


The last link works (it didn't appear as an image in the img tags 'cause actually it's not the image url. I used the right one in your quote), but if you see it is different from the other ones: photos.app.goo.gl vs photos.google.com

Other than this, you're right about CO keystone tool limits compared to Adobe's softwares transformation features. It's not possible to square everything in CO (it completely misses a skew feature) but if you look at the example in the keystone correction section of the user guide it seems impossible not being able to straighten a painting compared to building face (unless it's fake). If I cannot obtain the right result with perfectly positioned points I move them off-site to counteract correction flaws and I usually succeed. As a painter myself I've always taken pictures of my paintings and others from my colleagues too and sometimes in the worst possible conditions, even at exaggerated angles to avoid reflections, 'cause I never had a proper study or equipment to do it in a really professional way. Sometimes I had to take pictures of exposed works too. Before CO I used to correct perspective in Photoshop but later I don't remember I've had great problems with CO (at least at reasonable angles). Or maybe I used to manage them to cut the less possible or to pass images to Photoshop in the most squared state. It's been very long since I did it last time so I'm not sure about it. I should re-open some old sessions with my paintings inside or wait to take pictures of my new works.
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Re: Keystone Not Working

Postby NNN636774544166320981 » Wed Dec 18, 2019 5:28 pm

Okay yes, that is the conclusion I've come to. It's very troubling that Capture One does not have a transform function.

Here is the other image that didn't come through earlier. All of the points are precisely on all corners.

Image

Other than this, you're right about CO keystone tool limits compared to Adobe's softwares transformation features. It's not possible to square everything in CO (it completely misses a skew feature) but if you look at the example in the keystone correction section of the user guide it seems impossible not being able to straighten a painting compared to building face (unless it's fake). If I cannot obtain the right result with perfectly positioned points I move them off-site to counteract correction flaws and I usually succeed. As a painter myself I've always taken pictures of my paintings and others from my colleagues too and sometimes in the worst possible conditions, even at exaggerated angles to avoid reflections, 'cause I never had a proper study or equipment to do it in a really professional way. Sometimes I had to take pictures of exposed works too. Before CO I used to correct perspective in Photoshop but later I don't remember I've had great problems with CO (at least at reasonable angles). Or maybe I used to manage them to cut the less possible or to pass images to Photoshop in the most squared state. It's been very long since I did it last time so I'm not sure about it. I should re-open some old sessions with my paintings inside or wait to take pictures of my new works.[/quote][/quote]
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Re: Keystone Not Working

Postby ClauS » Wed Dec 18, 2019 5:43 pm

NNN636774544166320981 wrote:Okay yes, that is the conclusion I've come to. It's very troubling that Capture One does not have a transform function.

Here is the other image that didn't come through earlier. All of the points are precisely on all corners.

Image


It's indeed a skew issue 'cause both vertical and horizontal lines seem to be parallel. Was the canvas actually skewed?
What happens if you raise the amount?
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Re: Keystone Not Working

Postby NNN636774544166320981 » Wed Dec 18, 2019 6:52 pm

No, the canvas wasn't warped or anything. But in the even of some slight twist or warp in the stretcher bars, the transform tool in ACR/LR fixes it perfectly.

Yes, I've tried all of the amounts. I just reached out to a colleague and he said he experiences the same problem with C1.

I guess C1 just isn't what I need right now.
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Re: Keystone Not Working

Postby thomaskyhn » Sun Dec 29, 2019 10:19 am

NNN636774544166320981 wrote:No, the canvas wasn't warped or anything. But in the even of some slight twist or warp in the stretcher bars, the transform tool in ACR/LR fixes it perfectly.

Yes, I've tried all of the amounts. I just reached out to a colleague and he said he experiences the same problem with C1.

I guess C1 just isn't what I need right now.


Sounds like this problem is similar to one I've had, which I've described in this thread: https://forum.phaseone.com/En/viewtopic.php?f=78&t=37549&sid=89736dc0aca43d06c87faa48f83d2efe

Capture One's keystone adjustment options really seem rudimentary at best.
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Re: Keystone Not Working

Postby SFA » Sun Dec 29, 2019 1:47 pm

thomaskyhn wrote:
NNN636774544166320981 wrote:No, the canvas wasn't warped or anything. But in the even of some slight twist or warp in the stretcher bars, the transform tool in ACR/LR fixes it perfectly.

Yes, I've tried all of the amounts. I just reached out to a colleague and he said he experiences the same problem with C1.

I guess C1 just isn't what I need right now.


Sounds like this problem is similar to one I've had, which I've described in this thread: https://forum.phaseone.com/En/viewtopic.php?f=78&t=37549&sid=89736dc0aca43d06c87faa48f83d2efe

Capture One's keystone adjustment options really seem rudimentary at best.


"Transform" implies pixel pushing. Perhaps in a way that root Keystone and perspective adjustment is unlikely to handle in some cases.

To my mind the 2 dimensional appearance of, say, a distant building or a close to the camera picture on a wall may look similar in an image but the factors involved, photographically, are likely very different.
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Re: Keystone Not Working

Postby thomaskyhn » Sun Dec 29, 2019 5:26 pm

SFA wrote:"Transform" implies pixel pushing. Perhaps in a way that root Keystone and perspective adjustment is unlikely to handle in some cases.

To my mind the 2 dimensional appearance of, say, a distant building or a close to the camera picture on a wall may look similar in an image but the factors involved, photographically, are likely very different.


I don't think it has anything to do with the actual content, what matters is the lines you're trying to correct.

Here's an example: https://i.imgur.com/3E0u0Ny.jpg

There are three lines in this image. The one to the right is already vertical, so no need to do anything about that. The one to the left is close to vertical, so it only needs minor adjustment. The not quite horizontal line needs more correction. If you place two adjustment points at the intersections and the two remaining adjustment points somewhere at the top of the vertical lines (disregarding the distortion that may result) and press Apply, what you get is a horizontal line and two slanted "vertical" lines:

Image
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Re: Keystone Not Working

Postby Ian3 » Sun Dec 29, 2019 5:34 pm

I think that is because when you say you would place the two adjustment points "somewhere at the top of the vertical lines" you don't actually know how far up to place them and whether the points you choose are parallel to the known horizontal line. If you had, so a building frontage, with identifiable corners top and bottom, it would be a different matter.

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Re: Keystone Not Working

Postby thomaskyhn » Sun Dec 29, 2019 6:07 pm

Ian3 wrote:I think that is because when you say you would place the two adjustment points "somewhere at the top of the vertical lines" you don't actually know how far up to place them and whether the points you choose are parallel to the known horizontal line. If you had, so a building frontage, with identifiable corners top and bottom, it would be a different matter.

Ian


It shouldn't make any difference where they're placed – and the results are bad no matter where you place them. Obviously, if there was any content in between the lines, you'd see some level of distortion, but that's irrelevant here. The main issue is that Capture One is unable to handle this adjustment, while Lightroom, for instance, has no trouble with it.
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Re: Keystone Not Working

Postby thomaskyhn » Sun Dec 29, 2019 6:17 pm

thomaskyhn wrote:
Ian3 wrote:I think that is because when you say you would place the two adjustment points "somewhere at the top of the vertical lines" you don't actually know how far up to place them and whether the points you choose are parallel to the known horizontal line. If you had, so a building frontage, with identifiable corners top and bottom, it would be a different matter.

Ian


It shouldn't make any difference where they're placed – and the results are bad no matter where you place them. Obviously, if there was any content in between the lines, you'd see some level of distortion, but that's irrelevant here. The main issue is that Capture One is unable to handle this adjustment, while Lightroom, for instance, has no trouble with it.

Just to show that it makes no difference, here's an example where you can easily place the four adjustment points with complete precision: https://i.imgur.com/X2AWNMz.jpg

In the example, only two lines need correction, nevertheless the result is this:

Image

The only conclusion that can be drawn is already in the title of this thread.
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Re: Keystone Not Working

Postby Ian3 » Sun Dec 29, 2019 8:23 pm

I agree that the 4-way correction sometimes seems to work and sometimes doesn't. But if you only have two lines that need correction, why not use one of the 2 way options?

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