No problem. I will definitely look at it when I get home. In the meantime, if you shoot a lot of tall buildings, architecture in general, or anything with very straight tall verticals or three dimensional perspectives, you should really reconsider the purchase of Viewpoint. I use it quite often and it’s very effective.
Mark.
In my view, you use the tool correctly.
The problem is software inside.
Pascal
Perhaps, but I want to take a detailed look at his example and test it for myself before I’m willing to blame the software.
Mark
I just hit my own “problem image”) (its wrong in so many things but it was a turn and click thing. focus, highlights yikes.)
Back to straighten things:
its i think a bit of both:
The software is misguided, takes the wrong conclusions and you need to start somewhere else to get it straight.
See lines and horizon goes wrong
Had a chance to look at it at your example at home and it looks to me like the horizon line on the right hand side was placed very slightly lower relative to the edge of the stage than on the left thus accounting for the slight tilt towards one side. I tried it myself on three different images and adjusted the line very precisely and when cropped as you did, the edge of the crop was right on the horizon line all the way across.
The fact that your horizon line was off a bit is easily fixable in the Horizon palette. I rarely use the Horizon icon on the top and the line to straighten, as you did. I usually use the Horizon palette which is on the right side of your screen. By default, when I select Horizon in the palette I keep the auto horizon wand selected. Often that automatically gives me a perfectly straight horizon, but almost as often it is slightly off. When it’s noticeably off I adjust the horizon manually using the slider or, for finer gradations, the up/down arrows at the right side of the slider just before the wand. I can achieve precise leveling that way.
Mark
Thanks for checking, Mark.
Hm. I feel like I’m positioning the pointers in a straight line right on the lip of the stage, yet the program still doesn’t make it level. I guess I’ll just use the method you recommend to tweak in the future. Just seems strange that the program doesn’t nail it…
Using the line is only as accurate as your placement of it. When you use that approach its strictly manual. As I said, to my eye, based on your placement of the circles with the cross hairs in them, your line was very slightly lower on the right. It doesn’t take being off much to get the results you did. In any case its easily fixable.
Does the horizon change (slightly rotates) when you drag the line to the left or the right? Grab the line between its handles to do this. If the horizon rotates while shifting the line left or right, file a bug.
Hello 
,
@JonSF could you, please, provide me with the image? If you do not want to do it here in public, please, upload it to upload.dxo.com and let me know when ready.
Thank you,
Regards,
Svetlana G.
The horizon tool is not designed to straighten anything! It is designed to level the horizon when an image taken with a tilted camera. It will do the same thing with verticals.
It will not correct perspective or distortion issues. It’s really obvious with sun rise / set images fro0m the shore. Then the horizon truly shouldn’t be tilted or Columbus would have had it all wrong!
Hi Svetlana,
Uploaded. Please let me know what y’all find. This happened with almost all the photos I worked on straightening the other day…
I don’t believe its the software. This sequence is, I believe, identical to yours and the horizon line look fine to me after the crop. The first image is the original untouched. I drew a horizon line across the bottom of the box in the second image. You can see the circles. In the third image the horizon has been applied. In the fourth image you can see the crop line pulled up to the bottom of the box. In the fifth image the crop was applied.
Mark
Thanks Mark. Yeah, that’s how I’d THINK it’d work!
It works that way for me on every image if I am very precise when I draw the line. It occurred to me that perhaps the edge of the stage is not completely flat to begin with as a result of lens distortion or perspective distortion. Do you have example of other images of different subjects where you are having the same difficulties?
Mark
Hello Jon,
What name did you give to your folder (“Support ticket number" field) and name of the image file.
Thank you
Regards,
Svetlana G.
Oh, I named it “N/A” - sorry, didn’t know that’d be the folder name. File name is: “20181014 2878 TIMF 2018 - Sunday - Lord Huron.NEF”
I uploaded it again with a Support ticket number of 2468 just in case you can’t find it.
‘N/A’ original 
but I do understand as you do not have a support ticket number - usually in order I can identify your folders the users put either their login name or mail .
Anyway, now I’ve got the file and will check.
Update: I’ve sent you a reply via personal message.
Thank you
Regards,
Svetlana G.
If you look carefully at the video you linked to, you will see that there is barrel lens distortion. You only traced the stage edge on the left side of the image; therefore “straightening” the image to that slightly distorted line.
You need to trace the line fully from side to side of the image then after that correction, you need to apply a distortion correction to straighten the, now horizontal but distorted, line.
