I usually take numerous pictures when I’m out and about. I’ll see something that interests me, often an architecturally or historically interesting building, and take several shots of it to improve the chance of getting one where all the variables come out right–exposure, contrast, composition, and the camera not being held at a crooked angle. That last thing isn’t much of a problem anymore, thanks to the fact that the MS-Office Picture Viewer actually allows you to rotate a picture by any desired number of degrees.
What I’d like to find now is something that can straighten out the lines of photo for times when it hasn’t been possible to aim the camera in a way that would prevent it from happening. For instance, with this picture
I had to aim the camera somewhat above the horizontal to include the entire elevation of the building (well, almost), and as a result the walls of the building, instead of being parallel in the picture, converge towards each other. Is there any software out there that can fix this, either by “stretching” the image somewhat like a Mercator projection, or by a partial flip of a few degrees on the horizontal axis? Free software would be nice, or even better would be some tool in MS-Office 2007 that I’ve overlooked. On the other hand, as I’m getting increasingly into this I wouldn’t rule out something that has to be paid for.
So, you want to, say, make the vertical lines in the building parallel. Yes, Photoshop can do that. It’s quite easy, it’s also quite expensive (if you get it legally).
But, if Photoshop can do it, so can Gimp. While I’ve never used Gimp, I’m lead to believe it can do almost everything thing PS can do and it’s totally free. I also understand it’s a bit harder to get used to the PS, but what you want to do shouldn’t be that difficult, it’s pretty straight forward in Photoshop. That hardest part is probably going to be making a duplicate layer if Gimp doesn’t let you work on the original.
Paint.NET, a free program, will do this. However, it results in a trapezoid-shaped image; when you crop it to make it rectangular again, some image area is lost.
I did a quick edit of your photo … it looks a little “off” because I’m not an expert with this program by any means, but this gives you the general idea: http://www.picpaste.com/9533109967_10858170e4_c.jpg
Here is my result from Photoshop CS2.
Filters/Distort/Lens Correction
I could crop it square but I left it so you can see.
It’s not perfect. Needs some little tweeks. Like getting the line of the small wall in the foreground to run straight with the line under the three big windows.
Thumbs Plus built-in editor can rotate by any degree you want. It’s under Transform, Rotate
You’ll have to crop afterward to get a square pic (just like the earlier PS example).
There’s a free trial and you can buy it for $40. It’s my main slideshow viewer and I also use the editor for basic stuff like resizing, cropping, rotating, or adjusting brightness/hue.
I’m pretty sure the free trial is fully functional for 30 days. So you can try it, fix your photo, and then decide if it’s worth buying.
Here’s my version. I used Photoshop, rotated first, then distorted to straighten the walls, but I recommend Gimp as it’s meant to be great, it’s free, and the interface has apparently improved a lot more recently.
Adobe Lightroom will also do that for you and in Lightroom 5, there’s actually an automated version of perspective correction that does a decent job trying to figure out the lines for you.
For example, here is the result of your photo going through Lightroom 5. I just went to the Develop module and under “Lens Corrections” just clicked on the “Full” button. This is the result of just the fully automated adjustment, with no user input. Does a pretty good job, I have to say, and makes my life a hell of a lot easier. If you want to tweak it further, you can do adjust the numbers manually. Note that you really should take your photos a lot looser if you’re going to be using perspective correction, whether in Photoshop, Lightroom, or another program, as you need a bit of room on the edges to work with.
From looking at the samples, I can see that if the lines are completely straightened out, it may result in a somewhat unnatural appearance, like an architect’s drawing of the elevation. But even with that in mind, being able to eliminate some of the convergence should help.
It’s a compromise between recording the building as it actually is versus what I actually saw, which are not the same things.
Lightroom also has an automatic correction that isn’t as extreme. Instead of the “full” setting, you use the “auto” setting. For architecture, I tend to like it on full if the tilt isn’t too extreme, but once the tilt gets extreme it can look a little artificial. I personally think that for your photo, the full effect looks fine and look not much unlike what you would get with a perspective correcting lens.
