sodapop wrote:
I have used it successfully and Lightroom and in PHotoshop..My life is not "away", in fact I am enjoying it quite a lot. Thanks in part to a great piece of very reasonably priced software.
I hear you and I'm glad for you. I'm sure that LR and PS are great programs, regardless of pricing philosophy.
Julius wrote:
When I photograph tall objects, the sides converge. What is the name of this phenomenon and what software can be used to correct it. I currently use Lightroom and am shooting with Nikon 7100 with a Nikkor 18 - 140 lens.
One of the challenges of photography is that of representing a three-dimensional world on a two-dimensional sheet of paper or display screen. Loss of that third dimension generates distortion which can come in many forms. Taking a minute to understand what is happening can take you a long way down the road to fixing it.
For instance...you describe what you are seeing "the sides <of the building> converge." This in itself is not distortion. It is exactly what you see when you stand at the base of a tall building and look up at it. The sides of the upper floors appear closer together simply because they are farther away. You are seeing it exactly as it is...objects that are farther away appear smaller.
But...when you are looking at the building in real life, your brain knows that your head and eyes are looking up and makes a perspective correction so that everything seems "OK" to you. When you look at that same image rendered on a sheet of paper or on a screen, your brain makes an assumption that the face of the building is parallel to the sheet of paper or the display screen. Now we have a problem, because it isn't. The real problem is not the converging sides of the building. It is that the building appears to be leaning away from you...which causes a very uncomfortable sense of disorientation.
There is an incredibly simple fix for this problem, but it isn't very practical. Simply hold the image up higher than normal and put your eye very close to it. In other words, put your eye where the camera was when the shutter was snapped. Presto chango, the problem goes away (if you have your reading glasses on). This same sort of correction can also be applied to really wide panoramas. Curve them and require the observer to view them from inside the arc, from the position where the camera was positioned when the exposures were made.
I am saying all this to say that when you apply all of the perspective corrections that have been suggested, you do not have to get rid of the converging sides. All you really need to do is to reduce the apparent amount of "building lean" to a more comfortable level. You do not have to eliminate it, but rather just reduce it to a point where the brain can complete the fix. And if you do hang the resulting picture on the wall, hang it as high as you can get away with doing. Preferably high enough that viewers have to tilt their heads back a little bit to view it. It doesn't have to be a lot. Just enough to trigger those corrections in the brain.
My Garden-variety D 7100 does a good job with its menu programs. I forget which one, its been a while since I set it.
If the convergence isn't too severe, look for an elevation to take the photo from, if you have time, or some photo editors can correct some.
Look at Transform in your LR.
Another solution is to keep the camera plumb. If you have room to do that. Crop out the unwanted foreground later.
Or if you shoot an Olympus EM 1 Mark ll camera, you can correct in camera before you take the shot.
Gene51
Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
larryepage wrote:
For instance...you describe what you are seeing "the sides <of the building> converge." This in itself is not distortion. It is exactly what you see when you stand at the base of a tall building and look up at it. The sides of the upper floors appear closer together simply because they are farther away. You are seeing it exactly as it is...objects that are farther away appear smaller.
Actually it is a distortion. Our vision can easily compensate because the degree of convergence is familiar. It is how we see the world. However, when you tilt a camera upward at a building when it is fitted with a wide to ultra-wide lens, this is an exaggerated perspective, and the convergence is amplified. When you compare what you see in the viewfinder when using an ultra-wide lens is NOT exactly what you see with your own eyes.
I totally agree that many work too hard to make the converging lines parallel. Correction the convergence to a reasonable degree is often better than correcting it to perfection. The other thing that is rarely discussed is what happens to vertical scaling, which if you correct in camera, even with shift lenses, or in post processing - gets compressed.
billnikon
Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
Julius wrote:
When I photograph tall objects, the sides converge. What is the name of this phenomenon and what software can be used to correct it. I currently use Lightroom and am shooting with a Nikon 7100 with a Nikkor 18 - 140 lens.
It has been a while since I owned a D7100. My current Nikon's have a Perspective Control, Distortion Control, and a Straighten tool in the Retouch Menu. They are not as sophisticated as those tools found in Lightroom and Photoshop but sometimes are enough for some images.
cameraf4 wrote:
Keystoning.
Funny that, because the sides of a keystone diverge to its top, not converge.
I've also noticed the phenomenon described as "Vertical Perspective Error"... in the free photo
processing program RawTherapee (over the slider that is used to mitigate or remove the effect.)
The effect is also eliminated if you shoot the building with the camera level front to rear instead
of pointing the camera upward.
When we perceive a tall building from the ground our brain
(to a degree) "corrects" vertical perspective error.
Personally I often leave some of the "Vertical Perspective Error"
as it gives a building the magnitude it deserves.
Here I used a wide lens and aimed the camera straight up to enhance the "Vertical Perspective Error".
In the shot below I removed most of the vertical perspective error in post processing, but left a little so that the image seems "real" conforming (I hope) to how ones eyes/brain perceives the building in reality.
Nikon Capture NX-D has perspective control tools. The program is free. Almost all editing software has perspective control tools. You can also buy a PC lens.
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