Change angle of view in post

[pixmedic]

lets all keep it nice guys.
at least until the holidays are over. maybe a little longer. we'll let you know.
thanks.

 

[amolitor]

Merry Christmas to you too, pixmedic!

 

[Ysarex]

You guys are wonderful blessings to the forum, jesus saves.

What the dude wants to do is make the parts of the person that were closer to the camera smaller, as if the person was shot from a little farther away. Yes, he's wildly unclear, and he doesn't realize that he'd need to zoom in -- and step back, but if you're following along and paying attention it's obvious. He was too close when he took the shot, he used a wide angle setting. The noses are too big, the bellies are too big, the feet and ears are too small, everything looks distorted and unflattering.

This is gonna be hard, OP. You need to make selective adjustments to every element of the person that's in frame. The parts that were closest to the camera (noses, bellies, whatever) need to be shrunk slightly. The parts that were farther away need to be enlarged a bit. What makes this hard is that often the parts that need to be enlarged are tucked in behind something that needs to be shrunk. Imagine you took a close up face shot:

The tip of the nose, shrink it. The bridge of the nose, shrink it, but progressively less as you go up it., the eyes, enlarge a little. Chin, enlarge a bit MORE, it's farther from the center of the lens than the eyes, ditto forehead. Ears, enlarge quite a bit.

It's a 3D puzzle. Software cannot do it, because the 2D image doesn't have the 3D information needed to fix the picture, although I suppose it could guess. You can probably mitigate the effects of lens distortion a little with these sorts of adjustments, but push it too far and errors are going to creep in that make it look extremely weird.

Yes the OP is confused and it did take a few posts to figure out what he wanted to do. He did however make it clear enough that he has multiple photos to deal with and he's looking for an "enter a number in the box" solution. Responding to that with you need to shrink the nose and enlarge the ears isn't an idiotic suggestion?

The OP needs to distort his photos, but he needs an automated solution to do that. If you read back through the thread you'll find that one of us idiots did suggest a software solution that will at least simulate the effect the OP wants and can automate the process for multiple photos. I don't think I see any other real practical help being offered for the OP's present problem. Good thing for him an idiot was around and, Merry Xmas to all.

Joe

 

[leeroix]

What version of Photoshop? Some tools are not available on earlier versions...

 

[Ysarex]

I thought the OP was talking about the facial distortions too, such as in this article.
The camera DOES lie: Proof that a lens can be the difference between pretty and pretty ugly | Mail Online

but, I just try to avoid wide angle when I take people photos.
But the OP is trying to fix previous photos. Which sounds very difficult to do.

That is an incredibly bad article. It's probably that kind of junk that's responsible for the OP's confusion in the first place.

Joe

 

[amolitor]

Except that dxo won't do it. It's just applying algorithmic alterations with some sliders. It completely fails to deal with the on-axis perspective problems, of one thing behind another appearing too small, the "noses are too big" problem.

The OP wants to do this in an editor and I a) told him what's necessary and b) why it's essentially an intractable problem.

dxo is just a slightly more advanced perspective correction tool.

You cannot actually solve the "make this portrait look like it was taken with a longer lens" problem without a pretty accurate 3D model of the scene.

 

[Ysarex]

Except that dxo won't do it. It's just applying algorithmic alterations with some sliders. It completely fails to deal with the on-axis perspective problems, of one thing behind another appearing too small, the "noses are too big" problem.

The OP wants to do this in an editor and I a) told him what's necessary and b) why it's essentially an intractable problem.

dxo is just a slightly more advanced perspective correction tool.

You cannot actually solve the "make this portrait look like it was taken with a longer lens" problem without a pretty accurate 3D model of the scene.

I didn't say DXo Viewpoint would do it. I said this, "There is no post software option that can actually alter your photo to allow you to move the camera after the fact. There is however post software that can distort your image and may produce an effect similar to what you're fantasizing about."

Yes it is an intractable problem which, as you can see, I said. Viewpoint can distort the OP's image and may be able to do so in a manner that will make the OP happier than he is now. It's the best pragmatic option that has been offered him under the circumstance.

Joe

P.S. People don't look good with big ears -- just look at my avatar.

 

[gold333]

Thanks everyone.

To the guy who suggested I needed something called the "crop" tool thank you.



As a final attempt I will try to be as clear as I can (sorry for mixing up my terms earlier):



I am trying to do composite photography whereby I match a model shot in a studio against a backdrop shot outside. I shot both at 16mm.


Now I want to experiment with the "look" of my composites and am wondering what would have happened if I had altered the focal length between the model and the background. I now want to transform the image of the model into a field of view that is no longer 16mm but exactly 24mm.


@Amolitor:

Thanks so your saying that the liquify tool in Photoshop is my only solution. That's kind of extreme I was really hoping for an automatic FOV perspective changer or failing that some sort of pincushion or vanishing point tool before applying masks and liquifying ears and noses lol


@480: It's the first (basically the difference between 16mm and 24mm)

I have a bunch of pics that look (a little more like) the left, I want to turn them into (a little more like) the right.

Same principle, I have pics that look like at 16mm I want to make them look more to the left, specifically 24mm:

That's easy to do using pincushion, manual lens distortion or any other fisheye to rectilinear projection tool,..... but I was hoping for something that can automatically alter the FOV of a certain focal length image into (something close to) the FOV of another certain focal point image. Without having to take 2 shots, compare, and having to "undistort" things by hand.


PS: The lens profiles in PS don't do this, they just take out the optical "barrel" distortion that most lenses have built in and reduce it by a certain set amount. If I shoot using a fish eye and open the RAW and apply a 600mm lens profile in PS I don't magically get rectilinear projection. It just brightens up the edges a bit and takes out "some" optical distortion and whatnot, it does not change the FOV completely.

 

[amolitor]

Once again, there isn't any way to do what you want. The dxo tool will do an approximation, more or less by stretching and shrinking things based on how far away from the center of the frame they are. The problem is that you have to alter the dimensions of objects based on how far away from the center of the lens they are.

In cases where there's an easy geometric mapping of the 2D picture to a "distance from lens", then you can simply use that. This is what T/S lenses or the equivalent "perspective correction" tool can do, when you're talking about rectilinear structures. The dxo tool can do a more generalized version of the same thing, but still assumes that things farther from the center are farther from the lens -- and that this is all that's going on. If you're taking closeup pictures of people's faces with a wide lens then there is no such simple mapping.

 

[Derrel]

One of the biggest problems in this thread is the MIS-use of traditional terms. Like early on when Ysarex said there is no way to change the perspective, except to move the camera's position in relation to the subject. See, Ysarex understands the term "perspective" using the CORRECT definition. In the latest post, immediately above, the OP is referring to the "FOV" of one lens versus that of another, using the term FOV entirely incorrectly.

Early on in this thread, the terms "perspective", was being mis-understood to mean "apparent perspective distortion", with all sorts of arguing among people who don't seem to know the difference between the two issues, nor the difference between "apparent perspective distortion" and barrel distortion, and so on. All in all, a giant cluster-copulation of misunderstood terms, misappropriated terms, and arguing at cross purposes.

As far as the images in the shots above, the desire for a software solution to change close-range, wide-angle images into images that look like they were shot from farther away with a longer focal length lens...with precision, millimeter conversions...I'm not aware of anything that is that cut-and-dried, but there might be something.

 

[Ysarex]

Thanks so your saying that the liquify tool in Photoshop is my only solution. That's kind of extreme I was really hoping for an automatic FOV perspective changer or failing that some sort of pincushion or vanishing point tool before applying masks and liquifying ears and noses lol

As Amolitor suggested earlier you'd have to have your image 3D mapped in order to use a tool that would alter FOV. Such tools exist but only in the world of 3D modeling. You can fake it with 2D tools that distort the image and liquify away.

Joe

 

[Ysarex]

One of the biggest problems in this thread is the MIS-use of traditional terms. Like early on when Ysarex said there is no way to change the perspective, except to move the camera's position in relation to the subject. See, Ysarex understands the term "perspective" using the CORRECT definition. In the latest post, immediately above, the OP is referring to the "FOV" of one lens versus that of another, using the term FOV entirely incorrectly.

Early on in this thread, the terms "perspective", was being mis-understood to mean "apparent perspective distortion", with all sorts of arguing among people who don't seem to know the difference between the two issues, nor the difference between "apparent perspective distortion" and barrel distortion, and so on. All in all, a giant cluster-copulation of misunderstood terms, misappropriated terms, and arguing at cross purposes.

As far as the images in the shots above, the desire for a software solution to change close-range, wide-angle images into images that look like they were shot from farther away with a longer focal length lens...with precision, millimeter conversions...I'm not aware of anything that is that cut-and-dried, but there might be something.

Amen to that!

 

[amolitor]

You could probably do it pretty well with some mapping software. To really do it right you'd need to be able to tell the software "this point is in front of/behind this other point" and by about how much, creating an approximate model of the person. This is not super hard, but there is a bit of user input to do it. They you throw up a wireframe rendering for checking (or, if you're smart, you assume it's a standard human face). After that it's just geometry and bog-standard image processing.

Adobe is working on something that might come close:

Sneak Peek : Perspective Warp in Photoshop | Adobe Technology Sneaks 2013 | Adobe TV

This doesn't build full-on models, but does allow you to essentially build "enough" of a box model to fake it. This isn't available, alas, but illustrates some of the problems.

 

[Josh66]

I have a bunch of pics that look (a little more like) the left, I want to turn them into (a little more like) the right.

The way to do that (in camera) would be to use a longer lens and stand farther away. It can't be done without moving the camera.


Doing that after the fact, in PP ... I couldn't say off the top of my head how to do it, but I'm sure it's 'possible'. It may be more work than it's worth though - it would certainly be better to just get it right in the camera...