Perspective Control in PS2/3 or other vs Movements

[lightminer]

I put the main thread in Digital Darkroom, but want to make sure you guys see

it. Please respond over there if you have comments.

 

Basically I'm challenging digital darkroom people to straighten a picture

(below) along the lines of what you would use movements for.

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00OvOi<div></div>

[john_shriver]

Used "Warp" in Picture Window Pro 3.1. The horizon is a bit off level, I didn't try for 100% correction.<div></div>

[keith_clementson]

Without a lot of time/fussing necessary to make it right...<div></div>

[lightminer]

Both good! What is really funny is that the buildings are falling over still :). The 2nd one is the worst, and what is really funny is that John's will fall to the right in any major earthquacke or infirmness of ground, while Kieth's will fall to the left!

 

However - I have not played with Warp and will do so - the point here may be that warp is a good one to use. I've used perspective and distort so far.

[colin carron]

I don't think there is any right look to this sort of shot. You can correct the verticals etc in PS all you want and it still looks odd. I have shots which some people think are falling over when I see them as OK. It is often better to leave a little convergence in a shot anyway as that looks more natural. Bit like the Parthenon not having any straight lines in it but looking just right.<div></div>

[Troll]

What is "Warp?"

[john_shriver]

To do this perspective correction properly, you first need to correct for the fact that the camera was tilting downhill to the right. It should be possible to get all the verticials vertical, it just takes more time than any of us have chosen to invest in a "proof of concept".

 

Of course, no photo editor will be able to correct the plane of focus the way that could have been done by tilting the lensboard on a view camera.

[keith_clementson]

Bill,

 

"Warp" is a transforming feature in Photoshop. Go to "Edit", then "Transform", then "Warp". If

you had a shot that truly warranted the time and effort, you can fix some complex

distortions. It helps with barrel distortion and other deformities. If you're patient and do it in

phases, you can avoid the above sharpness issues by sharpening a little after each minor

correction. Can get tedious in some cases, but overall is a good tool to have.

[Troll]

Well, I'm still working in PS Elements 2 -- no "Warp" command here!<P>

1) Apply grid to see how bad it is;<P>

2) Rotate -1.0 to bring building roofs to level;<P>

3) Apply "Perspective" to bring power tower and buildings to vertical;<P>

4) Crop to rectangle;<P>

5) Remove grid and Save.<P>

What am I missing?<P><div></div>

[leonard_evens]

There appear to be two additional problems except the need for perspective correction. There is a slight rotation that should be corrected first. In addition, there may be some barrel distortion.<div></div>

[keith_clementson]

I agree with Leonard. I understood the challenge as the need to correct all of the distorted

elements - not just the buildings. My intention was to show what tool was capable of doing

that very thing IF you care to invest the time. "Warp" allows you to pull and tug in opposite

directions in a sort of liquified manner until everything lines up with the grid.

[keith_clementson]

Merging John and Bill's strategies - "Warp" and "Perspective" - I think is maybe even a better

approach. Maybe. In the right direction, anyway.<div></div>

[paul_miller10]

When I straighten building I use the SKEW function. It is important to pull the image out at the top a bit and push in a bit at the bottom to retain the proportions of the building.

Another trick is to use the tool window on the left side of your screen as a square--just drag it into the image area for reference. It's much easier to see than using SHOW GRID.

[david_thrower]

Hi All,

Here's my go at it.

When I straighten up verticals I use distort on each edge of the image separately then use scale to strech the building upwards to try to retain the shape.

Best regards

David Thrower

[david_thrower]

Sorry forgot to attach image!.

 

Cheers

 

David Thrower<div></div>

[mark liddell]

I know this is only a small jpg but I'm amazed at the degradation the PS filters do to the image.

[kelly_flanigan1]

The degradation may or may not be noticeable in the final image or print; since NO goals for the image are defined; a typical non pro problem. Since one is remapping the pixels by the warp, stretch; filter etc there are details lost that may or may not be a problem. The reasons for using a view camera with movements are more than just prospective; one might want to remove a lightpole by moving the camera sideways; then shifting to capture the building; and not the pole too. Here one doesnt have to retouch out the pole. In mapping work scale is often forced with photoshop where a scan of an old map was done; where the map shrank differently in X versus Y; or the scanner X-Y is off abit too.