Image Help - - Perspective

Charlene5 · #1 07-23-2007, 02:05 PM

This photo was committed by another one of my relations let loose with a Brownie box camera in about 1919

. It's a raw scan, tape and all. I plan to crop it. It's not an "important" picture (or even a very good picture) but I want to learn from it.

My question is this: What kind of distortion is this? The house appears to be falling over. If I correct the perspective on the house the rest of the picture goes whacko. I can cut the photo into two pieces - house in one, fence and dad in the other - and correct them individually and put them back together. Am I looking at barrel or vignette? Please instruct me

Cheers,
MJ

rovis · #2 07-23-2007, 02:39 PM

Wow! amazing photo. I have no idea how the house is distorted like that, definitely not barrel/pincushion... maybe the house has moved while the shutter has been closing

Or perhaps the film hasn't been straight in the camera.

I'd make 2 layers from the photo, mask out sky and house from top layer, and then rotate and maybe distort the bottom layer so that the house is straight. With distort I mean transform - distort.

Swampy · #3 07-23-2007, 03:17 PM

Made a selection along the top of the fence to include all above it in the photo. Put that on its own layer. I used Photoshop CS2's Distort - lens correction.Moved the angle dial clockwise till it looked right and set the scale for edege extension.

byRo · #4 07-23-2007, 05:46 PM

By my calculations (see pic) the house was really falling over - which may explain why someone took the unremarkable pic in the first place.

[Warning geometric mumbo-jumbo follows]
- The effect of perspective is that parallel horizontal lines will (seem to) converge to a point on the horizon.
- The crossing of the Green lines defines two points on the horizon. As these points are at the same level (given the tolerances of the photo) the horizon (Red line) is horizontal (duh!) so the photo was taken with the camera levelled.
- The Blue lines show that, as they converge to the same point, the side of the house is still horizontal and parallel to the fence.
- As the Yellow lines cross the horizon without converging, we must conclude that the front of the house is not horizontal - or, in other words, it's falling over!
[end mumbo-jumbo]

Rô

Charlene5 · #5 07-23-2007, 07:40 PM

Rovis - Thanks for the suggestion. I've never, ever seen a photo like this one

Swampy - Your fix is so perfect! Genius! I didn't even try adjusting the angle. Next time I'll know to try that.

byRo - You made me laugh out loud. The little boy in the picture is my dad and he grew up to be a mathematical genius and an engineer. He probably pointed out the remarkable house to his grandma who hot footed it outside with the Brownie box camera to record the event for posterity

I really love this forum. No matter how bizarre the question I get a really good answer. Thanks!!

MJ

pixelzombie · #6 07-23-2007, 08:20 PM

Quote:

Originally Posted by byRo

- The effect of perspective is that parallel horizontal lines will (seem to) converge to a point on the horizon.
- The crossing of the Green lines defines two points on the horizon. As these points are at the same level (given the tolerances of the photo) the horizon (Red line) is horizontal (duh!) so the photo was taken with the camera levelled.
- The Blue lines show that, as they converge to the same point, the side of the house is still horizontal and parallel to the fence.
- As the Yellow lines cross the horizon without converging, we must conclude that the front of the house is not horizontal - or, in other words, it's falling over!
[end mumbo-jumbo]

Rô
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thanks for the great explanation, maybe you could do a tutorial on perspective when you get some free time...

Swampy · #7 07-23-2007, 10:58 PM

Ro, great explanation! But isn't it wonderful that you can fix that house in Photoshop? LOL

albatrosss · #8 07-24-2007, 12:49 AM

Selected house above fence and put it on a new layer. Cloned out old house and placed this new layer above it. Got it the way I wanted using Transform and then cloned in the fence etc.

Alison · #9 07-24-2007, 05:02 AM

Hi charlene,

I used the perspective tool in photoshop, lost a bit of the house in the process, but I am assuming the image was about the little boy.

chillin · #10 07-25-2007, 09:57 AM

I think the fence isn’t straight.

Dave.Cox · #11 07-25-2007, 10:25 PM

Ro, I like the way you explained that with the perspective lines drawn in. I use that method whenever I have trouble determining the correct perspective, or when I am trying to illustrate it. Nice explanation.

Alison · #12 07-26-2007, 02:31 AM

Quote:

Originally Posted by chillin

I think the fence isn’t straight.

The ground isn't level either

I quickly did a hand colour on this, just for fun. Instead of using colour for the blend mode, I used overlay.

Charlene5 · #13 07-27-2007, 10:34 AM

Thank you, all of you!! Allison and Albatross - thanks for your illustrations and explanations. I've learned some new things and that's good!

The snapshot was taken in the backyard of my great grandmother's house in Memphis, Tennessee which isn't known for it's mountainous terrain

That fence is a real piece of work and I hope it was put up by the neighbor to the left. While cleaning up the tape marks I spent a lot of time looking at it. There are no support posts. The whole creation is nailed to what look like railroad ties plonked on the ground. Underneath the railroad ties are huge gaps and a strategically placed shim. Norm Abrams would be appalled.

I just scanned the one I'm adding. This time the wall on the left is leaning away and the house to the back appears to be falling on it's face. I'd love to know how GGM did it!

MJ