New Member- Help Needed On Perspective!

[alexcell33]

Hello thephotoforum!
Im new here and I need some advice on some photos. I posted these pictures on a non photo related forum and I was told I need to adjust the perspective of my photos to get straight lines in photoshop. A few people said this but I'm not really sure exactly what their talking about, should I just straighten the photos or do perspective adjustment, because they don't look crooked to me. Thanks for the help!
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[Msteelio91]

Welcome!

Except for #'s 3 & 4 I'd say your horizons are pretty straight. They may be talking about all of the "leading lines" that are created from the warehouse and objects within. I actually think #1 is a pretty cool shot, the rest aren't too exciting though. I'd say to just try and work on your composition.

 

[Designer]

I think they are referring to the distortion commonly generated with a wide-angle lens. Photoshop has a distortion-correction tool.

 

[Ysarex]

They're talking about this: Your camera was rotated 1.5 degrees clockwise and tilted back. Your lens has some mild barrel distortion. Fixed all three.

Joe

 

[alexcell33]

Thanks for the help everybody. I can definitely tell 3 and 4 need some work. Im pretty new to photagraphy still trying to get the hang of things.

 

[TCampbell]

There are two different issues going on here.

Most of the images are not "level" (your camera body was physically tilted slightly relative to the horizon line when you took them.) This is evident if you find something in the CENTER of the image that should be straight up and down (the support beams in the building work well for this). But note that you should ONLY look at objects in the center of the image... avoid left & right (they have a different problem.)

In image #1 for example, the camera was tilted just slightly left of plumb.

Next... if the lens was tilted either slightly up or slightly down AND you were shooting wide angle (and you were) then you'll get wide-angle distortions which skew the perspective. This is evident if you do the opposite of what I said above... ignore the center and now just look at the vertical support beams on the extreme left vs. the extreme right. Those beams "should" create parallel lines in your image (they are parallel in the real world... but not in your image.) They pinch inward because the camera lens was tilted slightly upward or downward.

In image #2 for example, the camera is mostly "level" based on the crate in the center of the room. But if you look at the extreme left and right edges, you'll see the vertical lines are pinching in as you follow the image upward. This is because the lens was pointing up above the horizon line so it causes this "pinched" perspective distortion. If a lens is perfectly level to the horizon line, this won't happen... but then you may not get the composition you actually wanted (not without finding a way to move the camera up to a higher shooting position.)

A "tilt-shift" lens (specifically the "tilt" function ... Nikon uses the term "perspective control" lens instead of "tilt shift") can correct this at the time the shot is taken. It would allow you to shoot from floor level, with a composition you want, and yet STILL have straight verticals. But Photoshop can fix this after-the-fact. But when you fix in photoshop you'll slightly pinch or stretch one edge of the image, turning it into a trapezoid (keystone shape) instead of a rectangle. The image then needs to be "cropped" back to a rectangle again -- so you lose some of the image when you fix it. For this reason, if you know you'll need to fix perspective because you don't own a tilt-shift lens (they are VERY expensive) you usually want to think about what parts of the shot you definitely want to keep in the image and then shoot it to leave a bit of room for cropping after fixing in Photoshop.