Getting perfectly straight verticals without editing?

[TCampbell]

Getting the horizontal lines level is easier... just make sure the camera is level left-to-right.

Getting the vertical lines plumb is a bit trickier.

If the camera lens is pointed up - rather than pointed level toward the horizon line - then vertical lines will pinch inward as you follow them up. If the camera lens is pointed down then the lines will spread apart as you follow them up. So the trick is to have the camera not just left from side-to-side, but also level from front-to-back.

This solves one problem, but creates another because now you're likely cutting off the tops of tall structures.

You can fix this either in post-processing (e.g. Photoshop's transform tools or it's lens-correction filters are two different ways to do it.) -OR- you can use a tilt-shift lens and use the "shift" adjustment.

Both of these images were shot with the same lens (and it is a tilt-shift lens) but in the first image the lens is in the neutral position (so it's basically acting like an ordinary lens - having no tilt and no shift adjustment dialed in.)


Riverhouse (uncorrected) by Tim Campbell, on Flickr

In this image, I've applied an upward shift (only the shift axis is adjusted to do this - no tilt axis is used.)


Riverhouse by Tim Campbell, on Flickr

There is one tip I learned a while back... which is that the verticals should not be perfectly plumb. They should pinch in... but just very very slightly. Basically you would adjust the shift until you think it's perfect... and then just back off the shift by a very tiny amount so that you're only maybe 98% correcting instead of 100% correcting. The reason for this is that the brain actually does EXPECT things to pinch in and if they don't pinch inward at least a tiny amount then the brain is tricked into thinking that the structure is actually getting wider as it goes up (even though if you overlaid a grid you'd see it's perfect). It's just an optical illusion. But pinch it in just a fraction and the building will look normal.

 

[KmH]

Using Wide Angle Lenses
Using Tilt-Shift Lenses to Control Perspective
Using Tilt-Shift Lenses to Control Depth of Field

 

[astroNikon]

All you can do is keep things level horizontal and vertical and if the property is very tall, you are SOL.

He only has to place the camera equidistant between the top and bottom of the image to be taken. A tall ladder might suffice , although it may not be the visual perspective that is best for the image. Otherwise the issue of convergence of parallel vertical lines has one real solution if no/minimal editing can occur by the photographer.

 

[john.margetts]

First, you need to identify whether the vertical lines aren't 100% plumb due to

a. user error
b. tripod balance issue
c. lens distortion
d. perspective distortion

e. sloping building

If you was to photograph Lincoln cathedral, you would be unable to get either of the west towers vertical as both lean alarmingly.

 

[plaxico89]

Thanks for all of the feedback everyone, it's very helpful!

 

[fmw]

What you need is a rectilinear (virtually free of barrel distortion) wide angle lens. It definitely won't be a zoom since none of them are rectilinear in the wide angle area. Be prepared to spend some serious money on a high quality rectilinear wide angle lens. The tilt shift lens mentioned above will prevent the image from appearing to be falling backward when you tilt the lens skyward. These lenses are normally rectilinear but they won't do anything in your case that any rectilinear wide angle can't do with a level orientation. I don't know enough about the Canon lens line to suggest something specifc but it will be an L lens.

Rokinon and similar brands sell a tilt/shift for around $700 or so. I doubt you can find an appropriate Canon lens for less. I don't know how rectilinear it is but chances are it will do the job.

 

[petrochemist]

Shift lenses are designed especially for this so if they're not rectilinear then they're pretty much useless. Tilt isn't actually going to add anything to the lenses usefulness for architecture but it's unusual to get shift without tilt as well.
I definitely sounds like a job for a rental lens unless you have a big contract to fulfill that will have you needing the lens for years. Even then renting to find the model that suits the subjects best might be well worth while.

I've not got Tim's experience in using shift lenses but agree with him completely on not fully correcting the verticals. Quite a few of the books I have show examples of shift lenses in action where they do completely correct the verticals & to me the uncorrected shots always look considerably better. Tim seems to have got the balance right so his corrected shot looks natural.