I'm trying to learn to do make better lattes and cappucinos. The guy I affectionately refer to as "the milk nazi" has an article on learning the technique to froth the milk into the perfect foam:
"With all of this said, I do not want to hear excuses that the drink you made today wasn’t as good or the foam not as tight because all of a sudden this milk is obviously from a Jersey cow and you’re used to milk from a Guernsey cow or that the cows are into the clover and alfalfa these days and we all know that dry feed produces the best flavoured milk…and so on. We’ll assume that the milk is generally stable and that if the foam isn’t there and the flavour isn’t there…well, it’s you."
Alas, I digress... but there is a point to this. I'm sure you are well meaning and probably believe this is the cameras fault. I've been shooting for a very long time (since about 1975). If your images are coming out slanted... it's YOU. And I do mean that in kind and gentle way. But this is one area where you can not blame the gear.
Before you beat yourself up over it, there are some reasons that even a "level" camera (left to right) can render objects leaning that were certainly not leaning in real life.
Most lenses and zoom lenses capable of wide angle photography are designed to be "rectilinear" lenses. This means that any "straight" lines in the image will actually be "straight" in the resulting image. But "straight" does NOT mean that there's no perspective distortion.
In a wide angle rectilinear lens (which is what most lenses are) the "straight" lines will "lean" in toward the "vanishing point" in the perspective. We know that railroad tracks are actually parallel in real life. But the distance between the rails seems to narrow the farther away they are.
If I take a photo of a telephone pole and the pole is precisely in the middle of the frame then the pole will appear to be "straight" and "level". But if I move the composition to the side so that the pole is ... say on the left side of the frame, the pole will appear to "lean" toward the center (even though in real life we know it is level and not leaning.)
This is a normal effect of wide angle distortion and not a defect.
BTW, the "other" type of wide angle lens is the "curvilinear" wide angle lens. It's more commonly called a "fish eye" lens. In that lens, straight lines will appear cuved... every "straight" edge will appear curved UNLESS it happens to pass exactly through the center axis of the image (in which case it will appear straight.)
You can minimize the effect of "leaning" if the camera is perfectly level not just left-to-right (which we'll call "tilt") but also level front-to-back (which we'll call "tip").
Tilt-Shift lenses (specifically the "shift" effect of the lens) is designed to correct for these perspective distortions that create "unlevel" images. You can also correct for perspective distortion in software BUT you need to leave a little extra space around the object you are shooting because the software will stretch the image into a shape which is no longer a normal rectangle and then it has to be cropped back to a rectangle... so you need to leave room to allow for the crop.
If you are concerened about testing for level, there are a number of two-axis spirit levels that slip into the camera hot-shoe. Just search the web for "two axis spirit level" and you'll find LOTS of them.
Here is just one: http://www.amazon.com/Opteka-Double-Bubble-Digital-Cameras/dp/B000YJ2Q9U/
Tim Campbell
5D III, 5D IV, 60Da
