photography and parallel lines help (keystoning)

I'm having a lot of trouble taking photos of doors and things with parallel lines.

Here are some of mine:





you can see it most of all on the door here:



Can you see how the lines that are parallel in real life, aren't in the photo?  They wander off to the vanishing point.  

I want them to not do that.  I want parallel lines to look parallel in the photo.  How do I change how I take the photo to do this?  

Yes, I know they can be fixed post-production, for a digital camera, but I want to learn to do this with my camera first for several reasons.
1. I don't always shoot digital (sometimes I shoot film)
2. every edit risks degrading the quality of the image
3. I feel very strongly that my learning style requires I need to learn to take technically accurate photos that require very little editing.  I know a lot can be done post-production, but I don't want to be wasting valuable time fixing mistakes that I could simply not make them when I take the photo.

Any thoughts or advice on how I can compose the shot better to make the parallel lines look parallel?  

Stand further back and use a longer lens (ie zoom in a bit). A wide angle lens will exaggerate the problem.  A longer lens will minimise it.

Also stand as 'straight on' as possible to the middle of the image.  With the door, you took it at head height so the bottom of the door is further away than the top. If you took it level with the middle of the door, it would still appear to narrow a little top and bottom, but not so much.  

If you stand back AND get at the right height, it will appear much better.

Go on - take a series of photos at different heights and different distances away (zoom so that the door appears the same height each time) and post the results.

Same with the sign - you're standing near the post end.  Try it standing further along.

What you see are the effects of how the lens is constructed… It can be corrected using software if enough data is avaible. (camera + lens + Zoom level + focus distance.)
I can try to correct one image if you upload a uncropped image (ideally directly out of the camera, that way all metadata is available for the software).

About composition: It may help to position the camera at the upper or lower edge of the rectangular object. That way you don't get that "bulge" in the middle, but rather only one side of it.

I can see the lense bulge.  I don't think there's much I can do to fix that outside of correction software.  

I'm more interested in the parallel lines issue.  I want to try to keep them parallel instead of having them wander off towards the vanishing point.

If you stand back AND get at the right height, it will appear much better.

Thanks, Burra.
I'm going to practice this and see what happens.

Burra is absolutely correct, what you are seeing is the distortion of a wide angle lens.

Eric

r ranson wrote:I'm more interested in the parallel lines issue.  I want to try to keep them parallel instead of having them wander off towards the vanishing point.

If you don't want to correct it in software, you can use a pinhole "lens". Basically a <1mm hole in front of the sensor. The downside is that you will need A LOT of light (and or long exposures). And they are not as sharp as a glass lens.

Looking a bit on wikipedia… how about the Nikkor 13mm f/5.6?

When photographing things that have parallel lines that are not equal, such as a door, window or a house, is called “keystoning” and is a result of perspective caused by not being properly oriented to the subject. For example taking a picture of a house from the sidewalk in front, the sides of the house at eye level are closer than the sides of the house at the roof, hence the distortion. 35mm cameras have long had “distortion control” lenses that are actually split in two and have a knurled knob on them you can adjust and see the sides of the house magically go into alignment. Old view cameras that had bellows were very flexible so the lense could be tilted to correct keystoning and other distortions.

The photographer can correct the keystoning by carefully aligning the camera so it is perfectly oriented in relation to the subject. Twin lens reflex cameras (such as the venerable Yashicamat) were great for visually aligning as the photographer was seeing the image upside down which removes the minds desire to correct the keystoning, because after all, the mind knows that window is square, unfortunately the film doesn’t agree (viewing a photograph or drawing upside down is a good way to gain insight into the composition, good or bad). The viewing screen at the top of the twin lens reflex also usually had a grid on it that assisted getting things straight. Professional 35 mm cameras could often have viewing screens with grids overlaid added. Software can correct the distortion relatively easily upon editing. I have an app for scanning documents on my phone that automatically reads the edges of the photographed document and assign edges that can then be adjusted to correct the keystoning.

James Whitelaw wrote:When photographing things that have parallel lines that are not equal, such as a door, window or a house, is called “keystoning”

Thank you so much.  Great post and now I have a word, "keystoning", I can feed to the googlemonster.

I did a bit better today.  This was taken with the lens set to 55mm and I got quite a bit lower.  Too low.  

But I can see now the advantage of getting further away from the subject.  I also think it would help if I paid attention to the front-back level instead of just the side to side one.  

Shooting with the smallest aperture possible given your light and exposure times may help. Not an expert though, somebody else needs to confirm.


Rufus

Tripods and/or camera quick mounts often include built in levels that can be useful for static shots. Additionally using a stable tripod (also locking up the mirror w/ a reflex 35mm and using a cable release) allows for a sharper exposure if vibration can be minimized. A camera with a built in level can even act as a rudimentary surveying device when coupled with a story pole.

Another issue is to make sure that your film plane (Image receptor in digital?) is perfectly parallel to the object that you are photographing. (Camera back is parallel to the door) Tipping the camera up, down or sideways will also cause this type of distortion.)

If you want to correct this problem you'll need a PC shift-tilt lenses.

Summary of your problem--- Keystoning is caused by not being exactly perpendicular (both ways) to the center of the door or house, etc. Bulging in our out is due to the lens, called lens distortion, and this varies quite a bit lens to lens, and if your're using a zoom lens, it will vary one way or the other based on focal length. Every lens is different; there are no rules; the newer the lens and more professional the lens, the better you will be. Wider angle tends to make things worse, but not so bad if you have a really, really good / expensive lens! Both of these problems are easily fixed in Photoshop (Lens Correction), so I would highly suggest trying this if you are serious about photography. If you try to minimize keystoning with camera placement, you will GREATLY reduce any creative input to your photos. You will be forcing yourself to be in a special spot, and you lose most creative potential for composition (which is always 90% of any photo). I'm an architectural photographer, and I must straighten EVERY picture I take, even when using tilt/ shift lenses. If you want things to be perfect (of course you do...) then you must jump into Photoshop or equivalent. I was typical portrait photographer for 16 years, then switched (almost overnight) to FT architectural (past 13 years). Yes, it happened--- but I had what you might call lots of "providential circumstances". If you are serious about photography, have a brainstorm session about how to SELL your work and MAKE MONEY. Then you can buy all kinds of fancy new gear and lens-- and if you make a magazine cover now and then, you are in "Photographer Heaven". I can teach you if you are serious...... Cheers------- Wayne

You could start using a view camera and shoot sheet film, but that’s a whole other rabbit hole to go down.

Wayne Johnson wrote:Summary of your problem--- Keystoning is caused by not being exactly perpendicular (both ways) to the center of the door or house, etc. Bulging in our out is due to the lens, called lens distortion, and this varies quite a bit lens to lens, and if your're using a zoom lens, it will vary one way or the other based on focal length. Every lens is different; there are no rules; the newer the lens and more professional the lens, the better you will be. Wider angle tends to make things worse, but not so bad if you have a really, really good / expensive lens! Both of these problems are easily fixed in Photoshop (Lens Correction), so I would highly suggest trying this if you are serious about photography.

Thank you.  There is so much to learn!

My learning style is that I like to learn to do things the technically correct way, then break all the rules to see what else I can do.  So I'm starting my camera adventure by focusing on getting the image as perfect as possible 'in camera'.  Once I'm happy with this (probably 6 to 12 months from now), I'm going to focus on learning what I can do in something like photoshop.  

If I can learn how to compose photos with minimal keystoning then I can learn how to control keystoning and use it when I want it.  

If you are serious about photography, have a brainstorm session about how to SELL your work and MAKE MONEY. Then you can buy all kinds of fancy new gear and lens-- and if you make a magazine cover now and then, you are in "Photographer Heaven". I can teach you if you are serious......

I am very interested in learning more.  I don't know if I have the artistic vision to be a great photographer, but I want to be a technically good one.  If it can make money with it, that would make me very happy.

There are little bubble levels you can attach to a tripod or camera, some cameras have built in electronic levels that can be activated onscreen. With practice you will just see it, feel it with your sense of balance, at least some of the time.
I hear the lenses that can perspective shift are very nice, a film setup with all the movements can be cheaper than a 35mm lens designed for architecture shots.

As you develop your photographer's eye for detail you will find that sometimes, its the buildings that aren't straight!