 Jnaneshwar Surabathula |
distortion, tilt using a wide angle lens
Thanks.
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W. |
Hi Jnaneshwar, what you see is typical wide angle perspective distortion. It comes with the territory. The extremer the wide angle lens, the extremer the effect. (And vice versa, of course). You can try to 'bend it back' in Photoshop. But next time you see that distortion through your viewfinder, slowly move the angle of your camera/lens up (in the vertical plane), and you will see the tower 'straightening'. Move up more and the tower will even end up tilted the other way! Good luck.
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Jnaneshwar Surabathula |
Thanks Smith, I shall implement your suggestion and see.
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W. |
BTW: to be able to judge easily if horizons are horizontal and perpendiculars perpendicular I use a grid in my viewfinder. It's also very helpful with composition. Especially the 'Rule of Thirds'.
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Jnaneshwar Surabathula |
I'd be glad if you could elaborate on that!
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W. |
There's not much more to elaborate on. Some digital cameras have that grid available. If they do it will be covered in the manual. It's a matter of switching it on somewhere in the menus (varies per cam of course). Some film cameras had it too, 40/50 years ago already. Then it was usually an engraved piece of glass that needed to be mounted inside the pentaprism assembly. I swear by it.
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Alan N. Marcus |
Hi all, What Jnaneshwar has discovered is known as Distance Distortion. Natural prospective causes far objects to appear smaller than nearby objects. A picture of a road or railroad track reveals convergence with distance. It makes no difference if we are viewing the scene for ourselves or if we photograph it. It’s a simple fact that nearby objects appears larger than distant objects. This is the major ingredient we use to gauge distances.. Stated another way; Things close to the camera reproduce larger than things further away. Now a short (wide angle) lens reproduces all objects small as compared to a normal lens. The short lens causes an exaggerated size difference between far and near. Consider tall buildings and telegraph poles. Generally the camera to pinnacle distance is greater than camera to base distance. This results in the tops being reproduced noticeably smaller than the bottoms. Walls and doorways known to be parallel and square reproduced rounded and distorted due to differences in distances, camera- bottom to camera-top. Stated another way, it’s the camera to subject distance plus the short focal length that amplifies the distortion. The long lens however goes the other extreme. It’s no comfort, but if you were viewing the picture at the “correct” viewing distance, there is no illusion of distortion. The correct viewing distance is the taking focal length times the image magnification. Say a 12mm lens is used and a 4x6 print is made. The magnification to make the print is about 6 times. Thus 12mm x 6 = 72mm or about 3 inches viewing distance. You can’t examine the print at that close range except by using a magnifying glass. If you looked with a glass and the eye is about 72mm away, there is no impression of distortion. That’s why the old faction hand slide viewer for 35mm slides was popular. It places the eye at about the correct distance for distortion free viewing. Happy New Year All
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Andy |
Hi Jnaneshwar. One of the Nikon film cameras, N80 (or F80 outside USA) has a On-Demand Grid Lines feature in the view finder to help composing with horizontal and vertical elements. That's the only SLR camera that I know of has that feature built in. I think there are some digital point-and-shoot cameras has that feature on the LCD too. The focusing screen in many high end (D)SLRs are replaceable. And those focusing screens has different line patterns to aid composition. Hope this helps.
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Jnaneshwar Surabathula |
I appreciate all the responses; it always helps in learning consistently.
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