 BetterPhoto Member |
how to keep lines straight I have a Canon Powershot S500 digital camera. I am doing a project and need to take several pictures for several paintings with sizes of 20" X 36" and 24" X 48". I run into following problem: I put a picture on the white wall and take the photo using optical zoom only. The distance is about 3 - 4 feets. The result showed that two vertical edges were not straight lines. The picture was wider in the middle and slightly narrower at top and bottom. Since I am new to digital cameras, I don't know what caused this problem and how to fix it. Please help.
|
|
|
|
||
|
Jon Close |
It is a common phenomenon (especially with zoom lenses) called barrel distortion. Pincushion is the opposite, with the vertical lines bowing in at the middle. This can be minimzed by backing up and using a longer zoom setting - many zoom lenses have barrel distortion at the wide end, pincushion at the long end, and fairly true somewhere in between. Alternatively, because the distortion is minimal in the center of the frame and becomes worse at the edges, step back (without compensating with zoom) and don't try to fill the frame with the picture. You can then enlarge and crop later with less distortion. Finally, there are software fixes that can be applied in an editing program, though I'm not familiar with the specifics.
|
|
|
|
||
|
Jon Close |
P.S. Best results are obtained if you are shooting exactly perpendicular to the painting. If the camera is to one side or higher/lower than the painting, it'll cause "keystoning," where the more distant side appears to be narrower than the near side.
|
|
|
|
||
|
Dave Cross |
Hi Yvonne. Do everything that Jon says :-) AND Don't use flash, use daylight off to one side if possible to avoid horrible reflections. You might try hanging a net curtain over the window to give more diffuse light. Do use a tripod. Get the centreline of the lens as close as possible lined up with the centre of the picture. This will minimise the keystone effect. Make several shots with different settings, particularly, bracket you exposures, digital is free, take many shots. Once you have your masterpiece in the computer you can tweek the image. If you have PhotoShop you can fix any remaining barrel/pincushon distortion or keystoning. If your image editing software does not do distortion corrections, crop the image so that you don't see the picture frame, the remaining visible distortion will miraculously disappear when you don't have the reference of the straight edges. The human eye is a wonderful thing, the distortion is obviously still there, you just don't see it. When you've done, post a couple of samples here, we all like to see the results of people following our advice :-) Cheers
|
|
|
|
||
|
This old forum is now archived. Use improved Forum here
Report this Thread |
||