DP2m Lens Distortion Problem

Started Sep 3, 2012 | Discussions thread
OP jbr Regular Member • Posts: 310
Re: DP2m Lens Distortion Problem

SandyF wrote:

Today I'm into processing the 17-Mile Drive, Pebble Beach, Carmel CA, set in which MANY of my horizon lines aren't straight... either DP2Merrill or 16-35mm f/2.8L II lens on the Canon 5DII. I've found on several that the 16-35mm actually HAS some barrel distortion, which I can fix in Canon's processor Digital Photo Pro (DPP).

For the DP2Merrill crooked shots, I've saved JPEGs or TIFFs, then opened them in DPP and used the adjusment/crop tool. It has grids and I can see by laying it on the horizon of the DP2Merrill shot that the DP2Merrill horizon actually does NOT have distortion... it's just plain crooked (by my holding of camera) and I've cropped and straightened. I'll get a few of the finished photos up onto flickr.

Sandy, I been looking at your photos and making some measurements to compare to mine. I did have to straighten the horizons. Here is a crop from one of yours showing just the horizon(cropped at the horizon). There is a curvature.

And here is the same image squished so that the curvature is more visible. It works out to be about 12 pixels maximum at the centre. That seems to be about the same as mine at that image height (around 600 pixels from the top edge). Maybe someone could enlighten me on what that means in barrel distortion terms. It is a very nice curve!

Joe

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