Are there any free or better alternatives to Fisheye-Hemi?

Question

I've been tempted to get a fisheye lens (The Nikon 10.5 DX specifically), and have seen the Fisheye-Hemi plugin for "normalizing" fisheye images.

Does anyone have experience of using the plugin or know of free or better alternatives?

Asked by Freed

Answer

As far as free alternatives you can try Fred's defisheye script for ImageMagick, or Fulla, which is a command line tool that comes with Hugin.

Fisheye-Hemi is superior to these, though, as instead of using a standard remapping to a rectilinear projection that softens the edges and requires an aggressive crop it uses a custom mapping algorithm that preserves much more of the original image and sharpness and still straightens out lines.

This blog post is interesting, the guy fed an image of a grid pattern through the Fisheye-Hemi plugin and then created a warp transform in Photoshop that approximately matches the deformation on the grid. Pretty clever.

Answered by Miguel

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Are there any downsides to applying the lens correction profile in Adobe Lightroom?

Question

Assuming that you are using a good lens profile, say one that Adobe has predefined in Lightroom, are there any downsides to automatically applying the appropriate lens correction profile when the photos are imported?

The lenses I am shooting with appear to be correctly identified by Lightroom so there is no risk of the wrong profile being applied.

It seems to me that applying it would give you the most acurate representation of what ever it is you are photographing.

Asked by Joe Solano

Answer

Most post-process lens corrections will cause a loss of detail, as they are not just modifying how the raw pixels are interpolated and what mathematical curves and adjustments may be applied...they change the position of pixels throughout the whole image. At the very least, you'll lose some amount of sharpness, and fine detail may be lost in some areas of the photo. Unless you have some very specific need, such as a photograph of a brick wall that is clearly demonstrating barrel or pincushion distortion, or pronounced CA, generally speaking I would avoid applying any lens profile.

If you want a simple rule of thumb...if your photo is clearly unacceptable without lens profile correction, and acceptable with it, then use a lens profile.

Answered by jrista

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How do I turn off lens correction in Lightroom 3?

Question

I'm trying to improve Lightroom performance on my Mac and have read that turning off Lens Correction can help the "Loading" times in the develop module.

I really don't care about lens correction and shoot "lomo", so how do I turn off this feature in Lightroom 3?

Answer

When in Develop, there is a Lens Correction panel. Within this panel you can turn profile lens correction on or off using the Enable Profile Corrections checkbox

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