what MM FL is left when you 'straighten' a 15mm fisheye on FF?

when shooting on a FF sensor with a 15mm fisheye and you get it into the computer and then use starightening software (e.g. DxO or LR etc -not the hemi etc plug ins etc as they dont really fully straighten)
what EQUIVALENT FL are you left with on average?

I'm kinda wondering about this too...
Here's some nice examples about it (http://photo.net/learn​/fisheye/ look in the comments also), which show you that the simple conversions give you a different aspect ratio, something more like 16x9. I've seen this in many examples so I guess it's a natural effect.

Do keep in mind that you'll lose quite some resolution near the edges though, since they're stretched significantly.

TweakMDS wrote in post #11063005
Do keep in mind that you'll lose quite some resolution near the edges though, since they're stretched significantly.

cheers.
Well IM kinda used to that as the 17-40 I use most, is poo in the corners

If I recall, and it's been a couple of years since I did it, a "de-fished" 15 mm fisheye works out to around a 12 or 13 mm rectilinear lens equivalent on full frame. It's definately wider than a 16 mm.

Tom W wrote in post #11063974
If I recall, and it's been a couple of years since I did it, a "de-fished" 15 mm fisheye works out to around a 12 or 13 mm rectilinear lens equivalent on full frame. It's definately wider than a 16 mm.

cool cheers