how can I eliminate the effect fisheye??

Hello to all
I have a Canon SX270 HS camera
with CHDK .
When I enable the photos in RAW camera saves files in dng
photos have a distortion problem, how can I eliminate the effect fisheye??

Please don't ask the same question multiple times.   The people here who can help you read all postings and will answer when time permits and they have something to say.

You probaby need to study what CHDK RAW/DNG actually is.  There is a lot of good information here :  CHDK Links : Raw & DNG

The short answer to your question is that a RAW/DNG image is a dump from the camera sensor with no corrections applied. What you see is what the camera sees.  So you need to correct any lens distortion effects in post processing (i.e. on your PC).  You may be able to use a lens profile with your post processing software to make this easier. 

I'm sorry I 'm inexperienced duplicate the question because I have not got any response so far.
then you can not solve or alleviate the problem by changing the settings is shooting from the camera ?

then you can not solve or alleviate the problem by changing the settings is shooting from the camera ?

Correct.

Although the problem will be less if you are not using the camera in wide angle mode.

In fact I noticed .
what program I can use to solve the problem of the distortion ?

For Adobe products (Lightroom etc.) you need a lens profile. Adobe provides a tool for creating lens profiles. But this is not easy to use.
=> https://www.adobe.com/support/downloads/product.jsp?product=193&platform=Windows

The best way is using RawTherapee, a very good program for RAW/DNG development. With a little training you get good results.
=> http://rawtherapee.com/blog/features

msl

edit: corrected link for RawTherapee (thx ww)

Thanks for the advice!

I so far I have used adobe CameraRaw but the results are not very satisfactory

My camera is a Canon SX270 HS
and his profile is not loaded from Adobe because originally no photos in RAW

I so far I have used adobe CameraRaw but the results are not very satisfactory

My camera is a Canon SX270 HS

The sx280/270 and sx260/240 models appear to use the same lens (or at least they have the same properties), so you may want to give a try to the sx240/sx260 lens profile. You can find that here: http://chdk.setepontos.com/index.php?topic=9268.0

If CR does not let you use that profile for your DNG files, try editing the .lcp file (it's text) and replace all instances of SX260 with SX270.

RAW Therapee also appears to support *.lcp profiles (with buggy preview), so you can also try applying the profile there.