Correctly exposing the sky

[Dao]

Yup, either OP need a recording medium that can response to higher dynamic range or just need to bracket the shots.

By bracketing the shots, it does not mean you need to tone map it. Take a look at the link I post earlier.

 

[rexbobcat]

What you can do if the horizon is fairly flat is that you can bracket shots, then place one over the other in Photoshop or GIMP and erase the parts of the overlaying photograph that you don't want. Basically it's like taking a photograph exposed for the ground, and then taking a photo exposed for the sky and placing the 2nd over the 1st. Then you would erase the incredibly underexposed ground in the 'sky photo', so that the properly exposed photo of the ground will show up. I hope that makes sense. It's like creating an HDR image, only I believe it can make the photo seem more realistic and it's more time-consuming.