You don't need octane to get good renders out of Poser. You just have to learn the materials and lighting, and that can be a challenge so it just takes practice to achieve the look you want. Become friends with the material room. I linked to a video tutorial about the material room in P10/2014 up above in my first post. 

To change gamma on the transparency maps, click on the eye in the top right corner of the transparency map node (in the materials room, with the hair selected), to expand the node and see all the info in it. Then click the word in white to the right of where it says 'image source:' .  A dialogue will pop up with the option to browse for a different image and gamma is at the bottom of that dialogue. Don't change the image, just check custom gamma and set it to 1.00

ETA: Sorry - correction, click the min/max button just to the left of the eye icon in the top right of the trans node. The eye will show the trans map (if there is one), the min/max button will expand or collapse all the values in the node. 

 

 

~Shane