I´m having poblems with high zoom on blobs. I was using PolyRay with no problems, but, when I changed for POVRay, thetransition area between the spheres had a gap.
 
blob.pov

#include "colors.inc"

camera {
   location <0,0,-1.5>
   look_at <0,0,0>
   up <0,1,0>
   angle 30
//   resolution 250,250
//   aspect 1
   }
//background SkyBlue
light_source { <-15,30,-25>, color 0.6 * White  }
light_source { < 15,30,-25>, color 0.6 * White  }
object {
    blob {
 
 
    // threshold 0.6
        // quase se encostam blob_1.tga
        // sphere { <0.6725250, 0, 0>, 1.0, strength 1.0 }
        // sphere { <-0.6725250, 0, 0>, 1.0, strength 1.0 }
 
        // se enconstam (blob_2.tga)
        // sphere { <0.6725125, 0, 0>, 1.0, strength 1.0 }
        // sphere {<-0.6725125, 0, 0>, 1.0, strength 1.0 }
 
        //sphere { <0.67252, 0, 0>, 1.0, strength 1 }
        //sphere { <-0.67252, 0, 0>, 1.0, strength 1 }
 
        threshold 0.5

        sphere { <0.7, 0, 0>, 1.0, strength 1 }
        sphere { <-0.7, 0, 0>, 1.0, strength 1 }
 
 
        sturm 1.0
 
     texture {
        pigment { color Red }
        finish {
            ambient 0.1
           diffuse 0.8
           specular 1
           phong 0.7
          }
       }
     //rotate <0,30,0>
    }
}