Stop Motion Camera Effect

I'm trying to achieve a stop motion effect similar to those claymation movies of the 50's. I seem to be running into a problem though.

I'm taking a "snapshot" of the scene then waiting till enough time has passed (framerate speed), then replacing that snapshot with a new one... over and over.

The script seems to be working, BUT there is kind of a stuttering effect. It seems as if the image that is getting snapshotted, is blank. (All I see is grey)

Here is the script. Let me know if you guys notice anything funky. Thanks!

 var frameRate:float;
 
 private var nextFrame:float = 0;
 
 function OnRenderImage(source:RenderTexture, dest:RenderTexture){
     if(Time.time >= nextFrame){
         Graphics.Blit(source, dest);
         nextFrame = Time.time + (1/frameRate);
     }
 }