r.hackett wrote:
If I remember correctly, I believe it's because you can also use a larger battery inside the grip which would not fit if you had 2 in there. I think if you use the larger battery you can get a faster frame rate. (I may be completely wrong as it's been a while since I Looked into the grip and I might be thinking of something else)
Thank you, I hadn't noticed but I'll bet that EN-EL4a is larger. They want $109 for it so I did not look too close.