Early scans - is one twin always out of focus?

Aislin
I'm not worried, just for the record.
Had another scan today (one baby measuring 8+2 and the other measuring 8+4) and saw both babies and both heartbeats. But we can only ever look at one baby at a time, because when the wand is focused on one the other disappears.
The sonographer says it's just the way the babies are positioned - but I only ever get scan photos of one twin in focus and one out of focus. (See, it looks almost like an empty sac but we saw baby fine, you can just about make him/her out at the bottom of the sac) 
Will I get two photos (one of each baby) when they're bigger? Or will they both be in focus by then?