I have a D7000, but lately I have been considering going FX to the D600. Up until 6 months ago, I mainly photographed birds and my dogs. But for the past 6 months, I have mainly been shooting my 6 month old son and people with my son. I've been shooting indoors and have found my go to lens is the 35 1.8, although it isn't my favorite lens I own. I love my 50 1.4G and 85 1.4, but find the focal length is just too long for the indoors and I can't quite capture what I want to capture. I have been thinking of purchasing the 35 1.4G, but with the price tag, I can't quite justify spending that much when I could go to FX and use most of my lenses. I was hoping to hear other's (who are more experienced and knowledgeable) opinions on this. I don't want to upgrade just to upgrade. Thank you in advance.