Building on the earlier suggestion, the technical side of a fast lens basically boils down to that f-number; lower numbers like f/1.8 let in more light and create shallow depth of field for that bokeh you're after. When I started out, I spent way too much on heavy f/1.2 glass before realizing f/1.8 is often the sweet spot for weight and price. For your $600 budget, these are solid alternatives:

• Panasonic Lumix S 85mm f/1.8
• Killer for portraits. The longer focal length makes backgrounds look even more compressed and blurry than a 50mm.
• Sigma 35mm f/2 DG DN Contemporary
• Great for Seattle streets. It's compact, built like a tank, and gives a wider view than a standard lens. I found that the 85mm made getting pro looking shots of family much easier since you dont have to be right in their face. Definitely check used listings to save some cash.

> my logic was that a 50mm f1.8 seems okay but then i saw more expensive ones and got scared. Unfortunately, cheap glass usually has compromises. Fast just means a low f-number like f/1.8, which lets in more light for that blurry look. I had issues with heavy focus pulsing on third-party lenses with this body. Just get the Panasonic Lumix S 50mm f/1.8. Its not as sharp as the expensive ones, but it actually works with the S5 autofocus system.

Quick follow up... are you shooting mostly tight portraits of your nephew or do you want more of the Seattle scenery in the frame? If you want a real street look, a 50mm can feel a bit zoomed in. I've used the Sigma 35mm f2 DG DN Contemporary for years and it's way better built than those plastic Lumix primes. Quick tip: you dont need f/1.4 to get blur, just get closer to your subject.