Nx300 Lense Buying

You've got a mirror less camera there so your subUS$300.00 options are phenomenal if you are prepared to go to old manual focus lenses. I have a number of macro lenses and the one that I always fall back on is the minolta MD 50mm macro. It has virtually no distortion and with the 1-1 adapter that comes with the lens you can't go wrong I did a quick check on ebay: heres one:

http://www.ebay.com/itm/Minolta-MD-...em2593c942bf

and another:

http://www.ebay.co.uk/itm/Minolta-L...em2593bf2c5c

I have a Modern Sigma 105mm EX macro and the Minolta MD50 mm macro outperforms it easily. At the price you can't go too wrong

You will also need an adapter to fit the lens to your camera heres one:

http://www.ebay.com/itm/Minolta-MD-...em33857bc5a0

With the adapter and lens the very most you should be spending is US$100.00. I know Minolta lenses best, but be aware there are old Canon and Nikon lenses that will also likely fit your budget. The good thing with you having a mirrorless camera is any of the old lenses you buy will also be good for every day photography( minus the 1-1 adapter).

Edit....these old lenses hold their value so you can buy try and resell if your not happy

Edit 2: Focus peaking( your camera has it) makes using legacy manual focus lenses easy, you will need to ensure the camera is set to operate the shutter with out a lens( as there will be no electronic contact between the lens and the camera, the camera in default setting will refuse to release the shutter) changing this setting should be very easy.