I've had my Tokina 12-24 f/4 for about a year now and it's been a fantastic lens (original owner). However, over time I've longed for something a bit wider and now I'm looking into the Sigma 10-20. My Tokina is in absolutely pristine shape. Any trade will have to be for a similar quality Sigma 10-20. If you are interested, please let me know and send some sample pics so we can compare before swapping. I'm proposing a straight up trade if qualities are comparable.