I've just got a new Sigma lens and wanted to try catch in focus, I found the info below but when I try it no picture is taken, any ideas?

1. Menu -> Custom 3 -> Item 20 "Catch in Focus" -> Toggle On.
2. Pop your camera to AF mode.
3. Switch your lens to MF mode if you have an AF/MF lens.
4. Switch your AF mode to AF-S.
5. Compose your photo where you predict your subject will be.
6. Press the button, hold and wait for the subject to come into the frame.
7. Camera fires when in focus.

I've ordered the Sigma lens, been up since 6:30 reading reviews of that and other lenses in that range it seems to fair well, I will see when it arrives

I was thinking of getting the Sigma 18-250mm DC OS HSM because it would replace 2 lenses, the 18-55 and 70-300 Tamron I have, but the more I look in to it the more I wonder am I doing the right thing, the shop I'm buying it from will give me the full value back for my Tamron as I only bought it from them a couple of weeks, they are both compared here link

If I get it I will need to order it tomorrow so any advice would be welcome

I've ended up buying a polarising filter I've book marked the above page and will have a full read of it.

Thanks for the replies I guess I'm not 100% sure what I need but looking in to ND filters I think I will get one as when I'm taking landscapes most of the time the sky whites out, afaik this will stop that?

I will have to take a trip to the local shop see what I can find, just picked up a Sigma 50mm EX DG Macro I take it I wouldn't need any sort of filter for macro work?

@Simonkit, just looked at your website, stunning pictures I would be happy if I could achieve results have as good

I'm using digital, what decent brand names should I be looking for?

I'm looking at getting some filters but I'm not sure what I want or need, the only one I have at the moment is a sky filter, is it worth paying more for one or are the cheaper ones ok?

A Tamron 55-300mm + a 2x adaptor, the locust was the 18-55mm that came with the camera

Thanks for the advice, I know they aren't perfect it was windy and the animals wouldn't stay still I will make the changes to my camera now and see how I go