Paragons of virtue

As I said in my first post the Sigma 70-200 would be my first choice, but as others have mentioned the 18-135 would be a good bet if you are going to be closer to the action. Ideally you would need both lenses with you.

As a rough guide (if I've got my sums right), to fill the frame at 70mm you would need to be about 5 metres from the rider. Any closer and it won't fit the frame. At 200mm it would be closer to 15 metres.

But if you are this close, then the 18-135 is a better bet.

+1 for the Sigma - fast autofocus and good image quality, and the in lens image stabilisation can be set for panning - but it's a heavy(ish) lens.

The Pentax 60-250 is lighter and has water resistance - autofocus speed is good enough, but it's likely to be the more expensive of the two.

This lens was purchased new from SRS in January 2014. Since then it has seen little use, so I have decided it's time to sell. It's in excellent condition with no scratches or marks that I can see, and is in perfect working order.
On offer at £200 including UK delivery.

True, but there are times when a card is just not recognised in the camera but can still be seen on the computer.

This could be a useful link for those of you who may have problems with SD cards (especially after formatting them via your computer rather than in the camera . . . . . . . ) and you want to reformat them correctly.

link

The following lenses are not supported according to Pentax; using these lenses with the converter will damage the lens or converter:

SMC Pentax-DA 15mm F4 ED AL Limited
HD Pentax-DA 15mm F4 ED AL Limited
SMC Pentax-DA 21mm F3.2 AL Limited
HD Pentax-DA 21mm F3.2 AL Limited
SMC Pentax-DA 40mm F2.8 XS

All other current lenses (as of March 2014) can be used with these caveats:

SMC Pentax-DA* 55mm F1.4: The largest usable aperture with converter is F2.4 (the same holds for the F and FA 50mm F1.4 lenses as per our tests)
SMC Pentax-DA 17-70mm F4: Contrast detect AF is unreliable, use phase detect
HD Pentax-DA 560mm F5.6: phase detect autofocus may be unreliable, use contrast detect
SMC and HD Pentax-DA 55-300mm F4-5.8: phase detect autofocus may be unreliable when zoomed in, use contrast detect


Read more at: http://www.pentaxforums.com/reviews/pentax-da-14x-aw-af-rear-converter/specifica...#ixzz3LLOKvkQg

I had a 0.7x wide angle converter paired with the 18-55 with my first DSLR. I found the results were perfectly acceptable. It will never be as good as a dedicated lens, but it's a good and cheap way to find out whether you really want a wide angle lens.

Thank you Andy.

Have fun with the new lens.

A 1.4x teleconverter is recommended for use with lenses of F4 and faster. On slower lenses the autofocus may not work (although you can resort to manual focus). The 18-135 goes from F3.5 to F5.6 so it may struggle a bit. May be ok on a good bright day, but in poorer light then probably not.