Choosing a lens, flash

[janjuc]

I have a Pentax K20D and want to take semi-formal/formal group shots (at tables; small groups etc); at night, low to medium lighting (as in a large ball room or conference dining room).
Another photographer is handling the more formal award presentation shots;
I am doing the "social" shots.
(I do have a Sigma 18-50mm F3.5-5.6 DC and am not sure if it will be good enough)
Can forum members recommend a lens and a flash unit that would suit this sort of work. I am not a professional, but greatly enjoy this sort of work.
My usual photography is of surf life saving competition http://janjuc.redbubble.com/
Budget A1000-1500.

[sambob]

You could look at a METZ 'hammerhead' flash unit. They are usable on just about any camera.

http://www.digitalcamerawarehouse.co...egory870_1.htm

[scottid]

its probably best to get a flash that has some sort of TTL function, that way you wont have to worry the whole time about the settings, just bounce the flash off the roof. im not sure if pentax offers an external flash... also that lens will work just fine

[kiwi]

You could look at a METZ 'hammerhead' flash unit. They are usable on just about any camera.

http://www.digitalcamerawarehouse.co...egory870_1.htm

for about $1500 plus accessories, im not sure its a good plan personally

[ving]

the lens you have should work ok, just buy a TTL flash unit of some sort that can be aimed.

[LEIGHTON]

for low light photography, a glass with an aperture value of F/2.8 or bigger is an advantage

[janjuc]

Thanks for all of that.
By the sounds of it, the 18-50 will do the job.

As far as the flash goes, I am now looking at a PENTAX-AF-540FGZ.
Best price so far is this one: http://www.camera-warehouse.com.au/p/pentax-af-540fgz

I have bought from them before and find their service pretty good.
Any advice will be welcome!!
thanks
andy

[janjuc]

A report back: Finally settled on a Sigma EF 530 ST for just on $300.
Stayed with the Sigma 18-50mm F3.5-5.6 DC lens.
With my Pentax K20D, the combination got a solid workout last night at Surf Lifesaving Victoria's Awards of Excellence Awards.
The photos should be up on LSV's site http://www.lifesavingvictoria.com.au (or their facebook page) sometime on Monday.
Thanks for your comments and help, particularly Kiwi and Ving!!
cheers,
andy