17-50 f2.8 & flash to replace 50mm f1.7?

HI,
I have a prime lens-50mm f1.7.
I'm thinking of selling it and buying a 17-50mm f2.8 and a flash.
Would they be a good substitute for the prime lens for indoor/low light shots of my kids?
Can the flash work on fairly auto mode or do I have to set stuff on it (distance etc) thus ending up missing shots?

I know I'll lose some dof with the f2.8 instead of 1.7
Cheers

You will gain rather than lose DoF!....

Sorry, that's what I meant- background will be less blurry/more in focus....

But you've a k-x... what ISO do you shoot at inside?

Flash would be a solution but it's not a simple thing to use effectively because if you use it just on the camera the flash would make your images look flat.

1. Provided the flash you choose features a swivel head (typical is 270 degrees), then if used on, or off, camera for indoor use you can bounce it off walls and ceilings for softer effects, and be much more congenial to the subject.
Kids (or any living creature) simply don't deserve to be harassed by bright flashlight smashed into their delicate eyeballs.

2. If the external flash you buy also supports wireless Slave Mode (and your camera model does too), then that's another worthwhile bonus to have.

3. The upper Pentax brand flash units, and Metz 58 model, are about as auto-friendly as you can get -- they can even communicate wirelessly with Pentax DSLRs (all recent models anyway) when used off camera to exchange and get optimal settings.

As well as being fully auto-everything (nearly) when fitted and used in the camera's hot shoe.
Plus when off camera they cooperate seamlessly in conjunction with the camera's built-in (pop-up) flash too, for added light as well as exchanging the wireless preflash syncing P-TTL protocols with it.

4. Bouncing helps 'spread' light too, needed for wider-angle lens shots like that 17-50 brings to your table.
Also all good flashes come with a built-in diffuser (and deflector) just for that purpose too.

So it basically becomes mostly a no-brainer. You can go on and worry about the framing etc. Not a more rocket science exercise just to take some family pics.

Hope I covered everything.

The downside? All that "Auto" comes at a price. So it pays to not jump into this area blindly - and buy something that will meet your needs and all of your expectations of it.

.R.

Thanks for the replies so far.
Yes, I have a K-X. What starter price would a flash with allentioned above start at?
I know keeping the 50mm lens would be ideal but If I want a 18-50mm f2.8 then I have to sell the 50mm to finance it.

Metz af48 would be ideal for your needs approx £140 & the 17-50mm 2.8 between £250 to £275

Metz 48 is being replaced with the af50 soon so bargains to be had

http://www.srsmicrosystems.co.uk/224/Metz-Mecablitz-48-AF-1-Digital-Flash---Pent...

I agree with cabstar's recommendation re: the Metz Mecablitz 48 AF-1 £145.00 with a set of eneloops + charger would be tough to beat in anyone's language.

Be aware of this statement though: "Oddly, while the 48 AF-1 can function as an off-camera wireless slave it cannot act as a camera-mounted controller for other slaves."
[ Ref: http://pttl.mattdm.org/ ]
[ Ref: http://pttl.mattdm.org/models:metz:48-af-1 ]
So if that minor might be a concern for your needs...

It shouldn't, your K-x inbuilt will act as either Master or Controller for the Metz when off camera.
And the Metz's full swivel & pivot head creates no probs when on camera!

As for the lens issue; have you considered a Pentax 'kit' 18-55mm zoom, should be common and inexpensive on the UK s/h market and is one way under-rated lens for the skimpy typical market asking price.

Its slower f/3.5-5.6 would not be a bother either with a decent flash.

Might save you having to sacrifice that beloved 50 after all.

.R.

I have the kit lens sitting in a drawer.
Why I like the 50mm and 17-50 lens is for the dof, bokeh/blurred background, very select area of focus.
The reason for selling the 50mm is as I find I have to step back a lot. Maybe the 35mm f2.0 could be good but Im thinking that the 18-50 would be more versitile.

I might see if I can wrangle finances and buy without selling the 50mm and then can be 100% sure that it's the right choice for me.

Easy two-step solution to that:

1. Buy a Stofen Omnibounce diffuser
2. Tilt the flash head to bounce the light off the ceiling

I can also vouch for the usefulness of the Metz 48.

If 35/2 tickles your fancy for performance, and budget to consider on the other hand, then why not look at the new kid on the block; "Pentax smc DA 35mm F2.4 AL Lens - £149.00"
http://www.srsmicrosystems.co.uk/5436/Pentax-smc-DA-35mm-F2-4-AL-Lens---IN-STOCK...

It's getting drool-level attention for its performance in the sharp & blur bits stakes (esp for the price).

There's a discussion on here about it, as is there in all other Pentax chit-chat venues -- c/w loads of sample pix incl. comparisons with other beloved P.prime lenses like 35/2, FA, 35/macro etc.

.R.

That reminds me; I wish the 17-50 ws macro, or the 28-75 f2.8...
I use my Panasonic TZ3 for 'macro' shots.

Yeah but it's not ideal though, certainly not if you've coloured walls.
Also if you tilt the flash the omni bounce becomes less effective so it's better to just bounce and that way save you a few quid and put less strain on the battery and flash.

What flash to buy... I think you should look at the new Metz 44, they seem to have make the interface easier on that flash.

The Sigma 17-70 is macro.

I built a diffuser condom out of sturdy bubble wrap, gaffa tape and velcro for my main flash. Makes a huge amount of difference.

I also built a mini one for the camera's inbuilt flash.

Cost ( because I already had the stuff kicking about) = £0

Never use the flashes without them now.