17-50 or 18-135 for beginner

Right now I have a Canon G9 and I will buy my first SLR, Pentax K-5.
For a beginner what's best? A Tamron 17-50 f2.8 and keep $$ for a later lens or a Pentax 18-135mm?
Maybe other lens/combination?
My photography will be family in interiors and outdoor/landscape.

I would deffo choose the Pentax as it compliments the K-5s WR capabilities. Get caught in the rain just once and you will wish you had bought the Pentax.

whats more impaotant to you better image quality or weather sealing. not that the pentax wont give great image quality but it wont match the tamron.

Zoom lenses have come on by leaps and bounds in recent years, but even so, a good short-range zoom will generally tend to beat any long-range zoom (such as the 18-135).

Rather than buy a Tamron (good though they may be), I should follow Gareth's advice and get a Pentax 16-50 (if you can afford it). This is a splendid lens that (until I drove off with it on the top of my car) was never off my main camera.

Long experience has taught me that you'll never regret buying the best. And as a general purpose lens, the 16-50 is certainly that.

G

What about a Pentax 16-45 f4, £225 at our favourite shop!

spot on but alot dearer than the tamron.(but worth it)

Depends on budget. For a one lens system I'd absolutely go for the 18-135. It may not be as fast as the Tamron but the noise performance on the K5 is so good that you can easily afford to use a higher ISO to compensate. It is weather sealed and will cover almost all situations admirably as you get the hang of things. If you then feel you need more quality glass you can review your photos and see which focal lengths you use most and choose accordingly. If you want to play with shallow depth of field get a cheap (but excellent) M or A series Pentax prime off ebay.

I think that Mark is right to recommend the 18-135, IF you confidently expect never to buy another lens.

But most of us do buy other lenses, and then the 18-135 will be redundant, except perhaps on holiday when you don't want the hassle of taking extra lenses.

If I am walking around a city, and only want to use one lens, then I take the 12-24. It's great for buildings, and you can take people from a couple of feet away, while appearing to be pointing the camera away from them. So an 18-135 would not interest me in that kind of situation.

If the 16-50 is outside your budget, then consider the 17-70 and the 16-45. Both are excellent. Then, if you find you need something longer, get the 50-135.

G

I have three lenses, covering the range 10-300, and I'd still love an 18-135 as a walkaround lens.

I take George's point about the 12-24 being good for buildings, but overall, I'd vote for the 18-135 with its extra reach.

You have to be very careful at close range with extreme wide angles, especially with people near the edges of the frame.

And given how the 18-250 was good, considering its ludicrous zoom range, I'd hope that the 18-135 would be better throughout its whole focal length range.

After all this time, it's still the 18-55 (with the 55-300 a close second) that's on my K10D the most, and I expect if I had the 18-135 it would be that instead - especially on the K-5 with its high ISO performance.

The DA17-70 would be a good compromise. Judging from others experience with the DA*16-50, the 17-70 at least matches the IQ of this lens at the wide end and is pretty close elsewhere through their common range. And the extra 20mm means it has a very useful range. Optically I'm sure it's a step up from the 18-135.

You might miss the f2.8 of the DA* (I do sometimes, though more for the ability to throw b/gs than low light options).

The Tamron would be an excellent cheaper alternative (it's a very good lens from what I've seen) - though it lacks the useful extra length.

Personally I would order your K5 with the 18-55 kit lens which will cost you next to nothing and is surprisingly good, you may end up keeping it for a long time. Use the money you have saved to buy a Pentax FA 50 1.4 which is another lens that is exceptional value and gives lovely results with shallow DOF and beautiful colours. Then at a later time you can upgrade your kit lens for something faster if you feel the need.

I wouldn't disagree with this.

The thing is, the OP is coming from a bridge camera with a substantial zoom range, so having only the 18-55 may feel like a retrograde step in that sense only, although of course there will be many other advantages.

So I still think that the 18-135 will be the single most useful one to get for now.

All this talk of FA50 and DA16-50, excellent though they are, is missing the point a little, I think.

For a beginner, coming from a bridge, all the benefits of a decent zoom range as well as the K-5 makes it a no-brainer for me, subject to funds available.

The 18-135 will also hold its value very well, so it's not as if there aren't plenty of options later on.

Actually Smudge and Chris A have a point. The K5 with the 18-55 WR kit lens and the DA 55-300 would be an excellent alternative and cheaper than the the 18-135 option. You will cover a greater range but lose the convenience of a single lens and full WR protection.

Thanks for all answers
The 17-70 and 16-45 are F4, so they are out.
I thought about Tamron 17-50 because I think it will cover 80% (maybe more) of my needs with this zoom range and the f/2,8. The Pentax 18-135 will give me extra range with WR (which is good) but I will sacrifice IQ.
I'm thinking to buy more lens in the future, but I would like to keep it "budget".

Why is F4 a problem? With the K5 it is absolutely not a problem. I have both the 17-70 and the wonderful 60-250* and do not find F4 a problem with either.

Rumour has it, though it has never been confirmed, that the 17-70 has quite a degree of weatherproofing, hence it's price.

The 18-135 is an F5.6 at 135 mm, and F3.5 at 18mm, so that surely must discount it regardless of IQ, given that A constant F4 is not enough for you.