[krishna]

I have an old Pentax K-x. The following are the lens I have at present:

Pentax 18-55 mm kit lens
Pentax 50mm prime
Tamron 70-300

I am not happy with 18-55 kit lens. Hence, was considering to buy a new one to fill this gap.

Some of the most common uses for the planned lens will be to take photos:
1) Indoor photos - like birthday parties
2) Landscape
3) Portrait
4) Flowers/birds

In short, more of a general purpose lens that does not compromise picture quality much.

The following are the lens under consideration after reading the reviews. Before I take the final decision, I would like to take some advice here as my camera is the old Pentax K-x.

Pentax 16-85 mm
Sigma 17-70 mm
Tamron 17-50 mm

Please help me with your input.

[pepperberry farm]

or even the DA 18-135mm?

[krishna]

Thank you for this recommendation. I really did not have a look at 18-135 mm. Let me check this as well.

[pepperberry farm]

Thank you for this recommendation. I really did not have a look at 18-135 mm. Let me check this as well.

you're welcome - it's a great walk-around lens...


there is also a thread dedicated to it:


DA 18-135 WR, Show us what it can do - PentaxForums.com

[normhead]

The Tamron 17-50 can be had at a great price right now. I always seem to go with best bang for buck. I'd tell you about it, but my wife has taken to this lens, and I get a dirty look if I even touch it.

[cataseven]

If sharpness and aperture is important tamron 17-50. If not 18-135. 18-135 was my favorite on k-01. Excellent colors

[normhead]

If sharpness and aperture is important tamron 17-50. If not 18-135. 18-135 was my favorite on k-01. Excellent colors

The 18-135 is still my favourite lens. If it worked on my K-1 as well as it worked on my K-3 I'd use it all the time. But if I were going on a hike with one body and one lens, it would be the K-3 and 18-135. To match it on the K-1 I need two lenses.

I gave my step-daughter-in-law a Sigma 18-250 to go with the white K-x we also gave her. She loves it, and we have some great images taken with it. But it's another level of sharpness below the 18-135.

[pres589]

The 18-135 is not impressively sharp throughout its entire zoom range. Things start to fall off around 75mm or so and continue outward to 135. From about 20mm to 40-something it's quite sharp, especially stopped down a bit. It's a great lens. The Weather Resistant rating provides peace of mind that a bit of rain or snow is not going to be an issue.

That said, Tamron 17-50 is probably more useful as it goes wider and is faster, making it potentially a better fit for the uses listed. Current pricing is excellent as well. I wouldn't consider the Pentax 16-50.

[Bman]

My choice would be the Pentax 16-85!

The Sigma 17-50 is quite underated as well. I have one and i like it a lot.

DA* 16-50mm vs. Sigma and Tamron 17-50mm F2.8 Comparison Review - Introduction | PentaxForums.com Reviews

[normhead]

The 18-135 is not impressively sharp throughout its entire zoom range. Things start to fall off around 75mm or so and continue outward to 135. From about 20mm to 40-something it's quite sharp, especially stopped down a bit. It's a great lens. The Weather Resistant rating provides peace of mind that a bit of rain or snow is not going to be an issue.

That said, Tamron 17-50 is probably more useful as it goes wider and is faster, making it potentially a better fit for the uses listed. Current pricing is excellent as well. I wouldn't consider the Pentax 16-50.

Actually this needs serious clarification.

The 18-135 has better centre sharpness throughout it's entire range than any other zoom lens with it's range. In fact at every focal length, it's has measured excellent centre sharpness. It's edge sharpness falls off considerably after 50mm. It's rating is brought down by how soft the edges are from 85mm to 135mm. But when you consider neither the 17-50 or 16-85 don't include 85-135 in their range, I'm not sure how that should be held against the 18-135.

It's rated excellent or near excellent in 17 of 53 measured FL and apertures.

By comparison the DA 16-85 which folks are always comparing it to is excellent or near excellent in 17 of 45 measured categories, and it has more range. The 16-85 tends to be stronger edge to edge but not always.

At 24 mm the lenses are pretty close to even.

You can't make a direct comparison but it appears the Tamron 17-50 exceeds them both at 24mm as des the Sigma 17-50, but they are constant aperture 2.8 lenses, so sort of a different class.

So as i said before, go for the best deal you can find. You aren't going to be unhappy with the sharpness of any of these lenses. The weakest premium lens in this category on the test charts is probably the Pentax DA*16-50, and many people love that lens. Worrying about the sharpness of an 18-135 is just crazy. Why not worry about that lack of range in it's competitors instead? It's truly a one stop solution. With other lenses, there will be times you wish you had the extra reach and may even end up buying a second lens to cover it. I would really only consider a 17-50 type lens if i was also getting the 55-300 PLM. 50mm or even 85mm is just to short to be an everything all the time type of lens.

Any of the mentioned lenses will be great for flowers, the 16-85 and 18-135 are pretty good pseudo macro lenses, but for birds the 55-300 is pretty much the bare minimum. But you have the 70-300 so you're covered for now. You'll probably want to look for something a bit sharper in the future.

[ChipB]

If you don't mind a slightly older lens, I have a prior generation Sigma DC 17-70 f2.8-4.5 lens that I'm very pleased with. It's been one of my "go-to" lenses for quite some time.

[timb64]

I would recommend the DA 16-85 WR

DA 16-85 WR,show us what it can do. - PentaxForums.com

Couple it with your 50mm Prime for low light/indoors and longer term get a DA 55-300 WR and you'll have most bases covered.

[normhead]

If you don't mind a slightly older lens, I have a prior generation Sigma DC 17-70 f2.8-4.5 lens that I'm very pleased with. It's been one of my "go-to" lenses for quite some time.

If you can find a 17-70 at a good price, they also have a great reputation, regardless of manufacturer. The 2.8 at the narrow end might make it more desirable for your purposes as well, although my preference would be the 50 1.8 or 35 2.4 for low light situations, couple with whatever zoom you decide on.

[mikesbike]

If you want a little more wide angle than your 18-55mm provides being a main concern, then the DA 16-85mm. The DA 18-135mm is definitely the most versatile. I do also have other more prestigious zooms like the 20-40mm Limited, a fast pro-style Sigma 24-60mm f/2.8, and others, but I find the DA 18-135mm fills a greater variety of needs. As for aperture speed, it can hold to f/3.5-4.5 wide open all the way out to 70mm. As to softer edges at longer focal lengths, on a recent thread was posted info as to DxO editing software being able to correct images having this issue.

The DA 18-135mm is remarkably compact, very well built, has WR, and its quiet AF is very fast and sure.

[ddharriman]

Hi krishna

Your 3 options are all very good and well prized by the users so it resumes to taste and (I would say) price?

Anyway, why not consider also the Tamron 28-75 f2.8?

I have shoot most of my photos with it in a Pentax Kx for 6.5 years and I was extremely pleased with the results (as I’m now with it on my K-S2).

Best regards,