[Texas Transplant]

This is my first post so please bear with me.

Bought a K-X with the 18-55mm kit lens in April. I just supplemented it with a Tamron 18-200mm. I know there is some overlap in the two lenses, but I wanted a good "walking around" lens. Somehow, though, when I take comparative shots at the same focal length and camera settings, the pictures with the Tamron lens seem just a little less sharply focused than those with the Pentax kit lens. Also, a lot of the shots with the Tamron seem to come out overexposed compared to the Pentax.

Is this just part of the trade-off with greater zoom on the Tamron?

[Marc Sabatella]

Yes, in general, it's not considered as sharp a lens. But posting samples would help people tell if you're seeing a larger difference than normal, or if perhaps the issue is simply that you didn't focus carefully enough.

Difference in exposure tend to be more random - exposure is subject to many different variables. But difference in sharpness will be fairly consistent/

[KxBlaze]

This is my first post so please bear with me.

Bought a K-X with the 18-55mm kit lens in April. I just supplemented it with a Tamron 18-200mm. I know there is some overlap in the two lenses, but I wanted a good "walking around" lens. Somehow, though, when I take comparative shots at the same focal length and camera settings, the pictures with the Tamron lens seem just a little less sharply focused than those with the Pentax kit lens. Also, a lot of the shots with the Tamron seem to come out overexposed compared to the Pentax.

Is this just part of the trade-off with greater zoom on the Tamron?

The Tamron is definitely not a great lens when talking about IQ but the versatility of it almost makes up for it. If you got a good deal then I would keep it. I have that lens and if I want to travel light with only 1 or 2 lenses then it is in my bag.

**A tip for getting sharper images: When shooting at 18mm to about 50mm set the aperture to 6.3 and anything above 50mm, 8.0. To me images with those apertures tend to be a bit sharper.

[hcc]

The Tamron 18-200mm (and the Sigma 18-200mm) is an older lens and the IQ is not the best. (See review in Camera lens tests, user reviews, camera accessory reviews - SLRgear.com! for example.)

On the other hand, the Tamron 18-250mm and its sibbling Pentax DA18-250mm are highly regarded and considered a better IQ than the kit lenses. In fact they are considered among the best all-around lenses across all brands including Canikons and co.

Unfortunately Pentax stopped the manufacture of the DA18-250mm that is harder to find. Instead the shops offer the older 18-200mm and the much more expensive Sigam 18-250mm OS HSM. The only viable alternative is to buy second-hand the DA18-250mm or the Tamron 18-250mm.

It does not solve your problem but may explain the limited choice of all-around lenses for Pentax mount right now.

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Last edited by hcc; 08-24-2010 at 12:06 AM. Reason: Typos

[MadAmos]

I have that lens and I'm very happy with it for what I paid. I've noticed that its AF isn't always perfect, it can a lot of time hunting for a focus point, but generally its acceptably sharp to me. As an example of what I thought was sharp enough, I took this over the weekend in when the dog was trying to wear out my son. I believe I had it in sports mode when I took the picture. Its cropped so its harder to see, but I had it set to the center autofocus point and had chosen the dog to focus on.

[Texas Transplant]

Yes, in general, it's not considered as sharp a lens. But posting samples would help people tell if you're seeing a larger difference than normal, or if perhaps the issue is simply that you didn't focus carefully enough.

Difference in exposure tend to be more random - exposure is subject to many different variables. But difference in sharpness will be fairly consistent/

Marc,

Thanks for the input. Still working on how to attach files to my posting.

[Texas Transplant]

The Tamron is definitely not a great lens when talking about IQ but the versatility of it almost makes up for it. If you got a good deal then I would keep it. I have that lens and if I want to travel light with only 1 or 2 lenses then it is in my bag.

**A tip for getting sharper images: When shooting at 18mm to about 50mm set the aperture to 6.3 and anything above 50mm, 8.0. To me images with those apertures tend to be a bit sharper.

Thanks for the response. I'll try your aperture settings to see if I can get better results.

[Texas Transplant]

I have that lens and I'm very happy with it for what I paid. I've noticed that its AF isn't always perfect, it can a lot of time hunting for a focus point, but generally its acceptably sharp to me. As an example of what I thought was sharp enough, I took this over the weekend in when the dog was trying to wear out my son. I believe I had it in sports mode when I took the picture. Its cropped so its harder to see, but I had it set to the center autofocus point and had chosen the dog to focus on.

I'd be happy if I was getting results that were that good.

[Texas Transplant]

The Tamron 18-200mm (and the Sigma 18-200mm) is an older lens and the IQ is not the best. (See review in Camera lens tests, user reviews, camera accessory reviews - SLRgear.com! for example.)

On the other hand, the Tamron 18-250mm and its sibbling Pentax DA18-250mm are highly regarded and considered a better IQ than the kit lenses. In fact they are considered among the best all-around lenses across all brands including Canikons and co.

Unfortunately Pentax stopped the manufacture of the DA18-250mm that is harder to find. Instead the shops offer the older 18-200mm and the much more expensive Sigam 18-250mm OS HSM. The only viable alternative is to buy second-hand the DA18-250mm or the Tamron 18-250mm.

It does not solve your problem but may explain the limited choice of all-around lenses for Pentax mount right now.

Yes, I was a little surprised at the limited number of choices available.

[rawr]

I have the 18-200. It's a perfectly adequate walkaround lens. Not stellar, but perfectly usable.

When I first bought it a couple of years ago I did make the big mistake of sticking a UV(0) filter on it (from Tamron). That softened the lens a lot, especially at the long end. Used without a filter (with a hood instead), the results are much better.

The photozone.de tests of this lens (on a Canon mount, but it's the same lens) are more positive than the SLRgear.com review results, and show where the lens is at it's sharpest and at it's weakest. In general, if you use the lens stopped down a tad to f5.6 or f8, and avoid the extremes of focal length, it is a perfectly decent lens.

Tamron AF 18-200mm f/3.5-6.3 Di II LD Aspherical (IF) XR macro - Review / Test Report

[Marc Sabatella]

Yes, I was a little surprised at the limited number of choices available.

There's three different 18-200's (two Sigma, one Tamron) as well as the 18-250 (only Sigma now that Tamron and Pentax have discontinued theirs) - how many different choices for a superzoom do you *need*?

As for how to attach pictures, do a search of this sitr as I know there is an article about it, but it's really quite simple, using either of two basic methods. One is to have an account somewhere else (like Flickr), upload the image the image there, then find the URL of the image (not of the HTML page containing the image), then click the "Insert Image" icon right about where you type your message here and paste the URL there. The other is to click the "Attach Photos of Files" button below where you type your message.

[Texas Transplant]

Thanks to everyone for the input. Sent the lens back to D&H today. I'm relatively new to digital photography, but I learned a long time ago, whether the subject was cars, tools, clothing, etc., that I was better off to do without, than to settle on something I was on halfway satisfied with.

[MadAmos]

Thanks to everyone for the input. Sent the lens back to D&H today. I'm relatively new to digital photography, but I learned a long time ago, whether the subject was cars, tools, clothing, etc., that I was better off to do without, than to settle on something I was on halfway satisfied with.

That's a good way to look at things. I hope the next one works out better for you!

[tomtor]

Thanks to everyone for the input. Sent the lens back to D&H today. I'm relatively new to digital photography, but I learned a long time ago, whether the subject was cars, tools, clothing, etc., that I was better off to do without, than to settle on something I was on halfway satisfied with.

I think that was the right thing to do, it's better to spend some more and be happy with it for many years.

I suggest getting a lens like the Pentax DA55-300, which will be a nice combination with the 18-55 lens you already have.

If you really don't like changing lenses, as suggested a second hand Tamron or Pentax 18-250 is quite good, but in my opinion changing lenses is part of the fun of owning a DSLR. The tele view of the 55-300 versus the normal/wide view of the 18-55 forces you to take different kind of pictures with each lens.