[audiobomber]

Often people claim the Pentax version has the SMC coating whereas the Tamron doesn't but any time you hear people reporting who have seen both lenses side by side they testify that they weren't able to discern any differences including the coating.

I'm assuming that the Tamron version will be supported by the K-7 in terms of distortion correction just as the Pentax version but that may be something worthwhile checking.

There was a thread about this in the other forum. It appears that the coatings are not identical, because the colour of the exterior elements is slightly different. The photos shown in the thread however, showed no practical difference in flare or CA.

As far as I've heard, the CA, distortion and vignetting correction on the new Pentax cameras will only correct the DA lens, not the Tamron. That's pretty significant to me. Lenses last longer than cameras. It's likely that all of the DA 18-250's will be mounted on a corrected body at some point.

In Canada I would only have gotten a one-year international warranty with a Tamron. Pentax Canada gave me two years. Statistically most failures will happen very early or very late anyway.

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Last edited by audiobomber; 11-19-2009 at 08:44 PM.

[Class A]

There was a thread about this in the other forum. It appears that the coatings are not identical, because the colour of the exterior elements is slightly different. The photos shown in the thread however, showed no practical difference in flare or CA.

Can you point us to this thread?
I only read ones where exactly the same colour of the coatings was reported.

As far as I've heard, the CA, distortion and vignetting correction on the new Pentax cameras will only correct the DA lens, not the Tamron.

There are people who reported that lens correction on the K-7 works for the Tamron 18-250.

[wwwmorrell]

I have the DA 18-250, my sister has the Tamron version, we have swapped the lens back & forth over the last couple of years trying to pick a difference between then.

There isn't any. IMHO

Just go with price, you are getting the same lens.

[heliphoto]

Tamron lenses carry a six year warranty - if you're planning on keeping it a while, I'd vote for Tamron.

[raider]

I would vote for Pentax if it is a choice between pentax and tamron...provided the price did not skyrocket and it is still available. Otherwise I will be contended with the Tamron.

[audiobomber]

Can you point us to this thread?
I only read ones where exactly the same colour of the coatings was reported..

Tamron & Pentax 18-250 - different coatings?: Pentax SLR Talk Forum: Digital Photography Review

There are people who reported that lens correction on the K-7 works for the Tamron 18-250[/url].

Did you read the entire thread you linked, or just the title? The OP reported that the K-7 corrected the Tamron, but then he says "I did not try to take advantage of correction on the 18-250. Just that I could could if I wanted to." ManuH initially supports the claim that the K-7 corrects the Tamron, then says he didn't test, just confirmed that the lens was recognized.

Two posters (falcon_wizard & John Schick) did actual testing. They found that the camera recognizes the Tamron lens but will not correct it. This is confirmed by Bich in the thread I linked above. That's convincing enough for me, but not solid proof. I'm sure we'll hear more about it as more posters buy K-7 and K-x cameras. In the meantime it would be prudent to err on the safe side. Those superzooms can really benefit from correction.

[Jasvox]

I have owned the Tamron version for almost 2 years and have never had any problems with my copy or have ever felt the need to "correct" anything with it.

I think you can compare ad neauseum between these two lenses and the sum of your findings will be based entirely on a personal opinion of either one, not any noticeable or tangible differences.

Go with the best deal you find on either model and get on to making great photography.

Jason

[DavidWasch]

The biggest reason for me to go with the Pentax is resale.

[audiobomber]

I have owned the Tamron version for almost 2 years and have never had any problems with my copy or have ever felt the need to "correct" anything with it.

You wouldn't like to correct this distortion at 18mm?

I think you can compare ad neauseum between these two lenses and the sum of your findings will be based entirely on a personal opinion of either one, not any noticeable or tangible differences.

A few months ago that was my view too, but I no longer agree, assuming that lens correction is available on Pentax lenses only. The 18-250 wide end has more vignetting at f3.5 and 4 than any lens I've ever seen, and CA is certainly present at times. These can all be corrected in software but I'd rather not bother when it can be done in the camera with no effort.

PS We bought a new house with a double garage after this photo was taken.

[dstar]

What about creep problem. I have 18-250 Pentax .Almost 2years and creep worst and worst.Try call pentax tech support ,but they brush me off.'This is just normal "typical response .may you advice how to fixed this issue ,

[heliphoto]

What about creep problem. I have 18-250 Pentax .Almost 2years and creep worst and worst.Try call pentax tech support ,but they brush me off.'This is just normal "typical response .may you advice how to fixed this issue ,

The solution I heard about a while ago is to put a large rubber band around the junction of the zoom ring with the lens body - this increases friction enough to hold the ring against creep .

[Jasvox]

Audiobomber, I would want to correct that kind of distortion, but thankfully I have never witnessed that degree from my copy.

Either way, if I did, I would be more inclined to back off to 20mm or so and I bet this goes away pretty quickly. (Or simple correction during PP)

The OP is about differences (if any?) between the Pentax and Tamron version, not the overall characteristics of the lens in general.

Jason

[audiobomber]

Audiobomber, I would want to correct that kind of distortion, but thankfully I have never witnessed that degree from my copy.

Either way, if I did, I would be more inclined to back off to 20mm or so and I bet this goes away pretty quickly. (Or simple correction during PP)

Distortion wouldn't vary much if any between properly performing copies, but it does vary by scene and FL. How do you correct for distortion? I don't have a program that will do it. I know PT Lens does but I haven't bought a copy.

The OP is about differences (if any?) between the Pentax and Tamron version, not the overall characteristics of the lens in general.

I don't think there's any IQ difference at all between the Tamron and Pentax versions, they're the same lens. But correction is a pretty nice feature with a superzoom IMO and worth considering.

I'm certainly not trying to dissuade the OP from buying an 18-250. It's a great lens, the best of its kind from anything I've seen. I love mine, but I'm looking forward to pairing it with a camera that corrects some of its weaknesses so that I don't have to avoid certain apertures and focal lengths.

Here's my 18-250 gallery, mostly taken on day one. No corrections, didn't even know the what settings to avoid: Picasa Web Albums - Dan - Pentax 18-250mm

[Jasvox]

Me either, just offering my 2 cents worth of fact/opinion between these two lenses. The OP is certainly entitled to his choice, but in all actuality, the differences between these two lenses basically boils down to either a green or gold pinstripe since no other proof has been offered between these two lenses since their releases a few years ago.

Distortion correction can be tweaked/controlled in CS2/3/4.

Jason

[cbaytan]

I'm certainly not trying to dissuade the OP from buying an 18-250. It's a great lens, the best of its kind from anything I've seen. I love mine, but I'm looking forward to pairing it with a camera that corrects some of its weaknesses so that I don't have to avoid certain apertures and focal lengths.

Here's my 18-250 gallery, mostly taken on day one. No corrections, didn't even know the what settings to avoid: Picasa Web Albums - Dan - Pentax 18-250mm

It'll be wifey lens, who did resist to upgrade to dSLR idea first, than convinced by the 18-250mm superglued to a Pentax body idea , just like her current dZLR.

From you samples I start thinking to get one for myself too, then I saw certain PP corrections in some extend they are like sharpening by high pass filter tecnique.. Is that true? Which camera did you use with this pictures I wondered, good combo.