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Old Oct 27, 2007, 11:09 AM   #1
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I received my Tamron 18-250 a few weeks ago and so far I am highly impressed with the quality and IQ. I know that there are certain trade-offs when buying a zoom, but I think it was well worth the money. It is nice to be able to run out the door with the camera and not have to drag the bag around with extra lenses. I highly recommend this lens as a walk around lens. The photo below is of my Desert Lynx, which is a cross between a Bobcat and an American Domestic cat.

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Old Nov 1, 2007, 8:19 PM   #2
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Nice shot of a great looking cat.

Here is a comparison of what the lens looks like compared with its Pentax counterparts

Sounds like the major difference is just the SMC.

Somebody brought one over from Japan to Taiwan


http://forum.pentaxfans.net/showthread.php?t=56285


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Old Nov 1, 2007, 11:24 PM   #3
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A few years ago I would have said that the SMC coating was a big deal, but today with the modern coatings that Sigma, Tamron use the difference if any is neglegable. So far I love the lens, I am getting some decent shots hand held and it is an all round great lens. When I went to the PDN Photo Plus camera show in NYC I was able to compare the two side by side and there was no difference at all.
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Old Nov 5, 2007, 7:39 AM   #4
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Had a Tamron 18-250 on my K10D since Sept and I have now taken about 400 shots with it.

I have now sent the lens back to Tamron, well Intro2020 in the UK actually, for Warranty Service, as it exhibits severe left side softness, which covers about 25% of the left side of every picture taken at less than f11, regardless of focal length. I thought at first it may have been the UV filter, but na same without it attached.

And wow look at that distortion at the 18mm end, Gulp. I would'nt say it was so much Barrel Distortion, more like Barrel + Wibble Wobble.

Maybe I just got a bad sample, but if it has'nt improved after the Warranty Service then it will be going back to the shop for a refund and I'll look elsewhere.

I'll post a sample tonight and keep the forum updated on the Tamron Service in the UK, although I'm not very optimistic about this.
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Old Nov 5, 2007, 5:31 PM   #5
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As promised here are some examples of what a fine lens the Tamron 18-250 is:

All the images are full size crops, with the left half taken from the left side of the original image and the right side taken from the right side of the original image.

As you can see the extreem left side softness does not get any better untill f/11 at the 18mm focal length.

And as can also be seen the distortion has to be seen to be believed.

A18-1.JPG is the far left and right, full size crop portions of an image taken at:
ISO 100, 1/200 sec, f/3.5, 18mm.
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Old Nov 5, 2007, 5:32 PM   #6
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A18-2.JPG is the far left and right, full size crop portions of an image taken at:
ISO 100, 1/125 sec, f/4.5, 18mm.
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Old Nov 5, 2007, 5:32 PM   #7
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A18-3.JPG is the far left and right, full size crop portions of an image taken at:
ISO 400, 1/80 sec, f/11, 18mm.
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Old Nov 5, 2007, 6:21 PM   #8
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I think you have a bad copy as I have none of these problems. Yes there is a slight bit of barrael distortion but nothing making it a big deal. Many of us on the dpreview have discused your post and if I hear anything new I will post it here.
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