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Old Jan 18, 2008, 6:25 AM   #1
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My Tamron 18-250mm came this morning; it's pouring with rain & the forecast doesn't look much better for next week!!

Even the cat's fed up & asleep.



Here's a close up of our Mac



And our Henrie



Desperate for something to photograph



All taken using flash.
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Old Jan 26, 2008, 1:23 PM   #2
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As reported in various reviews on this lens, vignetting is quite apparent across the zoom range when aperture is used wide open.

Fortunately, the lens correction facility found in the Photoshop CS/Filters/Distort/Lens Correction and in Adobe Lightroom, Photoshop ACR correct for this with good effect.

I should advise that if the correction is applied on a JPEG image, then care should be taken not to overdo things as something akin to Newton's Rings occur.

Applying the correction to RAW image in ACR or Lightroom doesn't suffer this phenomenon.

The first image shows the level of vigneting at 18mm f3.5



The second image with Lens Correction applied to the JPEG image in Photoshop



The third image with Lens Correction applied in ACR/Lightroom




A comprehensive set of images using this lens can be viewed here www.iwcam.co.uk for the walks dated 21.01.01 to 24.01.08.
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Old Jan 26, 2008, 9:45 PM   #3
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I love your cats! The lens looks like it does a good job for you. This does look like a good possibility for someone looking fora one-lens solution.
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Old Jan 27, 2008, 4:16 PM   #4
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does vignetting happens thru out the range?? even at 250?? if so it's seems to me that it's a horrible design error.. altho the shots are really center sharp.. it looks like they are making the image circle too small.

roy
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Old Jan 28, 2008, 4:18 AM   #5
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robar wrote:
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does vignetting happens thru out the range?? even at 250?? if so it's seems to me that it's a horrible design error.. altho the shots are really center sharp.. it looks like they are making the image circle too small.
The compromises in performance against it's 14x zoom range are well documented in reviews of this lens (http://www.bobatkins.com/photography/reviews/tamron_18_250_2.html) and something which is more to do with limitations in optics than 'design error'.

I would not have considered this lens if there was not a simple way to resolve the vignetting issue, which is really only an ussue when used at maximum aperture; I wanted to share this with others through the auspices of this forum.

It's a fun lens to use covering a wide range which is more than enough for general purpose use - for more serious use, then a decated lens could be used.
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