Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- User Rating: 
Summary for Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- nice lens
Notes on Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Pretty good.
What I don't like about is it's tendency to zoom out by itself if pointing downwards.
Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- User Rating: Summary for Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Pretty good lens
Notes on Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Not a bad lens considering that you would have to carry two lenses to do the same. The image quality is pretty good for a lens in this range. I've read three other 'professional' reviews that did more lab type test and they were all pretty impressed with the overall performance, at least they all agreed it was worth the money.
In reference to other reviewers, I didn't find purple fringing a big problem. It is there, but not as bad as I've seen for other cameras. As far as the specks on the lens causing spots in photos, I totally don't see how that is possible. I sprinkled a dozen or so grains of pepper on my filter in front of the lens and couldn't see anything at all in the way of spots in the image. It could possibly happen if light was hitting directly on the lens but this seems more like a dust on sensor or bad pixels problem.
I felt the biggest letdown was the vignetting, especially at max zoom. It was quite noticeable in the corners especially in sky shots. You need to stop down to about f11 before it starts to improve.
Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- User Rating: Summary for Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Serious quality control issue
Notes on Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Purchased this lens as a all around replacement for the kit 18-55mm. Intially it looked pretty good but when I started shooting lighter colored areas I discovered dust specks in the photos. I took a really close look and sure enough under the front lens were numerous (at least four I could see) specks of dust. I went back and looked at some of the photos taken when I first got the lens and sure enough after very close examination there were spots on them also in the same general areas. These were darker photos with broken up backgrounds so the specks didn't stand out like the lighter colored backgrounds. It took two emails to Tamron and almost two weeks before I got a reply and the reply was to send it in so they can evaluate it to see if it's a warranty issue and it will take 3 weeks.
After checking around online I have found others that have had this problem with Tamron lenses as well (I wish I had researched more). It seems that Tamron has a serious quality control issue. I'll be looking at a Pentax or Sigma lens to replace this one and I don't see myself buying a Tamron again as build quality and picture quality seem to vary widely with this company. Picture quality was ok but nothing outstanding. Focus was not as sharp as I was hoping for. For the money (or maybe a little more) there are better lenses out there. Do yourself a favor and read every review you can find on this lens (or any Tamron lens) before buying.
Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- User Rating: Summary for Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Best in Range
Notes on Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- I find this lens to be an excellent travel lens,and on the Pentax K10D with in body shake reduction,useful even when the light is on the low side.I would recommend this lens highly. I give it a 5 star on the basis of the 14X zoom and the sharpness not found in many zooms of lesser range.
Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- User Rating: Summary for Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- Very Nice but Problem with CA
Notes on Tamron 18-250mm F/3.5-6.3 AF Di-II LD Aspherical ...- I purchased this lens to replace the Pentax 18-55 and 50-200 lenses that came with the K10D I bought. The benefit of this lens is that it means you don't need to change lenses and miss shots as a result, and you get a little extra reach. When you build this much zoom into a lens it means that some image sacrifices will result such as sharpness, distortion, CA, speed. However, with this lens the overall performance is actually quite good when compared to other zooms and super-zooms in the same price range (see Internet professional reviews) and it's significantly better than Tamron's own 18-200. In doing a compare with the Pentax SMC DA 50-200, I found that the Tamron 18-250 is markedly sharper from center to corner at all focal ranges and aperatures. Color saturation and contrast is slightly better, too. Auto focus performance is on par with the Pentax kit lenses and is generally fast and accurate enough for most shooting with the exception of low light situations or fast moving subjects. Although it's not easy to focus accurately in manual mode with the smooth focus screens found on digital SLRs, don't be afraid to simply set the focus ring for the approximate distance to the subject for quick point-and-shoot situations if you have a good sense of distance. At a dark reunion event where auto focus and looking through the viewfinder for manual focus was impossible, I simply set the camera on manual focus and pre-set the focus ring to the distance I planed to shoot for the next wide angle shot. This allowed for fast "hit and run" candid flash shots that came out perfect, even with the lens wide open.
The big let-down I've found with this lens is the CA (chromatic aberration - or purple fringing) which is just a hair short of the point of being unacceptable. In bright sunlght I almost feel like I'm once again shooting with my Canon S3 ( a "super-fringer"), always hesitant to take pictures of those situations where dominant CA lives such as high contrast shots like tree branches with sunlight showing through, shadow details on a bright sunlit building, sunlight reflection off of chrome or ocean waves, even someone's skin in bright sunlight. I had a local camera store get out a new 18-250 Tamron, place it on a K10D and shoot one-on-one with my camera outside. The resultant CA in high-contrast shots was the same, so it's not my lens alone. The CA is the worst at the corners but can be reduced slightly by shooting around f11 to f16. Interestingly, the Pentax kit lenses have significantly less CA. This may be attributed to their SMC coatings. Pentax has its own version of the Tamron 18-250 just released with some believing it's actualy made by Tamron. What would be interesting is whether the Pentax version with SMC coatings will have reduced CA as a result. You may want to wait for the reviews to show up for the new Pentax lens and determine whether you want the Tamron or the Pentax based on the comparative results. Although I have not shot in RAW mode yet, I understand that CA can be corrected for with software when the picture was shot in RAW. I just don't like the idea of investing all the time and effort at the back-end when better lens performance can prevent all that in the first place.
Overall, the Tamron 18-250 is a respectable "walk around" and travel lens worth considering. Just be reminded that you'll need to shoot at ISO 800 or 1600 more often than you might think as a result of the slow aperature performence. It looks great on the camera, feels a lot better and is tighter than the Pentax kit lenses, the plastic has a nice quality texture to it, and it takes impressive pictures (including macro). If the CA was controlled to the same levels as the Pentax lenses, I'd rate the Tamron at five stars instead of four. With the CA issue, I'm between three and four stars, but rounding up to four because of the overall appeal and performance of the lens.
