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As a general travel lens this is brilliant. I use it on the Nikon D70 and D70s with great results on both. Having just returned from a trip to Northern Australia we managed a respectable 3000 shots through it in two weeks. Tamron 18-270 VC images are sharp in the center at 18mm with a wide open aperture. Stopping down does not improve center-of-the-frame sharpness. Both lens models have the same problem viz. inaccurate auto focusing from 18mm to around 50mm. However, they focus well with Live View. I see that the reviewer noted that the distance scale on the lens was inaccurate at close range - this may be related to the problem I have found. On AF, the lenses focus at a different distance to what I can measure with a tape measure. SInce two models of this lens show the same problem but on two different cameras, I think that the AF systems of the respective cameras may be implicated - not accurate enough for the soft focus seen at wide angle. It would be interesting iof any K5 or K30 users observe the same problem. Before I start, I wish to highlight that this is a lengthy sharing session of my personal experience with this lens but not too much on the technical specifications. You may skip to the Conclusion if you wish to, or just browse the photos. I do not have the 18-135mm but for street photography, prime lens is always my preferred preference. If you are looking for one lens for travel, this Tamron 18-300 should be the best option.
Other nice Tamron 18-270 features include VC (Vibration Control), a modest size & weight and a reasonable cost. This is very decidedly an external-zoom lens, meaning the lens barrel extends a lot (79 mm, about 3.1 inches) as you zoom from wide angle to telephoto. This is also an internal-focus design, which means that the front element doesn't rotate during focusing (or while zooming, for that matter), a nice feature for use with polarizers and graduated neutral-density filters. A standard bayonet mount hood comes with the lens, doing a good job of preventing flare at the wide angle end of the range, but a considerably poorer one at the telephoto end. (As you'd expect, any hood that doesn't crop your images at 18mm is going to be almost entirely ineffective at 250mm.) Jim found the hood a bit of a bother to put on and take off, but it didn't bother me that much. (And in practice, you'd rarely find a need to remove it anyway.) The optical design consists of 9 lens elements in 8 groups. Three of those elements are aspherical, and five of them are made of special glass types. Samyang has obviously done its best here. The diaphragm consists of 7 blades. You aren’t going to buy an 18mm wide angle with a brightness of f/2.8 for the bokeh, so those 7 blades are plenty. FOCUS
Optical Stabilization
I use this lens on a Sony A100. Not sure I would recommend use to someone using a camera with out image stablizing. Great lens for family outings, so long as there is enough light. Easy to always-have in bag. Still like it as much as when I bought it. Distortion is always a major issue for superzoom lenses, and the Tamron 18-270mm is not an exception to the rule. 5.62% barrel distortion was recorded at 18mm, which will be highly noticeable as buildings bow out fro the centre of the image. At 270mm distortion is present, but the 1% pincushion isn't overly disturbing. When I review lenses I take a look at who they are built for. I realize not every DPS reader wants to lug around a 5lb lens worth a couple month’s rent. While I love my main lens, it’s not for everyone and I’d be a fool to tell you you should buy it if you just want a portrait lens. The optical formula of 16 elements in 14 groups includes one hybrid aspherical element and one low-dispersion glass element to reduce aberrations such as distortion and chromatic aberration. Other superzooms tend to use more special elements, and this undoubtedly helps explain the Tamron’s low cost.
Hola! Muchísimas gracias por la reseña, tengo una XT3 y estoy entre este objetivo y el 18-135, no necesito una gran distancia focal pero si la tengo mejor, pero me preocupa perder mucha calidad. Si de calidad son más o menos me quedaria con el 18-135, puedes ayudarme? Two switches on the side of the barrel control image stabilisation and focusing mode. Like other inexpensive DSLR lenses, the focus ring shouldn’t be turned when the lens is set to AF. However, when it’s switched to M, the manual focus ring rotates smoothly enough. It traverses a pretty small angle from infinity to minimum focus, but despite this I found manual focusing to be straightforward and precise. Just to put it in perspective, the 18-270mm offers a 29-432mm equivalent zoom range when mounted on a Canon APS-C DSLR (27-405mm equiv. on Nikon or Sony). In the real-world, this gives the following effect (both shots taken from the same point):
It is a plastic lens body with a metal rear mount bayonet. To be honest, the experience is not as good as the metal-constructed lenses, but it still feels solid and does not feel cheap on my hand. Rotating the zoom ring is smooth while giving you some little friction. Do note that when the lens zooms to 300mm, the physical length of the lens does extend to almost 3/4 times its original length. And regardless of their true maximum focal lengths at any distance, all of these super zoom lenses have an awesome focal length range. This VC implementation is audible and not as well behaved as most of the recent lens stabilization systems I've been using - The wide open center-of-the-frame sharpness shows even further degradation by 35mm and the mid and corners remain very soft.
The distortion is fairly low with the Samyang AF 18mm F2.8 FE. If you don’t have too many straight lines straight along the edges, then you won’t see it. However, the distortion is not entirely linear, so it is not purely barrel-shaped or cushion-shaped, but a little wavy. You can’t easily eliminate that in Lightroom or Capture One if you want to. The image circle of this Samyang AF 18mm F2.8 FE is therefore large enough for full frame. But the lens is so small and light that it’s also not out of place on an APS-C camera. On the smaller APS-C sensors, this Samyang offers the field of view of a 28mm on full frame. On APS-C, the outer corners of the Samyang AF 18mm F2.8 FE remain out of view, and you only use the optically outstanding center. That doesn’t mean that you don’t get a good picture on full frame. On the contrary, the image quality is generally excellent. When you also look at the price, the quality is even ridiculously good. For landscapes or architectural shots that need to be sharp from corner to corner, it’s a good idea to stop down a few stops, but that is actually a good idea with every lens for such subjects. BUILD This lens is equipped with Tamron’s proprietary VC (Vibration Compensation) image stabilization, which helps to compensate for unwanted camera movements, especially under low light situations. While the official statement does not indicate the number of f-stops the lens can deliver, I tested and managed to get decently sharp photos at 1/14 sec at 300mm. I think I can confirm that VC does work reasonably well under such a situation. Some of the shots display shaowing around the edges at the 250 mm end but as long as you consider this when taking the photo these are easily removed br cropping. The Tamron 18-270 VC is, at review time, the lightest stabilized lens in the 18-2XXmm super telephoto lens class, but only barely so.
Overview
Image quality here is acceptable, but not great. The image is very soft overall at F6.3, with low contrast and blurring that's a signature of spherical aberration. But the centre sharpens up dramatically on stopping down to F8, beyond which it gradually degrades again due to diffraction. With our flat test chart the corners are very soft wide open, and while they improve on stopping down, they never really sharpen up fully. This most likely reflects curvature of field. Full Frame Coverage This is a must have lens, but you must no how to get the most out of it, for good sharp images I've found you must use f7 to f11. I have a lot of prime lenes but when Het beeld van die golvende, dichte mist staat nog op mijn netvlies. Twee foto’s in een van onze fotoboeken getuigen […] Tamron doesn't make a Pentax-fit model, but the recently-announced Pentax smc DA 18-270mm F3.5-6.3 ED SDM is in all probability essentially the same lens, again without the VC module. And if you are willing to give up the ultimate image quality and wide apertures a multi-lens solution will provide for the convenience of a super zoom lens,
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