Đánh giá tamron 70 200 f2 8 macro
(From Tamron lens literature) The new Tamron SP AF 70-200mm Di LD (IF) Macro (Model A001) is an ƒ/2.8 fast tele-zoom designed for full-size format SLR cameras. It inherits the product concept of the award-winning SP AF28-75mm ƒ/2.8 XR Di (Model A09) standard zoom lens that is highly acclaimed for its compactness and speed, which lets photographers enjoy a high cost to performance uniqueness. SLRgear Review December 29, 2008 by Andrew Alexander The Tamron 70-200 ƒ/2.8 telephoto zoom was announced in February 2008, updating and replacing their existing 70-200mm ƒ/2.8 zoom lens. The economical lens was originally available only for Canon and Nikon lens mounts; Tamron has now made versions for Pentax and Sony users, however on these bodies the ''one-touch'' AF/MF switchover mechanism requires that the camera body be set to manual focus as well. The lens features a constant ƒ/2.8 aperture across all focal lengths, and is designed to work on both sub-frame (APS-C) and full-frame 35mm image sensors. On sub-frame camera bodies the lens will have an equivalent field of view of either 112 - 320mm (Canon) or 105 - 300mm (others). Of all lenses in this category and specification, Tamron's is the lightest at 1,100 grams. The lens ships with a soft nylon case and a petal-shaped lens hood, and is available now for around $700. Sharpness Tamron has produced another lens that offers remarkable results for sharpness. Let's look first at the results of the lens mounted on the sub-frame D200. We see excellent results for sharpness when used wide open at ƒ/2.8. At 70mm we note central sharpness in the 1-blur unit range, with corner softness in the lower left and right areas at around 2 blur units; performance is similar across other focal lengths, with a sweet spot of 100mm, but 200mm shows some uneven performance with the center being somewhat softer than the corners (2 blur units in the center, 1.5 in the corners). Stopping down to ƒ/4 cures the majority of any corner softness (or in the case at 200mm, central softness), and ƒ/5.6 presents the optimum setting for this lens across all focal lengths. Setting the lens to ƒ/8 or ƒ/11 still presents excellent results - hard to tell from the results at ƒ/5.6. Diffraction limiting appears to set in around ƒ/11, but it's negligible, only really becoming a factor at ƒ/16, where the lens shows 2 blur units at 135-200mm. Results at ƒ/22 or ƒ/32 are uniformly soft, at around 3 and 4 blur units respectively. Performance on the full-frame D3 is even better, though the corners show up some softness that isn't apparent when used on the sub-frame D200. Between 70-100mm at ƒ/2.8, the lens produces tack-sharp results, but different lens elements must come into play at 135mm and 200mm, where we see significant corner softness (135mm) and odd central softness (200mm). Neither of these results is so extreme as to be overly noticeable, but they're worth mentioning. As with the D200, stopping down to ƒ/4 tames any wildness and we note essentially tack-sharp results across the frame at all focal lengths. Using ƒ/5.6 as the aperture again produces optimal results, but it's hard to tell the difference between this setting and ƒ/8 or ƒ/11. Diffraction limiting sets in by ƒ/16, but it's not until ƒ/22 that blur results even approach 2 blur units, and ƒ/32 where it barely exceeds that level. In a nutshell, the Tamron 70-200mm ƒ/2.8 produces remarkable results, seen more on the D3 than the D200. The results are slightly eccentric at ƒ/2.8 above 100mm, but stopping down to ƒ/4 cures anything that might be unpalatable. Chromatic Aberration The Tamron 70-200mm ƒ/2.8 handles chromatic aberration quite well. On the D200, we note some subtle CA in the corners at 70mm, but between 85-135mm this CA effectively disappears. Above 135mm, it returns, but only if you stop down to ƒ/8 or smaller; the worst case scenario is 200mm and ƒ/32, where we note significant corner CA (9/100ths of a percent of frame height) and also significant chromatic aberrations throughout the frame, not just the corners: in this case, just over 4/100ths of a percent of frame height. On the full-frame D3, the results are predictably amazing, as the D3 removes CA automatically when shooting JPEGs. Consequently we also shoot these test results in RAW mode and convert them with minimal processing in Bibble, to give a more accurate picture of how the lens performs. In this case it's similar to the performance noted on the D200: very good at 85-135mm, with some weak spots at 70mm and above 135mm. Shading (''Vignetting'') The Tamron 70-200mm ƒ/2.8 produces almost no light falloff when mounted on the D200; only when used at 200mm and ƒ/2.8. In this case, we note that the corners of the frame are 1/3 of a stop darker than the center. Not much to write home about there. On the full-frame D3 however, light falloff is a bit more significant. In this case using the lens at any focal length and ƒ/2.8 produces between a half-stop and 3/4-stop of corner darkening, with an emphasis on the telephoto range. Stopping down to ƒ/4 cuts this effect in half, and anything more drops this light falloff to below 1/4 of a stop. Distortion The lens contends with distortion very well, with some barrel distortion when used below100mm, and some pincushion distortion when used above 100mm (the lens is effectively undistorted when used at 100mm). When used on the D200, the lens produces 0.3% barrel distortion at 70mm, and -0.3% pincushion distortion at 200mm - in both cases, the results are evident in the corners. Average distortion is always barrel, but it's statistically negligible at under 0.1%. On the D3, the results are a bit more significant, following the same pattern as noted on the D200, but a bit more skewed. At 70mm we note 0.6% barrel distortion in the corners, and at 200mm it's -0.5% pincushion distortion. These aren't wild numbers, but if you need your straight lines to be straight, you'll need to apply some post-processing correction to your images. Autofocus Operation Tamron has moved away from mechanical lenses, by adopting electrical in-lens motors that move the lens elements. Consequently there is no screw to drive the elements, and older bodies that use this method will not be able to focus this lens automatically. However this does mean that the lens focuses significantly faster than previous mechanically-driven lenses, but it doesn't reach the blisteringly fast speeds of Canon's USM or Nikon's AF-S technologies. The lens also isn't as quiet as these styles, but it isn't objectionable. Then manual for this lens indicates that you shouldn't touch the focus ring when it autofocuses, as it could cause damage to the lens (presumably, because the focus ring moves during autofocus). This version of the 70-200mm f/2.8 doesn't seem to do this, suggesting the manual hasn't yet been updated. Macro The Tamron 70-200mm ƒ/2.8 is labelled as a macro lens, and with a reproduction ratio of 0.32x (1:3.1) it performs this function well. Minimum close-focusing distance is just over three feet (37.4 inches, 95cm). Build Quality and Handling The Tamron 70-200mm ƒ/2.8 employs a plastic lens body, allowing the lens to be much lighter, and presumably to cut down on the cost. Given the price point of the lens, there are no dust or moisture seals. The lens mount is metal; the filter ring is plastic. The lens offers a windowed distance scale, marked in feet and meters. Tamron uses a unique system for setting the lens into manual focus mode: you shift the focus ring backwards and forwards. A standard accessory of the lens is a removable tripod ring. The zoom ring is about an inch wide and rubber-coated, long ribs with small ridges in the middle. The ring takes about 70 degrees to turn through the entire zoom range. Because the lens uses an internal zoom operation, the lens doesn't extend and zoom creep isn't an issue. Interestingly, great attention has been paid to the focus ring, which is much larger than the zoom ring (2 inches) and uses a longer version of the ribs used in the zoom ring. Manual focus operation is very smooth, with only the finger and thumb required to glide the focus along. There's a good range of travel, just over 90 degrees so it's easy to achieve proper focus. The lens has hard stops at either end of the focus range, and will focus just past infinity. The front threads on the lens take a 77mm filter, and are plastic. However, the front mount doesn't rotate while focusing or zooming, so good news for polarizer users. There's no aperture ring, so it may not work with older film bodies that can't set the aperture of a lens. The petal-shaped lens hood works well to prevent lens flare, and reverses on the lens for storage. The interior of the lens hood is ribbed. Using the hood will add 3.5 inches to the overall length of the lens. Alternatives As the 70-200mm ƒ/2.8 is one of the most popular lens configurations, there is great competition among manufacturers. Nikon 70-200mm ƒ/2.8G ED-IF AF-S VR ~$1,600 The Tamron offers results comparable to the Nikon, however the Tamron edges out the Nikon for sharpness, especially at 200mm. We haven't tested the Nikon on a full-frame camera however, so take those results with a grain of salt. Autofocus speed and build quality is substantially better on the Nikon. Canon EF 70-200mm ƒ/2.8L IS USM ~$1,600 The Tamron is just slightly sharper than the Canon at ƒ/2.8, but stopping down to ƒ/4, the Canon shows better results. Full-frame sharpness is just slightly better on the Tamron. Other results are similar between the two lenses, with the exception of distortion, where the Canon provides just slightly better results. Again, the Canon USM autofocus and L-class build quality is much better than the Tamron. Sony 70-200mm ƒ/2.8 G ~$1,700 The performance of the Sony at ƒ/2.8 isn't as good as that found on the Tamron; stop the Sony down to ƒ/4, and it's comparable, with perhaps a slight edge to the Sony at 200mm. Other results are similar, with perhaps an slight edge to the Tamron. Pentax 50-135mm ƒ/2.8 ED AL IF SDM SMC DA* ~$725 Pentax doesn't currently offer a 70-200mm, so this is the comparable lens. Unfortunately, we haven't yet tested it. Sigma 70-200mm ƒ/2.8 EX DG HSM APO ~$800 Sigma has since updated their 70-200mm to a type 'II' version, so these results may be a bit out of date. The Tamron is sharper than the Sigma at ƒ/2.8, but stopped down to ƒ/4, the results are comparable. Results for chromatic aberration and distortion are almost identical, but the Sigma shows a bit more light falloff than the Tamron. Conclusion Price is obviously the major consideration when considering a lens in this category, and with exceptional results for image quality, it's not just about the money when considering the Tamron 70-200mm ƒ/2.8. Sharpness results meet and even exceed those for ''brand-name'' manufacturers, however the concession is build quality and autofocus speed. Professionals may require these; everyone else may not. Either way, if it's image quality you're after, the Tamron 70-200mm ƒ/2.8 delivers, and doesn't hit too heavily on the pocketbook. Sample Photos The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens. As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows. Tamron70-200mm f/2.8 Di LD IF Macro SP AFTamron 70-200mm f/2.8 Di LD IF Macro SP AF User Reviews8.2/10average of 11 review(s) Build Quality8.1/10 Image Quality9.1/10
9 out of 10 pointsand recommended by jonnyapple (6 reviews) image quality, MFD, cheap, fast, slow AF, no image stabilization, no range limiting switch I couldn't afford the 70-200 f/2.8 VR, and this one is a bargain at ~$1000 less. It seems a bit soft at 200mm and 2.8, but sharp everywhere else. I tried the 80-200 f/2.8 nikkor, and this is probably sharper than that lens wide open, and focuses at about 3 feet as well. Speaking of focus, that's one downside here, as Lex mentioned below. It's kind of slow, especially if you have to go through the whole range (maybe partly a tradeoff for doing better macro than the name brand lenses), and every once in a while it seems like the camera is jumping back and forth past the proper focus. I don't agree that the AF is loud, though. It's very quiet on the Nikon mount model. One note: some macro lenses (the tamron 90mm macro, for instance) have a smaller maximum aperture at close focus, but this keeps 2.8 no matter the focus distance. I would like to have a focus range limiting switch to be able to keep it from focusing closer than 3 meters or so. Bokeh is very nice. Image stabilization would be useful. In all, not much to complain about. It's got the important things down unless you're a serious fast sports shooter. |