Đánh giá tamron 70 300 vc usd năm 2024
In August of 2010 Tamron released an updated version of its 70-300mm telephoto zoom lens, with a few notable improvements. The first and most obvious is the addition of Vibration Control (VC) technology, to reduce the effect of camera shake and provide sharper images. The lens appears to be completely redesigned, with 4 additional lens elements and a new autofocus system. The lens was designed to fit full-frame film and digital SLR cameras, and on APS-C digital cameras, provides an equivalent field of view of 112-480mm (Canon) or 105-450mm (Nikon and others). This lens isn't a "constant" lens, in that as you increase the focal length, both the maximum and minimum aperture sizes decrease. The following table reflects the change in apertures as you zoom the lens: Focal length70mm100mm135mm200mm300mmMax. apertureƒ/4ƒ/4ƒ/4.5ƒ/5ƒ/5.6Min. apertureƒ/32ƒ/32ƒ/36ƒ/40ƒ/45 The lens ships with a petal-shaped lens hood, takes 62mm filters, and is available now for approximately $450 in Canon, Nikon and Sony mounts. Sharpness With the lens mounted on the sub-frame Canon 7D, the lens produced some exceptionally sharp images, more towards the ''wider'' end of 70mm than when zoomed in fully to 300mm. At 70mm and ƒ/4, the lens is quite sharp, with some light corner softness in the top right and bottom left corners; stopping down to ƒ/5.6 provides almost tack-sharp results (some very slight softness remains in those corners), but at ƒ/8 it's essentially tack-sharp. Diffraction limiting sets in at ƒ/11, but it's still quite sharp, until ƒ/22 where we begin to note some generalized softness across the frame. The mid-range of the lens (100-135mm) provides similarly good performance; again, very good at ƒ/5.6, and almost tack-sharp at ƒ/8. At 200mm the lens begins to show signs of weakness, with a bit of a soft center at its widest aperture of ƒ/5. You have to stop down to ƒ/8 to get past this, to what amounts to actually quite decent sharpness; it doesn't get any better at ƒ/11. Performance isn't any better at 300mm; ƒ/8 and ƒ/11 are the best settings here, where they provide adequately sharp images. The 70-300mm ƒ/4-5.6 VC USD stops down to quite small apertures, in this case, ƒ/32-ƒ/45, all of which will provide quite soft images, with the exception of ƒ/32 at 70mm, which provides only slightly soft images. Mounted on the full-frame Canon 1Ds Mark III, the lens doesn't betray any secrets - it's just a little bit softer at wide apertures. Otherwise it's mostly the same story as above - stop down to ƒ/8 to get maximum sharpness, and don't expect anything overly sharp at 200mm or 300mm. Chromatic Aberration The Tamron 70-300mm ƒ/4-5.6 VC USD offers good but not great CA tolerance, with some light magenta-green fringing appearing in areas of high contrast in corner areas. CA is more noticeable as the lens is stopped down, offering the best performance at 135mm and 200mm. Shading (''Vignetting'') Corner shading is virtually non-existent when the lens is mounted on the sub-frame 7D. On the 1Ds Mark III however, it's a different story: you have to stop down significantly to get images which don't show some kind of light falloff in the corners. At its worst, you're looking at extreme corners which are almost a full stop darker than the center - you see this at 100mm and 135mm when used wide open. To remove the impact of corner shading you need to stop down to at least ƒ/8. Distortion There's some distortion present in images shot with the Tamron 70-300mm ƒ/4-5.6, but no more than other lenses in this category. At 70mm, the distortion is almost negligible - just a slight amount of barrel in the corners. From 135mm and on, there's significant pincushion distortion in the corners. As usual, this distortion is much more significant when the lens is used on full-frame cameras such as the 1Ds Mark III. Autofocus Operation Tamron has employed a new focusing system with this lens, the Ultrasonic Silent Drive. The lens focuses very quickly - it takes about one second to go through its focusing range - and it does so nearly silently. The new system allows for full-time manual focusing, allowing the user to adjust autofocus results by simply turning the focusing ring. Focusing operations do not rotate the front element, making life that much easier for polarizer users. Macro Unfortunately, the new lens design no longer offers the 0.5x magnification of the previous design. The new lens offers an adequate 0.25x magnification at 300mm, with a minimum focusing distance of around five feet. Build Quality and Handling The Tamron 70-300mm ƒ/4-5.6 VC USD looks attractive with its matte black finish and polycarbonate construction; it is a new breed of telephoto zoom lens from Tamron, and not just an incremental upgrade from its previous incarnation. The lens is significantly larger and heavier for a start, adding an inch to its basic length and 12 ounces to its weight. No doubt this is a result of adding four new lens elements in three groups, as well as the whole Vibration Control (VC) system and the new USD focusing system. Despite all these changes it's still light enough to use comfortably without a tripod. The lens features a metal body mount and a smaller filter ring size (62mm instead of 67mm) composed of plastic threads. On the Canon and Nikon mounts, there are two control switches on the barrel: one to enable or disable autofocus, and one to enable or disable Vibration Control. On the Sony mount Vibration Control is not available, because Sony cameras include image stabilization in the body. The lens features a focusing scale in feet and meters (in a recessed and windowed scale) but does not feature an infrared index or a depth-of-field scale. The zoom ring is the larger of the two, rubber with long segmented ribs, measuring about two inches wide. The ring takes about ninety degrees to go from 70mm to 300mm, and does not show any signs of zoom creep. It's nicely cammed and takes only two fingers' worth of force to move it through its zoom range; doing so extends the length of the lens, adding about two inches to its overall length. The focusing ring is about 3/4'' wide, also rubber with ribs. The focusing ring ends at soft stops at the close-focus and infinity focus points, and will focus past infinity. The HA005 lens hood is quite long - about 3 3/4'' deep - a petal-shaped hood that attaches via a bayonet mount and can be reversed for storage. The interior of the hood is ribbed to reduce the impact of flare. Our image stabilization test is almost finished for this lens, which advertises four stops of improvement. Alternatives Each of the lens manufacturers produces a lens in this range, so let's see how they all stack up against each other. Tamron AF 70-300mm ƒ/4-5.6 Di LD Macro 1:2 ~$160 The first point of comparison is between the old and new. Apart from a bit of a price hike, the old lens matches the new for sharpness, and in some cases, betters it. However the new lens offers improved CA tolerance, and less corner shading, as well as the obvious benefits of USD focusing and Vibration Control. Canon EF 70-300mm ƒ/4-5.6 IS USM ~$600 It doesn't seem fair to match the new Tamron against Canon's latest L-glass, so we'll match it against this perennial favorite. This is a lens where Canon got it right - it meets and exceeds the sharpness performance of the Tamron, shows less CA, and less corner shading as well. Distortion is a bit more noticeable on the Canon; both lenses feature USM style focusing and image stabilization. (It should be noted that our test sample of the Canon 70-300mm ƒ/4-5.6L is actually on par with the Tamron in terms of performance.) Nikon 70-300mm ƒ/4.5-5.6G IF-ED AF-S VR ~$550 One of Nikon's better lenses, the Nikon offers superior sharpness, but poorer CA performance, when compared to the Tamron. We haven't had an opportunity yet to test this lens on a full-frame body. Otherwise, both lenses feature USM style focusing and image stabilization. Sony 70-300mm ƒ/4.5-5.6G ~$850 We haven't yet tested Sony's direct competition - it doesn't offer image stabilization because Sony dSLR cameras offer in-body stabilization instead. It does offer SSM focusing. Sigma 70-300mm ƒ/4-5.6 DG OS ~$350 Sigma has also decided to offer image stabilization in its 70-300mm range - we haven't tested this model yet. The previous model (tested here) offered adequate results for sharpness, good results for CA, and significant corner shading and distortion when mounted on a full-frame body. Conclusion Tamron has seemed to pay attention to what other manufacturers are offering and has created a new design for this lens. Instead of a lens which offered dual roles as a telephoto zoom lens and a capable macro lens, Tamron has chosen to emphasize the former at the expense of the latter, and has created an solid performer in this category as a result. Product Photos 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. Tamron70-300mm f/4-5.6 Di VC USD SP AFTamron 70-300mm f/4-5.6 Di VC USD SP AF User Reviews9.1/10average of 21 review(s) Build Quality8.6/10 Image Quality9.1/10
10 out of 10 pointsand recommended by pc998 (6 reviews) Very sharp even at 300mm. Good AF speed and color. VC is extremely effective. USD is not silence enough but not an issue It has absolute focus accuracy with D700 using 51-pt auto area or single focus point. While the USD focus speed is fast (but not the fastest), we can still hear the focus noise. In contrast, Canon USM is near silence. The VC is extremely powerful. It seems to me that the stabilization effect is even better than Canon’s IS and Nikon’s VR. For many other 70-300 zoom lenses over the market, the resolution drops starting 200mm and onward. However, this SP lens has excellent performance across the whole zoom range even wide open. Corner sharpness is almost the same as the center. For instance, the performance at 300mm is particularly good and looks even better than its 70mm. I think the XLD (similar to fluorite) is really powerful. In general, this is the highest quality Tamron SP zoom I have ever used. It outperforms the Nikkor 70-300 VR much. |