Overall I feel the Tamron is an excellent choice for those looking for a budget telephoto addition to the kit lens supplied with their camera. What makes it strange is that this only happens with this lens, and only close or at the 300mm end of the focal length, anything between 200-300 is likely to cause the error.

being a telephoto lens and also having 9 aperture blades helps a lot and this lens produces pleasantly Pincushion distortion increases over the focal length range until becoming moderately strong at 300mm. My copy has on the Sony DSLR-A300 a center resolution of 1500 to 1800 LPH and corner resolution is typically between 1300 to 1600 LPH, measured in the range of biggest aperture down to F8. One special observation is the good telephoto performance at 300mm and the widest aperture of f5.6: 1650 center, 1550 corner. The worst wide-aperture image quality is at 180mm and f4.5, where the LPH values fall to 1450 center and 1300 corner. Consequently, center resolution is acceptable for a 10MP camera, and corner resolution is just tolerable, with 180mm/f4.5 unsatisfactorily. Here are the focal length/aperture settings that I typically use for my copy:The Tamron 70-300mm F4.5-6.3 Di III RXD is the most compact and lightest 70-300mm zoom lens currently available for Sony's range of full-frame mirrorless cameras. To make the 300mm telephoto focal length more fun and accessible, TAMRON focused intently on designing a telephoto zoom lens that's both small and lightweight. Turning the conventional concept of a telephoto lens on its head, the 70-300mm F4.5-6.3 is only 148mm (5.8 in) in length with a maximum diameter of 77mm and a weight of just 545g (19.2 oz). This gives users the freedom to concentrate fully on shooting without worrying about lens size or weight. In addition to those wishing to pursue real telephoto shooting for the first time, the lens is also recommended for people who use cameras that have built-in image stabilization because they can leave the tripod at home. Of special significance, when paired with the APS-C mirrorless cameras, this zoom adds additional telephoto reach and while remaining comfortable to handle. Users can enjoy shooting with even higher power telephoto effects at a maximum equivalent focal length of approximately 450mm 3. To test the effectiveness of the image stabilization with the Tamron 70-300mm f4.5-6.3 Di III on a Nikon Z 7 camera body, I did a series of 140 test-shots hand-held at 300mm focal length with shutter speeds from 1/320 of a second down to 1/10 sec. I used the shots at 1/320 sec with VR=off as reference of how good my handholding was at the time of the test and Reikan FoCal did the chore of evaluating the sharpness of all shots.

With their deeper DOF (Depth of Field) with identical framing, APS-C camera bodies will not show the focus errors as readily as full frame bodies. Importantly, full-time manual focus override is also possible and the lens is also fully compatible with the "Direct Manual Focus (DMF)" system feature of Sony cameras that enables the user to instantly switch between autofocus and manual focus. Seals are located at the lens mount area and other critical locations to deter infiltration of moisture and/or rain drops and afford Moisture-Resistant Construction. This feature provides an additional layer of protection when shooting outdoors under adverse weather conditions. button half-way and wait for them to come . It also tends to hunt a lot in dim light i had a lot of problemsThe internal focusing mechanism also means that the front element neither extends nor rotates throughout the focus range, which is a bonus when using rotation-specific filters such as a circular polariser or graduated neutral density filter. The lightweight construction is a bonus from a handling point of view, especially for long periods of handheld shooting and simply for carrying the lens around. The electronically coupled manual focus ring and mechanical zoom ring both operate with smooth efficiency and, as usual for this class of lens, the inner barrel extends at longer zoom settings. With fully internal focusing, however, the front element and filter ring don’t rotate, which is another handling advantage. That’s really all we can say about handling, as there are no other switches or control rings to play with apart from the zoom and focus rings. Performance At 300mm, a commonly used telephoto zoom focal length, the design delivers excellent resolution from edge-to-edge. Overall, the efficient optical construction (which also contributes to its lightweight) plus Tamron’s BBAR (Broad-Band Anti-Reflection) Coating with its well-established reputation for anti-reflection properties, combine to enable the photographer to capture extremely clear, crisp images across the entire zoom range. While the lens features an advanced design with excellent core image quality, optical performance can be enhanced even further by employing the lens correction features found on Sony cameras. The Tamron 70-300mm f/4-5.6 Di VC USD Lens is not a small or light lens, but it is average for its class.