Автор: Amigo
Дата: 14-02-10 17:06
има ревюта в нета ![[smile]](https://photo-forum.net/forum/smileys/smilie1.gif) евтиното винаги излиза скъпо - това трябва да се има предвид
Tokina
Resolution
Sharpness results are very good indeed, especially for an ultrawide zoom. The lens is generally very sharp wide open, improving slightly on stopping down, with F5.6 - F8 the optimum apertures. The only glitch is at 24mm, where sharpness is compromised at F4 and F5.6; in our tests this appears to be due at least partially to a decentering of the zoom group as it reaches the end of its travel. Extreme corners are a little soft at the widest focal lengths, but this is unlikely to be problematic in real-world use. As usual on APS-C, apertures smaller than F16 are best avoided.
Falloff
We consider falloff to start becoming perceptible when the corner illumination falls to more than 1 stop below the center. The 12-24mm shows only modest falloff (1.3 stops) at 12mm F4, which disappears on stopping down to F5.6. Nothing to worry about here.
Tamron
Resolution
Sharpness is generally poor wide open, and examination of the checkerboard crops shows low contrast due to halation effects (quite possibly a result of the slight decentering mentioned above). The lens improves dramatically on stopping down; central sharpness is extremely high at 10mm, but diminishes progressively at longer focal lengths; however the extreme corners remain soft at all settings. As expected for this type of lens, best results are obtained at F5.6-F11, with the optimum aperture being F8.
Falloff
We consider falloff to start becoming a potential problem when the corner illumination falls to more than 1 stop below the center. The 10-24mm shows about 2 stops wide open at wideangle (with a slightly asymmetric pattern), but this decreases rapidly on stopping down, settling at 1.3 stops at F8 and smaller apertures. This will rarely be noticeable in real-world use, and usually swamped by natural lighting variations across such a wide field of view. At 13mm and longer, falloff is essentially a non-issue at any aperture
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