Mounted on the full-frame α900, the 35mm ƒ/1.4 shows the same improvement, but the corner performance is more startling. Fully stopped-down at ƒ/22, it's around 2.5 blur units across the frame. Diffraction limiting sets in at ƒ/11, but at this point we're seeing just under 2 blur units across the frame. At ƒ/5.6, the corners finally fall below 2 blur units, but there isn't much improvement in the center ƒ/8 shows a more even sharpness profile. There's further improvement at ƒ/2.8, but it isn't until ƒ/4 that we see performance worthy of a $1,300 lens, with around 1.5 blur units in the center, and 2-2.5 blur units in the corners. On the sub-frame α700 at ƒ/2, the central region of the image - a generous sweet spot in the middle - offers between 2-3 blur units of sharpness performance, but the corners improve only marginally. Stopping down the lens does provide improvement to image quality. On a full-frame sensor the image corners are even softer, reaching 6-7 blur units on the top of the image, and upwards of 11-12 blur units on the bottom of the image. Specifically, the majority of the image comes in at around 4-5 blur units, and the corners reach 6 blur units. With the lens mounted on the sub-frame α700, we noted very soft results when images were made wide open at ƒ/1.4. When the second lens tested identically, we accepted that this is just the nature of the lens. We tested two samples of this lens, as the first sample gave us what we considered to be unacceptably high softness wide open for a lens with this price tag.
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