Pentax DA 35mm F2.4 vs 40mm XS vs 40mm Limited
Image Quality: Flare
For this test, we placed the test camera on a tripod pointed directly into the sun. We shot each lens at f/2.4 or 2.8, 4.0, 5.6, 8.0, and 11.0. We then rotated the tripod mount so that the sun was in the upper left corner of the frame and repeated the shooting process. The DA 40mm f/2.8 Limited had its hood attached.
- Manual focus
- ISO 80
- JPEG (highest quality)
- White balance set to Auto
- Auto-exposure; Multi-segment / Evaluative metering
- Image mode set to camera default ("Bright")
- Dynamic range extension off; In-camera lens corrections off
- Camera on tripod, 2-second self-timer; SR off
Conclusions
All three lenses produce comparable results when shooting wide open with the sun in the center of the frame. The sun is rendered as an amorphous blob, but there are no distracting flare spots elsewhere in the image. As each lens is stopped down, the central blob emits star-patterned rays corresponding to the number of blades in the aperture diaphragm. The DA 35mm f/2.4's star is six-pointed, while the 40mm lenses produce nine-pointed sunstars. In general, the flare is superbly controlled when the sun is at the center of the frame. The stars, while not offensive, aren't as distinctive or (subjectively) gorgeous as those produced by lenses like the DA 15mm f/4 Limited.
With the sun in the corner of the frame, all of the lenses perform very well—there's really nothing between them. Wide open, all three control the flare with ease. At this setting, the only effect from the sun is a bright, diffuse glow that tapers off toward the lower right corner. Stopping down, a few rays are cast in that same direction, but they're faint and not really distracting in any way. It's true that prime lenses in general benefit from simpler optical construction than zooms, and often perform better with regard to flare resistance as a result, but in our opinion these three are truly exceptional.
