Pentax-DA* 200mm F2.8 Review
Vignetting
Vignetting refers to darkening in the periphery of an image, and is also known as light falloff. For this test, we shot images of the sky using the Pentax SMC DA* 200mm f/2.8 ED [IF] SDM at various apertures with the focus set at infinity.
| f/2.8 |  | f/4.0 |  |
| f/5.6 |  | f/8.0 |  |
| f/11 |  | f/16 |  |
| f/22 |  |
For evaluation purposes, we then determined the ratio between the average brightness in the corners versus the center of the test images. The resulting ratios (expressed as a percentage) are the following:
| f/2.8 | 95.01% |
| f/4.0 | 97.67% |
| f/5.6 | 98.11% |
| f/8.0 | 98.12% |
| f/11 | 98.17% |
| f/16 | 99.51% |
| f/22 | 99.55% |
Verdict
As can be observed with the ratios mentioned above, vignetting is insignificant in the DA* 200mm f/2.8 lens. We could state that, for all practical purposes, the DA* 200mm f/2.8 has no vignetting at all when used with an APS-C sensor DSLR. In this regards, we are highly pleased with the performance of this lens.
