HD Pentax-DA 35mm F2.8 Limited Macro

Vignetting

In simple terms, vignetting is the darkening of the corners of an image that occurs at wider apertures. Every lens, wide open, will exhibit some. Luckily, it need not be a problem for modern photographers. First, it is always possible to shoot at smaller apertures, mitigating the effect. Second, cameras released in the last few years often have built-in tools to remove vignetting in a way that's invisible to the user. Last, it is always possible to purchase higher-quality lenses that will show milder vignetting.

This section presents how the DA 35mm macro performs in regards to vignetting. Being a Limited and a macro lens, a good performance can reasonably be expected. However, like all APS-C lenses, it is likely that some vignetting will occur.

Vignetting Test

The test was performed by pointing the lens at a blank wall. In order to avoid the bias of the in-camera corrections, we shot each image both in JPEG and in DNG RAW, then used Adobe Lightroom to develop the RAW files (using default settings to develop the files). JPEGs and RAWs were scaled down, converted to grayscale for improved visibility, and exported. The following settings were used:

The following chart illustrates the darkening in the corners in terms of the exposure difference relative to the center, for the RAW images.

Verdict

As can be expected, JPEG files with in-camera correction show no visible vignetting, which is more a testament to the quality of the JPEG engine than to the lens. RAW files show levels of vignetting within our expectations. It is visible at F2.8, representing three quarters of a stop. Below F4, vignetting essentially becomes irrelevant. In each case, it can be easily corrected via post-processing.

In summary, the lens presents a good performance, although not perfect.