Pentax-DA 35mm F2.4 AL

Vignetting

In this assessment of the lens, we focused on the amount of vignetting produced by the lens, or the characteristic where the brightness of an image is not uniform across the entire frame, particularly the further one gets toward the edges of the frame.

Before we get to the images below, it's important to note that the complete removal of any and all vignetting from a lens' widest apertures, if not entirely impossible, would require an extremely complex design with very large optical elements (and thus big dollars). Even for the most expensive lenses available to consumers, across any brand, vignetting is expected.

Vignetting Test

For our vignetting test, we pointed the lens straight up into a very clear and bright blue sky. The following settings were applied across all the sample images during this iteration:

F2.4
F2.8
F3.5
F4.0
F4.5
F5.6
F8.0
F11

Verdict

As expected, wide open has some vignetting with a respectable less than 1 stop difference between the center and the darkest parts (the corners). Close the lens down a hair to F2.8 and the difference in exposure will have a negligible effect on any real-work photos. Make your way one-half of a stop further at F3.5 and all vignetting is effectively gone. A 1/2 stop more at F4.0 and there isn't the slightest trace of any exposure difference across the frame, a trend that is maintained for the rest of the aperture range.

So yes, the 35mm Plastic Fantastic exhibits vignetting wide open. But stopping to F3.5 or lower results in it being effectively eliminated, having no effect on your photographic pursuits.