Lomography Daguerreotype Achromat 64mm F2.9 Art Review
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. Most of the time, 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. Advanced software also often incorporates lens profiles which can seamlessly correct vignetting. Last, it is always possible to purchase higher-quality lenses that will show milder vignetting.
A fast lens is somewhat more likely to show vignetting than a slow one, although this is not a hard rule. A full frame lens also benefits from a sweet spot on APS-C, but shows its flaws more visibly on full frame cameras. A zoom is more likely to show vignetting at its wider focal lengths.
This section presents how the Daguerreotype Achromat performs in regards to vignetting.
The test was performed by pointing the lens at a blank wall. There is no in-camera correction for this lens. Resulting files were scaled down, converted to grayscale for improved visibility, then exported. The following settings were used:
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The following chart summarizes the findings with the regular aperture blades and with a sample of creative aperture shapes. "Open" refers to the lens without any aperture blade.
With the regular shapes, vignetting improves dramatically as the aperture closes. It stabilizes at F8, but is already almost negligible starting at F5.6. Even F4 is well controlled. In fact, these results are a bit of a surprise. Even wide open, vignetting is only three quarters of a stop.
Using "creative" aperture shapes delivers varying results. Shapes that are closer to a circle follow more or less the pattern of the regular apertures. Irregular shapes such as a heart have stronger vignetting. This can be a way to induce vignetting with smaller apertures if so desired.
The next images show the vignetting at various focal lengths and apertures. Click on any thumbnail to compare the vignetting at the given focal length.
Vignetting is easily corrected via software. Even with irregular aperture shapes, the resulting vignetting is mostly similar in each corner of the frame.
Vignetting is surprisingly well controlled for this lens, even wide open. Irregular aperture shapes yield increased vignetting relative to their effective aperture.