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Laowa 58mm f/2.8 2x Ultra-macro APO - Review / Test Report - Analysis |
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Lens Reviews -
Canon EOS (Full Format)
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Page 2 of 3
Distortion
Due to the lack of electronic coupling, Laowa has to rely on its optical design for delivering image distortions and they certainly excel in this respect.
The Laowa 58mm f/2.8 2X Ultra-Macro APO can produce distortion-free images, as you can see below.
Vignetting
The vignetting characteristic is a bit unusual. A light falloff of ~1.5 EV (f-stops) at f/2.8 is relatively normal. However, stopping down improves this less than expected.
At f/8, the vignetting is still higher than 1EV - not a big deal, but noticeable.
MTF (resolution) at 45 megapixels
The resolution characteristic of the Laowa 58mm f/2.8 2X Ultra-Macro APO is impressive, if not outstanding. The center quality is excellent at f/2.8, followed by a very good outer image field.
At f/4, the broader center is superb and the borders/corner improve a little bit as well. The overall peak performance is reached at f/5.6. Diffraction is limiting the quality thereafter but it only
gets relevant at f/16. Even f/22 is usable. However, we suspect that the aperture numbers aren't really accurate - the results "shouldn't" be as good at smaller aperture settings.
Nothing beats diffraction, really.
The field curvature is low. Unfortunately, our sample had a very strong centering defect on the left image side. The MTF readings for the borders/corners were taken on the right image side.
Please note that the MTF results are not directly comparable across the different systems!
Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure of sharpness.
If you want to know more about the MTF50 figures, you may check out the corresponding Imatest Explanations
Chromatic Aberrations (CAs)
Lateral CAs are basically non-existent and nothing to worry about.
Bokeh
Macro lenses are almost always used for scenes with a shallow depth-of-field - this is simply what you end up with at high object magnifications. Thus the quality of the bokeh should better be good.
And the Laowa lens delivers in this respect.
Out-of-focus highlights are nicely rendered with a smooth inner disc and little outlining at the edges.
As usual, the discs deteriorate towards the image borders - in this case, with a slight "cat eye" shape. Stopping down to f/4 corrects the near-center highlights, whereas the corner highlights are getting edgy.
If needed, it's better to avoid f/4 and go for f/5.6 for a better correction of these highlights.
The general blur characteristic resembles its 90mm f/2.8 cousin in being smooth in the image foreground and just a tad less so in the image background. See also our sample image sections. LoCAs/Bokeh fringing is also not a concern.
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