|
Sony E 30mm f/3.5 macro (SEL-30M35) - Review / Test Report - Analysis |
|
Lens Reviews -
Sony NEX
|
|
Page 2 of 3
Distortion
The Sony lens produces a slight amount of barrel distortion (~1%) which is usually not objectionable in field conditions.
Vignetting
The amount of light fall-off is hefty at f/3.5 (~1.6 f-stops) - this will be noticeable in most field images. Stopping down to f/4.5 eases the issue a little bit but it takes f/8 to reduce it to a negligible degree.
MTF (resolution)
This is our first test based on the Sony NEX 7. The camera sensor has a rather difficult resolution characteristic for lenses specifically at large aperture settings - the corner quality is substantially dampened based on what we've seen so far. However, we still feel that it is appropriate to restart our Sony E tests based on this camera. After all this is Sony's flagship model (as of 2012).
Macro lenses tend to be very good performers straight from the max. aperture but the Sony lens breaks this rule. The center quality is, undoubtedly, excellent if not outstanding but the border and corner quality falls totally apart especially at large aperture settings. Stopping down to f/5.6 boost the borders into good territory whereas the corners remain soft. The best image quality is reached at f/8 with a still excellent center and good borders and corners. Diffraction has a higher (negative) impact from f/11 onward. f/16 and especially f/22 should be avoided. Unfortunately the general performance can be regarded as inadequate for a macro lens.
The centering quality of the tested sample was acceptable but not superb. This is, unfortunately, not the first time that we saw a need for improvement here.
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 for sharpness.
If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations
Chromatic Aberrations (CAs)
Another weakness of the Sony lens is the amount of lateral CAs (color shadows at harsh contrast transitions). An average width of around 2.4px at the image borders is very pronounced especially for a prime lens.
The latest Sony NEX camera have the ability to correct CAs in the camera already so it's a good idea to take advantage of this option.
Bokeh
Macro lenses are often used in shallow depth-of-field situations so the quality of the bokeh (out-of-focus rendering) is a priority aspects. The Sony lens delivers acceptable results here.
Out-of-focus highlights can show an onion-like substructure which looks somewhat "busy". The highlights are nicely circular at f/3.5 (except towards the corners) but the edgy aperture shape gets already obvious at f/4.5 and beyond.
The out-of-focus blur is very smooth in the image background and slightly more nervous in the foreground.
|
