Article Index

Resolution

Sony E 30mm f/3.5 Macro clocked somewhat mixed performance with Imatest. Per chart below, the lens seems to produce non-uniform resolution across the picture frame. Center resolution is spectacularly high across all tested aperture levels, however border quality seems to suffer, in relative terms of course. We still get a reasonably decent border quality at all aperture levels, but it is not of the same magnitude as in the center. Moreover, border resolution does not seem to improve that much with stopped down apertures, which is quite surprising. But a much bigger issue is the ~40% variance in MTF between center and borders, which should, at least in theory, produce visible difference in image quality. So that's what we are going to check now.

 

30mm (Sony NEX-5n)

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Looking at the corner crops of the imaging target, we could see why Imatest believes that there is not that much improvement in resolution as we stop down the aperture - I don't know about you, but crops at f/3.5 and f/8 look very much alike. Maybe a little bit more detail at f/8, but only marginally so. I can't really say that image quality is absolutely superb here, but it's not disastrous either. It's just f/8 should have shows more improvement IMO. But let's see at some shots made at infinity.

 

30mm (Sony NEX-5n)

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Well, turns out that even in field testing at infinity, the lens behaves pretty much the same way as in controlled environment. The lens basically lacks punch around corners, no matter how much you stop down the aperture. It remains perfectly sharp in the center throughout the aperture range, but borders are somewhat soft-ish at f/3.5 and don't really improve much visually even when you stop down to f/8 or f/11. Just to be clear, corners are not completely soft - there is enough detail there, particularly if you're not pixel-peeping at high magnification, but it does leave you wanting more, particularly if you were hoping to use this lens for anything remotely landscape-ish.
 

Center (Sony NEX-5n)

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L.L. Corner (Sony NEX-5n)

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U.R. Corner (Sony NEX-5n)

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But while the E 30/3.5 Macro does not quite impress in image quality around borders, at least it delivers very consistent performance across pretty much entire spectrum of focusing distances. Here's a plot of average MTF50 results measured by Imatest at various focusing points. Maybe this could be a consolation prize for some.

 

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Color & Rendering

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Considering the somewhat sparse selection of native Sony NEX lenses, and particularly lenses from 3rd party manufacturers, comparison of color and rendering qualities of the E 30/3.5 Macro is done in isolation. Nothing wrong with this obviously, but I would have preferred to have tried another 30mm macro lens and be able to contrast it against the E 30/3.5 lens. But whatever...

Sony E 30/3.5 Macro is a moderate contrast lens, with an emphasis on mid-tones. Contrast levels remain fairly consistent throughout the aperture range, although there is a sight drop at close focusing distances, which is typical to many lenses. Tonal reproduction is average - there is nothing really special that the lens brings in this department. Mid-tones have a better representation under normal shooting conditions (i.e. no bright sun in the frame), at the expense of shadows, which get a bit compressed. But overall distribution is fairly standard, as long as you meter the scene correctly. And because of almost non-existent vignetting, there's rarely any need to adjust exposure compensation.

For the most part, the color reproduction of the E 30/3.5 Macro is fairly neutral. The gamut is well balanced (I'm shooting in Lab color space, which gives a slightly larger coverage of the color space than sRGB at the expense of requiring me to tinker with image in post-processing).

The lens does show moderate levels of chromatic aberration - per Imatest, lateral CA reaches ~1.5px in the corners at wide apertures and remains pretty much flat throughout the rest of the aperture range. Now, 1.5px is not particularly bad for general purpose or landscape type work, however, you are much more likely to notice fringing at macro distances, particularly with high contrast highlights, where the lens produces purple trails around highlight edges pretty consistently. Longitudinal aberration is also present, albeit it is not as pronounced in most cases and does not really degrade overall feel of image quality.

 

 

Lateral CA @ 30mm (Sony NEX-5n

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DOF & Bokeh

Sony E 30/3.5 Macro is one of the hardest lenses to characterize when it comes down to DOF and bokeh rendering. In the conventional theory, wide-ish focal length and fairly slow max aperture are typically going to be the primary elements of a mediocre DOF. However, this lens also offers an unusually short MFD (it's a macro after all) and so at 10cm your DOF is going to be very, and I mean, very shallow. 0.11cm to be precise. That's 1/10th of a centimeter! In other words, if you were to use a 100mm macro on a full frame camera like Sony a900, you'd need to shoot at f/2.8 and 30mm focusing distance to achieve the same DOF. You can't get an absolutely precise focusing with such a shallow DOF, regardless of whether you're relying on AF or manual focusing. But all that is a theoretical discussion since in practice you'd rarely be able to get to the absolute MFD (You want me to stick my lens in your left or right eye?), unless you're shooting something static on a tripod. More likely you would be shooting at 50-70cm rather than full macro distance, which is still close enought and would give you a DOF of ~8cm. Still not bad, but with more detail in the background, you also get a change in the rendering style of the OOF areas. Instead of smooth transitions across objects and blending of colors, you get rough patches that stick out of the frame and colors that have more distinct separation. Basically what I am trying to say is that you get this fairly noticeably change in behavior when you shoot this lens at MFD vs everything else. Is there a way to universally characterize the bokeh of Sony E 30/3.5? Nope. I don't even want to try. What I can tell you is that bokeh is very smooth and pleasant looking at MFD (check the macro section for some shots at MFD). At longer focusing distances it's a crap-shoot - you go from a neutral look at something like 30cm and f/3.5 to harsher feel at 1m and f/4 and to even harsher at 3m and f/5.6.
 

DOF @ 30cm

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DOF @ 3m

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Sample shots above as well as below should give you an idea of what I'm talking about. The rendering of OOF background changes quite drastically, which is something you would want to consider, if you're aiming for nice smooth bokeh. One thing worth mentioning here though is that you get some longitudinal CA at wide apertures, It is not very bad and would not ruin overall image quality, but would be noticeably in some shots, particularly if you're looking at them at higher magnification.

 

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