Sony FE 35mm F1.4 versus F2.8 - Sharpness Comparison
Marc Heijligers, 21-02-2016On this page you’ll find a detailed comparison between the sharpness of both lenses.
Summarized Results
The tables below show the summarized relative performance of both lenses I have tested in terms of their sharpness. As you can see, the Sony F2.8 is the overall sharper lens. Both lenses suffer from a tilted lens element (see the Sony Lens Quality issues page for more info), where the overall effect for the F1.4 is more intensive.
Test Conditions
Both lenses are tested on an A7RII.The first test is to judge the field sharpness of the lens. For this I use a bookshelf, which has a flat surface and a lot of books where the text on the book spines can used to test the subjective sharpness at a distance of 1.5 to 2m (not fully scientific, but sufficient to represent practical use cases for most of us). The camera is put on a tripod, where care is taken that the camera is perpendicular to the bookshelf (using the level indicator of the camera, visually checking the camera is in the middle, the bookshelf plates are symmetrical in the viewfinder, and double check with LensCal that the book spines are within the DoF range). The focus point for all photos is always in the centre (though other focus points have been checked for sanity, as well as multiple pictures to exclude focus differences). For lenses with different focal length, the camera is moved such that the composition of the scene remains the same in the viewfinder. Photos have been made with Steadyshot turned OFF, Silent Shooting turned ON, and a timer (but the differences are hardly visible with complementary settings in this specific setup). Pictures are taken in RAW, and processed in Lightroom with the Camera Neutral setting, and with Lens corrections enabled. For sanity, I’ve checked the difference between JPG, and RAW with corrections turned off, but the results are similar. Three regions are considered in the tests, one in the centre, one at the bottom-left, and one at the top-right. To investigate color fringing, tests have also been done closer to some books that have a high level of contrast.
The second test is to test the lens for sharpness at further distance. For this purpose I photographed a (boring cloudy) city scene from the balcony. This rules out the problem with the camera might not be absolutely perpendicular to the bookshelf. Furthermore, the larger distance increases the depth-of-field for distant objects, hence if there are internal or shifted lens elements, it also reveals unsharpness in those conditions. Also here three regions are considered the centre, the left, and the right side.
Detailed Comparison
Use the filter button below to select which cases you want to see and compare in detail (the buttons will limit the selection), and use the slider to compare the Sony F1.4 (on the left) and the Sony F2.8 (on the right).-
Bookshelf, Centre, Open Aperture (f1.4 and f2.8) - The F2.8 lens is much sharper open. Both show purple fringing, but the F1.4 lens is worse open, and has a haze around the letters.
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Bookshelf, Centre, f2.8 - The F2.8 lens remains sharper than the F1.4 lens at f2.8. There is still a slight haze at the white letters of the F1.4 lens. The F2.8 lens keeps on showing some purple fringing.
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Bookshelf, Centre, f5.6 - Both lenses are very sharp. The F2.8 lens is now free of purple fringing, and is a fraction bit sharper.
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Bookshelf, Left Side, f.open (f.14 and f2.8) - Both lenses are unsharp here. The F2.8 lens has less sharp text (“National Geographics”), and a slight green fringing.
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Bookshelf, Left Side, f2.8 - The F1.4 lens improves to a decent sharpness. For the F2.8 lens, it is unsharp, and has a slight green cast.
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Bookshelf, Left Side, f5.6 - The F1.4 lens is very sharp here, whereas the F2.8 lens hardly improves from f2.8. This phenomenon is caused by a tilted internal lens element. An older version of this lens had a similar sharpness problem on the right side, and was sharp left.
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Bookshelf, Right Side, f.open - The F1.4 lens is very blurred, the letters have an echo, like the image is moved (it is not!). The F2.8 lens is decently sharp.
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Bookshelf, Right Side, f2.8 - The F1.4 lens is still very blurred, similar to f1.4. The F2.8 lens is decently sharp.
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Bookshelf, Right Side, f5.6 - The F1.4 lens is still worse than the F2.8 lens. The F2.8 lens is a fraction more sharp at f5.6, but it is marginal.
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City, Centre, f.open (f1.4 and f2.8) - The F2.8 is definitely sharper here, though it shows a purple tint (color temperature of the photos is the same). Another obvious difference is that the F2.8 lens is more zoomed than the F1.4. This is not obvious with the bookshelf, as for each lens (e.g. 28mm, 55mm) I reposition the camera so that the same composition is created. For a scene at infinity this is not possible, revealing this interesting difference.
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City, Centre, f2.8 - Equal sharpness for both.
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City, Centre, f5.6 - Both are very sharp, the F2.8 lens still a fraction sharper.
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City, Left, f.open (f1.4 and f2.8) - The F2.8 lens is definitely sharper here.
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City, Left, f2.8 - The sharpness is about equal.
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City, Left, f5.6 - The F1.4 lens is even sharper than at f2.8, the F2.8 does not increase in sharpness compared to f2.8. Hence, the F1.4 lens is sharper here.
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City, Right, f.open (f1.4 and f2.8) - The F1.4 lens is very blurred here. The F2.8 lens is decent, though has some purple toning (where the color temperature of both photos is the same!).
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City, Right, f2.8 - The results for the F1.4 lens stay the same, it is as unsharp at f2.8 as at f1.4. The F2.8 is decent, and much better.
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City, Right, f5.6 - Here both lenses are sharp, the F2.8 lens a fraction sharper.
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Bookshelf Left, Sony 35mm F1.4, f1.4 versus f5.6 - One can see the sharpness increases quite a lot.
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Bookshelf Right, Sony 35mm F1.4, f1.4 versus f5.6 - Like on the left side, the sharpness increases a lot when stopping down this lens.
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Bookshelf Left, Sony 35mm F2.8, f2.8 versus f5.6 - The sharpness hardly increases when stopping down.
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Bookshelf Right, Sony 35mm F2.8, f2.8 versus f5.6 - The sharpness hardly increases when stopping down.
