Sony SEL1018 F/4 10-18mm Wide-Angle Zoom Lens was made for the E-mount APS-C range of cameras, e.g. NEX-6, Alpha 6000 (A6000) etc. Normally, using this type of a lens on the full frame cameras, such as A7, would cause a very heavy vignetting where the image, unless seriously cropped, would be pretty much useless.
Here is an example of using Sony SEL35F18 35mm f/1.8 Prime Fixed Lens on the full frame camera.
The E-mount APS-C lenses work fine with the full frame E-mount cameras when the camera runs in the crop-mode, but at cost of a reduced resolution.
However, the Sony SEL1018 f/4 full frame sensor coverage is surprisingly good, with the vignetting being a real issue only at the ends of the range. When using the lens between 12 – 16mm, the vignetting can be very easily addressed in post processing.
Below are the examples shot wide open at each millimetre on A7 II
Note: the images above are shot at f/4 so this is the worst case scenario. Once you stop the lens down it only gets better. For example, 12mm at f/8 is completely vignette free.
Below is a before and after example of a shot taken at 13mm at f/4 with the vignette removed in the post processing.
So does the Sony SEL1018 f/4 work on A7 cameras? Absolutely.
How wide it actually is? If we exclude the 2 widest millimetres due to a vignette, it’s as wide as any other 12mm lens on the full-frame sensor. Here is the comparison at 12, 14 and 16mm of the same lens on full-frame camera (A7 II) and APS-C sensor camera (A6000).