Canon EF 28mm f/2.8
The Canon EF 28mm f/2.8 is a very compact prime lens, one to which I took an immediate dislike for its cheesy build quality, twitchy manual focus, and herky-jerky noisy autofocus (it does not have Canon’s USM focusing). But for about $259 one cannot expect too much.
Optically, it’s a reasonable performer stopped down to f/8 out to the edges of the frame, but the Canon 28mm f/1.8 felt much more substantial, and focused faster and quietly too.
The 28/2.8 is very small and light, its biggest plus. No lens hood is supplied.
Build quality is plastic yuck, with herky-jerky autofocus and twitchy manual focus. It functions, but there is no pleasure in using it, and it feels like yesterday’s stuff right out of the box.
The Canon EF 28mm f/1.8 USM is a more versatile lens offering 4/3 stop more light gathering power.
The 28/2.8 not only cannot focus very quickly, and it can‘t focus very closely. Both drop its usefulness. The 28/1.8 focuses much closer, and much faster.
With 5 elements in 5 groups, the 28/2.8 is not well corrected, and likely breaks down in performance
|List price:||$259 street price|
|Aperture scale:||f/2.8 - f/22|
|Image ratio at close range:||1:7.7|
|Minimum focus distance||12 inches|
|Angle of view||75° diagonally|
|Number of elements/groups:||5 elements in 5 groups|
0.41 pounds = 186g (nominal)
|Dimensions (with caps):||2.6" in diameter, 1.7" in length|
The MTF chart shows that within the central 2/3 area, performance at f/8 should be quite high. But even before the edges are reached, performance is plummeting; this is field curvature, as field shots establish.
Astigmatism is well controlled, but one cannot expect much performance past the frame edge (eg the corners).
Overall performance at f/8 looks to be notably higher than the EF 28mm f/1.8, at least in theory. But performance at f/2.8 is likely to be in the favor of the faster f/1.8 lens, since it is stopped down by more than a stop.
On EF-S cameras (1.6X crop), sharpness should stay high over the sensor (out to the ~11mm mark as shown on the graph), so it could be a good choice on such cameras.
At about $259, the Canon 28/2.8 is worthy of consideration if you need a full-frame wide angle prime lens.
Even wide open, performance is high over the central 2/3 area, so on EF-S 1.6X crop cameras, performance should be very good, since the weaker edge and corner areas will just not be seen.
On full frame cameras, edges and corners are week, but stopped down to f/8 it offers quite good image quality over most of the frame. The rapid falloff towards the edges/corners is due to field curvature, so it could provide problematic for general purpose landscape shooting.