This lens is a specifically designed for full frame Sony mirrorless and has a linear STM autofocus system.
f/1.8 - 22
Hotspot Performance Notes
I love this focal length and speed, so I was very disappointed to see that the infrared performance here was not better. Although it scores worse than the Samyang 24/2.8 FE lens because it dips more than usua at f/8, it's actually much better wide open. Some of this is due to the wide open speed of the 45mm being over a stop faster however. For landscapes the 45mm does noticeably worse in regards to hotspot, but the corner performance here is so good that some will still prefer it for that reason.
Largely due to it being an almost exact "standard" focal length (closer than 50mm) there is very little colour separation in the corners with visible light compared to infrared. This makes lower wavelengths like 590nm or IR Chrome quite compelling. The latter especially so since it doesn't suffer much from hotspot.
I wish the infrared performance was better on this lens because I just love this focal length! Since the Sony/Zeiss 55mm f1.8 is so good in this regard I would recommend that over this for IR shooters if you can afford it and don't mind the slightly tighter field of view. If you really want a good IR performing fast-ish 45mm pancake lens, don't mind manually focusing and can adapt to it then I highly recommend the Minolta MD 45mm f2.