confused of Eastbourne!!!

[Chas]

I took this photo while waiting for a bus in Gildredge Road, the road in the image is Hyde Gardens I focused on the first building on the left hand side setting are as shown my query is I cannot understand how there is no fall off and if you focus in on the Natwest sign it is readable even though it is about 500

• ILCE-7RM3A
• FE 55mm F1.8 ZA
• 55.0 mm
• ƒ/1.8
• 1/1250 sec
• ISO 50

feet away