They say it has a mass of about 4 suns, which translates to an event horizon diameter of about 15 miles, so I think the lensing would be imperceptible unless yo

They say it has a mass of about 4 suns, which translates to an event horizon diameter of about 15 miles, so I think the lensing would be imperceptible unless you were right up close to it or it happened to perfectly occlude a visible star right when you were watching.