Fuji X100 - The benefit of stopping down for close ups

The only time that the 23mm lens on the X100 isn`t razor sharp is at very close focus with a wide open aperture.  Here`s a couple of substantially cropped shots of a rose centre, both shot at ISO 1600.

The first, shot at f2, is noticeably soft, but still quite acceptable.  The second, shot at f8, is razor sharp.  

Fuji X100 - f2, no flash

Fuji X100 - f8 wé flash

For the second shot, I ran out of light at f8 so I had to use the flash.  Very close up the flash doesn`t perform well, cropping the top and bottom of the shot from light.  I suspect that the bottom part of the shot was shaded because of the accessory hood adapter.