Chris gets the eyes in focus and the picture is already 90% perfect add her smile and the framing of this shot makes it work. Working with a bigger apeture 2.8 he cuts down the depth of feild- he hands nearer to the camera is blur but the face is in focus- this concentrates the focal point on her face. good technique here.
In apertures to "open up" means going for a higher f-stop 2.8 (smaller numbers) etc
the lower the number F-stop means the "faster" the lens because it can open up and allow more light in.
for example a 50mm F1.0 lens is faster than a 50mm F5.6 lens.
Most of the big lenses you see the pros carrying around are fast 300mm F.28 or 400mmF.2.8 lens.
Canon used to make a F1.0 50MM lens which is very fast and also very big
and to "close down" means going for a lower F stop F5.6 to F11. (bigger numbers)
Cheaper lenses are spec slower. For example you can get a 300mm lens at F5.6 or zoom lenses like
70-210 rated at F2.8-F5.6 which means at 210mm the F stop is at 5.6.
Pro zoom lenses are 70-210 F2.8 meaning at no matter where the zoom length is it stays constant at f.28- these lenes are bigger sized and much more expensive.
