surface brightness and photons

Some questions about a passage in the site:
http://skyandtelescope.com/howto/vis...ticle_78_5.asp
"When an image is magnified by high power, its surface brightness does
indeed grow weaker. But the total number of photons of light entering
the eye remains the same."

What does it mean "remains the same"?? Using higher power would reduce
the exit pupil, so the photons entering the eye should be less, not the
same, right??

Another one:

" (A photon is the fundamental particle of light.
Experiments show that most people can detect as few as 50 to 150
photons per second.) It doesn't really matter that these photons are
spread over a wider area; the retinal image-processing system will cope
with them."

What does it mean "spread over a wider area"?? The exit pupil is
smaller for higher magnification, so only the inner circle of the
retina surface can see them... so what does it mean "spread over a
wider area"??

Ch