How can photon have frequency if its time is zero?

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If I understand correctly:
"Time does not evolve for a photon."

However, a photon has a frequency (which is cycles/time).

Question: how can a photon have a frequency that is preserved while it travels despite the photon not experiencing any elapsing of time?
 
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The frequency is measured by an observer who sees the wave going by. The time is measured by that observer's clock.
 
Also, the concept of "photon not experiencing any elapsing of time" is questionable because (as has been discussed in many threads here) in order to talk about "elapsing of time" in a meaningful way you have to refer to a reference frame, and photons don't have inertial reference frames associated with them, that you can apply a Lorentz transformation to.
 
Thanks guys. It makes sense now.
 

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