Suggestions to interface a photodiode in the MHz range
I cannot speak to the digital question, but the analog is pretty straightforward. You should use a TIA with a 1000 lux sensitivity, about 8 kohm / full scale volt. Use about a 5 volt bias, and expect a photodiode capacitance of 4 or 5 pF. I'd suggest that you don't need a PGA, rather, use a pair of x10 amplifiers in series and an analog mux to select the active channel. Be aware that selecting the appropriate channel will not be trivial in some cases, especially where there is a lot of AC on the signal. All amplifiers need to be selected with fast overload recovery in mind, or incorporate clamps. Fortunately, your currents are so low that a decent clamp should be straightforward. Log amps are in principle a good idea except that it's hard to make a good log amp that is also fast. The other problem with log amps is that it's very difficult to produce the sort of precision you want over large dynamic range. 

ETA In response to a request, here's a TIA using an AD8651 and +/- 3.3 volts -







simulate this circuit &ndash; Schematic created using CircuitLab

The AD8651 is available for less than $4 in onesies. 

One thing to be careful about is the value of the feedback compensation capacitor. With the values shown, and an assumed total input capacitance of 6 pF (4 pF for the diode, 2 pF for the IC) my simulation gives settling time for a full-scale step (3 volts for 130 uA) of less than 300 nsec. However, this is quite sensitive to the value of the capacitor, and so is sensitive to layout considerations. A very compact layout is a must - which means that breadboards are absolutely verboten. Good decoupling of the +3.3 supply at the op amp is also a must - this is a 50 MHz op amp.