Oh, you mean the time response? If the load changes or set point voltage is modulated. I've never really looked at that. For this case there's a ~1meg resistor (changing ~1-10% with the light, IIRC) with cable capacitance down a probe... ~10-100pF? The time response is audio.
Oh I needed to give myself a head slap. Two circuits ago in the current project (at work), The 10 uA current source* is as above, with lnd150's on the the output line... in series with the output and not just the feedback to the opamp. (at 10 uA you don't really care about a kilo ohm.)
George H.
*diode temp sensor