validity of double probing

[electrolust]

Keysight recommends in AN 5989-7894EN to double probe, to see the effects of your probe on risetime.  Daniel also gave this recommendation in one of the livestreams for scope month recently.  You probe once, save the waveform, then attach another probe and see what the difference is.

How accurate is this method?  I mean is it reasonable or would there be considerable error.  ISTM you are doubling the capacitive probe load, so at least with a resistive circuit load it's reasonably accurate.  (With capacitance in the circuit load, the effect of the 2nd probe is less than double so you can probably account for that.)

[ebastler]

Yes.