I present measurements of the degree of second-order coherence $g^{\left(2\right)}\left(0\right)$ for spontaneous parametric downconversion fields and discuss the differences between two-detector (unconditional) and three-detector (conditional) measurements of $g^{\left(2\right)}\left(0\right)$ . An emphasis is placed on comparing measurements made using time-to-amplitude converters (TACs) to those made using a logic circuit, illustrating how the TAC measurements are adversely influenced by dead time effects. Finally, I show how the detrimental effects of dead time when using TACs can be mitigated by renormalizing the measurement results.