Background: Uncertainty quantifications are required for any measurement result to be meaningful. Objective: The present work aims at deriving and comparing a priori estimates of displacement uncertainties in T3-stereocorrelation for a setup to perform high temperature tests. Methods: Images acquired prior to the actual experiment (i.e., at room temperature) were registered using 3-noded triangular elements (T3-stereocorrelation) to determine displacement uncertainties for different positions of the experimental setup. Results: The displacement uncertainties were then compared to their a priori estimates. Conclusions: For the analyzed experiment, it is shown that noise floor estimates only differed by a factor 2 when compared to a posteriori measurements of standard displacement uncertainties.