  The observed incidence of strongly lensing clusters exceeds the predictions
of a Lambda-CDM model by about a factor of 10. We revisit the observational
side of this discrepancy by measuring the incidence of strong lensing in a
subsample of clusters drawn from the Las Campanas Distant Cluster Survey
(LCDCS). Among clusters with 0.5<= z <= 0.7, the redshift range in which we
focus our search, we find two strongly lensed systems within an effective
search area of 69 sq. deg. There is at least one other strongly lensed system
in the LCDCS outside of this redshift range, where we are less complete. Over
all redshifts, the Lambda-CDM model produces one large arc every 146 sq.
degrees. Assuming Poisson statistics, the probability of finding 3 or more
strongly lensing clusters in 69 sq. degrees is 0.012. The lensing incidence
within the LCDCS is in agreement with that derived from an X-ray selected
sample and what has been preliminarily presented from an independent optical
cluster survey. The origin of the disagreement between theory and observations,
which remains at least at the order of magnitude scale for the Lambda-CDM
model, lies either in the concordance cosmological model, in the
characteristics of the resulting cluster potentials, or in the adopted source
population.
