New Sigma 18-35: What does f/2.7 DOF equivalent mean?

[JumboShrimp]

HELP!!! According to DPReview: "The lens will offer the depth-of-field equivalent of a constant F2.7 on full-frame...". Yes, I have read the other thread on this lens, but still cannot understand the logic behind this. Is this the same basic premise that DOF increases as the sensor size decreases?

 

[Loswr]

Yes. For equivalent framing, you're further away on APS-C meaning the DoF is deeper. Basically, the 'crop factor' applies to DoF, too.