A fine question. Since T. S. Eliot popularized the term in his essay on Hamlet, it makes great sense to apply the idea of the objective correlative to the play. Since you asked about deceptive imagery, and focused on the first act, the very presence of the ghost is a good example. It could be a deception itself—it could be a demon, rather than dead Hamlet. However, it also functions as an objective correlative for Prince Hamlet's remnants of his father. His father is within him, as a memory, a longing, and parts of his superego; these things drive him to action. The ghost is an external representation of these things (in addition to being, well, a ghost). In the ghost's extended speech in Act I, scene 5, he uses imagery which is deceptive, even as he attempts to evoke for Hamlet the horror of the crimes committed. Look, for example, at these lines: "The leperous distilment; whose effect
Holds such an enmity with blood of man"

The very language deceives—the poison is not angry, parts of it do not rot and fall off—even as it provides an objective correlative for many emotional states. The king's brother, his blood, holds enmity for him; the poison symbolizes it.