Frank Finlay received his only Oscar nomination for portraying Iago in Othello.
Finlay's performance actually is probably the least theatrical in this film version. Basically no one tones down their performances from how they would portray the part in the theater, and the rather fail to utilize the medium of film. The reason Finlay really is the least theatrical probably comes down to the fact that Iago is a less theatrical character than many of the others, since he purposefully hides his emotions and true feelings, always acting collected to more easily influence others to fall into his plan.
Finlay though just is not the schemer I would like him to be. Yes he has that sinister stare, and head twist done, as well as the classic way in which he is always leaning over Othello's shoulder to convince Othello that Desdemona has done wrong, but I always wanted more from Finlay. There just not enough charisma in his performance really to make me fascinated with Iago. Yes Finlay appropriately makes Iago's front of confidant, frankly I wanted much more from his malicious interior though, and I really I still wanted even more from his front as well.
His interior maliciousness was lacking to me, I found not a great enough emotional drive in his plan. Yes there was a subdued hatred, but in his small moments alone Finlay could have perhaps really broken lose showing the true extent to Iago's feelings of anger and jealousy, but Finlay stays a tad too reserved. Also in his swaying of others Finlay is convincing enough, but never more than that. He never becomes a true unforgettable schemer, just a satisfactory one.
That really is the whole problem with Finlay's performance for me. Although he is consistently fine, despite a few small moments of overacting that are only ever extremely brief, he never is more. For example when he shares a scene with Olivier as Othello, Olivier always steals the scene with his weird but entertaining performance. I do not think it had to be this way, Finlay with charisma, or a greater emotional pull in his performance, could have made the scenes his but, he is never able to do this always making Olivier the most interesting performer.
Finlay is just fine as Iago, but only just fine. He has the language down well enough, but he never brings it to life as well as Olivier. He is a schemer sure, but never one on say the level of again say Laurence Olivier in Richard III. He conveys Iago's emotions technically, but never in a manner that makes his performance more than just suitable. He is able to be convincing enough, but he never is truly compelling in the role. He is never truly bad, but he is never truly great.