Schengen visa in Istanbul

Hi

I'd like some information about applying for a Schengen visa in Istanbul. I'm flying out to Greece from Istanbul and then doing a train trip to Brussels where I'll be flying out of the EU region. I spend approx. same amounts of time in different countries and my 1st point of entry is Greece.

Which embassy or consulate should I apply for the visa in Istanbul? Preferably an efficient one!

Appreciate your feedbacks.