Is the Eastern Orthodox opposition to the Immaculate Conception an innovation?

This question of mine springs from reading this article (Orthodoxy and the Doctrine of the Immaculate Conception ) referenced in this answer to this Christianity SE question: [What is the Catholic response to the Eastern Orthodox view that the Immaculate Conception remove Jesus' ability to redeem all of humanity?](https://christianity.stackexchange.com/a/20000/27623) Basically it contests the modern assertion of Orthodox teachers that the Eastern Orthodox church has always opposed the idea of the immaculate conception and instead taught that Mary became pure while raised in the temple as articulated in this podcast: [Perfection Possible](http://www.ancientfaith.com/podcasts/voicefromisles/perfection_possible) . I have a suspicion that the article imposes Western Catholic meanings on the writings of the Eastern fathers/teachers that they cite. I could not look up the references on the internet (for free anyways). Can anyone provide support for or argument against this article while actually citing texts from Eastern Orthodox teachers that I can read or at least providing quotes. Any citation from an EO teacher before the 15th century would be fitting, as the article maintains that it wasn't until this time that the Orthodox began to react against the immaculate conception. The one source I looked up this morning was from St. Gregory Palamas: [Sermon on the Entry of the Mother of God into the Temple](https://oca.org/fs/sermons/sermon-on-the-entry-of-the-theotokos) . Where he seems to teach something in complete agreement with the contemporary Orthodox view. Specifically, that the Virgin Mary was made pure not simply by election of God, but that her own will and ascetical efforts were involved as well. The corollary being that original sin doesn't need to be miraculously removed by the pre-election of God, but that our ancestral sin is removed by a participatory process.