This will be helpful, from the SEP article on Phenomenology:
". . .
Philosophers succeeding Husserl debated the proper characterization of phenomenology, arguing over its results and its methods. Adolf Reinach, an early student of Husserl's (who died in World War I), argued that phenomenology should remain allied with a realist ontology, as in Husserl's
Logical Investigations. Roman Ingarden, a Polish phenomenologist of the next generation, continued the resistance to Husserl's turn to transcendental idealism.
For such philosophers, phenomenology should not bracket questions of being or ontology, as the method of epoché would suggest. And they were not alone. Martin Heidegger studied Husserl's early writings, worked as Assistant to Husserl in 1916, and in 1928 succeeded Husserl in the prestigious chair at the University of Freiburg. Heidegger had his own ideas about phenomenology.
In
Being and Time (1927) Heidegger unfurled his rendition of phenomenology.
For Heidegger, we and our activities are always “in the world”, our being is being-in-the-world, so we do not study our activities by bracketing the world, rather we interpret our activities and the meaning things have for us by looking to our contextual relations to things in the world. Indeed, for Heidegger, phenomenology resolves into what he called “fundamental ontology”. We must distinguish beings from their being, and we begin our investigation of the meaning of being in our own case, examining our own existence in the activity of “Dasein” (that being whose being is in each case my own). Heidegger resisted Husserl's neo-Cartesian emphasis on consciousness and subjectivity, including how perception presents things around us. By contrast, Heidegger held that our more basic ways of relating to things are in practical activities like hammering, where the phenomenology reveals our situation in a context of equipment and in being-with-others.
In Being and Time Heidegger approached phenomenology, in a quasi-poetic idiom, through the root meanings of “logos” and “phenomena”, so that phenomenology is defined as the art or practice of “letting things show themselves”. In Heidegger's inimitable linguistic play on the Greek roots, “ ‘phenomenology’ means … — to let that which shows itself be seen from itself in the very way in which it shows itself from itself.” (See Heidegger, Being and Time, 1927, ¦ 7C.) Here Heidegger explicitly parodies Husserl's call, “To the things themselves!”, or “To the phenomena themselves!” Heidegger went on to emphasize practical forms of comportment or better relating (Verhalten) as in hammering a nail, as opposed to representational forms of intentionality as in seeing or thinking about a hammer. Much of Being and Time develops an existential interpretation of our modes of being including, famously, our being-toward-death.
In a very different style, in clear analytical prose, in the text of a lecture course called The Basic Problems of Phenomenology (1927), Heidegger traced the question of the meaning of being from Aristotle through many other thinkers into the issues of phenomenology. Our understanding of beings and their being comes ultimately through phenomenology. Here the connection with classical issues of ontology is more apparent, and consonant with Husserl's vision in the
Logical Investigations (an early source of inspiration for Heidegger). One of Heidegger's most innovative ideas was his conception of the “ground” of being, looking to modes of being more fundamental than the things around us (from trees to hammers). Heidegger questioned the contemporary concern with technology, and his writing might suggest that our scientific theories are historical artifacts that we use in technological practice, rather than systems of ideal truth (as Husserl had held). Our deep understanding of being, in our own case, comes rather from phenomenology, Heidegger held."
Phenomenology (Stanford Encyclopedia of Philosophy)