ACF Custom Loop with Filter

<?php
/**
* Template Name: Recepten Index
*/
get_header(); ?>

<section id="primary" class="content-area full-width" itemtype="http://schema.org/Blog" itemscope="itemscope" itemprop="mainContentOfPage" role="main">

	<header class="entry-header">
		<h2 class="entry-title" itemprop="headline"><?php the_title(); ?></h2>
	</header><!-- .entry-header -->

	<?php
	$args = array(
	'post_status' => get_field( 'post_status' ),
	'category__in' => get_field( 'categories' ),
	'tag__in' => get_field( 'tags' ),
	'post_type' => get_field( 'post_type' ),
	'posts_per_page' => get_field( 'posts_per_page' ),
	'orderby' => get_field( 'orderby' ),
	'order' => get_field( 'order' ),
	'nopaging' => true
	);
	$args['category__in'] = get_field( 'categories' );
	$args['tag__in'] = get_field( 'tags' );

	$postlist = new WP_Query( $args );
		if ( $postlist->have_posts() ) : ?>

	<ul id="filters" class="filter-menu">
	<?php while ( $postlist->have_posts() ) : $postlist->the_post(); ?>
		<?php $posttags = get_the_tags();
			echo '<li><a href="#" class="active" data-filter="*">Alles</a></li>';
			if ($posttags) {
				foreach($posttags as $tag) {
					echo '<li><a href="#" data-filter="' . '.' . $tag->name . '">' . $tag->name . '</a></li>';
				}
			}
			?>
		<?php endwhile; ?>
	</ul>

<div id="recepten-index" class="row">
	<?php while ( $postlist->have_posts() ) : $postlist->the_post(); ?>
		<?php $posttags = get_the_tags(); if ($posttags) : $links = array(); foreach($posttags as $tag)  {$links[] = $tag->name; } $links = str_replace(' ', '-', $links); $tax = join( " ", $links ); else : $tax = ''; endif; ?>

					<article id="post-<?php the_ID(); ?>" class="recept-item col-md-4 <?php echo strtolower($tax); ?>" itemscope="itemscope" itemtype="http://schema.org/BlogPosting" itemprop="blogPost"> <?php if( has_post_thumbnail() ) { ?>
							<figure class="entry-image">
								<a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'ikbenirisniet' ), the_title_attribute( 'echo=0' ) ) ); ?>"><?php the_post_thumbnail('featured_image'); ?>
								</a>
							</figure>
						<?php } else { ?>
							<figure class="entry-image">
							<a href="<?php the_permalink(); ?>"><img src="<?php echo get_template_directory_uri(); ?>/assets/images/default.jpg" title="<?php the_title(); ?>"/></a>
							</figure>
						<?php } ?>
						<div class="inner-content">
							<header class="entry-header">
								<h2 class="entry-title" itemprop="headline">
								<a href="<?php the_permalink(); ?>" title="<?php printf( esc_attr__( 'Permalink to %s', 'ikbenirisniet' ), the_title_attribute( 'echo=0' ) ); ?>" rel="bookmark"><?php the_title(); ?></a></h2>
							</header><!-- .entry-header -->
						</div>
					<div class="clear"></div>
					</article><!-- #post-<?php the_ID(); ?> -->
					<?php endwhile; else: ?>
					<div class="error-not-found">Sorry, no content.</div>
				<?php endif; ?>
				</div><!-- #recepten-index -->

</div>
</section><!-- #primary -->
<?php get_footer(); ?>