Hi @WPDragon
This is called a conditional statement:
<?php
$url = get_field('photographer_url');
?>
<p class="image_photographer">Image courtesy of: <?php if( $url ): ?><a href="<?php echo $url; ?>"><?php endif; ?> <?php the_field('image_photographer') ?> <?php if( $url ): ?></a><?php endif; ?></p>
