It sounds like a contradiction in terms but please give me a minute to explain. A search for “retro camera” turns up about 60 apps on the app store.
Apps for the iPhone include 6×6 which takes 6cm square images, this size was popular with old medium format film. Squara takes square photos too. Both apps has some advanced features and positive reviews.
There is a wide range of camera apps that will apply retro filters such as Instagram, which also offers sharing and is free.
HiLO Lens allows lets you “shoot from the hip” which is a similar position to looking down on the old Twin-lens reflex camera. So we claim our piece of the retro pie ! Shooting from the hip while being able to frame your shot is fantastic for Street Photography.