What are the square soft-focus filters that fit behind the lens?
Asked 2/2/2019
1 views
2 answers
0
I remember seeing a portrait photographer use a set of thick square glass filters that slid in behind the lens, between the lens and camera body. They appeared to have metallic-looking flecks or particles suspended in the glass at different depths, and they produced a glowing, soft-focus portrait effect similar to the classic "Barbara Walters" look. What are these filters called, and on what kinds of cameras or lenses were they typically used?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
4
Although not as common as they used to be, there are lenses made with gelatin filter holders on the back of the lens. Probably two of the most common ones still in current catalogs are Canon's EF 17-40mm f/4 L and EF 14mm f/2.8 L.
Most lenses with such filters are wider angle lenses that make it problematic to place a filter in front of the lens, due to either bulbous front elements or issues with vignetting due to the lens' wide angles of view.
Going back even further, square glass filters behind the lens were much more common with large format view cameras than they are with smaller format cameras such as FF and smaller digital cameras. They were common enough that everyone familiar with large format cameras seems to know that inserting a glass filter behind the lens will alter the focus distance to the film by 1/3 the thickness of the filter. Thus the camera should always be focused after the filter is in place.
Related:
Why would I use a rear gelatin filter over a front filter?
How do rear gelatine filters compare optically with "regular" front-mounted filters? Where to buy them? How to cut them?
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
7y ago
0
Generated from our catalog & community — verify before relying on it.
They were most likely rear-mounted soft-focus filters used on lenses or camera systems designed to accept filters behind the lens. This was more common on some older systems and especially on large-format view cameras, where square glass filters behind the lens were fairly common.
On smaller cameras, rear filter holders do exist, but they’re usually found on certain wide-angle lenses where front filters are impractical because of bulbous front elements or vignetting issues. Those rear filters are often round or gelatin, not thick square glass.
Your description of visible flecks and a glowing portrait look suggests a diffusion/soft-focus style filter. Because thick glass behind the lens can affect focus, these filters generally had to be used with equipment designed for them.
So the best match is: a rear-mounted soft-focus/diffusion filter, possibly from a large-format or specialized lens system, rather than a standard front-mounted portrait filter.
Recommended products
UniqueBot
AI7y ago
Your Answer
Related Questions
What does “Photo-Chromography” mean on an old glass photo, and roughly when was this process used?
How can I create a soft, canvas-like glow effect in a photo?
How can I get a smooth, glowing skin look in portrait post-processing?
How do I light a portrait for a soft halo glow while keeping facial detail?
How can I create a dreamy, misty look in backlit outdoor portraits?