P7-14 Filters again

Discussion in 'Native Lenses' started by Hypilein, Jul 13, 2015.

  1. Hypilein

    Hypilein Mu-43 Veteran

    Mar 18, 2015
    I am trying to create a filter adapter using 3D printing and need a bit of expertise from those who have already tried. My idea is to create a cylinder that slides onto the lens from the back. Because I know from everything I've read, that you cannot go flush over the lens hood petals without causing vignetting I was planning to then let the cylinder go outward. This is my first prototype in the software. P7-14 Filteradapter Prototype Pic.jpg

    Unfortunately I don't have my own printer and have to rely on online printing services to get this done. This means prototyping via trial and error is going to be massively expensive. (about 35€ per try)

    I currently don't have any filters of that size and I am wondering which filter size I need to plan this for. The biggest size of filters that I could usually find on amazon was 82mm. However, I would need to attach a filter ring onto the adapter and I cannot find any 82mm rings. Just adapters from smaller sizes (although I could take a cheap filter and remove the glass). In an ideal szenario I would have a step down ring onto 82mm from something larger providing me with a bit of leeway. The big question I ask of those who have experimented with p7-14 filters. Do 77mm filters suffice? Do 82mm suffice. Or do I need something larger in terms of filters and where would I get that from. I have also considered filters that go into Cokin Style filter holders. However they seem unnecessarily bulky and inconvenient, and seem to go for quite a lot of money.

    Any tipps are very much appreciated. If I get this thing to work I'll also happily share the file so that you can get this printed yourselves.
  2. Hypilein

    Hypilein Mu-43 Veteran

    Mar 18, 2015
  3. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Somebody already makes this (http://dfocussystem.com/adapter-714).

    Why not just buy one of those ($35), and a 77-82mm step-up ring, and use 82mm filters. You're looking at $40, plus the cost of your filters. No guess work involved.
  4. Hypilein

    Hypilein Mu-43 Veteran

    Mar 18, 2015
    Thanks for the suggestion. I am aware of their product (and in fact it gave me the idea for my own design). Except for the fact that it says the following in the advertisement (which is nice of them to include):

    Note: The 7-14 doesn’t have filter threads because at extreme wide angles a filter would show in the image frame. D|Focus Systems testing found that with this adapter you are limited to about 10-14mm without seeing the edges of the filter. However, when used on a smaller sensor camera, like the Blackmagic Pocket Cinema Camera, the entire zoom range of the lens can be used without seeing the filter in the image frame.
    I would like to be able to use the full wide angle. Why by an expensive super wide angle and then be restricted to only 10mm? I currently don't have any filters of those sizes (largest is 52mm) so that is not a factor. I just need the minimum size that does not show vignetting on the lens. It looks from some maths that I made that it might actually be way larger (around 95mm) than expected. I was just hoping some people with other working homemade solutions could shed some light onto the matter.
  5. RenaudVL

    RenaudVL Mu-43 Veteran

    Mar 21, 2011