Thread: 4x4 filter + Ursa mini Question

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  1. #1 4x4 filter + Ursa mini Question 
    Senior Member jambredz's Avatar
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    What's about the widest focal length that can be used on the Ursa mini/mini pro with 4x4 filters and a mattebox without starting to see the mattebox or filter when using the whole sensor (4.6k).
    Darren Scott
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    I grappled with this question for quite a bit, wanting to accomodate my GL Optics 11-16mm PL lens and a couple of 4x4 filters.

    It really depends on 1] the outside diameter (entrance pupil) of the lens, 2] the matte box, and 3] whether you want to stack filters. Also you should be considering the field of view as not all equal focal lengths have the same field of view. For example, some are fisheye.

    But here's a rough start based on my experiences:

    1] Firstly, I would recommend you don't use a wide angle lens with a greater front diameter of 95mm when using 4x4 filters. The GL Optics 11-16 is based on the Tokina which originally has a front diameter of 77mm - so quite small, but very wide. But if you were to use a Cooke 14-70mm T3.1, it has a front diameter of about 150mm. So even though it's wide, the 4x4 wouldn't come close to covering the front element.

    2] Not every matte box is made to cover really wide lenses like the 11-16mm. I ended up getting a Vocus 435 because it's versatile (can hold three 4x5.65" & one 138mm filters), excellent built quality, tough, great swing-away and it accommodates really wide lenses like the 11-16mm. I was looking at a few, and some other contenders - that hold 4x4 filters - were Bright Tangerine Misfit, Arri MMB-2, Chrosziel MB 450W super wide, Wooden Camera UBM-1 & O-Connor WM set, but the Vocas really ticked all the boxes and is one of the widest matte boxes made. Absolutely no regrets on that purchase.

    3] If you're using the GL Optics/Tokina 11-16mm on the UM4.6k, set to 11mm, you can only get away with one 4x4 filter. Just. If it's a polariser you'll start to see the edge of the filter as it rotates. I've found at around 12.5-13mm it's clear. But I've only got a couple of 4x4 filters. The rest of my filters are 4x5.65". So I can use one 4x4 (polariser or pro mist closest to the lens), and two 4x5.65.

    What lenses are you looking at?
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  3. #3  
    Senior Member jambredz's Avatar
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    Quote Originally Posted by trispembo View Post
    I grappled with this question for quite a bit, wanting to accomodate my GL Optics 11-16mm PL lens and a couple of 4x4 filters.

    It really depends on 1] the outside diameter (entrance pupil) of the lens, 2] the matte box, and 3] whether you want to stack filters. Also you should be considering the field of view as not all equal focal lengths have the same field of view. For example, some are fisheye.

    But here's a rough start based on my experiences:

    1] Firstly, I would recommend you don't use a wide angle lens with a greater front diameter of 95mm when using 4x4 filters. The GL Optics 11-16 is based on the Tokina which originally has a front diameter of 77mm - so quite small, but very wide. But if you were to use a Cooke 14-70mm T3.1, it has a front diameter of about 150mm. So even though it's wide, the 4x4 wouldn't come close to covering the front element.

    2] Not every matte box is made to cover really wide lenses like the 11-16mm. I ended up getting a Vocus 435 because it's versatile (can hold three 4x5.65" & one 138mm filters), excellent built quality, tough, great swing-away and it accommodates really wide lenses like the 11-16mm. I was looking at a few, and some other contenders - that hold 4x4 filters - were Bright Tangerine Misfit, Arri MMB-2, Chrosziel MB 450W super wide, Wooden Camera UBM-1 & O-Connor WM set, but the Vocas really ticked all the boxes and is one of the widest matte boxes made. Absolutely no regrets on that purchase.

    3] If you're using the GL Optics/Tokina 11-16mm on the UM4.6k, set to 11mm, you can only get away with one 4x4 filter. Just. If it's a polariser you'll start to see the edge of the filter as it rotates. I've found at around 12.5-13mm it's clear. But I've only got a couple of 4x4 filters. The rest of my filters are 4x5.65". So I can use one 4x4 (polariser or pro mist closest to the lens), and two 4x5.65.

    What lenses are you looking at?

    Thanks for the info. For now I'm using stills glass....the sigma art 18-35 and Rokinon DS 50mm and 85mm. Eventually I'll get cine glass but those quite likely will not exceed 95mm outer diameter. The widest I'd be going under normal circumstances is 18mm...and 14mm in special cases. So based on what you've said, I should be fine with 4x4 filters. I use a Tilta 2 stage 4x4 mattebox and I'm looking to get a set of Nisi IR ND filters.
    Darren Scott
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  4. #4  
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    Quote Originally Posted by jambredz View Post
    Thanks for the info. For now I'm using stills glass....the sigma art 18-35 and Rokinon DS 50mm and 85mm. Eventually I'll get cine glass but those quite likely will not exceed 95mm outer diameter. The widest I'd be going under normal circumstances is 18mm...and 14mm in special cases. So based on what you've said, I should be fine with 4x4 filters. I use a Tilta 2 stage 4x4 mattebox and I'm looking to get a set of Nisi IR ND filters.
    An 18mm should be fine.

    The Rokinon 14mm is very wide. And has the hood built in.

    A few questions I can foresee:
    1] will your matte box be compatible with a lens that wide? Not all are. Some will take an 18mm at the widest.
    2] can you get the 4x4 filter close enough without filter edge becoming visible? The hood seems to stick out about 20mm from the front element.
    3] how will the filter hood interfere with the matte box? For example, you may need nun's nickers an not a rubber donut.
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