adrjork wrote:... Which could be the order of these filters?
And with these filters do you think I really need some IR filter?
Some people recommend having the IR cut filter first, with any other filters (and the lens) "behind" the IR cut filter. Thought being that you're eliminating the unwanted IR "pollution" (magenta cast) before further filtration, and to prevent IR from bouncing back into filters placed before it (which they feel could cause IR reflections, optical artifacts, etc.)
Others are fine with positioning the IR cut filter either in the middle of the filter stack, or last (closest to the lens), and report no problems.
The IR cut filter I own is a screw-on 77mm Hoya IR/UV cut filter, so I typically place it first before other filters such as my screw-on 77mm Tiffen ND filters. However, I sometimes position polarizer and/or graduated ND filters in my matte box before (in front of) the Hoya filter. I haven't noticed problems with this, but I confess I want to give another closer look to see if I'm causing any issues by doing so.
You may wish to do some careful tests yourself and look at the results on a full 1080p monitor to determine if you see a benefit one way or the other.
In general it's a good idea to use as few filters as possible to minimize optical flares, ghosting, reflections, unwanted diffusion, etc.
Of the filters you mention, unless you're shooting a scene containing a lot of undesirable fog or haze, the Tiffen Digital HT Haze 86 (UV filter) could be completely unnecessary, or it might cause the issues mentioned above in your footage. Likewise, unless you're shooting in an environment with flying sand or other debris, the Tiffen Digital HT Ultra Clear filter is likely to cause unwanted issues like those mentioned above, with little benefit.
When in doubt, shoot careful tests in the sort of conditions you anticipate, and view the original footage on as accurate a monitor as you have available.
Cheers.