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I got in on the Blackmagic Pocket Cinema Camera (bmpcc) fire sale and in preperation for receiving my new camera I have been researching neutral density filters. What I would like to know is what are people's preferences between single ND filters and variable ND filters. And also your thoughts on IR filtration for the bmpcc. I already know if you go the "straight" variable ND route Tiffen seems to be a good trade off as far as quality and price. Dave Dugdale did an incredible review of "straight" variable ND filters. Honestly it is amazing it took an amateur like Dave to do such a test. I see so many posts on the internet from people who could have either saved themselves money or used a higher quality product had someone simply done what Dave did and test them out. These people are pros mind you! So the choice was simply, right? Wrong! I then came across another video showing IR (near infrared) issues with the BMCC... and other cameras including Alexa products. So there are numerous solutions. One could say the near IR pollution thing is nonsense and just get a "straight" Tiffen variable ND. Or you could go with a set of individual ND filters and skip the variable. You could also get an IR cut filter and use either single NDs or variable ND. Or you could get the Tiffen combined IRND variable filter. Or you could get the single IR ND filter sets. B&H has a strong three filter set for $164.50. Okay, that is a lot of options. The reason I posted is I want to know which one will give you the best results. I know the variable NDs have the polarization "issue." Sometimes I like using a polarizer on video so it isn't always an issue for me. Also there is a hack where by you turn the whole filter assembly en bloc to reduce or get rid of the polarization effect. I don't know how effective that is. This guy shows the "hack" to optimize the use of a variable ND filter... Here is a video showcasing the Tiffen IRND variable filter. So what should I do?
[size=4][font=arial, helvetica, sans-serif]I am trying to better understand the difference between of these filters. I have come across several resources: From Tiffen: [quote][color=#000000]Unlike many photographic films, the CCD or CMOS of a digital camera is inherently susceptible to infrared contamination, even when the manufacturer attempts to reduce this problem by adding an infrared absorbing filter on top of the image sensor. Because these filters do not have a sharp cutoff at the infrared wavelengths there has to be a compromise in order not to exclude visible red wavelengths. This results in some infrared wavelengths being allowed to pass. While minor infrared contamination does not normally cause much of a problem for visible images, when using conventional neutral density filters especially denser grades, this issue is multiplied by the filter factor[/color][/quote] From Cavision: [quote][color=windowtext]The Hot Mirror filter reduces the amount of infra-red light entering the lens while having no affect on the wavelengths of light in the visible spectrum. Digital sensors are especially sensitive to IR light, which can cause aberrations and colour shifting in the image. The hot mirror filter is especially useful when using a neutral density filter because the ND filter will increase the ratio of IR light to visible light. The Hot Mirror ND filter accomplishes both tasks in one combination filter, freeing up an extra filer stage in your matte box.[/color][/quote] Is there anyone using IR or hot mirror filters that can clarify? How significantly do these filters improve your image?[/font][/size]