Can I use a linear polariser with my Nikon F3?

Discussion in 'Nikon' started by johncarvill, May 5, 2010.

  1. Is the info on this page correct, i.e. is it true that a linear polariser can be used on a Nikon F3 without affecting metering?:
  2. I think so. I have never experienced problems with linear polarizers on my F3.
  3. As I understand it, linear polarizers can cause problems when the camera uses a beam-splitting mirror to divert some of the light hitting the mirror to the metering cell - this portion of light usually passes through the reflex mirror and is reflected down to the metering cell via a smaller piggyback mirror. The beam splitter is effectively a semi-reflective polarizer - it sorts light on the basis of wave orientation, allowing some orientations to pass through to the meter and reflecting the remainder up to the viewfinder. Depending on the orientation of a linear polarizer fitted to the lens, a greater or lesser proportion of the incoming light will make it through the splitter to the meter. For example, if the polarizer is orientated at 90 degrees to the splitter, little or none of the light will get through the splitter, cutting down the amount of light reaching the meter, and resulting in significant overexposure. If there's a beam-splitter in the AF light path, a linear polarizer may also screw up AF. While a circular polarizer orientates light waves, it still allows all orientations through, to the correct proportion of light makes it through the beam-splitter to the meter, and exposure is unaffected.
    The F3 also has a pass-through mirror, a piggyback mirror and a mirror-box metering cell - the difference is that it doesn't use a beam-splitter. Rather, the F3 mirror contains an array of near-microscopic holes in the mirroring - large enough for light to pass through, but too small to be seen through the viewfinder. Although almost invisible, compared to light waves, these holes are like barn doors, and do not impede the passage of light in any form - polarized or not. If you take off the lens and look closely at the mirror, you can see a faint dark oblong shape with a circular cutout on the mirror - this is the array of pass-through holes.
    So, for example, I need to use a circular polarizer on my OM-4 (beam splitter) but not on my F3 ("barn doors").
  4. According to Nikon, linear polarizer is fine with all non-autofocus cameras - none of them is using a beam-splitter design for the metering system:
  5. You should be fine using a linear polarizer with an F3 (A circular polarizer would work too).
    The TTL metering system is behind the mirror, which has fine perforations in the reflective surface for the light to pass through. Beam splitters are not used.
  6. In general, linear polarizers can often be used even on cameras where circular polarizers are recommended.
    The effect on the camera depends on a number of different variables, so you do need to be continually aware of how well things are working out in use.
    I've got a whole collection of the Spiratone Colorflow™ polarizers that are all linear, but can be used on modern digital cameras to good purpose, again, with attention to what is happening.

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