lev29 Loc: Born and living in MA.

Although I now see that it has been known for a few years that a Linear Polarizer (LP) Filter will function as expected on a Mirrorless camera without interfering with the phase detection autofocus mechanism, I only just learned of this. Does anyone here have actual experience using such a filter for [visible light] photography? If so, did you find the filter to do just as well as a CP Filter, worse, or better?

Are there any other known theoretical considerations which argue against the use of LPs? Finally, is it known whether LP Filters interfere with the Hybrid Autofocus mechanisms featured in some mirrorless cameras?

Thank you.

speters Loc: Grangeville/Idaho

It has nothing to do with mirrorless or not, it has to do with the autofocus systems, linear will work fine for cameras/lenses without af! If you're shooting with a set-up that uses af, you need to use a circular filter, linear ones do interfere with the af system!

User ID

Verrrrrrrry theoretically, linear has the advantage of fewer
layers making up the sandwich. I've always used linear
polarizers just cuz I've owned them since long before CPS
were common items.

LPLs work on ANY camera with no detriment to the imaging
process. The only drawback to using LPLs where CPLs are
recommended is a loss of convenience, or the disabling of
convenience features ... but NO loss or disabling of imaging
abilities. It all boils down to semi-mirrors. If any feature of a
camera views the scene [or partial scene] via a semi-mirror,
then using an LPL becomes an inconvenient 2-step process.
AF will work and metering will be accurate with an LPL ... if
the LPL is oriented to "favor" the semi-mirrors. But this may
not be the orientation for your desired pictorial effect, thus
re-orienting makes using an LPL a 2-step wiht such cameras.

There is nothing about phase detection AF that requires a
CPL .... unless the PDAF views the scene via a semi-mirror,
as is the case with AF SLRs. OTOH on-sensor PDAF systems
do NOT view the scene via any mirror at all, so an LPL is no
problem at all.

User ID

My linear polarizers do NOT interfere at all
with the AF in most of my cameras. All the
Sonys and M43s are no problem. The SLRs
do need the CPLs.

lev29 Loc: Born and living in MA.

Thank you!

lev29 Loc: Born and living in MA.

Thanks again!

lev29 Loc: Born and living in MA.

From the few responses thus far, it is apparent that not everyone is convinced that Linear Polarizing Filters do not interfere with the autofocus mechanisms employed in mirrorless cameras.

In fact, I now question whether the concept I stated in my first post is accurate, thanks to both User ID and my doing a literature search (employing Duck Duck Go) with a number of keywords. Three results from my search are cited below with their associated key sentences. Note that all three are from photography fora; I failed to find an actual article validating what I had read.

Ok to use linear polarizers with mirrorless OM-D?
http://photo.stackexchange.com/questions/92093/ddg#92105
Yes, you can use linear polarizer with mirrorless cameras, including OM-D E-M1.
No, phase detect autofocus in mirrorless cameras is not affected by linear polarizers.
Phase detect autofocus sounds like something that belongs to DSLR, hence the confusion. Indeed, AF might be affected in DSLR cameras (usually it is not), where the light is reflected to a separate AF sensor. Mirrorless cameras use the same main sensor for phase detect AF, without reflections and without polarization issues.

https://www.talkemount.com/threads/circular-vs-linear-polarizer-on-mirrorless.15421/
As said when we were going off-topic in another thread, I think you're right. Circular polarizers are needed when there are other optical elements in the light path that polarize in some way or another, like semi-transparant mirros can do; this is relevant for both viewing and capturing. In mirrorless cameras there's nothing between the lens' rear element and the sensor and so linear polarizers work perfectly. I have used old Nikon linear polarizers on my Panasonic G1 with perfect results.

http://mirrorlessphototips.com/filters-for-mirrorless-photography/
Polarizers are available in either linear or circular versions and the word around the water cooler is that it doesn’t make any difference for mirrorless photography. I use circular Polarizers because they also work with all of my cameras—mirrorless or not.

So I ask the Hog, do any of you know of and can cite actual articles validating that there is no significant difference between Linear Polarizer filters and Circular Polarizer filters when employed on mirrorless cameras? If not, do any of you have experience, such as User ID appears to, either supporting or negating my contention?