linear or circular polariser? Samsung Nx lens

[northlondon43]

Hi everyone

Firstly I'm not sure whether a linear or circular lens is 'best' as most info I've read from experts is incredibly technical and way over my head. Some websites selling filters say linear for MF cameras, circular for AF. Thoughts?

That aside, there doesn't seem to be much choice bar v expensive B&W (way too much compared to the price of my Samsung nx lens) and old Hoya filters (they don't seem to make their Pro 1 series for the required 43mm thread). Any suggestions for mid priced filters? I'd like to pay around £40 with something that's multicoated (am I in dream land??)

Thanks

Adrian

[Shadowman]

Why not include a neutral density filter in the mix. And why do you feel you need a filter?

[Mike Buckley]

If you're using auto focus, you really do need the far more expensive circular polarizer. If you only use manual focus, the linear polarizer will work fine.

[Manfred M]

You cannot use a linear polarizer on any modern camera; as Mike stated, it will interfere with your autofocus. What he did not mention is that you light meter will also give incorrect readings, so your exposures will be off. My 35 year old film camera has the same issue and must use a CPol for this reason.

The more work that goes into a filter, the more it will cost you. So if you want all the bells and whistles (multicoating), be prepared to pay for them. The other feature of more expensive filters is that they use expensive brass mounting hardware, rather than aluminum. Aluminum can bind and lock (getting it off your lens can be a problem).

Good CPols are expensive.

[Mike Buckley]

What he did not mention is that you light meter will also give incorrect readings

I didn't know that. My Minolta X-700 film camera, which was released in 1981, had a light meter built into it and I always got accurate readings always using a linear polarizer. The same is true of a backup Minolta film camera that I had, though I don't remember the model. I didn't use a circular polarizer until I began using auto focus digital cameras and never associated the need with anything having to do with modern light meters.

[jcuknz]

If the price of a 43mm filter is exhorbitant due to lack of demand and production through put you could get a cheap step up ring to match the more reasonably priced larger and more common filter. Usually it works the other way as when I wanted a CU lens which cost me $26 at my size[55mm] ... fortunately I didn't need a 77mm which would have cost me $146

[Manfred M]

I didn't know that. My Minolta X-700 film camera, which was released in 1981, had a light meter built into it and I always got accurate readings always using a linear polarizer. The same is true of a backup Minolta film camera that I had, though I don't remember the model. I didn't use a circular polarizer until I began using auto focus digital cameras and never associated the need with anything having to do with modern light meters.

My Leica R3 uses a semi-silvered mirror and has a hinged secondary mirror attached to it that reflects light onto the meter cells. The semi-silvered mirror is the issue with that design, so I was one of the first people I know that had to invest in a CPol. They were quite rare in those days and were darn expensive.

[rpcrowe]

If you're using auto focus, you really do need the far more expensive circular polarizer. If you only use manual focus, the linear polarizer will work fine.

For some manual focus cameras, a circular polarizer would ensure better exposure metering. I had a Pentax ME 35mm manual focus 35mm SLR which would give erratic exposure metering when using a linear polarizing filter. A Tiffen Company representative gave me the first circular polarizer that I had ever seen (probably that was sometime in the early 1980's) and the CPL cleared up the exposure metering problem...

I was in the Navy and was the Training Officer of the Pacific Fleet Audio Visual Command and the filter was just one of the little perks we sometimes got from manufacturers. In those days, the Tiffen filters were considered pretty high grade and were used by many professional cinematographers. I don't have any idea what the CPL that I received cost...

[Tringa]

As polarising filters are expensive have a look for a second hand one - boot sales, photo fairs etc. When I bought my current DSLR a few years ago I was concerned that an old (ie bought about 40 years ago) polariser would have to be replaces, but I found it worked with no problems.

Dave

[northlondon43]

Thanks all for your thoughts. So now I know a) I need a circular, not linear, polariser b) I have to accept that I will pay more for a multicoated filter (and not 100% sure I need one) c) I could use a step up ring if it meant I had more choice ref number of filters available.

Cheers all :-)

[soundrich]

Hi, I'm afraid that everyone who has replied above is actually wrong about which type of polarising filter you would need.

Either a circular OR a linear filter will work just fine on the camera you have.

The need for a circular filter for AF on a camera stems from the use of a partially silvered mirror to allow light to be reflected to the AF sensors in an AF SLR, DSLT or DSLR. Most older, manual focus SLRs also use a similar system to transmit light to metering sensors, and so show better exposure accuracy with a circular polariser.

You, however, have a Samsung NX camera. This is a mirrorless camera, and has therefore no mirror. AF and metering are performed directly from the image sensor itself. This means there is no specific requirement for a circular polarising filter. I am unsure, however, if cameras with on-sensor phase detection AF would be affected by the type of polariser, so YMMV.

In short, you can use any type of polariser you like, because your camera has no mirror. Other cameras unaffected by polariser type include all fixed lens cameras, micro-4/3 cameras, sony NEX system cameras, all rangefinders and any manual focus cameras where the metering system is in the viewfinder prism e.g. Nikon F2.

[northlondon43]

Thank you Soundrich - I have to say that was in plain enough language for even me to understand :-)

I've ended up going for a Dorr DHG slim filter which I found for £36 (most sites £45). It may be a prestigious make but I'm sure it'll suit my amateur needs.

Adrian

[Manfred M]

Hi, I'm afraid that everyone who has replied above is actually wrong about which type of polarising filter you would need.

Either a circular OR a linear filter will work just fine on the camera you have.

The need for a circular filter for AF on a camera stems from the use of a partially silvered mirror to allow light to be reflected to the AF sensors in an AF SLR, DSLT or DSLR. Most older, manual focus SLRs also use a similar system to transmit light to metering sensors, and so show better exposure accuracy with a circular polariser.

You, however, have a Samsung NX camera. This is a mirrorless camera, and has therefore no mirror. AF and metering are performed directly from the image sensor itself. This means there is no specific requirement for a circular polarising filter. I am unsure, however, if cameras with on-sensor phase detection AF would be affected by the type of polariser, so YMMV.

In short, you can use any type of polariser you like, because your camera has no mirror. Other cameras unaffected by polariser type include all fixed lens cameras, micro-4/3 cameras, sony NEX system cameras, all rangefinders and any manual focus cameras where the metering system is in the viewfinder prism e.g. Nikon F2.

Good observation. I wish I had a linear polarizer to test on my MFT.

I wonder how the AA filter impacts this. On my D800 it essentially is a 2-stage beam splitter (stage lets part of the light through and shifts part of if 1 pixel) the second stage does exactly as the first but is turned 90 degrees.