Simplistic M polarizer use

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This may be a little _too_ simplistic, but I got the idea from my sunglasses. I've been noticing that the glasses manufacturer align the lenses in a certain fashion, to give at least a moderate effect in most cases, and sometimes a dramitic effect in fewer cases.

Motorists probably have seen me tilt my head from side to side to check the effect...

This made me think about a "set and forget" approach to polarizer use on the M. While not idea, it would be faster, simpler and easier. For critical use, you could still use the "compare to a handheld filter" technique whenever you wanted to.

Anybody doing this? or have and thoughts on it?

-- Charles (cbarcellona@telocity.com), April 20, 2002

Answers

The effect of the polarising filter has depends on the direction the light is coming from. So set and forget will not work.

-- John Collier (jbcollier@shaw.ca), April 20, 2002.

I know that that much, but how is it then that the glasses manufacturers get it so close to optimum for darker blue skys? I mean, they're not terribly far off from having maximum sky saturation for the most part.

-- Charles (cbarcellona@telocity.com), April 20, 2002.

I think you should calibrate your filter to match one of your sunglass lenses--just a mark on the filter ring that corresponds to the top when it's the same as the sunglasses. Tilt your head until you're satisfied, and tilt the filter the same extent in the same direction. :-)

-- Michael Darnton (mdarnton@hotmail.com), April 20, 2002.

I see your question, and it does not translate well to a phot filter, which only has one axis for comlpete control(if you mark the axis, you can "point and shoot" by pointing the axis mark towards the sun (light source) -- some polarizers are marked, some require a mark placed.

sunglasses, I don't know - any opticians out there? two guesses (only that), 1. they standardize assuming a given angle, and accept what they get (and the darkness of the regular tint aids); or 2, the have a double layer, at 90 degrees, so some effect is usually there.

-- l smith (lacsm@bellsouth.net), April 20, 2002.


Well, there's one way to do it. Get a B+W linear polarizer that fits your lenses. Get another linear polarizer that is it's "mate."

Take both polarizers outside and individually turn them until you get the darkest sky in each.

Place a mark on each polarizer that corresponds to the "darkest sky" position.

Place the primary polarizer on your lens.

After determining the angular location of your shot to the sun, take the other polarizer, place it at the same angle and horizontal elevation as what you're shooting, and twist it until you get the desired effect through the hand-held filter on the same sun-photo axis.

Transfer the angular position of the mark on your hand-held polarizer to the one on your camera, e.g, . two o'clock to two o'clock.

Compose and shoot with your M6 or M7. The reflective light meter in the camera will compensate for the filter.

Now, you will always won't get what you want, but you'll be surprised at what you *do* get.

-- George C. Berger (gberger@his.com), April 20, 2002.



George, I've done just that, no problems encountered so far.... but was thinking there ought to be a faster way to increased saturation, maybe not the BEST saturation, but better than no effect at all, and... also in the ballpark so to speak.

Actually, I liked the idea about calibrating my glasses to the filter. THAT would be faster - no joke!

And... calibration is simple: look thru both until the image thru the filter is the darkest (nearly black), then make a mark 90 degrees from that, and it will be in line with the top dead center of the glasses.

It sounds goofy, but I think it might just work!

-- Charles (cbarcellona@telocity.com), April 20, 2002.


Try this.

-- Lutz Konermann (lutz@konermann.net), April 21, 2002.

or do it yourself:



-- stefan randlkofer (geesbert@yahoo.com), April 21, 2002.


I don't have a pair handy, but I think polarizing sunglasses are set at an angle whereby the reflections from flat ground are minimised, whether it is a beach or a road for example.

It would be easy to set a polarizing filter on camera in a same way. It would minimise reflections from sand or water, but not work properly on darkening the sky or on reflections from windows. Or when you turn the camera on its side to take a vertical composition. So in practice, fixed setting on a polarizer would not be that good an idea.

Ilkka

-- Ilkka (ikuu65@hotmail.com), April 21, 2002.


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