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Fun with Polarizers

S

SNC1923

Guest
I took a rare solo ride through the Kern River Canyon (Hwy 178) this afternoon in search of some photos. What I ended up with was an object lesson in the many benefits of using a polarizing filter. If you're not familiar with them, polarizers are adjustable, dark filters that adjust the incoming light. They work best when photographing a 90 degree angle to the sun.

First and foremost, a polarizing filter can be used to bring out the blue in the sky.







I'm pleased to note that the self-cleaning sensor on my Canon 40D seems to be working quite well.

A second benefit of a polarizing filter is its ability to saturate the image by reducing or eliminating reflections, in this case, on the water's surface.



Kern River taken at 17mm (28mm equivalent)



Kern River taken at 85mm (135mm equivalent)

The third benefit of a polarizing filter is that it functions also as a neutral density filter. The dark filter reduces the amount of incoming light by two f-stops. This is true of all polarizers, though specific neutral density filters can be purchased in 4, 8, or more stops of density.

Why would anyone want this? Sometimes you want to shoot something with a low shutter speed in bright daylight. You can lower the ISO to 100, and you can stop the lens down to f/32, but sometimes you need a little bit more. That's where an ND filter, or in this case, a PL filter, comes in handy.



1.3 secs. @ f/32



2 secs. @ f/32



8/10 sec. @ f/29



1/2 sec. @ f/29

It should go without saying the four photos above were all taken on a sturdy tripod. A darker ND filter would have resulted in slower shutter speeds and a more "painterly" quality to the water.

Click on any image for EXIF info.
 
Feb. 17, 2008 -- Nikon D300 & Hoya circular polarizer.

The white 1967 R60/2 in the foreground causes the exposure to darken the sky even more.
 

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Nice shots!

I discovered the G9 has an ND filter built in, reduces the f stop by a factor of 2 (I think?0 I used it a few times on my recent trip for some of the really birght daylight high noon shots. I'll have dig those out when I get a chance.


Love the water fall shots at slow speeds very nice effect.

RM
 
Nice shots!

I discovered the G9 has an ND filter built in, reduces the f stop by a factor of 2 (I think?0 I used it a few times on my recent trip for some of the really birght daylight high noon shots. I'll have dig those out when I get a chance.


Love the water fall shots at slow speeds very nice effect.

RM

I think it's actually a factor of 3 (3X). I haven't had a chance to use it yet, but I was sure impressed to find it there. It's mechanical too; you can hear/feel a "thunk" when you deploy it from the menu. Pretty cool. . . .
 
I think it's actually a factor of 3 (3X). I haven't had a chance to use it yet, but I was sure impressed to find it there. It's mechanical too; you can hear/feel a "thunk" when you deploy it from the menu. Pretty cool. . . .

So you have new toy in hand, eh?:laugh

RM

Toys are good!
being able to afford them.....




priceless :laugh
 
Polarizing filter

Anybody using one? Any thoughts on them? Use one for outdoors?
 
Yes, use it almost exclusively outdoors. I love it for green foliage on rainy or overcast days. It takes away the reflections and deepens the greens. And of course, there are times I want a more dramatic sky, or more emphasis on the clouds, so I use it then, too.
 
It's an indispensable accessory. Far from a bauble or a gadget, it can have a profound effect on your images. Get one for each filter size you have among your lenses.

You'd use it at the same times as you would tend to use a pair of polarized sunglasses. It works most effectively when shooting at a 90 degree angle to the sun. And it does all the things Dan outlined above. See the thread Jeff points to for a number of samples.

I'm not sure if linear polarizers are even still available, but be sure you get a "circular" polarizer as it is what will work with your autofocusing system. Get a good one (Hoya, Tiffen) but you don't need to go crazy (B+W) unless you're a frantic like me.

Nikon makes an awfully nice one. Theirs used to take a dedicated hood, too. . . .
 
Just be careful to not over saturate your photos...

Amen. Black skies on sunny days aren't cool. ;)

I use polarizers a lot. I use them occasionally indoors to minimize surface reflections, particularly if glassware is involved. The downside is you lose a couple stops.

Also there are a number of polarizers that incorporate other filtration such as 81 warming filters, etc. They are nice too and save the effort of using two discrete filters.

Lastly, if you purchase the more expensive polarizers/filters, you can use step down (or is it step up?) rings to use them on different size lenses as opposed to having many expensive filters waiting to get damaged/scratched in your travels.
 
In the last 35 years, each time that I buy a new lens, I also buy a polarizer filter for that lens. Used in the right conditions, it saturates outdoor colours, eliminates reflections and darkens skies, with both colour and black and whites images.
 
Amen. Black skies on sunny days aren't cool. ;)

Question: Is the sky in the photo below too "black?"

<img border=1 width=900 src=http://jeff.dean.home.att.net/weiss-left.jpg>

Personally, I like the sky's color. Of course, part of it is due to being in Arizona, where the sky is usually a deep color, and part is due to the exposure meter reading the white bike, thus darkening the sky.
 
Polarizers are a necessity for mid day shooting.

But there are other occasions when they're important.

I have both the Cokin set up for linear polarizers and a few circular polarizers for each lens.

I use the cir for mid day to get blue in the sky. On one occasion both the cir and linear were appropriate. That was at the Bonneville salt flats where the ground was absolute white and full of glare & the sky was bleached.

If you want a sunset and want to keep some detail in the foreground (rather than silhouettes) then a linear polarizer will help. I have a graduated Cokin that goes as dark as 3 stops (you can adjust to 1 or 2 stop).

But make sure you don't just slap either polarizer on and expect it to work; you have to adjust it, which is easy to do.

This is the best example I have of the value of linear polarizers. I got fog detail in the foreground while reducing the super glare of the sunset to get a definitive orb

189326447_NLrrj-M.jpg
 
Question: Is the sky in the photo below too "black?"
Personally, I like the sky's color. Of course, part of it is due to being in Arizona, where the sky is usually a deep color, and part is due to the exposure meter reading the white bike, thus darkening the sky.
Jeff, I'll take a stab at answering your question, but it's really a matter of taste more than "too black". In my opinion, the sky seems unnaturally dark, particularly in the upper left hand portion. When showing a wide expanse of sky a polarizer will often yield uneven results unless the entire sky is at roughly the same angle from the sun. I'm guessing you may have used somewhat of a wide angle lens for the shot, and the polarizer is not able to provide an even amount of polarization across that vast expanse. But maybe you already know that. By the way, I love the shot, regardless of the technical nit I'm picking!
 
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