Quick filter explanation

[Curtis E. Niedermier]

So, without directing me to a long post or story, can someone give me the simple, one-paragraph explanation about filters so I can better understand what guys are doing with some of the images they post here?

What are they? How do they work? And when/where/why do you use them?

Keep it simple. I just want a basic explanation. Don’t need the detail.

Thanks.

[Zach Matthews]

The only filter which is still relevant on a day to day basis today is a circular polarizer.  Almost all older filters simply cast the shot in a slightly different color, which is easier to do now in photoshop.

Circular polarizers look like venetian blinds on a minuscule level; they only let in light which is bouncing in one direction, rather than scattered.  As a result they make skies bluer and cut glare off water significantly.

There are many other things filters can do and a lot to be said about how to use them, but as you asked for the brief explanation, there it is.

Zach

[kurt budliger]

I don’t think there is a very simple response to your question(s), especially not one that can be answered in one paragraph (although Zach did a good job on the polarizer).

[Mike Anderson]

GND and ND filters aren’t necessarily for beginners but they are very useful. While I know Zach is alot more proficient then I am with PS, fixing a blown out sky is a major pain. I’ve yet to do one in PS that I could honestly say wouldn’t have been better if the right filter was used.

I have a series of random sky photos now that I can use sometimes to replace a blown out sky but again, I’d rather just fix it in the camera.

Kurt has put up some great sites to learn from.
Check out this thread as well.
http://www.itinerantangler.com/cgi-bin/board/YaBB.pl?num=1287540179/0

[John Bennett]

Swore I wouldn’t respond 🙂

Mike you can’t fix blown skies in PS. Anything above a white point of

[Mike L.]

I always use yellow when I am shooting black and white film which is pretty much all the time.

[Zach Matthews]

I have Singh-Ray GNDs that I ought to use more but they are so damn awkward that I usually leave them in the bag.  For your typical consumer photographer, looking to take “good fishing shots” and pictures of the family, the only filter I would really recommend getting would be that circular polarizer, which is why it’s all I mentioned.

Also John is 100% correct on clipped skies.

[Jason DeBacker]

I’m very new to dslr’s and filters and in my few weeks playing around have only used a CP- although I already see that a GND would be extermely helpful for just about all lanscape photography that includes a horizon.  

How effective are two CPs at achieving the effects of ND filters?  I thought I’ve read that you can turn then CPs to vary the amount of light let in (anywhere from none to a 4 stop loss of light)- like when you take two pairs of polarized glasses and turn one of them.  Wondering if I really need to add ND filters to the bag or if another CP will suffice.

Thanks,
Jason

[John Bennett]

Jason.
When stacking 2 CPs you negate the “polarising” effect but do gain additional light reduction. So in a sense its a ghetto ND but at the cost of polarising? Best just to get an ND imo.

Do you need it?
depends on what you like to do. The best time to do long exposures is in low light. The best time to waterfalls for cotton candy water is on overcast days or even a light rain/drizzle. In both cases you want a CP to cut the glare of rocks and foliage. If your shooting a scene with alot of green you want to start roughly 2/3rds underexposed. Fact of the matter is *we* are often out and about doing what we do at all times. If you want flowing cotton candy water mid day you *will* need one.
Shot around 1pm with a 2 stop GND, a CP and a variable ND set around -7
ISO 50
f14
13 seconds

I have and use a SR variable ND. I dont use it much but when I do I’m glad I have it. I can shoot flowing water *any* time of day or use it with fast glass to get a narrow DoF in brighter light when I still want a slower shutter speed.

ISO 50
f2.8 (for narrow DoF, I was panning and wanted nothing but my daughters face in focus)
1/15 for motion blur and panning

Its one of those things thats great to have when you *want* it but rarely used and pricey

Here Im shooting directly into the sun for a sunrise pic.
A G/B CP to change colors (-2 stops)
A 3 reverse GND ( to balance sky/sun/foreground)

But I also wanted motion blur in the waves and without the variable ND I couldnt get my SS slow enough given I shooting right into the rising sun ( if memory serves me right I set it around -5 stops)

ISO 100
f18
0.75 second

[Jason DeBacker]

Well, I don’t know enough physics to know why the polarizing effects would be lost, but that is good to know!

[John Bennett]

I haven’t played with it myself, someone more knowledgeable than I explained it once a long time ago. I do know if I look through a cp with polarized glasses it’s wonky. Always take my glasses off when using them as you may not get what your seeing

[Curtis E. Niedermier]

Excellent. Excellent. Excellent. I was curious about the “cotton candy” effect, as one of you called it. Long exposure, with the proper filter. That’s the connection I was hoping to make.

My photography experience is pretty slim. I shoot what I can for our magazine, but it’s primarily grip-n-grin stuff. However, I’m trying to advance my skills so that I can do some more artistic projects.

Zach, I love this site. The fly-fishing info is great, but I love the photograpy and writing boards most. I could probably get this information from a dedicated photography or writing forum, but the people here are applying those skills to the same field as me. Perfect.

Thanks guys.

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