# Let's talk filters



## Luvmyzoocrew (Oct 13, 2010)

When should you use a filter and when not too?

i got three filters with my new lens one is blue, one is clear and one is red. The blue one you can turn to change the darkness of the blue, i used it the one day when i was outside playing around ewith the camera and i took a pic of the trees across the street and as i turned the blue lens it really made the treee color nicer. So I need to know about them,lol


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## MikeScone (Oct 13, 2010)

*Luvmyzoocrew wrote: *


> When should you use a filter and when not too?
> 
> i got three filters with my new lens one is blue, one is clear and one is red.


The clear filter is probably a "skylight" or "UV" filter - basically, it's clear glass and its primary function is lens insurance. That is, it's a lot cheaper than the lens, so keep it on and let any scratches, fingerprints or whatnot happen to the filter, not to the lens. Some people say that there could be a small effect on sharpness from the extra layer of glass, but I have never seen it and I have UV filters on all my lenses. This summer I had the bad fortune to drop my 18-200 zoom, and, thank goodness, the UV filter took all the damage. Better a $20 filter than an $800 lens.

Colored filters are of more use in film photography than in digital, because most (if not all) digital cameras attempt to fix color imbalances automatically. That's the "auto white balance" setting in your D3000. If you put a color filter on the lens, and leave the white balance on "auto", it's just going to force the camera to try to restore the normal white balance. So, if you put a blue filter on, the camera's going to shift the white balance to try to take out the overall blue cast you just introduced, and make the whites white - which is going to do unpredictable things to everything else. You could turn off auto white balance, and select sunlight, so the camera doesn't try to fix the color - which would then make your picture blue. If that's what you want, go for it, but frankly I don't see the point. 

The red filter is used in black and white photography, again mostly for film. It darkens blue skies to make white clouds stand out more. I wouldn't use it in digital photography, since you're better off taking the picture in color and then converting to black and white in the computer later on (I never use the black-and-white setting in the camera - why throw away any information you can never get back?). When you convert, most photo editing programs (Photoshop, etc.) will let you introduce the same effect by controlling how the black-and-white conversion is done and many include software "filters" which simulate standard photographic filters of all sorts. I could post some examples, if you're interested. 

I'm surprised you would get a blue filter in a kit. True blue filters (deep blue) were rarely used in black and white work. They would lighten blue skies, reducing the contrast of clouds, and also lighten trees and grass to some degree, neither of which are things people normally want, and they'd render skin tones sort of icky. 

There were bluish filters which people used to correct for tungsten light with outdoor film - they're not bright blue, but just kind of light blue tinted clear glass. Even those aren't used with digital cameras, since you get the same result, only better, with auto white balance. 

The only common filters which are useful for digital cameras (other than clear protective ones) are polarizers and, sometimes, neutral density (grey). 

Polarizers are like polaroid sunglasses - as you rotate them, they darken blue skies and eliminate reflections. That can be very useful. 

Neutral density filters just reduce the light entering the lens, like regular sunglasses. That lets you use a slower shutter speed under bright conditions, say if you want to blur moving water or something like that, but there's just too much sunlight to let you slow down the shutter enough. 

Less common (and more expensive) are graduated filters. These are shaded across the filter so that half is dark (or colored) and the other half is clear (or lighter colored). I have a few of these in the Cokin system, which are square plastic filters which fit in a special holder. I don't use them much, but they can be useful. Say you want to darken a very bright sky while not affecting the darker earth and grass below - you'd use a graduated grey filter to hold back the sky, while the clear lower half lets the grass be exposed normally. I've also got a graduated blue and a "sunset" filter which is graduated from a sort of dark orange to a warm yellow.


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## Luvmyzoocrew (Oct 14, 2010)

http://rabbitsonline.net/view_topic.php?id=61422&forum_id=97

here is the thread from earlier and i posted some pics from the new lens, and in the scenic pic i used the blue filter, i was just shooting different types of pics to see what a filter does,lol.

I would love to see your examples.


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## MikeScone (Oct 17, 2010)

*Luvmyzoocrew wrote: *


> I would love to see your examples.



OK, here they are.

We had a nice day this afternoon, so I went outside with a stack of filters to show the effects different filters had. 
First, this is what the scene looked like â just the view down my road from in front of my house:






Hereâs a color picture with a red filter:




Basically, red filterâ¦ red picture. Not much point, in my opinion. 

Red filters are designed for black and white photography. I turned the camera to black-and-white (which I normally wouldnât do, but for the purpose of this demonstration, here we are). 
No filter:





Red filter: 





As you can see, the red filter darkens the blue sky, and lightens anything red, like some fall leaves. 

There are filters which are designed for color use. Iâll demonstrate a few of them here. 

Probably the most common filter for color is the Polarizing Filter. Thatâs an interesting one because it doesnât have any color itself, so you donât need to worry about white balance. The filter blocks light which vibrates in one direction, and passes light vibrating in another. So, you have to rotate the filter in its holder to see what effect it has â in one position, it will darken blue skies:





Turn the filter 90 degrees, and the sky is much lighter: 




The amount of darkening of the blue sky depends on the direction of the sun. There's almost no darkening in near the sun, maximum darkening at right angles (north, usually, at least here in the northern hemisphere). 

Reflections are strongly polarized, so a polarizing filter can also be used to reduce (or even eliminate) reflections off glass or water. Interestingly, you can also use a polarizer to deepen the colors of grass and leaves, since it will block the blue light reflecting from the sky. 

Photographers would use âwarmingâ or âcoolingâ color filters with color film. These were very faintly orange or blue, and made a scene correspondingly slightly warmer or cooler. If you used them with a digital camera on auto white balance, the camera would just adjust them away. Thereâs no point in using them with manual white balance, either â just use âautoâ without the filter and adjust the camera for warmer or cooler colors. 

Still, there are color filters which can be useful with digital cameras. As Iâd said, if you leave Auto White Balance âonâ on a digital camera, unless a solid color filter is very dark, the camera will just adjust the white balance to eliminate the effect of the filter. So, before taking any of the following pictures I set white balance to âsunlightâ. 

âGraduatedâ filters are good examples of filters which can enhance color pictures. A graduated filter is one which is not a solid color, but rather changes in color (or depth of color) from one side of the filter to the other, with a gradual transition area between. All of the graduated filters Iâm showing here were in the Cokin system, which uses square plastic filters. Because the filter is square, you can slide it in the holder to move the graduation point to where you want it in the picture. Round graduated filters exist, but youâre stuck with wherever they put the dividing line. 

This is a graduated grey (or graduated neutral density) filter. Itâs clear on the bottom and grey on the top. Itâs useful in holding back a bright sky to allow more exposure for the darker land below (or invert it to hold back bright snow): 




I have graduated grey filters in two strengths, depending on how much darkening I need. 

A graduated color filter can be used to add color to the sky â hereâs a graduated blue filter (clear on the bottom, blue on the top):




You can turn a graduated blue upside down to add some blue to an expanse of water or snow, too. 

This is graduated pink (clear, shading to pink):





Graduated tobacco (clear, shading to brown):




Once you know what that looks like, youâll be surprised how often you can spot the use of a graduated tobacco filter on TV shows. 

The âSunsetâ filter is yellow on the bottom, red on the top, and shades continuously through orange in the middle. This probably isnât the best picture to show that off: 





This is a better example â the sunset over the Gulf of Mexico was fairly âblahâ, but it became much more interesting with the sunset filter:





Here are a few more examples - I took the same view (the island of Filfla, off the south coast of Malta), without filter, and then with sunset and graduated tobacco filters. 















One final example â this filter is not really colored, itâs black. Thatâs right, black â you canât see through it at all. The filter passes only infrared light. Obviously, you canât see through the viewfinder, either, and because most digital cameras have internal filters which block IR, it needs long exposures too. Basically, put the camera on a tripod, aim as best you can, and you never know what youâll get. Live foliage tends to be orange or red, clouds are red, sky is blackâ¦ or not. 





One final thought. I said that I donât use the black-and-white setting in the camera. Instead, what I do is take pictures in color and, if I want them in black and white, Iâll convert them in Photoshop. I think that results in a better quality result â and, of course, if you decide the picture looks better in color, youâve got that option. 

Hereâs the picture above, converted to black and white using the âblack and whiteâ filter: 





I actually think you get a better result (and more control) by using the âchannel mixerâ, which lets you control how much effect each color has on the final black-and-white image. Hereâs the same picture, but I tweaked the levels in the channel mixer:






That allows you to easily simulate the use of a red filter, simply by reducing the level of all of the non-red colors: 






Hereâs an actual example, from my trip to Scotland this summer. The picture was taken from the ferry to Islay. 





The picture just seemed like a perfect candidate for black-and-white conversion, so I tried it:





Any questions?


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## Luvmyzoocrew (Oct 18, 2010)

lol no questions but my head is trying to retain all that,lol. Thank you


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