[MariesMeow]

Hiya, I just ordered a Pentax k-x and I heard from a few friends that getting filters for my lenses would be a good idea. I have a 18-55mm and a 50-200mm. I have absolutely no experiences with DSLR's so I'm not really sure what they are used for. Could someone give me a quick description of what kinds of filters there are and if they would be something worth investing in? Thanks!

[Ben_Edict]

Hiya, I just ordered a Pentax k-x and I heard from a few friends that getting filters for my lenses would be a good idea. I have a 18-55mm and a 50-200mm. I have absolutely no experiences with DSLR's so I'm not really sure what they are used for. Could someone give me a quick description of what kinds of filters there are and if they would be something worth investing in? Thanks!

If you don't miss them, don't buy them!

Some people think, polarizing filters are indispensible, as they can darken blue skies and increase colour saturation. Some people find UV or clear protection filters indispensible. But there is always a trade-off between the protection, the filters offer to the front element of ypour lens and the increased flareing and ghosting, which they also introduce.

So my recommendation would be, to use the search function in this forum and search for "polarizing" and "protection" filters. YOu will find a wealth of infos, sometimes quite diverging.

There are two more filter varieties, which are useful, the neutral density filter (should be clean grey), which does nothing, but reduce the amount of ,light, which enters the lens and the graduated neutral filters, which are graduated grey. The reduce bright parts of an image, but leave others as they are. Great to reduce excessive contrast in a scene. Mostly used to reduce sky brightness.

Though I personally use these two last types most often, I think, you should only use them, after you have gained some püractical experience with your camera and see, how need for these filters arises.

All the other filters, which had been useful in film photography (colour correction, contrast enhancing etc.) are basically obsolete today. May be, good (and very expensive) diffusors should be excluded from that (search for David Hamilton photographies on the web and you'll see, what I mean), as a good softening effect is hard to achieve in computer post-processing.

Ben

[epqwerty]

Filters are really a deep deep field.

There are plenty of different types for use in different occasions. One of the more common ones that people use are UV filters. They are really just used as a layer of protection for the lens other than that they serve very little purpose.

In my opinion some good ones to have are Neutral density filters, and circular polarizers. Other than that filters one serve as you see fit. One can get away without a warming or cooling filter. Before there were soft focus, star pattern ones which can now be replaced by computer manipulations.

[song_hm]

They are really just used as a layer of protection for the lens ...

If your objective is lens protection, consider using a lens hood. You have the added benefit of lens flare prevention.

[Rondec]

I am one of those people who uses UV filters for "protection." I just find that I am clutzy enough that I will get my front element scratched otherwise. Probably not as big a deal with the kit lens, but particularly with expensive glass, I would rather replace the filter than the lens itself. That said, a lens hood can serve similar purpose.

As mentioned above, a circular polarizer can give some really cool effects when taking photos. Makes the sky bluer, reduces reflections from glasses and water. The nice thing is that both of your lenses will take the same size filter (52mm) so one should get you by.

The one place where I would always take my filter off is when shooting into bright lights (sun, etc.). You will find that your lenses are much more prone to flare and loss of contrast if you leave the filter on.

[RioRico]

I have a 18-55mm and a 50-200mm.

I'm not familiar with the 50-200 so I don't know if both zooms have the same front diameter. If not, you'll need more than one set of whatever filters you want, or you may reserve certain filters for just one lens (and any same-diameter lenses you buy later).

Many filters necessary for film work are unnecessary (or worthless) for digital cameras. All filters add another layer of glass between the camera sensor and the world, with some drop in image quality (IQ) -- you can decide if that's important. We can break down filters into 3 classes - protection, common effects, and special effects.

PROTECTION: Clear (daylight) filters WILL protect your lens. So will a stiff lens hood, except from head-on projectiles. UV filters are NOT needed; those are for film. (For me, protective filters just get in the way - I only use them in harsh environments.) Any of the effects filters will also protect your lens. Some filters cost more than some lenses, so you must decide just what really needs protecting.

COMMON EFFECTS: As mentioned above, polarizers will darken skies and reduce reflections. The merits of circular vs linear polarizers are argued elsewhere, at length. Neutral density (ND) filters cut light and are useful if you want to shoot wide-open and/or with a slow shutter in bright light. Use a welding-glass filter, shoot a busy street with a 10-minute exposure, and all moving objects disappear. Graduated density filters are half-gray and half-clear, useful when shooting something like a bright sky and darker landscape together.

SPECIAL EFFECTS: As mentioned above, diffusion filters can give an image a unique softness. Most other effects filters can be simulated in image editors. The colored filters common in film work are mostly useless for digital, with the exception of spectrum-slicing, to exclude all but certain bands of color. The most common are InfraRed (IR) filters, which block various amounts of visible light. These are discussed at length elsewhere. I sometimes work with actinic (UV-violet-blue) light to emulate early B&W photo emulsions. Forensic and scientific photographers may use other spectrum-slicing filters to look for details unseen in visible light.

Similar to filters, but more optically active, are add-on lenses. These may be thin DIOPTER (close-up) lenses, which look like clear filters; or thicker close-up adapters; or wide-angle and telephoto adapters. The close-up add-ons can be handy if you don't have money or room for a macro lens. Wide and tele adapters are usually miserable crap with lousy optical properties, which some people nonetheless cherish. Cf. HOLGA.

I think that about covers the basics of filters etc. I could blather on about infrared and spectrum-slicing, but I'd better stop now. Some members here are probably tired of that.