Steve's Digicams Forums

Steve's Digicams Forums (
-   Add-On Lenses (
-   -   Lenses/Filters (

wrams Oct 3, 2006 6:58 AM

Hi People,

Can anyone help me with lenes/filters what types there are and what there main reason for use are (i'm a Novice) So please help??

granthagen Oct 4, 2006 1:09 AM

For digital, there are only three types of filters generally used:

1) Polarizing filter. These are useful for darkening blue skies and lessening or removing reflections from non-metalic objects. This can let you see into water "through" the reflections on the surface, into car or shop windows obscured by reflections or get increased color saturation in landscapes (or any other reflective surfaces) by removing the reflective "hot spots" from rocks, foliage, etc.

There are "circular" and "linear" polarizers. The circular types are a bit more expensive, but you can use them on any type of camera without affecting the cameras autofocus. The linear ones can throw-off the autofocus on cameras that use a prism system to redirect some of the light entering the lens to the autofocus sensor. You might be able to use a linear, or not. Find out the manufacturers recommendation.

2) UV (ultraviolet) filter. With a digital camera, people usually use these just to protect the front lens element from poor weather or getting whacked. There are two camps on this subject. One bunch says that they would rather have one of these on the lens at all times while others say that putting another layer of glass in front of the lens contributes to a loss of image quality by contributing to flare and ghosting and that a lens hood is good enough protection.

3) Neutral Density filters. These work like sunglasses for the camera, cutting down the light entering the lens. They come in various strengths and are stackable for even greater light reduction.

People use these to get those smooth pictures of running water or to get creative motion-blur shots or very selective depth of field in thier pix. Less light means that much slower shutter speeds can be used in bright daylight to blur motion or larger lens apertures can be used to minimize the depth of field (area of acceptable focus).

A sub-category of these are called, "Graduated Neutral Density" filters. These are usually square, requiring a special adapter. They do a similar job of cutting down the light to the camera, but the effect fades gradually down the length of the filter. These are useful for scenes where there is a large degree of difference in brightness between two areas -- like the sky and the foreground. You arrange the position of the filter so that the darkest part of the filter is covering the brightest part of the picture and you can get shots where the sky and foreground are more properly exposed in relation to each other than they would be with no filter. People can do this sort of thing with an editor, too, but if the bright areas are so bright that they are "blown" (straight white), you can't fix it later. You'd have to completely replace the blown area or live with it.

There are many other filters that can be useful, but they mostly fall into the "special effect" category which are too numerous to describe. Any web search will show you dozens if not hundreds of special effect filters. Most digital shooters find plenty of special effect filters built into their editing software.

Check out this link for a recent discussion on the quality level of different filter brands:;forum_id=2

This is just a basic description of useful filters. Google each type and you can learn much more about them as well as any other term used that you don't understand.

I don't know what kind of auxillary lenses are made for your camera, but there are generic, screw-on lenses that are used rather like filters. These are mostly wide-angle (increasing the angle of view) and telephoto (decreasing angle of view -- bringing things closer). The optical quality of these is generally no where near the quality of a multi-element add-on or a lens made for a DSLR.


wrams Oct 4, 2006 6:07 AM

Thanks very much Grant,

I'm a Novice when it comes to,How can i put it "Up-Graded Photography" so i'll take your advice and read up on the effects of Filters/Lenses.

Thankyou again for your time

wrams Oct 4, 2006 6:08 AM

What is a Skylight Filter??

As iv'e got one!!!

granthagen Oct 4, 2006 10:47 PM

Skylight filters are in a similar category to UV filters. They reduce the "blue-ing" of distant objects by ultraviolet light. While the UV filter is supposed to be color-neutral, skylights have a pinkish cast that "warms up" the excess blue that transparency films can produce when shooting in the shade or in sunny conditions with a bright blue sky.

With a digital camera, you can get the same results by changing the white balance setting to overcast or shade. If you want to use this filter as lens protection rather than pop for a good UV (provided you want any filter for protection), it will affect the color balance of your shots, though the effect will likely be subtle. If you use auto white balance, that might compensate for the slight tint.


wrams Oct 5, 2006 4:17 AM

Thanks again Grant.

All times are GMT -5. The time now is 7:22 PM.