Filters

Can anyone provide a list of basic filter types and their applications for future reference?

What are the merits or otherwise of buying filters for lens protection?

Are filters marketed for digital cameras any different from ones for film cameras, and if so how?

Hi

If you do a google search you will find plenty of sites which explain what

Hi

If you do a google search you will find plenty of sites which explain what filters do what.

Lens protection.......... I reckon if you do a poll you will get a pretty balanced result. I personally dont use filters for lens protection. If I was taking an expensive lens onto a windy stormy beach, I would probably put one on though.

Digital Filters ? I would suspect that a filter marketed as "digital" would have more coatings to prevent flare which the digital sensor is more prone to than film. Oh, and a reason to charge more of course !

Shooting exclusively digital now, I only carry a polariser now. Warming, cooling, and skylight filters are redundant, as I believe are coloured filters that are used in black and white photography, but perhaps a b+w expert can confirm.

I dont generally have the need for one but ND filters are also good for when shooting under bright conditions. Living in England that usually isnt a problem I have to face very often.

There was a 'bit' of a debate about 'digital' filters here: https://www.pentaxuser.com/forum/viewtopic.php?t=5521

Dan

I have done a search on Google and I only seem to find retailers telling me why such and such filter will help me (in other words they are trying to sell me something).

What I would like to find is an unbiased objective breakdown of types of filters and how they can affect the image, or why they might be used in certain light conditions.

Are they as important now that you can do so much with an image on a PC?

If anyone knows of a site that provides what I want could you post a link
please?

A book on photography will explain in detail, but in summary filters are used with black and white film to correct and/or enhance particular colours and with colour film to change the colour balance. Virtually all of this becomes redundant with digital as it can all be done to the colour file in Photoshop, and that's what I generally now do.

When I used film, these are the filters I used most often:

Black and white:
Red: Makes blue skies very dramatic
Orange: More natural rendition of skies

Colour slides:
81A: Warming filter
80A: Correction filter to use daylight film in tungsten light

The only filter I might use these days is the Polariser, to reduce reflections on water or perhaps to intensify colours by reducing reflections.

I don't believe in using filters for lens protection on the basis that filters virtually never get damaged, so why should lenses? And why cause any potential degradation in quality by adding more glass?

Hope that helps!

Aren't they a bit like insurance,you hope younever have to claim, and you don't like paying for it , but you sure are grateful when something does go wrong. I must say I have only damaged one filter in 30 years, but my luck says as soon as I take them off I'll scratch a lens! So you see I've got my self into a sort of supersticious belief about them so I better carry on fitting them.

Rob

Rob,
I used to use the Hoya Pro-1 filters for "protection". (Emphasis on "used"
What I found is that a small impact (even in a case, falling a few inches) could be enough to smash the filter... and the filter splinters into razor sharp shards.

Now that I have 100% Pentax SMC glass I don't use filters. SMC is reportedly very, very tough. (And I keep a hood on at all times so that can take the brunt of any accidental impact )

The only filters I use now are Lee 100mm Neutral Density Graduated filters (and the occasional polariser). (Used to use the Cokin P size until I needed 77mm filters!)

Matt

Rob

I was the same when I first started digital photography. From what I have learned on forums and from some (pretty unscientific) experience "in the field", I learned that because the digital sensor is more sensitive to stray light than film, you can degrade your image more easily. Therefore I abandoned the skylight filters I would automatically use on film.

It is the same reason why a hood should be compulsory for digital photography, and as a side benefit the hood will also provide protection to your front element.

Insurance ? I have never scratched a filter/lens front, and am willing to take that small risk if it means my photos will be better as a result. After all if you buy a new car and are worried about it getting scratched, would you leave it permanently in the garage ?

Has anyone here had any actual evidence that with a decent, say, UV filter, the image really is degraded in any noticeable way, compared with no filter?

Other than maybe a bit of vignetting, perhaps, at very wide angles.

Or is it just a theoretical thing?

In the long distant past the point has been demonstrated, and Pentax even introduced the "ghostless" filter (curved to match the front element curvature of the 55mm lens). The idea never caught on.

The biggest factor I can see is the addition of two extra lens surfaces to reflect light and it may well cause additional flare. Also, the filter is generally quite far forwards of the front element of a lens and is therefore not so well shielded by the lens hood.

In any event, the filter is not part of the design of any lens, so why add something in unless it is absolutely necessary? With film it often is necessary, but not so with digital.

The only filters that do anything that you can't do in photoshop are polarizers, ND filters, IR filters, and I guess, some "special effects" (like turning every light you see in the picture into a star etc, though I dont know why you would want that).

Since this thread is up - I have a quick question.

I'm pretty sure I will get a new lens for Christmas - Thank you Santa .... and I'm pretty sure it is the Sigma 10-20.

I have never used polarizer filters yet, but guess I will be needing one very shortly.

Could some of you - who got this lens - tell me which polarizer you use and why. I guess you use a circular polarizer??

Anyway....all info regarding the use of polarizer is appreciated..

Well, I don't have that lens, but I do use polarisers.

I have two, a Cokin P and a Hoya 72mm.

And, heretical though this may be, they are both linear polarisers, and they both work fine with my K10D. I've noticed absolutely no problems with either AF or metering, both of which are supposed to be messed up in dSLRs (and presumably, AF fSLRs) with LPs.

I had them from my film days and thought I'd give them a try before lashing out on the much more expensive CPs. And very glad I am that I did...

ISTR others here saying that they've used LPs with Pentax dSLRs too with no problems...

No guarantees though - I'm just saying what I've found.

I thought the only filters that could not be replicated by software were ND, polariser and skylight/UV, the later because it cuts out atmospheric haze as well as adjusts slight colour casts. Even ND can be replicated somewhat by HDR and IR by colour/channel adjustments. Is this wrong?