Filters - Which and why??

All, got a question on filters.
Having just got my K-x, I was wondering which filters I would require??
I guess I would need a Polarizing filter, and possibly a UV or Skylight filter, but haven't got a clue about what & why, nor on if they come in different sizes, can/should you use them together.
Same on Lenshood, with my standard set of lenses (18-55 & 50-200)

Your help (and especially patience) much appreciated

umm you are going to find this a VERY interesting thread

I have skylight , UV and Circular Polarising and I'll admit to having a Skylight on the 18-55 and the 50-200 lenses - not yet on the 40mm but I expect that to be used mainly inside .

Fred - look at the Cokin P system as a starting point. P system can be used on any lens you're likely to use with your K-X.

Most useful filters - Grad Grey, Grad Blue, ND4 and polariser. System filters mean they can be used on different size lenses with a change in the adaptor ring on the filter holder. Holder take up to 2 filters at a time - but not if using an extreme wide angle as it will vignette - ie dark corners to the image. Cokin do a special holder for a single filter for these types of lenses.

A lot of people use UV or Skylight filters on the front of their lens to protect the lens front from accidental damage. It's a personal choise which probably dates back to our film based days.

HTH


Steve

Depends what you want to do. If you think that you're not likely to use filters frequently, then buying one or two circular threaded filters may be a more useful option than buying into the square filter systems.

If so, don't forget that if you have lenses with different filter diameters, you can always buy a filter to fit the largest lens, and then inexpensive step up rings to enable you to use it also on smaller lenses.

With the two kit lenses, you might want to use a lens protector, but I'd give higher priority to a lens hood because that is more likely to have a direct impact on improving image quality (by reducing the incidence of flare), as well as protecting the lens.

If I was starting from scratch, the only filter I would start with is a circular polariser. I'd try and buy a good one because they tend to be thinner (less vignetting on your lens) and have higher quality coatings. They are worth searching out on the www, as the prices vary enormously and you can find them remarkably cheaply if you look carefully. I've had good filter bargains from Amazon.

Over time you might want to add others, and if it gets to the stage when you decide you want to use neutral density filters (you'll know when you want them - if you need to ask at this stage, then don't bother just yet!) then that's also the time to consider buying into a system like the Cokin P mentioned above. An alternative and similar system, which is slightly more expensive but also of higher quality, is Hitech - I have their filter holder and some ND and grad filters that I am very happy with.

I'm a great believer that if you don't know why you have a filter on your lens - don't!

I've got some Circular Polarisers (49mm for the A/50mm, 77mm for the DA 12-24mm) which are useful outdoors, but only if you are facing in the "right" direction, otherwise they just knock a couple of stops off.

I've also had some UV and Skylight filters that came with some of the cheap lenses I bought second-hand. A quick "with/without" check showed all they did was make the pictures look soft and add distortions, so they have been tossed away!


If you have some time, have a read of the various articles on Luminous Landscape to understand a bit more about CPL's and Grads etc...

In all honesty the only filter I would advise to begin with is a polariser. I got mine from here, it's cheap and cheerful and I have yet to spot any flaws in the glass or coating.

Leave the others until you work out what sort of photography you enjoy most, and which lenses you'll use most. The one in that link will fit your kit 18-55mm lens, that's exactly the setup I used on my K-m to take this a week or two after buying the camera:




You may want to consider Cokin or Lee filters, I'm not so keen as they require a large filter holder to be attached and given I'm prone to using old manual primes with a view to making the camera more compact and less of a "mug me" sign the filter holder would rather defeat the object!

Skylight/UV filters are a personal taste thing. There's no technical need for them on digital, some people like them as lens protectors while others feel they have an adverse effect on image quality. Personally I don't bother with them, my old lenses are not horrifically expensive and I always put the cap on when I'm not taking photos.

For digital photography, the polariser is almost the only filter you will ever need. Everything else can be done in Photoshop without putting extra glass in front of the lens.

Bear in mind that there's no point putting colour correction filters on if you use AWB - the effect will be removed or watered down.

As regards protection filters, this is a moot point. Personally I have never damaged the front element of a lens. Some here have had a lens damaged by a fracturing filter. The exception might be at the coast where it could be useful to protect a lens against salt spray.

Filters will potentially degrade image quality, not least because the glass is not fully shielded by the lens hood, being further forwards than the front element of the lens.

My advice would be to always use a lens hood. This will reduce flare, improve contrast and also afford some protection in itself to the front element.

Thank you all very much for the kind replies.
Let me first get lens-hoods, and see where I go from there.

I agree with that however I would at Natural Density & Graduated Natural Density filter to the list. For ND I would get threaded one, maybe even a Vari ND and for GND square system are better because you've more controll where to place the transistion.
If you don't know what I mean Google thee filters and you see what I mean.

GND are very handy when shooting landscapes with clear skies, the sky is then often brighter then han the ground and a GND darkens the sky but leaves the ground unthouched, that way you can get a nice ven balanced exposure without a burn-out sky.

Sky light or UV are of almost no use on digital because these wave-lengths are already filtered out by the filter that's infront of the sensor.

For the DA40 I would just leave the hood on it's of metal and the entrance is only 3cm wide or so. You need to be very unlucky if something would go through that that would damage your lens.

An entertaining old thread...

K.

If others in the UK are looking at this thread and considering buying a set of P series ND and grad filters, I have recently purchased a set of Hitech filters: 3X ND of various strengths and 3 X ND grad (ditto), for total of £50+VAT on special offer from Teamworkphoto.

These are good quality filters that are considered to be more neutral than the Cokins (and rumoured to be made by the same people who make Lee filters), and given the quality, this is a very good price. Teamworkphoto superb - great service and delivered in less than 24 hours.

Regarding the lens hoods you can order genuine Pentax ones from SRS and of course postage free when you quote your forum username

Rob