Filters question

marklarry28 · August 3, 2006

Hi Grinners,
I'd like some help about filters.

How many filters should I have?
Is there a walkaround filter?

When should I take shoot with filters and when I never should use one?

Thanks

mkress65 · August 4, 2006

I can't give you a definite answer, but I can share a bit of what I've discovered over the past few days as I had the same questions.

Filters for protection of lens elements:
Seems to be split down the middle; there are some anecdotal stories about impacts w/ sticks, rocks, etc. that broke the filter and the owner was convinced that it would have broken the lens.
Others had stories about seeing a Nikon rep hit the front element of a lens w/ a screwdriver and it showed no apparent damage (so their point is, you don't need one.)
Most of the people against protective filters are concerned about introducing another layer of glass that can increase ghosting/ flare and/or impact image quality in general.
Everyone agrees that you get what you pay for and that cheap filters can really screw up your images; there were several images w/ odd "banding"/ diagonal lines in the bokeh which was corrected by removing the cheap filter.
There were concerns from people who were over-zealous in their cleaning of their lenses (or used improper technique and rub the heck out of their lens when it was covered w/ sand) and their point, well taken for people w/o an understanding of how to clean a lens, was that a filter is cheaper to replace than a lens if you scratch it whilst cleaning. Then again, some of the better filters for 77mm can run around $150, so, for me at least, that still ain't cheap!
Still others voiced concerns about environmental elements such as salt water spray, sand, llama spit (seriously...), lava (really...), or other toxic/ corrosive airborn particles. I never saw much of a consensus (except about lava -- and if you're getting lava on your lens, you've probably got bigger problems). It seemed to boil down to the comments about cleaning properly (see above) and, if you know that you are going into a toxic environment, then it probably wouldn't be a bad idea.
You can check DPReview for a whole bunch of threads on this topic. The most informative (which, naturally, I didn't bookmark) was from a gentleman named Thomas who appeared to have done a lot of writing for Nikon -- he listed a lot of reasons why he did NOT use protective lenses (most of which I've covered above.)

Specific uses for filters:
There should be a fair amount of info regarding circular polarizers which need to be rotated based on your angle to the sun and are not effective w/ the sun at your back (although I'm not sure that applies to reflected light from waves if the waves are in front and the sun is at your back.) Anyway, use these for reducing glare associated w/ reflected light from water, snow, etc.
Neutral density filters (graduated or not) are recommended for use when the sky is bright (cloudy and white and likely to be blown out) and the subject on the land is darker. Effectively reduces the exposure for the stuff at the top of the scene (assuming the darker part of the filter is at the top). Same effect can be had by shooting RAW, using a tripod and taking multiple shots of the same scene w/ different exposures (expose for sky, then for subject) and combining w/ some of the HDR (high dynamic range) software available (included in PhotoShop CS2, iirc.)

Warming filters, etc.
Not generally recommended as most of those effects can be applied in the photoediting software (easiest if shooting RAW.)

When not to use filters:
Take the filter off if the subject is backlit as this is likely to increase flare.

Lens Hoods:
Vast majority consensus: always use your lens hood. Provides good protection for the lens and helps minimize flare. There was some discussion about the efficacy of current lens hoods designed for lenses that were intended for full frame cameras vs. lenses designed for cropped frame cameras (20D w/ its 1.6X crop, for instance) but, in the end, everyone agreed that the hood should always be on.
And that is about 8 paragraphs longer than I intended (maybe I actually learned something over the past few days.) If you made it this far, then congratulations

, b/c you now have exactly as much knowledge regarding filters as I do!

And for anyone else reading, if I made an error, please feel free to correct.

gluwater · August 4, 2006

That is a pretty good explanation of filters Matt

. Mark a lot of people using DSLR's will only use UV or Skylight(to protect the lens), Neutral Density (ND), Graduated ND, and Circular Polerizers. Like Matt said you will get about 50/50 split on opinions on UV Filters and if they are necesary. If you want more detailed info try a search here for any of the forementioned filters, they have been discussed in detail, or ask about a specific filter you are interested in.

marklarry28 · August 4, 2006

Matt and Nick

Thanks a lot...
Great explanation and now I understand a litte bit more about it.

wxwax · August 4, 2006

I only have two filters.

Circular polarizer, for those blue skies. I don't shoot much water, but it would also remove lare.

Neutral density, for long exposures.

Everything else can be done in Photoshop.

mkress65 · August 4, 2006

wxwax wrote:

I only have two filters.

Circular polarizer, for those blue skies. I don't shoot much water, but it would also remove lare.

Neutral density, for long exposures.

Everything else can be done in Photoshop.

Yeah, I really wish I would have looked into filters (esp. polarizer) BEFORE my trip to Crater Lake. Managed to capture the blue of the water, but the sky is always much hazier/ paler than I remember it. Guess that means we'll have to go back again!

I have managed to get some OK shots using the Photomatix HDR software, but it just takes more time in post.

USAIR · August 4, 2006

wxwax wrote:

I only have two filters.

Circular polarizer, for those blue skies. I don't shoot much water, but it would also remove lare.

Neutral density, for long exposures.

Everything else can be done in Photoshop.

Only thing I might add is I would start with the polarizer first
I use it all the time...I shoot mostly landscape

Fred

mkress65 · August 4, 2006

USAIR wrote:

Only thing I might add is I would start with the polarizer first
I use it all the time...I shoot mostly landscape

Fred

One question, if I may -- does the haze filter actually do anything? I read that it works mostly if the haze is composed of water vapor, but not if its smog or other dust particulates. Since I seem to photograph landscapes w/ mountains (the Cascades) in the distance, and the mountains usually appear hazy, would the haze filter help?

Thanks,

claudermilk · August 4, 2006

Good explanation Matt. You did forget one environmental hazard...sheep snot (yes, really).

For digital I would think that only polarizers, ND filters, and UV would be of use. All the rest of the effects can be achieved in PP with better control & not lock you into that forever.

mkress65 · August 8, 2006

Canon's position on filters
One update for the OP -- for some odd reason I was actually reading the manual for my Canon 16-35 L lens, and on the first page of the English info under Features they state, "Sealed construction for higher dust- and water resistance compare to previous lenses. (For maximum protection, a filter must also be attached to the front of the lens.)"

edit:

upon further reading (about 2 paragraphs later) they reiterate that, "Although the lens is dust- and water-resistant, a filter must also be attached to the front of the lens for complete protection. (The front of the lens moves during zooming.)"

Filters question

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