[alamo5000]

I now have a small collection of lenses to go with my new K-5 and almost all of them have UV filters on them.

My MAIN reason for having a filter on there is to protect my lens. Period.

I have no other reason for having a filter on my lenses except as stated above.

That being stated, what is the stated purpose of a lens filter (other than protecting the lens)?

Do they have straight up 'clear' lens filters? All the ones I have seem to have a small 'tint' to them.

Maybe we can have a discussion about the different filters and what they do and so forth. Pros, cons, whatever.

[sterretje]

UV and clear filters have no other purpose on dSLRs; and they may affect image quality. I have taken mine of after I noticed reflections in night shots that disappeared after I removed the UV filter. I will only put them back on in adverse conditions (e.g. sandstorm).

Some often used filters:

** polarizer filter (circular (CPL) and linear (LPL))
from wikipedia

The polarizing filter has two applications in both color photography and black-and-white photography: it reduces reflections from some surfaces, and it can darken the sky.

** neutral density (ND) filter
blocks light allowing the use of longer shutter speeds to achieve effects like silky waterfalls during bright daylight

** graduated neutral density (GND) filter
identical to above but effect is stronger at one side; can be used to reduce the intensity of the sky so it is not / less washed out

[Zafar Iqbal]

The stated purpose of UV filters is to reduce the amount of UV light - however, this isn't an issue with digital cameras.

UV filters are often also (I suspect) referred to as Protection filters. The stated purpose in these cases is to protect the front element of your lens.

Regarding the tint - never noticed it or if I did, it never bothered me - I must admit though that it's been a while since I regularly used UV filters on my lenses. If I look into my Samyang 85, I see a deep red/purple tint - but my pics don't come out red/purple. Perhaps same goes for these filters (better quality ones at least). No idea on this one, really.

I no longer use filters on a daily basis, but I would use them if I were to shoot at a beach, children's birthday party, a nightclub and stuff like that where there are increased risks.

I sometimes use Pol filters and have a single IR filter - never really used it properly yet. My plan is to get me some ND filters as well, for bright sunny day situations.

Ps. I rely more on the lens hood for protection.

[jatrax]

In film days filters were important as they were the only way to correct color balance (white balance). So you used a filter to correct if you were shooting indoors with outdoor film, or if you were shooting on a blue cloudy day or under fluorescent light or whatever.

Today there is a greatly reduced need for filters due to digital adjustment of white balance. The only filters you cannot easily duplicate in the computer are a polarizing filter and neutral density filter. The polarizer will reduce glare and reflections and also deepen the color of the sky. Neutral density filters allow you to use slow shutter speeds in bright light to, for example, show motion in a waterfall.

There is some debate in whether a UV filter has any use on digital. In general the consensus is no, but in certain cases they can help reduce haze from humid air.

There are completely clear 'protective' filters available now as well since the standard UV filters do have a bit of a cast although the camera should correct for that if WB is set on auto.

There is also some debate on whether protective filters provide any benefit. I think the majority belief is that with modern lenses and coatings the danger of damage to the lens is greater with a filter on than with it off. This is because modern coatings are quite hard and scratch resistant. The danger is if you have an impact that breaks the filter and then drives shards of broken filter into your lens. Of course you can make the case the other way as well and I definitely do not want to still up that particular hornets nest. If you feel the need for filter protection by all means do so.

I do think that you get equal protection by using a good lens hood, the difference being that a lens hood will actually improve the image quality and a filter will always detract from it. The only time I would consider a protective filter would be in salt spray or driving sand or dust, not because they would harm the lens but because the filter is easier to clean with less risk of causing damage.

[alamo5000]

I am going to return to this thread later on... its late and I need to sleep...

But a question on lens hoods... what is the purpose of a lens hood...? Other than protecting the lens...

I have a couple of the hoods but they seem cheap and flimsy.

[Pentaxtic]

When shooting, stray light from another source ie sun or street lamp will not cause flares or light seeping into the image.

[sterretje]

But a question on lens hoods... what is the purpose of a lens hood...? Other than protecting the lens...

The primary purpose of a lens hood is not to protect the lens. It prevents light from the sides affecting the image.

[Zafar Iqbal]

+1

An image is worth more than 1000 words, so here's a with and without example for you:
http://upload.wikimedia.org/wikipedia/commons/3/33/Lens_hood_comparison.jpg

As can be seen, using a lens hood can be very benifitial

[abmj]

The lens hood is almost a must when shooting outdoors for the stated reasons - to cut down on side glare. Another name for the hood is "lens shade," which is what it actually does. You almost always want it on except in some street photography where you want to stay as unobtrusive as possible. The great Jay Maisel avoids using a hood while shooting New York street scenes for that reason.

[AOShep]

Lens hoods can provide protection even though that is not it's primary purpose. I shot a soccer match and I got hit right on the lens with a soccer ball. The hood held up and the ball was not able to make contact with the front element.

[Marc Sabatella]

Maybe we can have a discussion about the different filters and what they do and so forth. Pros, cons, whatever.

You might want to try a forum search, or Google. There have been hundreds of previous threads on the perceived advantages and disadvantages of "protection" filters. And it isn't like there is some new filter technology that renders the older discussions moot.

[PPPPPP42]

Yup, tons of arguing on this if you search, but I will give a first hand account. While working near some limestone cliffs with my K20D and my 35-105 F3.5 I moronically turned around wrong and planted the lens right into the cliff, left deep gouges in the 67mm UV filter but the lens was fine, I will always use a filter after that. Any impact that would shatter the filter and drive it into the lens would totally gouge the hell out of the lens even without a filter so I consider that arguement not relevant.
You have to be a scientist or positively anal to see the difference in a normal picture in the IQ, a ton of other things will effect it more. You do have to get a high quality multi coated filter though, cheap stuff makes a mess of things, I reccomend B&W. The color tint you see in stuff reflected in it is from the coating and will usually make reflections look blue or violet, just like a good lens.
As far as hoods I use rubber because they collapse nice for storage and provide a shock bumper that usually folds over the lens if bumped into something, wheras the steel ones act as a nice lever to transfer all the shock to the mounting threads. Unless of course the lens comes with a stock reversible plastic one, then I just use that, it'll break off before it takes the lens out or so I hope, and it doesn't take up storage room when reversed..

[StephenHampshire]

Yup, tons of arguing on this if you search, but I will give a first hand account. While working near some limestone cliffs with my K20D and my 35-105 F3.5 I moronically turned around wrong and planted the lens right into the cliff, left deep gouges in the 67mm UV filter but the lens was fine, I will always use a filter after that. Any impact that would shatter the filter and drive it into the lens would totally gouge the hell out of the lens even without a filter so I consider that arguement not relevant.
You have to be a scientist or positively anal to see the difference in a normal picture in the IQ, a ton of other things will effect it more. You do have to get a high quality multi coated filter though, cheap stuff makes a mess of things, I reccomend B&W. The color tint you see in stuff reflected in it is from the coating and will usually make reflections look blue or violet, just like a good lens.
As far as hoods I use rubber because they collapse nice for storage and provide a shock bumper that usually folds over the lens if bumped into something, wheras the steel ones act as a nice lever to transfer all the shock to the mounting threads. Unless of course the lens comes with a stock reversible plastic one, then I just use that, it'll break off before it takes the lens out or so I hope, and it doesn't take up storage room when reversed..

Yep, my 16-45 took a tumble to concrete, the plastic lenss hood split, but the lens was fine. Rubber hoods are cheap, easily pushed forwards or backwards and act as a nice shock absorber. I still don't use UV filters myself, extra air/glass interface, generally poorer coatings. I did use them back in film days , ovdr the years allthe lenses I have damaged have been dropped which normally breaks things like aperture rings and focus mechanisms, never been unfortunate enough to actuall scratch or smash a filter or front element, but I can see how it could happen. As Marc syas above, this is a debate that will run and run, but lens hoods are always useful, and can be mounted on filters too!

[mgvh]

I always use a hood, and it has saved my front glass at least once. I do not use a filter for protection BUT for one exception: On my Sigma 10-20, the hood is not very long and since this is a UWA lens, the front glass bulges out. I put a good UV on this one for protection.