The significance of a UV filter...?

[Hickeroar]

Here's something that always puzzled me:

Glass blocks UV light all by itself. It's just a property of glass....

Lenses are made of glass.

UV Filters...as far as I know...are just a pane of glass.

What's the point? The glass in the lens should stop the UV light.

That said...I use them because they protect the lenses...

[HowLowCanYaGo]

My UV filter is mainly for protection.

[readingr]

Here's something that always puzzled me:

Glass blocks UV light all by itself. It's just a property of glass....

Lenses are made of glass.

UV Filters...as far as I know...are just a pane of glass.

What's the point? The glass in the lens should stop the UV light.

That said...I use them because they protect the lenses...

Not quite; from memory it blocks 90% of the lower figure (300nm) UVB and UVC but allows the majority above that figure through UVA.

Roger

[poker]

I thought I read that UV filters don't mean anything to digital photography. I use it to protect my lens. I don't want to ever touch or clean the front element. I do it on my kits lens though.

Somebody put a link up here once that showed a website analyzing the adverse effects of filters and the difference of cheap and costly filters. I know many people don't use filters and feel their lens hood is enough protection.

Makes sense but you need to remove a lens hood in many cases when you need to use your flash or else it may leave a shadow on the image. It happens.

[Hickeroar]

Not quite; from memory it blocks 90% of the lower figure (300nm) UVB and UVC but allows the majority above that figure through UVA.

Roger

Ah... So is the UV filter coated with something to block the rest?

I still only care about the fact that it protects the REAL glass though. I haven't noticed any difference in picture quality with or without the filter.

[SmartWombat]

UV used to excite the film and give a colour cast as the re-radiated light fogged the film a little. But film has improved over the last 3- years (and I've gone digital since then) so I don't know if a UV filter is still needed.

The major effect you'll see is from a cheap filter, with reflected light off the front element of the lens onto the filter, ang back again. Also you may find cleaning the inside of ht filter and the lens front element a bit of a pain.
BUT it will be cheaper than getting a new lens if you happen to crack the filter on something - far better than than your lens.

[readingr]

When taking landscapes I still occasionally get a blue cast which I have always put down to UV getting through; I could be wrong. I am not aware of any UV filters in front of the sensor. There is however an IR filter.

Roger

[mwfanelli]

When taking landscapes I still occasionally get a blue cast which I have always put down to UV getting through; I could be wrong. I am not aware of any UV filters in front of the sensor. There is however an IR filter.

Roger

Glass blocks some wavelengths of UV but not all. Modern lenses absorb almost everything due to their construction and special glass in their elements. UV filters are used for special protection (sand, for example) and by those who are believe that the filters will "save" a lens.

Film has not been UV sensitive for at least 20 years. Digital sensors do have a UV filter (also IR) as sensors are very broadband devices.

Excess blue (the actual light) is handled by the white balance control on digital camera or by 81A, B, and C for film.
.

[Hickeroar]

Great information guys. Thanks!

[Ronnoco]

Just to point out that in digital, software filters can be more useful that on camera filters since there is more control in strength, position, effect, and even selectivity in area of the shot.

Ronnoco

[freygr]

Here's something that always puzzled me:

Glass blocks UV light all by itself. It's just a property of glass....

Lenses are made of glass.

UV Filters...as far as I know...are just a pane of glass.

What's the point? The glass in the lens should stop the UV light.

That said...I use them because they protect the lenses...

The Problem is that plane window glass does block UV, but not necessary optical glasses or plastics. The UV cut off is not even close to visible spectrum allot of the time, but the UV filter has a known cut off point just out of the visible spectrum.

[freygr]

clip...

Film has not been UV sensitive for at least 20 years. Digital sensors do have a UV filter (also IR) as sensors are very broadband devices.

clip.....

All B&W film is UV sensitive, in fact all original film was only sensitive to BLUE light until ortho film (sensitive to green light) was developed then pan film (sensitive to red gren and blue light) after which color film was developed. All Silver based films are sensitive to UV its the chemistry and can't be changed.

[mwfanelli]

All B&W film is UV sensitive, in fact all original film was only sensitive to BLUE light until ortho film (sensitive to green light) was developed then pan film (sensitive to red gren and blue light) after which color film was developed. All Silver based films are sensitive to UV its the chemistry and can't be changed.

I don't know about B&W, I'll take your word for it. Color film, also silver-based, now has a coating on it that blocks UV. I took slide film with me to Antarctica under the ozone hole, more UV than anyone is likely to see anywhere else on the planet. There was absolutely no difference between UV filter on and UV filter off. None. To me, more than old enough to remember the "blueing" of film without a UV or Skylight, this proved it more than anything else could.

[JSPhoto]

. UV filters are used for special protection (sand, for example) and by those who are believe that the filters will "save" a lens.

.

Everyone of my lenses have been saved by using a UV filter. I have had rocks and even car parts hit my lenses and never got a scratch, although I have now had three UV filters destroyed, not even a scratch on the front element though And I don't have to worry about some snot nosed kid sticking their finger on the front element.

Filters do affect digital photos, and using the wrong UV filter will too. I used to get a color cast from the UV filters but didn't realize that was the problem until I had to replace one that got cracked and Matt at Roberts Distributors said I should try the Hoya UV (0) as it won't affect color....Matt was right and I have used them ever since. Try a cheap one then try the Hoya UV (0) and you'll see a difference.

JS

[Greg McCary]

I always have some sort of filter on my lens. I have owned 35mm cameras since 1987 and have never scratched a lens. I may store my camera in the case with only a lens cap, but when I start to use it I put one on and here lately a lens hood too. My tripod has fallen over twice with the E500 on it, once the wind blew it over.
Greg