What do UV or sky light filters do ?

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I have a couple of cameras with Skylight filters on ( came with the camera) but other than protecting the lens what do these and UV filters do to the shots ? Does it make any difference if it is for Film or Digital ?

Thanks all
 
With film use they made or could make a big difference to outdoor colour photography, reducing the effect of haze in a distant landscape, much of which can be done with software these days.
These days I tend to wander around with a camera and a couple of small lenses in my jacket pockets, rather than using a camera bag, as such I regard UV or skylight filters as transparent lens caps to protect the lenses in my pocket rather than to protect them in use.
 
On film, skylight filters slightly warm up images on bright days and UV filters reduce haze. On digital, white balance adjustments take care of the slight colour cast and most sensors have a UV filter in front of them negating the need for an extra filter. The protection value of a thin piece of glass is a hotly debated issue!!!
 
The greatest protection you get from a filter is from yourself.
The worst damage a lens suffers is from cleaning. If you check an older lens with a magnifier you will often notice a mass of very small swirling scratches caused by cleaning dust off a lens with a cloth. This always degrades an image especially when taken towards the light.
When a filter is fitted it is very rare for a lens front surface to need to be cleaned at all. However any such possible damage falls on the filter which is easily replaced. Major impact damage is better prevented by the used of a lens hood.

High quality filters rarely degrade an image at all.

Some lenses waterproofness is improved by the use of a filter especially rain and condensation. Both of which also increase the need for cleaning the surface.
 
As with above, the UV filter is really helpful with protecting the front element when it needs protecting.
I don't always use it when I'm out shooting as the hood normally provides ample protection.
But if I'm shooting in rain, snow, dusty, sandy places then it stays on.
All in all its useful to have when it's needed. Normally I just treat it as screw on lens cap.
 
I've had at least two lens saved from having a filter. One I think a 50mm? got dropped face down when a camera strap failed, it smahed the hood and shattered the filter, lens was fine (and camera still good too) the second was a 300mm 2.8 lens I was following a model up a flight of stairs on a jetty and she pulled a pose for my second shooter at the top and kicked out her heel right into my filter, massive scratch, front element would have needed replacing if I hadnt had a filter.
I always use them.
 
On digital, they not only degrade image quality (varying from almost no image quality loss to a lot, depending on the quality of the filter), they also have a flat surface, right at the front of the lens, which can create severe unintended flare.

Basically, they are a hangover from the days of film. I never use them.
 
Others have already covered the photographic properties of UV and Skylight filters - and why from that perspective they are not needed on digital (and indeed, should be avoided as the only impact they may have is to possibly reduce IQ and induce flare).

From a protection perspective - again, I'd say avoid them.

There are cases where it is advantageous to have a filter on for protection - shooting where there is salt spray, or mud, dust, etc flying about.
In these cases, use a dedicated protection filter - they are designed to be optically clear, have coatings to minimise flare and scratching, and use a hardened glass to improve impact resistance.

For general impact resistance (particularly drops), they will have negligible benefits - there are cases where a filter has smashed and the front element is untouched - however the front element is a LOT stronger than a filter (it's a much bigger bit of glass), so the force required to smash a filter is much less - making it impossible to say if the filter actually protected the front element, or simply broke because it's weaker.
 
I do use a thin high quality coated protection Filter on most of my lenses. I have not ever seen a loss of quality in the resulting images. I compare results with and without when I buy a new lens. The only new lens I do not use one on is my 7.5 mm Samyang Fisheye where it would both obstruct the view and cause other optical problems. this would be true of some ultra wide lenses too. The difference between a protection filter and a UV one is absolutely negligible when used on a digital camera. but high quality protection filters are harder to find so a UV serves equally well.. If you shoot in dusty humid or wet conditions, and have to clean your lens often then a protection filter is advisable.
 
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The biggest degradation to a lens with or with out a filter is condensation or a greasy or smeary lens surface. This will be obvious to glasses wearers.
 
I've had at least two lens saved from having a filter. One I think a 50mm? got dropped face down when a camera strap failed, it smahed the hood and shattered the filter, lens was fine (and camera still good too) the second was a 300mm 2.8 lens I was following a model up a flight of stairs on a jetty and she pulled a pose for my second shooter at the top and kicked out her heel right into my filter, massive scratch, front element would have needed replacing if I hadnt had a filter.
I always use them.
I didn't know that you could put a filter on the front of a 300 f2.8 lens. The Canon 300 f2.8 lenses have a protective element placed in front of the front element.
 
They keep you from having to clean a big thumbprint of the front element and can stop other liquids getting on the front element, like blood at boxing matches and mud at motorcross events ect.

But they need to come off for night photography as they can cause flare.
 
They keep you from having to clean a big thumbprint of the front element and can stop other liquids getting on the front element, like blood at boxing matches and mud at motorcross events ect.

But they need to come off for night photography as they can cause flare.
I Never use filters and, if you always use a lens hood, that should provide a lot protection to the lens. I suspect many people only put finger/thumb marks on the lens when changing filters but as I never use filters this never happens to me. I would consider adding a protective filter if there was a significant risk of things flying on to the lens. Even at a MotoCross event it was unnecessary because I took my shots head on at bends. Of course if you took shots of the bike going away from you, it would be risky for the camera and photographer. Never photographed boxing myself.

Dave
 
Most of the cameras I have filters on are film cameras but the one digital camera I have a filter on ( Sony a6000) does suffer really bad flare in bright light I generally keep this in a leather case in transit but take the filter off in bright light. I don't think a lens hood wood fit without taking the camera out of its case sort of defeating the point of the case !
 
Most of the cameras I have filters on are film cameras but the one digital camera I have a filter on ( Sony a6000) does suffer really bad flare in bright light I generally keep this in a leather case in transit but take the filter off in bright light. I don't think a lens hood wood fit without taking the camera out of its case sort of defeating the point of the case !

Time to toss the case then.
 
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I didn't know that you could put a filter on the front of a 300 f2.8 lens. The Canon 300 f2.8 lenses have a protective element placed in front of the front element.
It wasnt a Canon, Sigma 120-300mm
 
I use some kind of filter on all my lenses, to protect the front element. Because as has already been said; a filter is a lot cheaper to replace. Having had two lenses suffer frontal impact, and have the filters 'sacrificed' to prevent further damage, I'll continue to use them.
On digital, they not only degrade image quality
I have tested this theory, by taking a series of shots on different lenses, with and without. Even by pixel peeping, there is no noticeable degradation in image quality. I've been hearing this mantra since my film days, and I think it's one of those things that in theory may be true, but in practice just doesn't factor at all. Perhaps it affects things at a level beyond human perception, and is only genuinely measurable with sophisticated scientific equipment. I can understand that a heavily marked/damaged/scratched filter could introduce issues, but one important thnig to remember is that the filter is nowhere near any point of focus, so any effects will be so minimal as to not be worth worrying about. A scratch on the lens element will however potentially cause much more noticable issues. I've seen very expensive lenses ruined by scratches on the front element; for the sake of a few quid you're protecting the resale value if nothing else.
 
I use some kind of filter on all my lenses, to protect the front element. Because as has already been said; a filter is a lot cheaper to replace. Having had two lenses suffer frontal impact, and have the filters 'sacrificed' to prevent further damage, I'll continue to use them.

Fair enough, that's your opinion. And I accept that they can offer protection in some circumstances, e.g. in a sandstorm or similar.
I've seen very expensive lenses ruined by scratches on the front element; for the sake of a few quid you're protecting the resale value if nothing else.
Personally, I don't care about resale value because I don't sell - my equipment is usually worn out through use after a few years, but again a good point for people who do chop and change around.
I have tested this theory, by taking a series of shots on different lenses, with and without. Even by pixel peeping, there is no noticeable degradation in image quality. I've been hearing this mantra since my film days, and I think it's one of those things that in theory may be true, but in practice just doesn't factor at all.
Have you seen this thread? Admittedly he stacked two lenses together, adding to the problem, but the problem is always there https://www.talkphotography.co.uk/threads/rainbow-at-my-photos-it-wasnt-there.749692/#post-9333590
 
A dirty smeary filter is as bad as but no worse than a dirty smeary lens, both will be most noticeable when hit by direct light or at night. in the same way ad dirty glasses affect vision in the same circumstances.
In theory and at a scientific level adding lens surfaces will cause additional loss of light and the possibility of additional internal reflections. however modern coating systems reduce these effects to statistically unimportant levels. High quality filters are made to the same standards as lens elements.

The use of Polarisers and graduated filters are usually fabricated and coated to far lower standards. the internal surfaces of polarisers are rarely if ever coated at all.
However no one is suggesting such filters should never be used.
 
Fair enough, that's your opinion.
Based on experience of fact. Tested using several lenses, and I found no difference.
So have I, and I found the results to be 'bloody awful'. I can only assume you have bad eyes, a bad monitor or use an old camera with a tiny sensor (or all three).
My eyes are fine, my display is high quality, and my camera sensor is excellent. You can assume all you want; you aren't in possession of the facts here. No offence.

My results were the same a this bloke's:
That video is about promoting that guy's business; I have no idea of his exact methodology, or the veracity of his claims, so I'll choose to file it under 'ignore'.
Personally, I don't care about resale value because I don't sell
But many do. Hence why using a filter is a good idea. The irony is that a damaged front lens element surface will degrade your IQ much more than using a filter ever will.

In theory and at a scientific level adding lens surfaces will cause additional loss of light and the possibility of additional internal reflections. however modern coating systems reduce these effects to statistically unimportant levels. High quality filters are made to the same standards as lens elements.
Yes. But I've found even cheap filters are fine really. Scouring the internet finds no conclusive evidence using filters is 'bad', so I'll just stick with what I know. It's served me well over the years...
 
The use of Polarisers and graduated filters are usually fabricated and coated to far lower standards. the internal surfaces of polarisers are rarely if ever coated at all.
However no one is suggesting such filters should never be used.
Polarising screens (polarisers) - which are not in fact filters at all, together with ND filters, are the only "lens accessories" that have a unique and useful function.
The effect of all other filters can be added in post-processing, better and with much more control.

Having learned my craft on film, where filters were often essential, it took me a while to realise this after switching to digital, but I got there in the end:)
 
So have I, and I found the results to be 'bloody awful'. I can only assume you have bad eyes, a bad monitor or use an old camera with a tiny sensor (or all three).

My results were the same a this bloke's:

View: https://youtu.be/EjEKoF8eDsQ
The argument will continue. As your and his experience is not repeatable by everyone.
In his case I would argue that no two image are ever equally as sharp as each other. This is ever more true when shooting at great distance.

A statistically significant blind test would no doubt include results that showed differences in sharpness favouring both with and without filter shots.
It is far from ever being a cut and dried situation.

What he is showing is more his ability to shoot consistently sharp images. which is true of everyone.
 
Polarising screens (polarisers) - which are not in fact filters at all, together with ND filters, are the only "lens accessories" that have a unique and useful function.
The effect of all other filters can be added in post-processing, better and with much more control.

Having learned my craft on film, where filters were often essential, it took me a while to realise this after switching to digital, but I got there in the end:)
Apart from protection filters, I have polarisers for each of my lenses. However they are very little used. I no longer use any other filters for digital work, because in all cases better results are obtainable with post processing and/or multiple exposures. I do not shoot the sort of images that need ND filters. However polarisers always provide a degree of ND filtering were it to be necessary. Unfortunately neither polarisers nor ND filters are ever completely colour neutral.
 
@Terrywoodenpic Terry which brand of " protection " filters do you prefer ?

thank you

stu

I use the Kenko Pro1d protection filters, they are ultra thin multicoated.
They are the same as the Hoya filters and come out of the same factory, but are branded for different markets.
So get which is ever the cheaper. I have never had a problem with them.
 
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