[Jocko]

Do you think a UV filter is a useful addition or just a degrader of the image and a harbour for dust?

[MrB]

Glass absorbs UV light; a UV filter is a piece of glass; but a camera lens is a combination of many pieces of glass; so is it actually neccessary to add another (very thin) piece? In practice, it would seem unlikely to make any positive difference but, depending on its quality, it might have a negative effect, due to its addition of two more air-glass surfaces to reflect, refract and scatter light. A UV filter might offer a bit of protection for the camera lens; however, a lens hood will also do that, while being positively beneficial to image quality, by reducing the effects of unwanted light.

Cheers.
Philip

[WDHewson]

Good question Jocko.

In the silver halide days, I recall that the addition of a UV filter seemed to giver bluer skies and more truth to other colors. But this recollection goes back 30+ years, and its focus is not sharp.

Some glass such as quartz will let UV through, and who knows what type of glass camera's lenses are made with. I think it was mainly a coating on the glass that blocked UV, and are our lenses so coated?

Then with the tiny lenses we have in a lot of cameras these days, the lenses may be very small and thin and there is not much there to absorb the UV.

And, lastly, are our sensors wavelength tuneable not to capture the UV. Maybe.

I'll try to learn a few things and report back with anything interesting.

[dave1712]

I have tried to test if a UV filter degrades/changes colour etc on a number of lenses. The only noticeable difference I ever detected was with high altitude sunny mountain views on holiday in Norway - the filtered version does look clearer. Hardly definitive test but it seems to me if there is lashings of UV about, then a UV filter can help.

I used to fit them as extra protection and on one single occasion I dropped a lens which broke the filter and left the lens undamaged other than being covered with millions of minute fragments of glass! I had to wait until I got home and got those of with a blower as didn't dare use a wipe - so on at least one occasion it did save a lens.

After that I decided to use a lens hood always as I think it gives better impact protection - resilient plastic, further from the glass to the edge, no smashed filter glass over the lens. Also has the side benefit of reducing flare on occasions

But I recently got a sigma 120-300 f2.8 lens which has a huge front element which is very close to the front of the lens and to be honest, looks a bit silly with an equally huge lens hood fitted when working indoors in a theatre. So am looking again at some protection filter.

The only ones I think I'll consider are hardened ones. Sigma have brought out a ceramic 'lens protector' filter which is said to be 10x stronger than conventional filters, and is 'crystal' clear. I've been looking for reviews before buying as a branded 105mm hardened filter costs more than some lenses!

Which brings me to the final point - it seems to be pointless to spend hard earned cash on a lens, then fit a £4 filter from ebay. if doesn't matter if the lens is high or moderate quality, i don't want to reduce the inherent lens optical quality (high or modest) with a poor filter. So if I think the filter has to be of similar quality, which for me will need to be one of the multi coated quality manufacturers. I'm not saying generic/ unbranded filters aren't any good - I just don't know and have no way to test. So for repeatable quality it seems to me the 'big' brands should be more reliable.

[Jocko]

Years ago I worked for OCLI Optical Coatings Laboratories (HEA filters, coatings on missile nose cones, laser protection lenses, Dichroic sunglasses etc). At the time I had just bought a set of Cokin filters, including their UV filter, so I had one of the design engineers test it for me. He said it was just a piece of plain glass and low quality glass at that. It went straight in the bin.
For years I kept a Polarizing filter on my camera, for the protection it offered, but not since changing to digital.
A lens hood can offer good impact protection. I opened the car door and my D80 with the long lens rolled out onto the pavement. Luckily it landed on the lens hood and no damage was inflicted. Taught me not to lay the camera on the car seat, even for only 5 minutes driving between shots.

[dave1712]

thanks for that Jocko,

Although things may have changed since your colleague's scientific testing I suspect not a great deal - especially with unbranded or 'who are they' filters. I bought a set of ND filters from a well known chines manufacturer and they gavea significant green cast. They went the same direction as yours. Your view pretty much summarises my own wrt lens hoods and nice to know it worked when tested.

I still use a CPL filter on occasions when it helps - gives great skies, and reduces reflections on water, when conditions are right, but of course have a negative effect on exposure.

For pure protection the sigma ceramc looks effective - but at the cost of the lens and the filter I would find the ball and take extreme action if anyone threw one at my lens

https://fstoppers.com/gear/sigma-shows-s...est-110946

[MrB]

Given the cost of those ceramic filters, even if they have no optical disadvantages, wouldn't it be simpler, more sensible and more economical to have insurance against theft and accidental damage, which would cover not only the lenses but ones whole set of camera gear?

Cheers.
Philip

[dave1712]

Hi Philip,

yes I have insurance for my 'toys'. Problem is if you claim they waz up the premiums (as I found when I broke my expensive prescription glasses and I 'paid' for them over the next 3 years premiums.) So with something as cumbersome as a large lens, which cost shedloads (even secondhand) used in often cramped spaces, with a large exposed front element, I'm thinking prudence might be sensible - or maybe I'm just a bit clumsy so need to take more precautions

[EdMak]

Are you inside or outside the UK Dave. Ed.