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A Clear or UV Filter for Lens Protection or Not??
- Thread starter Dbltfarmer
- Start date
Phil A Martin
Veteran Member
Good but other's might not realise.
Michael Fryd
Forum Pro
As others have mentioned, there is no need for additional UV protection on a digital camera. You can use either a UV or a clear filter.
In terms of whether it noticeable affects image quality, that's going to depend on the specific shooting conditions. Particularly with digital bodies, filters increase the chances that you will get flare. The chances go way up if there are sources of light in, or near, the field of view.
The most common issue is veiling flare. This is an overall reduction of contrast in the image. Unless you are doing an A/B comparison with and without the filter, you likely won't notice it.
If you have a high quality filter, and are not shooting towards a light source (or bright object) then you likely won't have a noticeable reduction in quality.
I do suggest that if you do use a filter, that you get one with coatings that are at least as good as the coatings on your lens.
If you are shooting in a dusty environment, then the real issue is not dust on the front lens, but dust getting into the barrel of the lens. The front element is easy to clean. Dust inside the lens can muck up delicate mechanisms, and requires lens disassembly to clean.
If your lens changes length when you focus or zoom, then it has breathing holes to let air in and out (usually under the focus or zoom rings). You need to keep dust away from these holes so that the dust doesn't get sucked into the lens. Filters don't make a difference here, as dust does not get sucked through the solid front element.
In terms of using compressed air to clean your camera and lens, I would recommend against that. Compressed air can blow dust deeper into cracks and crevices. Spray compressed air into your camera body, and you can easily damage your shutter. Use nothing more powerful than a hand squeeze bulb.
Cans of compressed air, generally contain other chemicals. If you are not careful they can spew out very cold liquids. Thermal shocks are not good for your camera, and when you cool something down, you need to be concerned with contamination from condensation.
The bottom line is that if you really want to protect your lens, worry about the barrel before the front element. Replacing a front element might actually cost less than completely disassembling a lens to clean the internal mechanisms.
If you do you use a filter, please get one with coatings at least as good as the coatings on your lens.
If you are shooting with light sources in, or near, the field of view (such as shooting at the beach, with a hair/rim light, or a an overly lit white background) you may want to consider removing the filter to avoid veiling flare.
In practice, the biggest difference the filter makes will be a mental one. If a filter makes you feel more comfortable, then use one. If you worry about extra glass in the optical path then don't use one. How it affects the way you feel is likely to more significant than any difference in image quality or lens protection.
KENTGA
Veteran Member
Didn't read all of the replies but I'd never use a UV filter.
Kent
Kent
Michael Fryd
Forum Pro
I rarely use them.
However, there's nothing wrong with spending money to make you feel more comfortable. If a filter makes you feel more comfortable, then go ahead and spend the money. The only caveat, is that if you are shooting in challenging conditions, you may want to consider removing the filter to avoid flare.
If filters make you uncomfortable, then don't use them.
We all have different needs. The fact that I rarely use them is irrelevant to the question as to whether or not others should use them.
Smaug01
Veteran Member
Yes, for every layer of glass light passes through, you lose contrast. It's part of why primes usually are more contrasty than zooms, even without exotic coatings.
A better habit, IMO, is to use hoods to protect the front element from hits, and just clean it gently when it gets dusty. Canned air is fine (though clunky to carry) and soft brushes, too. If you're just gentle, you won't mess up the coatings.
I don't know HOW many used lenses I've bought with a filthy, scratched-up UV filter on the front, and when I remove the filter, the front element is just pristine. On the one hand, they DID accomplish their mission of protecting the lens, but since they didn't even clean the filter, their images must have suffered quite a bit. If he had used a hood to protect again scratches (and flare) and just gently clean the front element of the lens now and then, he'd have been better off.
Thanks for keeping it mint for me, sucker!
I replaced my UV filters with clear filters. Have always used quality filters. Any image quality reduction, in my experience, is not distinguishable. Once in awhile flare happens.
Once an impaired person approached with a wood dowel and smacked the front of my lens. Cracked the filter but not the lens. Once I dropped a camera and it hit the corner of a hotel coffee table. Cracked the filter but not the lens. Since my favorite lens is no longer manufactured, the issue of using a filter is case closed. Quality filters are worthwhile.
Once an impaired person approached with a wood dowel and smacked the front of my lens. Cracked the filter but not the lens. Once I dropped a camera and it hit the corner of a hotel coffee table. Cracked the filter but not the lens. Since my favorite lens is no longer manufactured, the issue of using a filter is case closed. Quality filters are worthwhile.
Tom Axford
Forum Pro
This poll shows that opinions are divided on the use of filters for protection.
Personally, I use them most of the time, but not always.
This article contains an example of a situation in which a protective filter causes ghost images of very bright lights. These ghost images can be produced by any filter (provided it is flat) used in front of the lens.
Personally, I use them most of the time, but not always.
This article contains an example of a situation in which a protective filter causes ghost images of very bright lights. These ghost images can be produced by any filter (provided it is flat) used in front of the lens.
Michael Fryd
Forum Pro
Yes. Filters are far more fragile than the typical front element. High end quality filters tend to be made from thin pieces of glass. Front elements tend to be made from thick pieces.
When it comes to a wood dowel hitting the front of your lens, a filter actually increases the chances that your front element will be damaged. Wood won't scratch glass. However broken filter shards can scratch the front element. The real danger is that the dowel can press the filter shards against the front element.
I wouldn't worry, as this isn't likely. Filters rarely make a difference in terms of protecting your front element.
In terms of dropping a lens, the real danger is the shock when the lens lands. That sudden stop can knock internal elements out of alignment, or even break an internal plastic piece. A filter doesn't make a difference either way. If you want to protect your lens from impact damage, get a neoprene Lens Coat for the barrel, and a lens hood for the front. The lens hood will flex and absorb some of the impact. The neoprene sleeve around the barrel provides some cushion. You still need to worry about the lens hitting the floor mount first.
Again, the biggest difference a filter makes is usually emotional. You feel more comfortable with a filter on your prized lens, so you should use one.
Dareshooter
Veteran Member
I’ve always used them but take them off when I know the filter is going to cause a problem like shooting into the light for example . Thirty years experience in photography and I’ve never seen image degradation from reasonably priced filters .
Chris Noble
Veteran Member
Every lens surface reflects some of the incoming light. If there are point light sources, you may see ghost images on the image due to reflections off the lens-side surface of the filter. Under some conditions these can be very noticeable. Most of the time not.
Michael Fryd
Forum Pro
One of the differences between film and digital cameras is that undeveloped film has a matte surface, and a digital sensor has a mirror like surface.
A filter has a mirror like surface that is parallel to the sensor. This can set up an infinity mirror effect.
When using filters, digital shooters need to be more careful than film shooters, about light sources (or bright objects) in (or near) the field of view.
Michael Fryd
Forum Pro
You bring up two issues here.
First, you have thirty years of experience. This suggests that you started with film. It would not be surprising if your opinions on filters and image quality were formed during your film days.
It turns out that filters are more likely to cause image quality issues with digital than film. This is because undeveloped film has a matte finish, and digital sensors have a mirror like finish. Having a mirror like sensor parallel to a flat piece of glass noticeably increases the chances of flare and/or ghost images.
.
The second issue is your claim that you have never seen image degradation from reasonably priced filters. I think a better phrasing would be that you have never "noticed" degradation.
Most of the time the degradation isn't noticed unless you do an A/B comparison with and without a filter.
For instance, if the filter introduces some veiling flare, it may manifest itself as a loss of contrast. That's not the sort of thing that most people would see as a filter issue. They would simply up the contrast when processing the image. Perhaps they might think a higher quality lens would give them images with more "pop".
Honestly, you can have veiling flare with or without a filter. There really isn't any way to tell without doing a comparison.
Even the comparison can be tricky. You need to do it under your actual shooting conditions. For instance, in a studio with controlled lighting, even a cheap filter might not make a noticeable difference in quality. Yet a high quality filter can easily cause issues if you are shooting at the beach with the sun setting behind the model. Shoot in the studio and something as simple as adding a rim light or hair light can cause filter flare issues.
Far too many people test in easy circumstances, and then extrapolate that the results are indicative of challenging circumstances.
Tom Axford
Forum Pro
Michael, you are straying well into the realms of cloud cuckoo land with comments like that!
Can you produce any evidence? I think not.
Filters can produce ghost images with film just as with digital sensors. I have experienced it myself in years gone past when I used film. If you give it a few minutes thought, you will see that the ghost images depend on the mirror-like surface of the filter, but not of the sensor or film. Any surface works, as long as some of the light is scattered back into the lens.
Michael Fryd
Forum Pro
Actually, this is from Canon's excellent book "EF Lens Work II The Eyes of EOS" (September 2006, Eighth edition). This book contains discussions of the challenges facing lens designers, and how they address them.
According to Canon: "The reflective characteristics of the image sensors in a digital camera differ from those of film in that they possess a higher reflectivity as well as a characteristic known as regular or “mirror” reflection, which has the effect of creating flaring and ghosting inside the lens when light from a bright source enters the lens and reflects back to the image sensor."
and "Players in a stadium or racecars whizzing round the circuit. All are lit up by the bright lighting in the stands, or the headlights on the cars, creating numerous bright light sources. Ordinary super-telephoto lenses have protective glass in front of the first lens unit. If this glass is flat, any light entering the lens from a bright light source will be reflected off the image sensor and back onto the inside of the protective element, causing spot-shaped ghosting.* To prevent this, meniscus lenses are used as the protective glass on all of Canon’s largeaperture IS super-telephoto lenses. Meniscus lenses are spherical lenses which have the same curvature on both sides of the lens. By using these lenses as the protective glass, the light reflected off the image sensor forms an image in front of the image sensor and then disperse."
and "*When a filter is mounted on a regular lens, ghosting can occur above the same spot where there is a strong light source inside the frame. When this occurs, remove the filter to photograph."
But you do bring up a good point. Many people are quick to dismiss facts if they don't match their world view. I should have included a reference in my previous post.
If you search around on the web, you may be able to find a PDF of the Lens Work book. If you are interested in issues surrounding the design and use of lenses, it really is an interesting read.
Chris Noble
Veteran Member
What??? You forget something between the filter and the sensor/film, called the "lens".
Also, "infinity mirrors" depend on almost-100% reflection properties. Camera filters transmit most of the light energy and reflect only a small portion (especially if they are coated). So your "infinity mirror" would attenuate below detectable level after one or two reflections.
Add-on filter ghosting occurs between the filter and the top surface of the first element of the lens.
Last edited:
Michael Fryd
Forum Pro
Even one or two visible reflections might be a problem in an image.
According to Canon, digital cameras do introduce issues with reflections between the sensor and a flat filter.
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