is UV filter reduce image quality

[fishy wishy]

the amount of image degradation is so small (assuming you use good quality filters) that it is irrelevant.

My objection to UV filters is not about image quality, so much as it is they don't actually DO anything.

I'm sure you will get a variety of people vigorously defending the use UV filters. But after 45+ years in photography, I'm reasonably certain that I've hear ALL the arguments in UV filter's favor. None of those arguments have moved me yet.

I hate using lens caps

You also hate raw, flippy mirrors and big cameras, Don. I'm surprised you are not focusing light on the sensor with a pocket magnifying glass by now.

 

[Donald B]

the amount of image degradation is so small (assuming you use good quality filters) that it is irrelevant.

My objection to UV filters is not about image quality, so much as it is they don't actually DO anything.

I'm sure you will get a variety of people vigorously defending the use UV filters. But after 45+ years in photography, I'm reasonably certain that I've hear ALL the arguments in UV filter's favor. None of those arguments have moved me yet.

I hate using lens caps

You also hate raw, flippy mirrors and big cameras, Don. I'm surprised you are not focusing light on the sensor with a pocket magnifying glass by now.

Im a convert and shooting raw :-0 new computer

 

[Donald B]

going to have some fun soon ? a friend is going to buy a d810, em1mk2 and just picked up a d500

Don

I forgot and the 500mm f4

--
Olympus EM5, EM5mk2 my toys.
http://www.dpreview.com/galleries/9412035244
past toys. k100d, k10d,k7,fz5,fz150,500uz,canon G9, Olympus xz1

 

[m1ks]

topic

"Does a filter affect image quality" is a trick question.

No, it's a simple and straightforward one.

Yes it does, put anything in front of a lens element it will affect the image quality.

The question is are you satisfied with the quality when using one, that's all that matters.

 

[Michael Fryd]

topic

"Does a filter affect image quality" is a trick question.

No, it's a simple and straightforward one.

Yes it does, put anything in front of a lens element it will affect the image quality.

The question is are you satisfied with the quality when using one, that's all that matters.

There are lots of things that affect image quality, however if the magnitude of the effect is very small, then we tend not to worry about it.

For instance, an A/C vent blowing a stream of cool air between the camera and the subject will affect image quality. The temperature of the air affects how it interacts with light. If the room ambient temp is 75°, and the A/C is blowing 65°, then the impact of quality is so small, we likely won't care. If the air is 30° and a someone is cooking on a large an very hot grill, then we may not want to shoot through the heated air above that grill.

With filters the practical question is whether or not the impact on image quality is large enough to be an issue. There are two parts to this question:

1. What is the magnitude of the impact?
2. Is that magnitude large enough to be an issue?

In terms of the magnitude of the impact, that's something that can be measured. Unfortunately, the magnitude of the impact can vary with the situation. The magnitude one sees at the beach on a sunny day, can differ greatly from the magnitude one sees on a cloudy day at the park. We see a lot of arguments over the magnitude of the difference because there is such diversity.

Whether or not the magnitude is large enough to be an issue is also a question that varies by situation. This one can be very controversial because it involves a judgement call.

When it comes to filters, the helpful discussions are about what situations are more likely to be an image quality problem, and what can be done to reduce the issue (lens hoods, flags to shade the lens, different brand of filter, different lighting arrangements, etc.).

A problem with filter discussions is that the image quality issue tends to mixed up with the financial and emotional issues of filter use.

 

[beatboxa]

There are hundreds of threads on this and nothing has changed to warrant yet another thread on the subject really so what is it you need to know that you couldn`t find in all the other threads?

Agreed.

OP: here's one past one, with same images from:

• No filter
• Well-coated, high-quality filter
• Cheap filter

UV filters affect flare & contrast--but the degree that it matters to you depends on many factors. It's a balancing act like so much in photography, so you'll just need to figure out if it's worth it to you.

 

[fishy wishy]

What's technically the most challenging angle for stray light and filters? In the corner of the frame?

I had bad flare around indoor lights due to a filter once. It's true that I didn't try with the filter off, but then again I never saw the problem anywhere else with any other lens either.

 

[beatboxa]

What's technically the most challenging angle for stray light and filters? In the corner of the frame?

I had bad flare around indoor lights due to a filter once. It's true that I didn't try with the filter off, but then again I never saw the problem anywhere else with any other lens either.

I don't think there's a simple answer--there are so many dependencies. Even light outside of the frame can affect flare (which is why we *should* use lens hoods!)

In many cases when I know there's a lot of potential for flare (bright light sources in or near my frame), my filter is usually off. I don't even think about it. But when I'm scared of smudges or front-element contact and am willing to compromise a slight bit of IQ, my high quality filter is on and it's not moving. My preference is Hoya HD3.

Any free or cheap filters are never on my camera except when they are on trial. They are banned.

 

[Teila Day]

http://www.pbase.com/teiladay/uv_filter_pro_or_con

It rarely makes sense. To protect a lens... insurance makes the best sense in most cases.

It depends on the lens you are using.

Absolutely. Relatively few people today use vintage glass, so my comment was directed for the most typical case. You are indeed correct and I'm glad you mentioned it.

If you are using a vintage lens a good UV filter may reduce lens flare, CA and purple fringing. There are pages on the web where people show these effects very clearly. Also coatings of vintage lenses are soft compared to those of modern lenses - and it is better to clean them not very often as each wisp will iake away a little of the coating or will cause scrathes. All my high quality lenses are vintage lenses and for this reason all these lenses have a high quality UV filter.

Excellent point. There are great lenses where the CA and flare control isn't the best... a high quality filter can suppress such on some lenses.

It's a different situation for modern lenses as these lenses often have the hardened glas as front element that is resistant against scratches. I know it at least from Pentax lenses that they use this technology. For these lenses UV don't make any sense: The front element of the lens does not need a mechanical protection, modern coatings and lens designs don't have problems with lens flare, CA or purple fringing and a UV filter would be a waste of time.

There is one aspect of an UV filter that may have to be considered: UV light is extremely powerful. In situations where you have a lot of it (at the beach, on the top of mountains) this high qunatity of UV may effect the light metering system of your camera and may cause wrong exposures. No problem for me as I always shott with control of the histogram (exposure to the right) - but if you trust your atuomatic you may be surprised about the resualts - if you have not an additional protection for UV from a good filter.

Wonderful comments Holger, thanks for bringing that information to the forefront.

Best regards

Holger

Best in photography to you

 

[Michael Fryd]

What's technically the most challenging angle for stray light and filters? In the corner of the frame?

I had bad flare around indoor lights due to a filter once. It's true that I didn't try with the filter off, but then again I never saw the problem anywhere else with any other lens either.

You really can't know how a filter is affecting a particular situation unless you test both with and without a filter. A few years ago I did a quick test of the same scene with and without a filter. The image with the filter looked fine. I didn't see any filter related issues. When I took the filter off, the image got better. Overall contrast went up, and a "reflection" in the original image went away (it turned out it was flare). Obviously, one shouldn't extrapolate a single test to all situations. But my point is that sometimes you don't realize you've lost some image quality until you compare.

Of course a reasonable perspective is that if you are happy with your quality when you use a filter, then you don't have a problem that needs to be solved.

====================

There is more than one type of flare, and the problem angles will vary.

One issue is that the flat filter parallel to the highly reflective sensor can produce an "infinity mirror" effect. This is more of a problem for light sources that are actually in the frame. Film cameras did not have this issue as unexposed film emulsion is not very reflective.

Canon mentions this issue in their excellent "Lens Work" book. They point out that some of their high end telephoto lenses have a built-in protective element. The protective element is specifically not flat in order to avoid these internal reflections.

My expectation is that the further the light is from the field of view, the less of an issue it will be. This is true whether or not you are using a filter, but filters can make the issue worse.

If the light is outside the field of view, then you may wish to shade the filter/front of the glass. Use a lens hood if you can. If you are outside, and the sun isn't behind you, use something (a magazine, black cardboard, your hand) to put the front of the lens in shade.

====================

Remember, not all filter use is "protective". Polarizing filters and Neutral Density filters all you to do things that would be very difficult in post processing. These filters have the same flare and contrast issues as "protective" filters. No matter why you have a filter on your lens, you should be aware of these issues.

 

[tko]

Maybe you should go out and run some tests, answer your question. You know, put a filter on, take a photo, take it off, take a photo? How hard can that be?

A subject like this shouldn't really be a discussion. On YOUR camera, YOUR lens, under YOUR circumstances, does adding a filter has more degradation that what YOU can tolerate for YOUR application. You'll find a lot of people with strong opinions who haven't done the tests or the A/B comparisons.

 

[Graham Meale]

This question is asked in these forums with monotonous regularity.

I once went on an overseas photography tour with two "celebrity" photographers. One used protective filters all the time and swore by them; the other never used them as he didn't want to degrade the image.

I use them, but only the very best. They must degrade the image, but about as much as placing a feather on an elephant's back will make him heavier.