Image Stabilization

[Graystar]

Sorry, but I believe that to be a myth. You cite one example above. But where is the evidence that demonstrates that in real world shooting and viewing situations, that a good filter causes discernible image degradation?

Well you know, convincing evidence is hard to come by...especially on the internet!

Lenstip.com has a series of tests of UV filters showing some of the effects.
http://www.lenstip.com/113.1-article...ters_test.html

Heliopan results - http://www.lenstip.com/index.php?art=113&roz=11

And the Lenstip tests didn't even explore the kind of degradation that I had mentioned.

Others have told me the same...that they don't see any image degradation caused by their UV filter. Then I ask..."do you always take the same picture with and without the filter?" And the answer is no. That fact is that people don't know if their UV filter has damage the IQ of an image because they're not taking the same shot with the filter off.

[Photon Hacker]

I really don't understand, why people would pay a premium for a high quality lens, and place a $50 piece of plastic over it. It's really comon sense.......................if you were shooting out of a window???? Would you place the lens right against it???? Or simply open the window before you take the shot??? Covering your lens is like shooting through a window, all the time. Personally i would open the window

I think you got too emotional (!!!!). Those who use a filter with expensive lens do so to protect it; they have either determined the filter in question don't significantly degrades technical image quality or don't care; they (I assume) don't use a piece of plastic. Your analogy with a window is outright fallacious.

[thequacksoflife]

Just ask yourself which one you'd rather get scratched.

I appreciate there are reasons for filters BUT I think people are too quick to buy them. If you're buying a £1000+ lens and want filters then buy good ones! Too often its a case of "ooh I'll scratch my lens I must buy a filter" so they buy some £5.99 one.

I'm always puzzled when I walk around about the number of people who have a filter on and no lens hood!

Curiously I came across this line on UV filters "However, UV filters have the potential to decrease image quality by increasing lens flare, adding a slight color tint or reducing contrast." - some website called Cambridge in Colour....

[Colin Southern]

In my experience, lens hoods provide excellent protection ... against stray light hitting the front element of the lens ... and that's about it. On a wide-angle lens they're generally sturdy, but far too shallow to provide any front element protection. On longer lenses the hoods are so deep that the mechanical moment produced from anything more than a light knock generally either knocks them clean off or puches them down the lens barrel (kinda like the photographic equivalent of fingernails down a blackboard!).

In terms of photographic difference - yes - in practice - it can make a difference, but those high-contrast scenes are well documented - and it's easy to remove a filter from them. For general shooting there may (or may not) be a difference in theory, but in practice, it doesn't make any difference - full stop, end of story.

In terms of "what would I rather scratch - a filter or a front element", add to that also "which would I rather run under the tap to disolve away salt mist?" - "which would I rather clean a greasy print or smudge from a wet dogs nose from?". It's also interesting to note that Canon explicitly say in the manual (with regards to weather sealing) that "weather sealing is not complete unless a front element filter is fitted".

Having a filter fitted has saved me twice now ... here's one of them "after the event" ...



PS: $3500 lens front element was just fine

In my mind, using a lens without a filter is like driving a car without a seatbelt; accidents happen - and it's not about the number of times we get away with it - it's about being prepared for the one time we don't "see it coming".

[Colin Southern]

PS: With regards to IS ...

On a crop factor camera - at 200mm - you'll need approx 1/320th second on average to minimise camera shake without IS. With an IS lens (current generation) you stand a good chance of getting away with 1/20th second - the difference is HUGE.

[thequacksoflife]

Hi Colin

hardly a cheap filter tho!

[Colin Southern]

Hi Colin

hardly a cheap filter tho!

It's not too bad - only about NZD $175

[rpcrowe]

PS: With regards to IS ...

On a crop factor camera - at 200mm - you'll need approx 1/320th second on average to minimise camera shake without IS. With an IS lens (current generation) you stand a good chance of getting away with 1/20th second - the difference is HUGE.

Colin is right on. When I shot with a non-IS 70-200mm f/4L, I needed at least the 1/320 second to ensure I had a sharp image. Since I was shooting with earlier model DSLR cameras, 1/320 second was often difficult or impossible to achieve when I was hand holding in lower light levels. With the addition of IS, I can now achieve sharp images at 1/60 or even 1/30 second and the IS has freed me from depending on bright conditions. My easily transportable f/4L IS lens has become an all-around lens which I can use in a variety of conditions and light levels.

[kdoc856]

1/320 to 1/20 is a MASSIVE difference. How might the use of a monopod factor in- would it add much to in-lense or in-camera IS?

[Colin Southern]

1/320 to 1/20 is a MASSIVE difference. How might the use of a monopod factor in- would it add much to in-lense or in-camera IS?

The least amount of camera shake the better - so a monopod is better than hand-holding, but worse than a tripod. Keep in mind though the IS doesn't do anything to freeze subject motion.

[Glenn NK]

I really don't understand, why people would pay a premium for a high quality lens, and place a $50 piece of plastic over it. It's really comon sense.......................if you were shooting out of a window???? Would you place the lens right against it???? Or simply open the window before you take the shot??? Covering your lens is like shooting through a window, all the time. Personally i would open the window

I agree. I buy a premium lens and put a premium filter in front of it. My filters cost $150 plus.

Who makes a plastic filter? I don't have one.

Covering a lens with a filter is not like shooting through a window - that's nonsense.

A good filter is high grade optical glass, not a window - there is a huge difference.

This is one of my premium lenses:

http://www.photozone.de/canon_eos_ff/603-canon24f35tse2

The picture doesn't show it accurately, but the front element is about 1/8 inch (3 mm) behind the front edge of the barrel. The hood adds another 1/2 inch (12 mm) at best.

You want to take a chance on scratching the element on this ($2,400) lens? I don't.

Glenn

[Colin Southern]

Some camera manufacturers put the IS in the camera body which means the lenses can be simpler and all become image stabilised.

Dave

Unfortunately, it can produce a sub-optimal result. In-lens IS units (Canon anyway) are designed to counter the kinds of movement typical of that lens (including shutter induced vibration, mirror slap, hand tremor, wind); the kinds of abberations experianced from, say, a EF70-200mm F2.8L IS USM II are different to those experienced from, say, an EF800 F5.6 IS USM, and thus require different IS performance.

[Glenn NK]

Others have told me the same...that they don't see any image degradation caused by their UV filter. Then I ask..."do you always take the same picture with and without the filter?" And the answer is no. That fact is that people don't know if their UV filter has damage the IQ of an image because they're not taking the same shot with the filter off.

Well, for the sake of discussion, let me put it this way:

If you don't take the same image with and without a filter, then how do you know that a filter causes degradation?

And if you did, and found some degradation, how do you know it wasn't because it was a poor filter?

I use filters because I live near the ocean - mostly the water is salty, and when near the ocean, it tends to be always windy. I know someone that lives five or six blocks from the water, and after a windy night, he has salt deposits on his dark blue car.

Glenn

[Colin Southern]

If you don't take the same image with and without a filter, then how do you know that a filter causes degradation?

I agree Glenn. What I have found - WIDESPREAD across the net - is a lot of "In theory" -- many folks with good-sounding theories (definately not aimed at anyone here), but in my opinion, their thinking lacks what I'll call "real world balance". Filter -v- no filter is one example - refusing to use zoom lenses (because primes are "sharper") are another - refusing to use a high ISO mode because of "noise" (ruining it in the process with camera shake) is yet another - buying an 18MP camera over a 16MP camera because of the extra resolution (and then displaying images online containing less than 1MP) - refusing to print an image above anysize that drops the resolution below 300 DPI (in case someone inspects it with a microscope) the list goes on and on.

The more I continue to evolve my photography, the less importance I attach to any of these things. Far too many folks ruin the image trying to save the pixels.

[Ken MT]

Try this article re stacking filters
http://www.lensrentals.com/blog/2011...th-bad-filters

[timplog]

+1000
like the 'microscope' imagery

cheers

[Gingerbaker]

In my experience, lens hoods provide excellent protection ... against stray light hitting the front element of the lens ... and that's about it. On a wide-angle lens they're generally sturdy, but far too shallow to provide any front element protection. On longer lenses the hoods are so deep that the mechanical moment produced from anything more than a light knock generally either knocks them clean off or puches them down the lens barrel (kinda like the photographic equivalent of fingernails down a blackboard!).

In terms of photographic difference - yes - in practice - it can make a difference, but those high-contrast scenes are well documented - and it's easy to remove a filter from them. For general shooting there may (or may not) be a difference in theory, but in practice, it doesn't make any difference - full stop, end of story.

In terms of "what would I rather scratch - a filter or a front element", add to that also "which would I rather run under the tap to disolve away salt mist?" - "which would I rather clean a greasy print or smudge from a wet dogs nose from?". It's also interesting to note that Canon explicitly say in the manual (with regards to weather sealing) that "weather sealing is not complete unless a front element filter is fitted".

Having a filter fitted has saved me twice now ... here's one of them "after the event" ...



PS: $3500 lens front element was just fine

In my mind, using a lens without a filter is like driving a car without a seatbelt; accidents happen - and it's not about the number of times we get away with it - it's about being prepared for the one time we don't "see it coming".

I don't think a picture of a smashed UV filter as if that proves anything other than the fact that UV filters shatter as easily as dropping a hat, therefore supplying hundreds of shards of razor sharp glass the opportunity to do damage to your lens.

Here is a picture of my Canon 24-70, which has never touched a UV filter, [actually a photo lifted off the web, but this is merely for illustration purposes] which I have dropped twice (once onto concrete):


Notice that it is not broken, and does not have nicks from glass shards defacing the glass./snark.

Here is the other side of the coin in regard to UV filters. Back in the early days, you needed a UV filter to... wait for it... filter UV light which could interact with some film emulsions. Today, you don't actually need a UV filter unless you own a Leica M8 or a hot-rodded sensor that doesn't have a UV/IR filter in front of the sensor. They are, basically, in most situations a beloved profit center for photography shops.

Can UV filters be useful? Absolutely. If you are around flying sea spray, or hot molten metal, or driving sand or other extraordinary conditions, they can protect your lens. And they can help to complete the weather-sealing on weather-sealed lenses. But do they really protect your lens better than a lens hood?

There are hundreds of anecdotal testimonies by photographers who jump to the same, IMO, faulty conclusion - that because their UV filters shattered, that means that they protected the actual lens. I, and many others, are highly skeptical of these claims. Today's lenses are made of tougher stuff than earlier generations. They are much tougher than UV filters, that is for sure. So, how can a UV filter actually protect a lens?

If one were to drop one's lens in such a way that it would land in such an unlucky fashion, and with enough force, as to be pierced by an object that is long enough to get past a lens hood, then the flimsy glass of a UV filter is not going to offer any significant deterrent. Of course, that is a one in a million scenario. What happens typically is that one bumps or drops their lens, and the UV filter shatters as they are wont to do, and the lens glass itself remains fine. Which is exactly what would occur if there was no UV filter on the lens in the first place. If they made these things out of hardened watch crystal, that would be another story, but they don't, do they?

And the problem is that, besides being a waste of money, they do, in fact degrade image quality. Indeed, the last time this old march was conducted - here in these very forums - you conceded, Colin, that one should remove their UV filters if one was shooting indoors with artificial light sources like lamps or outdoors at night if there were artificial light sources, like street lights. Which is basically all city and indoor shooting. And we haven't even begun to discuss normal outdoor daylight shooting at particular angles to the sun. And all that is just about unwanted reflections, we haven't touched on other degradative anomalies and distortions.

The fact is that modern lenses use computer-generated designs and high-tech materials that don't require UV filters, and are not designed with UV filters in mind. Aside from special circumstances when it does make sense to use a UV or protective filter, all they are likely to do is degrade your image quality, offer no significant penetration protection, drain your wallet, and provide sharp glass shards in the vicinity of your lens's front element.

Which is why, as far as I can tell, most pros (at least the ones who write articles for the web) don't use them.

[Glenn NK]

1) Is there some science based evidence that high quality filters reduce image quality on all occasions? There are obvious situations where a strong point light source is shining directly on the front of the filter/lens can degrade the image - I have proof of this myself. As a generalization and without supporting evidence, it isn't a fact - it's an opinion.

2) What hard scientific evidence is there that "other degrading anomalies and distortions" are significant. Keep the word "significant" in mind. Example: very many images exhibit noise when viewed on a screen - how often does the noise appear in a print? Noise is not always significant - could noise reduction programs be a beloved profit centre for software writers?

3) I thought that UV was filtered out by the filter on the sensor. If I'm wrong, I will stand corrected.

4) "All they likely do is degrade image quality". Without evidence, this is opinion. (I understand the use of the word "likely" - it's a hedge word that I often use myself. That way I can't be proven completely wrong. )

5) I will neither suggest nor argue that a filter will protect a lens from an accidental fall onto a hard surface. And I won't suggest that something hard and forceful will be stopped by a filter - they are fragile and when they shatter they pose an extreme scratching danger to the lens. What I do know is that a lens like my TSE 24 could use some scratch protection as the front element is very exposed and the hood is extremely short and of little use for anything.

What I'd like to see is some unbiased fact based evidence. Other peoples' opinions, however well meaning, are not evidence no matter how famous or well-known they are.

Unfortunately what I see on forums are heated over-statements and beliefs too often masquerading as fact.

Belief is not fact, no matter how strong the belief.

[GrahamH]

I've tried taking the same pic with and without a UV filter on. As long as there's no direct sunlight hitting the front glass I can see no discernible difference between the two pics.
If I think there's going to be a problem I can always remove the filter.
The argument for and against has done and will do for ages to come. Many successful pros are on record as using them (yet still sell many images), many pros are on record as not using them (and still sell many images).

As for stacking 5+ filters, I prefer to stay in the real world.

I used one near a geyser, ended up with mineral salts all over the front element. I had to scrap the filter as it wouldn't clean off sufficiently. Oh well, it was only the filter and not the way more costly lens.
Graham
(klutz, sometimes belt and braces is needed)

[Graystar]

As for stacking 5+ filters, I prefer to stay in the real world.

Well with a Lee filter holder you can have your polarizer to deepen the sky, didymium to deepen fall colors, GND to control shadow regions, ND for water...that's four. Oh, and a UV filter...that's five