Will Canon "protect" lenses hurt image quality ?

[mangurian]

Canon sells these and says they can be left on all the time.   Is this a high quality glass ?

Any info on how they effect image quality appreciated.

[ebiggs1]

I guess you are referring about protecto filters?  Yes, well some are better than others. I prefer B+W but I have used a few of the Canon brand and found them to be just fine. I will say they are mostly on my film lenses though.

The cheap junk filters are just that .... junk. Remember no filter is 100% perfect but B+W filters are close and they screw off as easily as they screw on. If you notice a problem in a certain situation remove it and replace it when done.

[RobertTheFat]

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@ebiggs1 wrote:

I guess you are referring about protecto filters?  Yes, well some are better than others. I prefer B+W but I have used a few of the Canon brand and found them to be just fine. I will say they are mostly on my film lenses though.

The cheap junk filters are just that .... junk. Remember no filter is 100% perfect but B+W filters are close and they screw off as easily as they screw on. If you notice a problem in a certain situation remove it and replace it when done.

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I guess it's just a matter of individual preference, but I provide that degree of protection by using my lens cap and hood more than most people probably do. The only filters I ever use on my digital cameras are circular polarizers.

But what I see people (including professionals) do far more often is use a camera without its neck strap or other comparable restraint. I think that's far more dangerous than not using a filter or lens cap.

[ebiggs1]

"I provide that degree of protection by using my lens cap and hood more than most people probably do."

A filter is still just another tool to use. Use it correctly.  One big advantage is you don't have to clean the front lens element as often. Hoods do nothing to lessen that. It is better to clean an easily replaceable filter.  Now you might argue the cost of a high quality filter also plays in to this and I agree. A cheap lens does not benefit as much as a high dollar lens does.

Straps are again just a tool.  Use it when it does the job. Don't when it don't.  I never use a strap when shooting weddings or Senior photos, etc.  I do when I am out hobbying around. On my recent New York shoot I used my Black Rapid all day long.

Protecto filters have their place and they offer a real benefit. So do hoods, lens caps not so much and are more a pain than help.  Straps work well in certain situations, not so much in others.. In order, use what works. Simple?

[Waddizzle]

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@mangurian wrote:

Canon sells these and says they can be left on all the time.   Is this a high quality glass ?

Any info on how they effect image quality appreciated.

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I think it is good idea to use clear, protective filters.  I have never used Canon’s filters, just Tiffen and B+W.  Some of Canon’s “L” lenses need a protective filter to actually become “fully resistant” against dust and moisture.  In some cases, they are actually recommended for many shooting scenarios.

Filters are also easier and safer to clean than the front element of an expensive lens.  I have never cleaned the front element on any of my L lenses, just the clear filters.  I put a clear filter on a lens as soon as i take it out of the box. 

One time I was at an outdoor food fair taking photos of the various chefs and their grills and smokers.  When I downloaded the photos later that evening, I noticed some photos lacked contrast, and sort of looked blown out.  My clear filter on my EF 24-105mm f/4L IS USM had become hazy with smoke.  A simple cleaning cured it.

Protective filters do offer protection that a hood cannot provide, namely when you are carrying a spare lens in a bag.  Most people remove lens hoods, or mount them in a reverse position when storing a lens.  My son once dropped his camera bag while carrying it and the baby to the car.  He broke the protective filter on his lens, but the lens was fine.

”Where was your lens cap?  What happened to it?”  [ crickets ]

[TCampbell]

Can vs. should are really two different ways to think about these protective filters.  You can put a piece of clear plastic cling-wrap stretched across the front of the lens but it probably wouldn't give you great results.

The main thing is there is no "this is always the better way to handle it" answer to your question.

The filters are flat glass.  That glass can create reflections that can show up in your image.  The better filters are coating with anti-reflective coatings.  This reduces the reflections ... possibly to the point where most of the time they are not noticeable.  But no coating can 100% eliminate reflections.  If there's a bright light source in the scene, you'll probably still see reflections.

The reflection would usually show up on the opposite side of the frame (relative to the center point).  E.g. if you took a photo in a dark room and there's a bright light source in the upper left corner ... then the ghost of that subject will probably appear in the lower right corner.

For most day to day shooting you probably wont see these reflections.  If you have bright lights visible in an otherwise mostly dark frame (for example... a nighttime city-scape scene) then you may see the ghost reflections of strettlights in your images.  

Use them as you want... but keep in mind that if you see reflections (or are shooting a scene where you realize there's a strong potential for these reflections) then you may want to remove the filters for those shots.

[ebiggs1]

It seems like a lot of folks forget filter come off as easily as they go on. "But no coating can 100% eliminate reflections." However, high a quality protecto filter will do so 99% of the time in real world daily photography.

I probably know as many people that have never had a lens issue and never use a protecto filter.  They tend to think them unnecessary.  On the other hand I probably know as many folks that the protecto filter saved an expensive lens.  They tend to swear by their use. If you have a $100 lens it is probably not good sense to put a high quality $100 protecto filter on it.  By the same standard, if it is a $1200+ lens, it seems a $100 protecto filter is a good idea.

I know pros that throw the front and rear lens caps in the trash when they get a new lens.  So, it does take all kinds and whatever works for you is best.

[Lumigraphics]

Canon sells them because many of their lenses require a filter for weather sealing. If you are going to use the camera in a wet or dusty environment then its a good idea. Otherwise, I've been a photographer for 36 years and never damaged the front element of a lens during use. YMMV of course.

[Tronhard]

To me it's all about risk management and the environments within which you do your photography.  If you work in a controlled environment, such as a studio, with lots of lights etc. then a filter may not be necessary or even desirable.  But if, like me, you work outdoors a lot, in sometimes very hostile conditions, then you want all the protection you can get for your gear.

I was brought up as a kid and then trained by the military with the motto "look after your gear and it will look after you" (that and ALWAYS be aware of your surroundings!).  I carried that into my photography career and am very careful with my equipment for two reasons: I know it will work when I want it to and to the level I expect, and it saves sometimes expensive maintenance or repairs.

As far as lens protection goes, when I get a lens it lives in the box I bought it in, in its wrapping until I require it. I use both filters and lens hoods on all my lenses for the following reasons:

1. Mechancial and chemical protection:  If something strikes the front element of the lens and damages it I lose functionality and I have never seeen a cheap repair on a lens.  So I use a quality glass lens protection filter to take the hit from angled impact (such as dropping) - which has happened at an airport security check.  Such a filter will also protect against abrasion from sand, sae water or other blowing elements.   The lens hood reduces the potential for reflection from the filter and protects agains frontal impact, such as my 3 yo great newphew hitting my camera with his fire engine (that was last week, actually!)  Both things are cheap compared to a repair.

2. Protecting the Sensor:  As has been mentioned a filter reduces the chance of dust particles flowing into a lens when it is extended or retracted.  Doing so reduces the risk of dust making its way onto the sensor and requiring a cleaning.

I don't change lenses in the field.  I would rather carry an extra body with an alternative lens attached than have to change.  This for two reasons: first I reduce the chances of dust entering the camera.  Since I consider it a total folly to have the camera on and the body open at the same time - the sensor will attract dust like a magnet.  Seond, if I did switch lenses then I would logically have to turn off the camera, switch lenses and then turn it back on again.  WIth the lenses on bodies I can switch lens ranges very quick when shooting requires it.  I have my cameras ready to go and it takes perhaps 3 seconds to have the other camera to my eye. For much of the shooting I do that is a critical issue.

I have no issue with those who choose not to use either protection mechanism, it's a personal choice, but so far my gear (some of which is almost 19 years old) has not needed repair or cleaning.  If I have sold bodies or lenses I have got a better price, both from the fact I have the packaging and documentation, and the obvious great condition of the gear.

[Waddizzle]

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@Tronhard wrote:

I don't change lenses in the field.  I would rather carry an extra body with an alternative lens attached than have to change.  This for two reasons: first I reduce the chances of dust entering the camera.  Since I consider it a total folly to have the camera on and the body open at the same time - the sensor will attract dust like a magnet.  

Second, if I did switch lenses then I would logically have to turn off the camera, switch lenses and then turn it back on again.  WIth the lenses on bodies I can switch lens ranges very quick when shooting requires it.  I have my cameras ready to go and it takes perhaps 3 seconds to have the other camera to my eye. For much of the shooting I do that is a critical issue.

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Amen to that.  I do not like to change lenses in the field, either, most especially out in the depths of nature somewhere.  But, how do you carry two bodies?  This is how I do it.

I do not like to change lenses when I am shooting sports, either.  

EOS 6D Mark II, EF 70-200 f/2.8L IS II USM 

EOS 7D Mark II, EF 100-400mm f/4.5-5.6L IS II USM.

My “field kit” bags when I am shooting sports.  Notice how the bodies are turned to make the big lenses fit better.  

This is my “travel light” bag.  LOL.  The only accessories I really need are a Zeiss cleaning kit and Zeiss wipes for the B+W Clear lens filters, spare memory cards, and a 1.4x III extender.  I can easily take 4000+ photos in a single day with this setup.