RF 50mm f1.2 users (and probably EF version as well), do you use a protective filter on it?

Master619 wrote:

Let me start off by saying that I'm typically not a filter guy. I don't use any filters on any of my lens, unless it's for special purposes like ND and polarizers (and very rarely as well). I followed the (somewhat common) mindset that if I've paid a good amount of money for top-notch glass, I don't want to put some cheap glass in front of it. I've rocked multiple big, heavy, large front lenses like the Sony 100-400, various 70-200 including the IS ii, 85mm f1.2,... with just their hoods and no filter needed.

But now that I just got the RF 50mm f1.2, the front moving parts of it got me a bit concerned (and I noticed the previous EF version also had that). So for you guys who have been using them for a long time, do you feel the need to have a filter to prevent dust from getting into the inside of the lens? Is the weather seal reliable? Are some blower squeezes at the end of each session enough? If you use a filter, which one did you go with? Did it affect the IQ in any noticeable way?

Any input is greatly appreciated, thanks in advance!

My new RF 85mm f/1.2L USM lens - with a protective HOYA filter on the front.

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Mention Filters and some people get wound up. I don't care about their experiences. I care about my lenses, my image quality and my own experiences. I personally recommend a filter. Whether you use one is up to yourself. But for an expensive lens, be sure to use a reasonable quality lens filter. You don't have to buy the most expensive filters, just one that is coated appropriately and from a known seller. I prefer Hoya Digital filters myself.
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I'm using the RF 85mm f/1.2L USM lens and will eventually obtain the EF 50mm f/1.2L USM lens in the near future. I made sure to fit a filter to my RF 85mmL lens before leaving the store and did the same when I purchased the EF 85mmL II lens a few year ago as well. On the new RF lenses wit seals (L-series), you don't really need to worry about dust or moisture getting into the lens. Although I'd say that protecting the front element with a lens hood is the LEAST you can do to protect your investment. Forget anyone who says that lens coatings are so hard they can't come off, even with harsh and abrasive abuse. I can assure you that it happens.
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First day out with the older EF 85mm f/1.2L II USM lens - and its protective filter.

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The RF lenses with seals are great for dust and moisture although I won't walk about without a protective filter on my front lens element. Best best reason I can give is thhat it's easier and cheaper to replace a filter than a lens element. So many photographers end up scratching a front element with a set of keys and then panic and try to resell it on eBay or Craigslist while claiming that this scratch has no effect on image quality (which is usually a lie). It's such a small price to pay for the protection and you can always remove a filter for critical photographs involving light-sources that can trigger internal reflections. However, unless you bought a really cheap filter, most have multiple coatings to eliminate ghosting, light flares and internal reflections. Canon and Hoya make protective filters solely for the purpose of reducing damage to the front element of a camera. The only time I've every noticed a potential need to remove a filter is when photographing a very bright light source. I often shoot near the ocean and after 20 minutes there's a distinct salt layer on top of the lens filter. I can swap it out with another filter, and not need to worry about grinding the salt crystals against the thin lens coatings. When I return home I can carefully clean the affected filters before letting them dry and using them again. It's a little like riding a motorcycle without your helmet visor down. The helmet is there to protect your head from accidents. Even the ones that are not your fault. The visor protects your eyes from stones and insects that could cause catastrophic injury if flicked up from another vehicle or when impacting an errant insect.
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Example of Sunscreen-etched lens coatings from a Canon L-series EF lens.

Yet another 24-70mmL lens with lens coatings wearing away with minimal use

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First time I walked outside with a brand new EF 85mm f/1.2L II USM lens, I ended up with droplets of tree sap on the front filter and was immensely grateful to have used a filter. The warm weather was causing the local trees to "sweat" particles of amber sap into the air and it was incredibly hard to remove from the filter. I've seen people wear away the vapor-deposited coatings on the front of their expensive L-series lenses with one specific lens proving problematic to Canon and was known for easy removal with just a smear of sunscreen. The penetrative oils were able to travel between the coating and the optical glass and the Titanium/Zinc Oxides simply wiped the colorful coating from the lenses.
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I once attended a large public convention in a crowd and a woman walked past me, allowing her engagement ring to slam into my 50mmL lens, etching the filter deeply. She flinched but she didn't stop walking. I removed the filter and put on a spare. The filter cost me nearly $200. A replaced front element would have been many times more expensive with no assurances of reliable image quality afterwards. I can't even count the number of times (or the expense) of having to repeatedly return lenses to Canon to have them repaired after they bungled the prior repair... and the repair before that one... resulting in contaminants inside the lens array or decentered lenses resulting in soft corners or soft centers when zoomed. Nothing beats a new lens that was purchased straight from the factory.
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My reasons for using a filter on most of my lenses is as follows:
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* Front element on a 50mmL lens Vs diamond engagement ring = disaster.
* Enjoy photographing food? If it's hot food it will end up spitting on your lens.
* General oils in the air in enclosed rooms lead to "fogging" on a front element.
* Cost of replacing front element of all EF lenses went up by 500% since 2014.
* Likelihood of a repaired lens performing as new - less than 4% (my estimate)
* New filters with coatings can transmit as much as 99.8% of the light.
* Lens Filters can easily be removed for critical photography.
* Vapor Deposited Coatings on lenses CAN be removed by repeated cleaning.
* Resale value of lenses is always higher than Camera body resale.
* A lens that's been protected by filters usually retains much higher resale value.
* A filter is often required to Seal the front end of an "weather sealed" lens.
* A filter will reduce dust and moisture ingress - and potentially mold spores.
* Sunscreen (Zinc-Oxide + Titanium Dioxide) is abrasive to lens coatings.
* Filters are inexpensive and can be cleaned, reused or discarded.
* If you can't afford a new lens to replace a damaged one, or if you don't want the suffer the irritation of an incorrectly repaired lens, then use a filter.

raytracer81 wrote:

I'm more concerned about dust getting into the gap around the extruding front element. But putting a filter brings another question, where does the air go when the front element extrudes? Will the air get suck into the lens?

If there is an airtight filter in place and you extrude the front element, then the air between the frontmost glass and the filter is compressed while the air in the interior of the lens is decompressed, resulting in a pressure differential that will cause an air flow from the front part into the interior through the gap around the front element until both sides reach the same pressure (equilibrium). There is no reason to breathe in air and dust from the outside because the total volume inside the lens barrel of the 50L is constant, regardless of the focus element position. (This makes the story different from the likes of 24-105L and 70-200L, which have extending barrels that require air to come in from the outside when zoomed out.)

And now the simple question: Why are such filters not part of the original lens? Obviousky because of disadvantages... No optical engineer would add an additional plan parallel element without critical need since it will degrade contrast and adds flare. 50% of our calls concerning UFOs or strange nocturnal light phenomena at my observatory  origina from pics taken by people with front filters. Its always my first question. When I hear frpm a second moon or a unknown "comet".

Franz Kerschbaum wrote:

And now the simple question: Why are such filters not part of the original lens? Obviousky because of disadvantages... No optical engineer would add an additional plan parallel element without critical need since it will degrade contrast and adds flare. 50% of our calls concerning UFOs or strange nocturnal light phenomena at my observatory origina from pics taken by people with front filters. Its always my first question. When I hear frpm a second moon or a unknown "comet".

Thanks, that's a good angle (no pun intended) to the problem. Guess if Canon engineers were to do it, it would need to be a curved glass piece like the front element of similar lenses (like RF 85mm 1.2 I think?), not the typical straight filter glass.

Franz Kerschbaum wrote:

And now the simple question: Why are such filters not part of the original lens?

Why even bother installing filter threads on a camera (with clearly marked filter sizes printed on the lens) at all?   I seem to recall that your observatory equipment uses (and/or has tested) special filters in order to maximize the light transmission of certain wavelengths.  The same can be said for conventional photography.

Obviousky because of disadvantages... No optical engineer would add an additional plan parallel element without critical need since it will degrade contrast and adds flare. 50% of our calls concerning UFOs or strange nocturnal light phenomena at my observatory origina from pics taken by people with front filters. Its always my first question. When I hear frpm a second moon or a unknown "comet".

Well - when it comes to UFOs (and I've seen some amazing UFOs whilst in the company of pilots in the past that defy logical explanation) that's because some people are incapable of simple reasoning deduction when assessing something unfamiliar to them.   I've attempted to photograph UFOs on three such occasions but was prevented from successfully doing so by circumstances at the time.  The only thing that interferes with my enjoyment of the night sky is Elon Musk's pesky StarLink satellites.
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The image on the left was taken with what presumably cost millions of dollars to install on a mountain in Chile.  The image on the right was taken with a UV filter on the lens and is an unprocessed JPEG with an exposure time of 6 seconds. I was in a rural landscape at the time.
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Someone should tell Canon to stop this.

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It's also why Canon manufacture protective filters that perform no other purpose than to protect the lens.  It's also why Canon instructs the purchasers of certain "sealed" L-series lenses to "fit a filter to the front end of the lens to complete the seal".  It's not a verbal suggestion, it's actually printed on the instruction manuals supplied with the lenses.
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When I purchased my RF 85mm f/1.2L USM lens earlier this year, I was immediately asked if I wished to purchase a filter to "protect it". Normally, this would be considered a normal "add-on" worthy of a sales promotion by the server.  But we chatted for a while about the practical benefits of using a filter to protect the lens itself.  It comes down to choice.  Some people won't use a filter.  Others might need to protect it from the elements and the harsh realities of travel. I needed TWO filters.  One for polarizing the light (which adds another advantage of allowing me to shoot with the aperture wide open in bright daylight... something the lens cannot do at f/1.2 by itself) and the other for protecting against splatter... which is something I'm not interested in hahving to risk my lens coatings over.  Salt air and food oils always ends up on my lens if I don't wear a filter.  And I'm sure Canon didn't anticipate the front end of an expensive EF lens getting etched by a stranger's diamond engagement ring.  But that's the risk we take.  I chose to lower/eliminate that risk by fitting a high quality optical filter that allows 99.7% of the light to pass through with the added benefit (and price) of anti-flare coatings and anti-reflection rims.  Your experience/requirements may differ.

Dear Marco!

I have nothing against filters. They are often the critical elements in the imaging chain. But, they should should do their job and do more good than harm. I have a huge pile of filters: passbands, pols, neutral, narrow band interference, you name it AND even protective ones and I use them when needed and remove them when not. If eg a protective whould do no harm and would be needed all time Canon (and others) would have them included in the optical design (or at least as part of the package for the expensive ones). But they are not. Every optical enginieer trys to minimise additional air/glass surfaces as much as possible and a plane parallel in Front is in many cases not a very good solution (eg that was changed in the original big whites which hat a permanent protective plane parallel front element, now the convex one gets special treatment). It leads to unwanted reflexions in high contrast szenarios. You like night photography and make great pics! Put one streetlamp somewhere in the periphery of one of your pics and you will have a centersymmetric reflexion (often greeniish). That is unavoidable even with the best filters. In less contrasty situations it may be less of a problem.Its good to have protective filters in your bag if you go to the beach, or the dessert or similar environments that produce fine aerosols that may be entering your lens or cover the frontsurface, In most other cases the protection by a sunshade is much more effecive and does always more good than harm. It increases contrast and protects.

My other 2cts...

Clear skies Marco!

Franz

Master619 wrote:

Let me start off by saying that I'm typically not a filter guy. I don't use any filters on any of my lens, unless it's for special purposes like ND and polarizers (and very rarely as well). I followed the (somewhat common) mindset that if I've paid a good amount of money for top-notch glass, I don't want to put some cheap glass in front of it. I've rocked multiple big, heavy, large front lenses like the Sony 100-400, various 70-200 including the IS ii, 85mm f1.2,... with just their hoods and no filter needed.

But now that I just got the RF 50mm f1.2, the front moving parts of it got me a bit concerned (and I noticed the previous EF version also had that). So for you guys who have been using them for a long time, do you feel the need to have a filter to prevent dust from getting into the inside of the lens? Is the weather seal reliable? Are some blower squeezes at the end of each session enough? If you use a filter, which one did you go with? Did it affect the IQ in any noticeable way?

Any input is greatly appreciated, thanks in advance!

If you shoot on a windy beach often and come home to find the front element coated in salt spray you will start using clear filters for protection.

i put one on all my lenses as soon as I take them out of the box and they very rarely come off.

i always get the best quality filters and have never had any image degradation problems due to a filter. Avoid the cheap brands and you will be ok.

landscape photographers use filters such as polarisers and nd’s all the time and a lot of these are cheap versions and they never complain but again if you use top quality filters you won’t have any problems with image quality.

Master619 wrote:

jwilliams wrote:

I never use a protective filter on any lens. Ever. In fact my 50 1.2 is the last lens I'd ever do that to if somehow I was forced to start the practice. It has the best optics of any lens I have ever owned. Why would I want to screw that up by adding something else to the front of it that the only possible effect would be to degrade the image quality of such a fine lens?

Lens hoods and lens caps are for protection. Filters are for changing the way the image is recorded.

In 30+ years of photography I've never used any sort of protective filter. I've never managed to damage any lens, but once did load a camera/lens to someone and it came back with a chip in the front lens element. Lesson learned, don't lend your camera gear out to others.

People worry way too much about something happening to the front of their lenses when in fact it is actually very hard to do something to a lens that actually produces a noticeable effect on the image recorded. In my case of the lent lens I was never able to detect any effect on the images taken with that lens and it actually had a chunk of glass missing from the front element.

The most likely way to do something to a lens that would actually impact the images taken with it is by being aggressive and zealous in cleaning the front lens element. Enough small scratches will eventually have an effect, but a single mark, scratch, chip will generally not be detectable.

Save your filter money and go buy something that actually helps you with your photography.

No offense, what you said totally makes sense and I agree wholeheartedly 100%. Just that it feels like a generic response to "should I use filters to protect my lens's front element from scratches". In this case I'm asking specifically for protection from tiny dust entering the crack of the lens (this 50 1.2 has an open barrel that provides access to the exposed moving front element). For most lenses where the front element stays in place I have no such worries. Thanks anyway.

Even canon on lenses like the 16-35 say a clear filter competes the weather sealing due to the moving front element.

highdesertmesa wrote:

jwilliams wrote:

highdesertmesa wrote:

I always say there are two kinds of photographers: photographers who don’t use protective filters and photographers who have been sh!t on by a bird.

Quit taking pictures of birds asses and your problem will be solved

Somehow I've managed 30+ years of photography without ever getting bird sh!t on my lens.

Lol. Well, insert whatever experience made you realize Murphy's Law is real.

Best thing about a nano-coated filter like the B+W clear is mist/rain/dust/birdsh!t can be cleaned off with a t-shirt. The filterless crowd gotta get their Zeiss buttwipes and microfiber cloths out and have a major production.

So your gonna ruin a $100 filter with your T shirt?

I think the only $100 protective filter I've had was the 95mm for the RF 28-70, and I've since sold both in perfect condition. Some bottled water and a soft t-shirt don't seem to have any ill effect on the B+W nano coating.

If it doesn't have effect on $100 filter why should it have effect on $2000+ L lens with the latest coatings available on the front element?

I think the sunscreen or other oil example above is rather extreme, but sure, buy filter if you walk on a hot beach on sweaty shirt full of sunscreen. I manage just fine without filters, using just lens hoods and caps, sometimes cleaning by water and paper tissues too, without negative effects. Yesterday I did first cleaning of my RF 28-70 with compressed air to get out the accumulated dust and it's doing fine. It has been in mountains and on beaches. I'm more concerned with the extending plastic barrel when zooming and I clean it more often to minimize any dust ingression.