cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

This is NOT Meant to be Click-Bait - Protecting Your Front Lens Element

Tronhard
Elite
Elite

OK, I have just come from observing a discussion that started off civilly, but eventually degenerated into abuse and counter abuse, and it really wasn't necessary, as there are good resources to look at to gain knowledge on this.  What am I talking about? ....  Protective measures for your front element.

It makes sense that folks will want to avoid destroying the lenses which they laboured long and hard to afford.  However there has always been a debate as to how effective, or not, such measures are.  One simple approach is to consider how much it would cost in trouble and dollars (or whatever currency) terms if the front element was seriously compromised.  In anything but the very cheapest lenses, I would submit that it will cost more than that of both a filter and a lens hood - Canon please note, you will stop people complaining if you would include a lens hood with ALL lenses, not just the majority of L glass - it's just a piece of plastic, after all.

Logic suggests that one should establish exactly what threats the lens can suffer, so we can assess the counter-measures that are appropriate. Good research practice suggest seeking information from respected and authoritative sources, as well as one's own (but possibly limited) experience. 

Now, I could just ask GPT4, but it has a habit of making things up, so I went back to seeking sources that have gravitas.  One such is the team at Lens Rentals: after all they have to deal with supplying thousands of the things to a wide range of users, who take them to all sorts of places, and do all sorts of things to them.  So, here is one reference I found that is worthy of your review:

Lens Rentals | Blog: How to Ruin Your Camera and Lens

So from this is what I have come up with:

  • Direct Impact damage - i.e. the sort of thing that happens if something hits the front element head on.  The risk here is the shattering of the front element, and/or displacement of it and other optical components.
  • Oblique impact damage - often when a camera is dropped, it may topple to place the lens lowest and may strike something solid (like planet earth), but not perpendicularly.  The risk here is as above but also the distortion of the lens focusing or (when appropriate) zoom mechanism
  • Environmental Damage - from sand, paint, salt, chemicals or something hot.  All of these can damage the front element, but they can also insidiously work their way into the mechanism and wreak havoc with those components.  This may not be sudden, but it can be every bit as destructive.

There are several approaches to mitigate this:

  1. Never take your camera out where it might suffer harm - that seems a bit restrictive to me, but whatever...
  2. Use a lens hood
  3. Use a glass filter on the front of the lens

These last two are where the "fun" and debate begins...  This swings back and forth between always and never for each, and then folks break out the abuse and weaponry.  It seems to be one of those topics that inflame passions, people take positions, and let fly at the opposing views. 

So, let's try to approach this in a structured manner...
I'm going to leave option 1 out of the discussion - there may be some folks who collect optics as museum pieces or paper weights but I suspect they will be in the minority.
Luckily, doing my research, I found there are other article from our oracles at Lens Rentals on the subject of protection.  The first one was written in Dec 2016: Lens Rentals | Blog and that has been further updated later in May 2018: Lens Rentals | Blog, finally in June 2017: Lens Rentals | Blog  Roger Cicala was a busy chap!
Now, I would encourage you to read all of these because they are inciteful, and have some great technical data, but if you want the spoiler, here it is:

Lens hoods will protect the front to some degree from head on impact and some oblique strikes because they should project ahead of the front element.  Note: this does not apply to someone attacking your lens with an ice pick or being shot at with a bullet - just saying...   The plastic will take some impact and just flex, deform, or in worst case crack, but that should reduce the risk.  What a lens hood does not protect from is environmental damage - as listed above.  Usually there is no impact - these are mostly abrasions, chemical or electrical issues.

OK, so is a filter always necessary? - inevitably it depends on the expense of your optic and how or where you are using it.  If one works in a controlled environment, then the risk of damage or degradation is much less, but if one works in a harsh environment - and that can be any coastal area, for example, then the risk increases.  Using a lens in sandy, particularly blowy conditions can push dust across the lens and remove the coating, and I have had molten metal eat into a filter when doing a shoot in a foundry - so really, its about risk mitigation not absolutes or guarantees.

A filter can, under certain circumstances, actually provide some protection from oblique impact.  When travelling with a lens, attached to a camera body, in a padded holster, as I went through airline security the chap dropped the whole thing from about 200mm (8") onto the conveyor.  When I checked the filter was completely shattered and the metal ring was so distorted as to require to be sawn off. However, tests indicated the lens had not suffered damage or were the optics displaced.  The good news was it was cheaper and faster to replace the filter than send the lens off for repair, which would have impacted my photo shoot.  I actually had a lens hood attached but it was reversed for travel in the padded holster - go figure...

Without doubt putting a rubbish piece of glass in front of your beloved lens is not going to help your images.  Logic suggests that one should stick to name brands and higher cost units, but Roger's tests indicate that this may not be a hard and fast, universally correct rule.  Some of the modest-priced filters performed quite well optically and a couple of name brand units were less than stellar.  Also, getting filters on the cheap as kits with a ton of other (likely useless) accessories off box stores, or on line, is not the most reliable source for anything, but particularly optical components.  So, conventional wisdom says buy from a reputable dealer after (as always) doing your research - and I don't mean by asking all of social media what to get... 

There is going to be a cost/benefit equation here.  If you are using a really cheap lens, it might not be worth putting an expensive filter in front, but as Roger commented in his later articles, the sad news is that the cost of replacing the front element of a lot of lenses has skyrocketed massively in the last few years to the point that a good quality filter is now much more of an economically-viable consideration.

So, what do I do? I use both, as required.  To me it's all about risk management, not guarantees.


cheers, TREVOR

"The Amount of Misery expands to fill the space available"
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris
16 REPLIES 16

Are you making the false assumption that the only reason to use a filter is for impact protection?  Because it sure sounds like it..  

Ricky cited the EF 50mm f/1.2L USM lens as a lens that REQUIRES a filter to complete weather sealing.  Another lens that requires a filter is the EF 17-40mm f/4 IS USM.

Why do these lenses need filters?  It has been my understanding that there are air vents around the front element.  As the lenses focus internally, air chambers inside of the lens body between lens elements can change in volume, which creates significant pressure changes.  

These chambers are vented around the front element.  As the rear chamber pushes air out, the front may pull air inside the lens body.  Adding filter closes the loop, closes the ventilation system.  Instead of venting to atmosphere, air is exchanged between the front and rear chambers of the lens.

--------------------------------------------------------
"The right mouse button is your friend."


@Waddizzle wrote:

Are you making the false assumption that the only reason to use a filter is for impact protection?  Because it sure sounds like it..  

Ricky cited the EF 50mm f/1.2L USM lens as a lens that REQUIRES a filter to complete weather sealing.  Another lens that requires a filter is the EF 17-40mm f/4 IS USM.

Why do these lenses need filters?  It has been my understanding that there are air vents around the front element.  As the lenses focus internally, air chambers inside of the lens body between lens elements can change in volume, which creates significant pressure changes.  

These chambers are vented around the front element.  As the rear chamber pushes air out, the front may pull air inside the lens body.  Adding filter closes the loop, closes the ventilation system.  Instead of venting to atmosphere, air is exchanged between the front and rear chambers of the lens.


EF 16-35 f/4L also specifies a filter "to ensure dust- and water-resistant performance"

 

John Hoffman
Conway, NH

1D X Mark III, M200, Many lenses, Pixma PRO-100, Pixma TR8620a, Lr Classic

normadel
Authority
Authority

I have two L lenses, and their manuals say that in order to have full weather sealing a filter must be mounted. 

This is one of the subjects that has driven me crazy for years....those who VEHEMENTLY argue that a hood is all you need, and filters degrade images, PERIOD!!!

To me, any degradation a good, clean filter may possibly cause is far outweighed by the risks of even just cleaning a lens. I put a clear,  UV (also optically clear),  or skylight filter (film cameras) on any lens I have had for over 60 years of photography.. I can't think of when I've ever had to clean a front element of a filtered lens.

rs-eos
Elite

I found an image I put together from tests with various B+W filters.  As a baseline, no filter was used on my lens.  Everything manual to include Kelvin value.

In Lightroom, I then performed any adjustments (notated in the image) to match the original baseline.  However, I believe what I should have done was to take at least three images (baseline plus with all the filters) and average them out.  It could be that the variations were due to slight inconsistencies with flash output (I was using a 600EX-RT at the time).

I'll repeat this sometime with my new lights.

B+W filtersB+W filters

--
Ricky

Camera: EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L
Lighting: Profoto Lights & Modifiers

So what is your conclusion from this series of tests?

RamfromAlaska
Contributor

I am not as professional photographer, just a person who enjoys taking photos at the local sled-dog and skijoring races, the Northern Lights, and the occasional wildlife (I live in the interior of Alaska).  I do understand that a filter to protect the front element is a good idea in some instances, but not all.   All I use is the lens hood, because the only thing the front lens element is exposed to is a minuscule amount of dust.  I have seldom had the need to wet-wipe any of my lenses. Also, I would never wipe a lens that has not been dusted first.

However, I posted somewhere in this forum about a RF 100-500mm lens that is now out of warranty, a lens that does have a scratch or two on the front element, scratches that have no idea how they how they got there.  When I purchased the lens the glass was immaculate, and I only had to dust it with a soft leans brush now and then, carefully... as I have always done with my other lenses. I only noticed the scratches about a year later when I decided to dust and wet-wipe the lens for the first time.   Money is not an issue, so I could buy another lens like this one, but I am somewhat reluctant because I am not certain if the Canon lens coating can resist the contraction/expansion generated during the extreme cold temperatures I expose this lens to.  None of my EF lenses have scratches like that.  I still have to ship the lens to Canon to have it repaired, even if the scratches don't interfere with the image when taking a photo, but I can't stand having a scratched front element, nor do I trust the lens coating under extreme cold temperatures (-30 to -40 degrees F).

I use quality clear glass on all of my smaller lenses because I shoot a lot of outdoor sports and there are times when I have to wipe it dry/clean quickly with anything available.  So for my use, a quality front "filter" is a sacrificial/disposable item when needed to protect the lens.

The "great white" primes are designed for a rear drop in filter since the front element is too large for a practical filter.  Those lenses have very deep hoods compared to the 70-200 f2.8 and shorter "zoom" lenses with the deep hood providing a great deal of protection and the coatings Canon used for these fast tele primes was selected with the knowledge that there wouldn't be a protective element in front.  So far in over 20 years of sports shooting, I have never damaged a lens element but I have replaced several glass "filters".

Rodger

EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
Announcements