Kaouthia wrote:

I'll buy you a pint next time I'm in Notts to make up for it.

You're on. Get your people to talk to my people.

Jim McSmith wrote:
So what would make the biggest quality difference? Not using a tripod without a UV filter fitted or using a tripod with a UV filter fitted?

It depends on your shooting situation.

If you have a fat shutter speed and a backlit subject, then you may be better off without the filter.  A tripod won't make much difference either way.

If you are shooting a dim, but evenly lit scene, you may be better off with a tripod.  A good filter might not make a big difference in these circumstances.


Whether or not tripods, filters, pro lenses, pro bodies, etc. will make a difference depends on your shooting situation.  If you're not going to tell us what your shooting situation is, you shouldn't expect a simple, definitive answer.

Mike Collins wrote:
According the Seth Resnick, author of a few books on Camera Raw and Lightroom and teaches pretty good workshops, advises NOT to put a Skylight or UV filter on a lens when shooting digital.  And it has nothing to do with protection.  It has to do with the way light travels through the lens and why lenses have a slight curve (meniscus curve) whereas most filters do not.  They also reflect back the light that would otherwise leave the lens after hitting the sensor.

Personally, I have no clue what he's talking about but top end shooters trust his findings and teachings and so will I.

There's a good discussion of the this in Canon's "Lens Work" book, page 133-134.

The vastly simplified overview is that a digital sensor is flat, shiny and acts like a mirror.  The filter is flat and parallel to the sensor.  Having two perfectly parallel surfaces is bad.  You end up getting a lot of light reflecting back and forth between the two.  This situation is worse on longer telephoto lenses.

Generally, Canon designs the front element to be inexpensive to replace.  In those situations where the front element is expensive, Canon will sometimes build a "protective" element into the front of the lens.  The key is that this front element must not be flat (flat glass reduces contrast and increases flare and ghosting).  The sacrificial protective element is a "meniscus" element.  The element has a curve, but constant thickness.   


This is according to Canon.  Judging from the quality of their high-end lenses, I think it's safe to say that they know something about lens design.



Whether or not someone should use a filter is a different discussion as to whether they affect image quality.  The science overwhelmingly supports the conclusion that filters affect image quality.  Some claim that the difference is too small to matter.  Others claim that the loss of quality is grossly unacceptable.  The truth varies with shooting conditions and usually lies somewhere in between.


The trick is to assess both the advantages and disadvantages of filters in your circumstances.  Then make an informed decision on what's best for you.

Personally, I find myself in few situations where filters provide any real protection.   Since I am rarely in a situation where a protective filter will help, I rarely use one.

When I do find myself in a situation where I want to protect my lens, it is usually a situation that's the most challenging for filters (i.e. sunset at the beach) or a situation where I need every bit of contrast/quality I can get (i.e. a foggy or rainy environment).

Photographers who shoot in other circumstances may reasonably come to a different conclusion.

Jim McSmith wrote:
Come on, let's get this old chestnut up and running again. Do you believe in using a UV or Skylight filter to protect your lens or not and what are your reasons?

I used a UV or skylight filter back when I was shooting black-and-white film. I don't know. Some companies (B+H, Heliopan, Hoya, etc.) now offer clear filters, and that's what I use.

Why do I use a filter? To protect the lens. It's much easier (and safer) to keep a lens clean than to clean it.

Camerosity wrote:

I used a UV or skylight filter back when I was shooting black-and-white film. I don't know. Some companies (B+H, Heliopan, Hoya, etc.) now offer clear filters, and that's what I use.

Why do I use a filter? To protect the lens. It's much easier (and safer) to keep a lens clean than to clean it.

Are you keeping your lens clean to maintain resale value, or are you keeping your lens clean to maximize image quality? 

If you want to maximize resale value, then there are definite advantages of using a filter.

If you want to maximize image quality, then a fingerprint on the filter is as bad as a fingerprint on your lens.  Cleaning a lens is no different than cleaning a filter (except that the lens is more likely to have a stronger coating).

Of course, if you replace your filters once a month, then you have effectively eliminated any cleaning damage buildup from your optical path.


If you feel that cleaning a filter is "safer" because the filter is easier to replace, then this becomes a simple economics exercise.  How often do you damage lenses by cleaning them?  How much is the repair?  How much are your filters?

If you've damaged one lens in 20 years, and the repair was $150, then your filter budget for all your lenses probably needs to be under $150 to make an economic sense.  If would seem strange to spend $50 each on filters for your 5 lenses to prevent a $150 repair.   

Actually, your expected cost would be $300. $50 for a filter for each of 5 lenses, and then a $50 replacement filter for the one filter you damage during cleaning.

Perhaps it's just me, but I can't afford to spend $250 to $300 in an attempt to prevent a $150 repair.

Camerosity wrote:
I used a UV or skylight filter back when I was shooting black-and-white film. I don't know. Some companies (B+H, Heliopan, Hoya, etc.) now offer clear filters, and that's what I use.

Why do I use a filter? To protect the lens. It's much easier (and safer) to keep a lens clean than to clean it.

Michael Fryd wrote:
Are you keeping your lens clean to maintain resale value, or are you keeping your lens clean to maximize image quality? 

If you want to maximize resale value, then there are definite advantages of using a filter.

If you want to maximize image quality, then a fingerprint on the filter is as bad as a fingerprint on your lens.  Cleaning a lens is no different than cleaning a filter (except that the lens is more likely to have a stronger coating).

Of course, if you replace your filters once a month, then you have effectively eliminated any cleaning damage buildup from your optical path.


If you feel that cleaning a filter is "safer" because the filter is easier to replace, then this becomes a simple economics exercise.  How often do you damage lenses by cleaning them?  How much is the repair?  How much are your filters?

If you've damaged one lens in 20 years, and the repair was $150, then your filter budget for all your lenses probably needs to be under $150 to make an economic sense.  If would seem strange to spend $50 each on filters for your 5 lenses to prevent a $150 repair.   

Actually, your expected cost would be $300. $50 for a filter for each of 5 lenses, and then a $50 replacement filter for the one filter you damage during cleaning.

Perhaps it's just me, but I can't afford to spend $250 to $300 in an attempt to prevent a $150 repair.

To maximize image quality AND minimize the cost of repairs AND the downtime during repairs.

If I get a fingerprint on a filter, I have no problem with scrubbing the filter with a piece of soft cotton fabric and lens cleaning fluid if that's what it takes to remove the fingerprint. In my experience filters will take more cleaning without showing micro scratches and rub marks than today's lenses.

If I do damage the filter, so be it. If I have to send a lens to Nikon (and $150 for a lens repair at today's prices seems cheap), I'll be without the lens for about six weeks. I can order a replacement filter from B&H and have it in two days. But since I have three more 77mm clear filters than lenses that use that filter size, I wouldn't even have to do that.

Also, if I have a lens that's very sharp now, it might not be as sharp after the front element is replaced. Sad but true.

Camerosity wrote:
To maximize image quality AND minimize the cost of repairs AND the downtime during repairs.

If I get a fingerprint on a filter, I have no problem with scrubbing the filter with a piece of soft cotton fabric and lens cleaning fluid if that's what it takes to remove the fingerprint. In my experience filters will take more cleaning without showing micro scratches and rub marks than today's lenses.

If I do damage the filter, so be it. If I have to send a lens to Nikon (and $150 for a lens repair at today's prices seems cheap), I'll be without the lens for about six weeks. I can order a replacement filter from B&H and have it in two days. But since I have three more 77mm clear filters than lenses that use that filter size, I wouldn't even have to do that.

Also, if I have a lens that's very sharp now, it might not be as sharp after the front element is replaced. Sad but true.

You are making the assumption that a lens with 'micro scratches' will be lower quality than a lens without micro scratches, but with a protective filter.   Is this a gut feeling, or do you have some indication that micro-scratches on the front element affect image quality more than filters?

Obviously, your shooting situation will make a huge difference in the results.  If you frequently shoot backlit subjects, you may be better off with micro scratches.

You may want to invest in a real lens cleaning supplies.  A good microfiber cloth or Pec-Pads should get your lens clean without scratches.  Pec-Pads are also useful for sensor cleaning.  They don't make removable protective filters for sensors, so you need the right cleaning supplies.

If you use proper cleaning techniques, then your lens should not develop micro-scratches.


How many lens do you have, and how often have you scratched one?  You sound like you have a lot invested in protective filters.  Perhaps more than the cost of repair (and you may never need that repair).


Six weeks for a lens repair is unacceptable.  I'm a mid-level member of CPS (Canon Professional Services).  When I dropped my 70-200 f/2.8 lens, I overnighted it to Canon on a Tuesday.  They got it Wednesday, shipped it back Thursday, and I was back shooting with it on Friday.  Cost was $118.34 including return shipping.  If I had the higher level CPS membership, the repair would have been under $70, and Canon would have paid overnight shipping in both directions.  The lens came back perfectly adjusted.  It was as sharp (perhaps a hair sharper) then when it was new.  Canon also throws in a few free clean and checks with CPS membership.  I suspect they know how to clean the lens without causing micro-scratches.

You should join NPS (Nikon Professional Services).  I suspect it has similar benefits to CPS.   I have a good friend in Los Angeles who is a Nikon Shooter.  He swears by NPS support.  They have saved him many times over the years.  He's one of those people who will never consider switching to Canon.  It's nothing to do with camera quality, just the superb support he has gotten from NPS.


You are correct that there is a possibility that a repair will leave your lens in worse condition.  As a NPS member you shouldn't have to accept that.  If the lens comes back less sharp, send it back and have them get it right.  The lens should come back from a repair as sharp, or sharper than it was when it went in.

Camerosity wrote:
To maximize image quality AND minimize the cost of repairs AND the downtime during repairs.

If I get a fingerprint on a filter, I have no problem with scrubbing the filter with a piece of soft cotton fabric and lens cleaning fluid if that's what it takes to remove the fingerprint. In my experience filters will take more cleaning without showing micro scratches and rub marks than today's lenses.

If I do damage the filter, so be it. If I have to send a lens to Nikon (and $150 for a lens repair at today's prices seems cheap), I'll be without the lens for about six weeks. I can order a replacement filter from B&H and have it in two days. But since I have three more 77mm clear filters than lenses that use that filter size, I wouldn't even have to do that.

Also, if I have a lens that's very sharp now, it might not be as sharp after the front element is replaced. Sad but true.

Michael Fryd wrote:
You are making the assumption that a lens with 'micro scratches' will be lower quality than a lens without micro scratches, but with a protective filter.   Is this a gut feeling, or do you have some indication that micro-scratches on the front element affect image quality more than filters?

Obviously, your shooting situation will make a huge difference in the results.  If you frequently shoot backlit subjects, you may be better off with micro scratches.

You may want to invest in a real lens cleaning supplies.  A good microfiber cloth or Pec-Pads should get your lens clean without scratches.  Pec-Pads are also useful for sensor cleaning.  They don't make removable protective filters for sensors, so you need the right cleaning supplies.

If you use proper cleaning techniques, then your lens should not develop micro-scratches.


How many lens do you have, and how often have you scratched one?  You sound like you have a lot invested in protective filters.  Perhaps more than the cost of repair (and you may never need that repair).


Six weeks for a lens repair is unacceptable.  I'm a mid-level member of CPS (Canon Professional Services).  When I dropped my 70-200 f/2.8 lens, I overnighted it to Canon on a Tuesday.  They got it Wednesday, shipped it back Thursday, and I was back shooting with it on Friday.  Cost was $118.34 including return shipping.  If I had the higher level CPS membership, the repair would have been under $70, and Canon would have paid overnight shipping in both directions.  The lens came back perfectly adjusted.  It was as sharp (perhaps a hair sharper) then when it was new.  Canon also throws in a few free clean and checks with CPS membership.  I suspect they know how to clean the lens without causing micro-scratches.

You should join NPS (Nikon Professional Services).  I suspect it has similar benefits to CPS.   I have a good friend in Los Angeles who is a Nikon Shooter.  He swears by NPS support.  They have saved him many times over the years.  He's one of those people who will never consider switching to Canon.  It's nothing to do with camera quality, just the superb support he has gotten from NPS.


You are correct that there is a possibility that a repair will leave your lens in worse condition.  As a NPS member you shouldn't have to accept that.  If the lens comes back less sharp, send it back and have them get it right.  The lens should come back from a repair as sharp, or sharper than it was when it went in.

If you're asking whether I have done extensive testing by scratching my lenses and shooting controlled tests, before and after, the answer is no. That would rather defeat the purpose, don't you think?

If you're asking whether I have ever seen reduced quality from lenses with scratching and scuffing, the answer is yes - but not with my current generation of lenses. Even scratches and scuffs that are barely visible to the naked eye can cause reduced sharpness in the form of flare, without much predictability as to when it will occur.

I have eleven autofocus lenses and four manual focus lenses that I kept but have not used in a long time, not counting large format lenses. Two of the AF lenses I don't use anymore. I need to send them in for repairs and sell them. One of the other AF lenses has a serious front focus issue that Nikon has been unable to correct. Yet another is a 35-70mm f/2.8 lens that has been heavily used to the point that there is no friction in the push-pull zoom function. It is still very sharp, and it is a backup lens.

Six weeks is Nikon's turnaround time - or it was in March, when I sent two bodies in for repair. That time was reduced to three weeks (and suddenly everyone at Nikon was my best friend) after I contacted a vp of Nikon USA with whom I am acquainted.

I've started the process of joining NPS. There are layers of hoops to jump through, and I know of people who have spent more than a year in the processs before their memberships were finally approved. I don't like to impose on friendships, but...

NPS does not discount repairs for members. They simply expedite them.

Mike Collins wrote:
According the Seth Resnick, author of a few books on Camera Raw and Lightroom and teaches pretty good workshops, advises NOT to put a Skylight or UV filter on a lens when shooting digital.  And it has nothing to do with protection.  It has to do with the way light travels through the lens and why lenses have a slight curve (meniscus curve) whereas most filters do not.  They also reflect back the light that would otherwise leave the lens after hitting the sensor.

Personally, I have no clue what he's talking about but top end shooters trust his findings and teachings and so will I.

That happens with both film and Digital.

Kodachrome with a Pentax K1000 50mm with UV filter 1983.


GoldenGate by FullMetalPhotographer, on Flickr

fullmetalphotographer wrote:

Mike Collins wrote:
According the Seth Resnick, author of a few books on Camera Raw and Lightroom and teaches pretty good workshops, advises NOT to put a Skylight or UV filter on a lens when shooting digital.  And it has nothing to do with protection.  It has to do with the way light travels through the lens and why lenses have a slight curve (meniscus curve) whereas most filters do not.  They also reflect back the light that would otherwise leave the lens after hitting the sensor.

Personally, I have no clue what he's talking about but top end shooters trust his findings and teachings and so will I.

That happens with both film and Digital.

Kodachrome with a Pentax K1000 50mm with UV filter 1983.


Post the one you took without the filter.

Michael Fryd wrote:

Are you keeping your lens clean to maintain resale value, or are you keeping your lens clean to maximize image quality? 

If you want to maximize resale value, then there are definite advantages of using a filter.

If you want to maximize image quality, then a fingerprint on the filter is as bad as a fingerprint on your lens.  Cleaning a lens is no different than cleaning a filter (except that the lens is more likely to have a stronger coating).

Of course, if you replace your filters once a month, then you have effectively eliminated any cleaning damage buildup from your optical path.


If you feel that cleaning a filter is "safer" because the filter is easier to replace, then this becomes a simple economics exercise.  How often do you damage lenses by cleaning them?  How much is the repair?  How much are your filters?

If you've damaged one lens in 20 years, and the repair was $150, then your filter budget for all your lenses probably needs to be under $150 to make an economic sense.  If would seem strange to spend $50 each on filters for your 5 lenses to prevent a $150 repair.   

Actually, your expected cost would be $300. $50 for a filter for each of 5 lenses, and then a $50 replacement filter for the one filter you damage during cleaning.

Perhaps it's just me, but I can't afford to spend $250 to $300 in an attempt to prevent a $150 repair.

How much does it cost to replace a front element?

Probably the same cost as a decent filter or less.

fullmetalphotographer wrote:

That happens with both film and Digital.

Kodachrome with a Pentax K1000 50mm with UV filter 1983.


GoldenGate by FullMetalPhotographer, on Flickr

There's proof the image quality is fine. It's just an entirely different image.

Michael Broughton wrote:
here's an idea: don't handle your gear carelessly in the first place. also, they make these things now called lens caps.

I gotta snicker at comments like that.   It's like saying don't ever have an accident and you'll be okay.

Easy to do if you never touch the gear.    Shit happens..   

I'm a believer in protective filters..no matter what they are.   I use to have 81A filters on all my lenses.  At the time, I shot only transparency film and it gave me a very nice warm tone to the film.   

I've had a few occasions in my career, where they've protected the lens from an unforeseen impact.

MC Photo wrote:
This should end the debate.

http://www.youtube.com/watch?v=vzOLbMPe0u8

It won't end the debate. 
I can hear it now...

"At the end of the video you can see a micro scratch on the lens.  If he had a filter on the lens then it wouldn't have a micro scratch!"

KevinMcGowanPhotography wrote:
...   
I'm a believer in protective filters..no matter what they are.   
...

There is a difference between a "UV" Filter, and a filter that actually provides real mechanical protection.

An 81A filter provides optical protection against colors that are a bit too cool.   It does not protect the lens from damaging impacts.   You could achieve the same effect with a proper color balance.  If you want to exactly match the 81A filter, you can add a slight contrast reduction in post processing.  Matching any ghost images of light sources is a bit more complicated, but not at all impossible.


As many others have pointed out, the big advantage of filters is that it moves fingerprints, dust, debris and potential "micro scratches" from the front element of your lens to the filter.  Somehow these things don't affect image quality when they are on the filter.

Many have claimed that filters save money.   The reasoning is that it is better to spend a lot of money upfront, in order to reduce the possibility of a smaller expense later on.

Whether or not this makes financial sense depends on how often you destroy a front element.

Generally, buying "protective" filters for all of your lenses will cost more than a single repair.  If you believe you can keep your lens failure rate to one or two lenses, you may save money by paying for the repairs.   If you find yourself destroying a few front elements per year, then it may make sense to spend money on preventing the problem.  Keep in mind that filters only help if you are destroying your lenses by over zealous cleaning.  You could also save money by learning a better cleaning technique.

If filters protected your lens against all hazards, and never affected image quality, then they might be a very good solution.  In the real world, filters protect against a very small set of hazards and can easily affect image quality.   If your lens is routinely exposed to one of those specific hazards, then a filter may be helpful.  If you are like most photographers, then you rarely encounter those situations.

The obvious example is that video of someone hitting their lens with a hammer.  Put a filter on that lens, and now you are smashing broken filter glass into the front element.   In order for a filter to provide physical protection, the impact must only be to the glass, and must be weak enough not to break the filter.  Furthermore, the impact must be strong enough that it would have harmed the lens.  There are very few impacts that fall into that range.

Even a filter made of inch thick lexan won't protect your lens from all hazards.  Shoot a bullet into the lexan.  The lexan won't break, and your front element will be fine.  The shock of the impact will likely cause internal damage to the lens.

KevinMcGowanPhotography wrote:
...   
I've had a few occasions in my career, where they've protected the lens from an unforeseen impact.

Can you describe the impact?  I am curious as to what sort of impacts you have run into that would have damaged the lens if you had no filter.

KevinMcGowanPhotography wrote:

I gotta snicker at comments like that.

really? you snicker at the idea of not casually tossing your camera onto car keys and keeping the cap on your lens when you're not shooting? ok then.

Michael Fryd wrote:
Many films were sensitive to UV light.  When shooting film outdoors there is a real benefit to filtering out UV.

They typical digital camera has builtin UV filtering.   There is no need for additional UV filtering on a modern DSLR.


Modern DSLRs have very shiny sensors.  Most undeveloped films have matte finish emulsions.  Shiny sensors make DSLR's more susceptible to filter induced flare.   There are many situations where filters will not cause a serious problem if you are shooting film, but switch to a DSLR and you might get noticeable additional flare.

[Shhhh.  I was teasing. And...it's a little ironic that the guy that started the witty banter fell for my witty banter]
Mission Accomplished.  I am king of the thread!!!!

Robert Jewett wrote:

[Shhhh.  I was teasing. 
{it's a little ironic that the guy that started the witty banter fell for my witty banter}  Mission Accomplished.  I am king of the thread!!!!]

Sorry.

Sometimes it's a bit difficult to tell who is teasing and who is serious about the amazing things that a filter can do.

Michael Fryd wrote:

KevinMcGowanPhotography wrote:
...   
I'm a believer in protective filters..no matter what they are.   
...

Can you describe the impact?  I am curious as to what sort of impacts you have run into that would have damaged the lens if you had no filter.

Quite easy. I do some landscape work. Quite often find myself changing lenses in the field from a crouched position. When hands are cold it's easy to fumble the lens and it falls onto ground where there may be some rough or rocky patches.

Jim McSmith wrote:

Quite easy. I do some landscape work. Quite often find myself changing lenses in the field from a crouched position. When hands are cold it's easy to fumble the lens and it falls onto ground where there may be some rough or rocky patches.

When your lens falls, does it always fall filter down?

Does the filter break?  What makes you think the lens would be harmed if there was no filter?

ACPhotography wrote:
The best protection for your equipment is insurance!

That goes without saying, but you can't just unscrew insurance from the end of your lens and carry on shooting.

Kaouthia wrote:

That goes without saying, but you can't just unscrew insurance from the end of your lens and carry on shooting.

Which is why I always have backup bodies and lenses...

You drop a lens front down and if it's enough to crack your filter I'm going to bet there's more internal damage going on than you think...

Kaouthia wrote:

That goes without saying, but you can't just unscrew insurance from the end of your lens and carry on shooting.

I guess my problem is that I look at things differently.

If the impact was minor enough that I can unscrew the broken filter and continue, then without the filter there probably would not have been any damage.

In the case where I had a filter, I have to buy a new one, and lose 30 seconds while I unscrew.

In the case where I didn't have a filter, there is no damage, no expense, and not even a 30 second delay.

ACPhotography wrote:
Which is why I always have backup bodies and lenses...

As do I, but if I can remove a filter and carry on shooting with a $2000 lens, I'd rather do that than go to a $300 backup that isn't as fast or as sharp.

Not everybody's backup gear (although in an ideal world it would be) is identical to their main gear.

Kaouthia wrote:

As do I, but if I can remove a filter and carry on shooting with a $2000 lens, I'd rather do that than go to a $300 backup that isn't as fast or as sharp.

Not everybody's backup gear (although in an ideal world it would be) is identical to their main gear.

Why are you shooting with a $2,000 lens?

Depending on your shooting circumstances, you may get better results with an $800 lens and no filter than a $2,000 lens with a "protective" filter.

Michael Fryd wrote:
I guess my problem is that I look at things differently.

I just see it as "extra insurance", during times when it might get a bit rough.

I've seen rocks a lot sharper than that claw hammer while I've been out shooting, and while it may not break through the glass of a lens (or indeed a filter), with the weight of a person behind it, they'd sure as shit leave a big scratch.  Not had it happen to a lens, but I've had it happen with a phone with a glass front when I slipped on location once.

The quality ones don't impact IQ enough to make a difference for me, so I leave them on most of the time.  My main concern is flaring if I'm using them when it's a bit darker and there's light sources in the scene.  I remove 'em if I'm fitting the Z-Pro holder too.

Michael Fryd wrote:
Depending on your shooting circumstances, you may get better results with an $800 lens and no filter than a $2,000 lens with a "protective" filter.

I ain't seen a 70-200mm f/2.8 for sale at $800 anywhere.

Michael Fryd wrote:

I guess my problem is that I look at things differently.

If the impact was minor enough that I can unscrew the broken filter and continue, then without the filter there probably would not have been any damage.

In the case where I had a filter, I have to buy a new one, and lose 30 seconds while I unscrew.

In the case where I didn't have a filter, there is no damage, no expense, and not even a 30 second delay.

The filter is a thin piece of plate glass sandwiched in a metal ring in front of the lens... The front element is a thick piece of glass recessed in the lens and cushioned by it's mounting... Of course the thin piece of plate glass is going to break! (hope it doesn't scratch the recessed element when it does)

Jim McSmith wrote:
Come on, let's get this old chestnut up and running again. Do you believe in using a UV or Skylight filter to protect your lens or not and what are your reasons?

Yes, especially outdoors. I don't use lens caps at all.

Kaouthia wrote:

I just see it as "extra insurance", during times when it might get a bit rough.

I've seen rocks a lot sharper than that claw hammer while I've been out shooting, and while it may not break through the glass of a lens (or indeed a filter), with the weight of a person behind it, they'd sure as shit leave a big scratch.  Not had it happen to a lens, but I've had it happen with a phone with a glass front when I slipped on location once.
...

How thick is your filter that it will stop a rock?

If the rock isn't strong enough to break the filter, it likely won't hurt a filterless lens.

If the rock is strong enough to break through the filter, then you aren't protecting the lens.

There are very few scenarios where the filter will actually make a difference between a damaged and an undamaged lens.

Kaouthia wrote:

I ain't seen a 70-200mm f/2.8 for sale at $800 anywhere.

But the 70-200mm f/4 L is currently $629 at B&H.

I suspect the 70-200mm f/4 without a filter will frequently beat out a 70-200 f/2.8 with a filter.  Particularly under difficult circumstances (i.e. shooting outside in bright sunlight).