When do you use a CPL ?

Crotal Bell

Crotal Bell

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Keith
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I have a CPL for my bridge camera, and I have to admit I haven't used it yet, however, after spending some time learning their benefits I think I should carry it all the time.

I never realised that they cut out reflections from wet surfaces and add more detail, wet leaves and moist rocks etc.

So just wondering how often you people fit a CPL on your cameras?
 
I only carry two filters, CPL and graduated ND.

I use a fine white POSCA pen and put index marks on them :)
 
I used mine assiduously for several weeks after I bought it about ten years ago, decided I prefer pictures without and have never used it since.
 
They can help balance brightness of sky and land, but only when the light is falling in the right direction. I used one a lot on a trip to Israel some years ago, but it's generally not worth the hassle.
 
Crotal Bell said:
Just had a look on your FB page, wonderful pictures.
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Thank you Keith, appreciate that.

The one thing you do have to watch when using a CPL is for cross polarisation when shooting wide angle, it'll give you a dark patch in a part of the image, usually more noticeable in the sky, when polarised.

They have their uses, as you mention, taking the sheen off water or wet foliage, glass etc, but will also boost the saturation, especially in the woodland at this green time of year. You'll also lose roughly 2 stops of light on the average CPL, so shutter speed is also something to watch out for when using one.
 
I haven't used one for years and years... There must be a youtube vid on this :D but I'd guess whenever reflections could be an issue. Water, windows etc.

Actually another use for mine... To drop the shutter speed down still further when I didn't have dark enough filters to do it :D
 
Steelo said:
Thank you Keith, appreciate that.

The one thing you do have to watch when using a CPL is for cross polarisation when shooting wide angle, it'll give you a dark patch in a part of the image, usually more noticeable in the sky, when polarised.

They have their uses, as you mention, taking the sheen off water or wet foliage, glass etc, but will also boost the saturation, especially in the woodland at this green time of year. You'll also lose roughly 2 stops of light on the average CPL, so shutter speed is also something to watch out for when using one.
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Thanks for the tips, they'll come in handy when I try it.
 
Interesting feedback, seems mostly those who use them a lot, or those who use them hardly ever at all.
 
Crotal Bell said:
I have a CPL for my bridge camera, and I have to admit I haven't used it yet, however, after spending some time learning their benefits I think I should carry it all the time.

I never realised that they cut out reflections from wet surfaces and add more detail, wet leaves and moist rocks etc.

So just wondering how often you people fit a CPL on your cameras?
Click to expand...
They don't just cut reflections the boost them as well if that's the desired effect (something a find at least as useful).

Polarisers are probably the most useful filters, but even so I don't use them all that much typically less than once a month.
When I do use them I've got results that would simply not have been possible without.

This shot was using a polariser (actually sunglasses) to boost the reflections:
Roadside pond, NZ by Mike Kanssen, on Flickr
Somewhere I have shots showing the bottom of the pond too with the polaroids rotated 90 degrees to kill reflections, but I find those shots less interesting.

Then more recently using a laptop screen as a polarised light source I shot this, showing the stresses in a moulded filter case.:
Stressed filter by Mike Kanssen, on Flickr
 
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Petrochemist said:
They don't just cut reflections the boost them as well if that's the desired effect (something a find at least as useful).

Polarisers are probably the most useful filters, but even so I don't use them all that much typically less than once a month.
When I do use them I've got results that would simply not have been possible without.

This shot was using a polariser (actually sunglasses) to boost the reflections:
Roadside pond, NZ by Mike Kanssen, on Flickr
Somewhere I have shots showing the bottom of the pond too with the polaroids rotated 90 degrees to kill reflections, but I find those shots less interesting.

Then more recently using a laptop screen as a polarised light source I shot this, showing the stresses in a moulded filter case.:
Stressed filter by Mike Kanssen, on Flickr
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Nice examples, thanks for the help.
 
its on the camera all the time but may be turned to have no effect, it does act like an ND filter - mines about 2/3 of a stop so comes off if I need more light and dont need the effect
 
After a bit of effort, I discovered that "CPL" stands for circular polarizer/linear and refers to a polarising filter in a rotating mount - just like the polarising filters I used 40 years ago.

Is it an attempt to make yourself look knowledgeable or an attempt to be part of the "in" crowd?

Why not call it a "filter mount polariser", instead of using an acronym? If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?
 
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AndrewFlannigan said:
After a bit of effort, I discovered that "CPL" stands for circular polarizer/linear and refers to a polarising filter in a rotating mount - just like the polarising filters I used 40 years ago.

Is it an attempt to make yourself look knowledgeable or an attempt to be part of the "in" crowd?

Why not call it a "filter mount polariser", instead of using an acronym? If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?
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This sort of thing does seem to irk some people but like it or not CPL is in common use. It's not something I'd get bent out of shape over as I'd guess, and it is just a guess, that most people reading this will now what a CPL is or if not googling cpl filter will tell them pdq. That's Pretty Darn Quick.
 
I use mine a lot to remove reflections on windscreens and bonnets when shooting motorsport. I’ll often have it on for general walk about too but like has been said, it can ruin your skies.
 
AndrewFlannigan said:
After a bit of effort, I discovered that "CPL" stands for circular polarizer/linear and refers to a polarising filter in a rotating mount - just like the polarising filters I used 40 years ago.

Is it an attempt to make yourself look knowledgeable or an attempt to be part of the "in" crowd?

Why not call it a "filter mount polariser", instead of using an acronym? If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?
Click to expand...

The CPL acronym has been about for as long as I remember so I don't think it's a recent 'in crowd' thing.
 
Steelo said:
Mine's very rarely off the camera tbh
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And me.....I'm beginning to think it's an addiction.

Apart from the obvious darkening blue skies situation they have all sorts of uses as others have said. With wide-angle lenses you can get uneven polarisation. In Lightroom its very easy to deal with it......select the darker area using the radial filter and work on it with shadows/contrast/exposure until it disappears.

This seems to be more of a problem with DXO Photolab, where there doesn't appear to be a radial filter........
 
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LeeRatters said:
The CPL acronym has been about for as long as I remember so I don't think it's a recent 'in crowd' thing.
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Clearly, I haven't been reading the write things... :naughty:
 
AndrewFlannigan said:
After a bit of effort, I discovered that "CPL" stands for circular polarizer/linear and refers to a polarising filter in a rotating mount - just like the polarising filters I used 40 years ago.

Is it an attempt to make yourself look knowledgeable or an attempt to be part of the "in" crowd?

Why not call it a "filter mount polariser", instead of using an acronym? If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?
Click to expand...
Did someone get out of bed on the wrong side.
This forum and indeed the whole photography world use acronyms why is this suddenly bugging you?

DSLR, CPL, ND, OS, AF, OVF, EVF, RF. Their are so many.
 
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robj20 said:
Did someone get out of bed on the wrong side.
This forum and indeed the whole photography world use acronyms why is this suddenly bugging you?

DSLR, CPL, ND, OS, AF, OVF, EVF, RF. Their are so many.
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Because some people are just awkward and difficult. (No names mentioned, of course)
 
robj20 said:
why is this suddenly bugging you?
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Not in the least sudden, it always has.

I dislike acronyms for the same reason I dislike algebraic notation: both serve to conceal and confuse.

Out of interest, I used an acronym finder on "CPL"...

CPL Couple
CPL Complete
CPL Compliance (OSHA)
CPL Corporal
CPL Cleveland Public Library
CPL Control Panel (Windows file extension)
CPL Cost Per Lead
CPL Continuous Pressure Laminate (surfacing)
CPL Chicago Public Library
CPL Canadian Premier League (soccer)
CPL Cyberathlete Professional League (gaming)
CPL Courants Porteurs en Ligne (France)
CPL Criminal Procedure Law
CPL Chalmers Publication Library (Chalmers University of Technology; Sweden)
CPL Cerebral Palsy League (various locations)
CPL Content Policy Language (Symantec)
CPL Commercial Pilot License
CPL Coastal Plain League
CPL Concealed Pistol License
CPL Civil Procedure Law (various organizations)
CPL Celje Pivovarna Lasko (Slovenian handball club)
CPL Comprehensive Personal Liability (insurance)
CPL Call Processing Language
CPL Carrefour des Pays Lorrains (French local development group)
CPL Classical Propositional Logic (mathematics)
CPL Child Protection Law (various locations)
CPL Combined Programming Language
CPL Clinical Pathology Laboratories Inc.
CPL Current Privilege Level
CPL Chandler Public Library (Chandler, TX)
CPL Coût par Lead (French: Cost per Lead)
CPL Center for Progressive Leadership
CPL Characters Per Line
CPL Chemistry and Physics Laboratory
CPL College of Physicians of London (UK)
CPL Central Power and Light
CPL Carboplatin
CPL Canadian Pacific Ltd. (various locations)
CPL Complementary Pass Logic
CPL Carrollton Public Library (Carrolton, MO)
CPL Calgary Public Library (Canada)
CPL Carolina Power & Light
CPL Computer Programming Language
CPL Center for Public Leadership
CPL Certified Professional Logistician
CPL Chelmsford Public Library (Chelmsford, MA)
CPL Cats Protection League
CPL Cambridge Programming Language
CPL Coralville Public Library (Coralville, IA)
CPL Certified Professional Locksmith
CPL Courant Patriotique Libre (French political movement)
CPL Conforming Products List
CPL Canine Partners for Life
CPL Circularly Polarized Light
CPL Congenital Pulmonary Lymphangiectasia
CPL Closing Protection Letter (real estate)
CPL Codices Palatini Latini
CPL Conversational Programming Language
CPL Class Precedence List (LISP)
CPL Critical Parameter List (engineering)
CPL Certified Parts List
CPL Capillary Pumped Loop
CPL Certified Professional Landman
CPL Carnegie Public Library (Ohio)
CPL Circular Polarizing Lens
CPL Centre Professionnel des Lubrifiants (French: Professional Center of Lubricants)
CPL Cooperative Processing Language
CPL Current Flight Plan
CPL Crash Position Locator
CPL Computational Physics Laboratory (various locations)
CPL Commissioner of Public Lands
CPL Corona Public Library (California)
CPL Council of Prison Locals
CPL College of Physicians of London (UK)
CPL Central Power and Light
CPL Carboplatin
CPL Canadian Pacific Ltd. (various locations)
CPL Complementary Pass Logic
CPL Carrollton Public Library (Carrolton, MO)
CPL Calgary Public Library (Canada)
CPL Carolina Power & Light
CPL Computer Programming Language
CPL Center for Public Leadership
CPL Certified Professional Logistician
CPL Chelmsford Public Library (Chelmsford, MA)
CPL Cats Protection League
CPL Cambridge Programming Language
CPL Coralville Public Library (Coralville, IA)
CPL Certified Professional Locksmith
CPL Courant Patriotique Libre (French political movement)
CPL Conforming Products List
CPL Canine Partners for Life
CPL Circularly Polarized Light
CPL Congenital Pulmonary Lymphangiectasia
CPL Closing Protection Letter (real estate)
CPL Codices Palatini Latini
CPL Conversational Programming Language
CPL Class Precedence List (LISP)
CPL Critical Parameter List (engineering)
CPL Certified Parts List
CPL Capillary Pumped Loop
CPL Certified Professional Landman
CPL Carnegie Public Library (Ohio)
CPL Circular Polarizing Lens
CPL Centre Professionnel des Lubrifiants (French: Professional Center of Lubricants)
CPL Cooperative Processing Language
CPL Current Flight Plan
CPL Crash Position Locator
CPL Computational Physics Laboratory (various locations)
CPL Commissioner of Public Lands
CPL Corona Public Library (California)
CPL Council of Prison Locals
CPL Carnegie Premier League (various locations)
CPL Continuing Professional Learning (University of Saskatchewan; Saskatoon, Saskatchewan)
CPL Cadila Pharmaceuticals Limited (India)
CPL Certificate of Pending Litigation
CPL Colorado Procedure~@~SLaboratory (Colorado Department of Transportation)
CPL Composites des Pays de Loire (French composites company)
CPL Cincinnati Public Library (Cincinnati, OH)
CPL Color Position Light (railroads)
CPL Consolidated Procurement Directive
CPL Cost per Lesson (various organizations)
CPL Cell Processing Laboratory (various organizations)
CPL Contention Period Length
CPL Confinement Protection Limit
CPL Cost Per Loan (mortgage/banking)
CPL Centre for Public Law
CPL Corporate Price List
CPL Computer Program Library
CPL Capability Password Level
CPL Center for Plain Language
CPL Communist Party of Lithuania
CPL Community of Profound Learning (UK)
CPL Comparative Planetology Laboratory
CPL Central Point of Lunate
CPL Comparative Price Level
CPL Campbellsport Public Library (Wisconsin)
CPL Cornerstone Propane Partners
CPL Canadian Protestant League
CPL Common Prototyping Language
CPL Centrale Paysanne Luxembourgeoise (French: Luxemburg Farmers Union)
CPL Correct Path Loss
CPL Community Public License
CPL Carbon Power & Light
CPL Change Part List
CPL Center for Process Learning
CPL Center for Productive Longevity
CPL Common Program Language
CPL Command Priorities List
CPL Compliance Pipeline Newsletter
CPL Constant Phased Limiting Amplifier
CPL Confirmation-Packet Loss

152 entries
 
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Your just being obtuse now. Try searching within the topic ie Photography CPL, and it's the only result.

I can't think of any topic or industry that doesn't use acronyms.
You'd love where I work CAA, EASA, ICAO, DOA, DPP, PPP.
 
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robj20 said:
Your just being obtuse now. Try searching within the topic ie Photography CPL, and it's the only result.
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I'm not being in the least bit obtuse.

I've been a photographer for well over 50 years; I've used everything from Minox to 5X4 as well as several digital cameras; I've run a professional darkroom; I was fairly successful in earning a living from photography and I've kept up with the technical side throughout.

Yet, until this discussion, I had no idea what CPL meant in a photographic connection. What chance will a newcomer have in try to decode this discussion?

While we're at it, I haven't got an obtuse, so there's no point in mentioning "your obtuse" to me.
 
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AndrewFlannigan said:
After a bit of effort, I discovered that "CPL" stands for circular polarizer/linear and refers to a polarising filter in a rotating mount - just like the polarising filters I used 40 years ago.

Is it an attempt to make yourself look knowledgeable or an attempt to be part of the "in" crowd?

Why not call it a "filter mount polariser", instead of using an acronym? If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?
Click to expand...
A CPL is a different than just a filter mount polariser, as that would be a linear polariser. I have filters from the 1980s that are marked CPL (and others marked Pol) as well as many books from the film era that refer to CPLs.
Circular polarisers basically have a 'quarter wave plate' added behind a normal linear polariser. This converts the polarised output into a spiral polarity which stops it interfering with AF & auto exposure systems of many SLRs.

Linear polarisers for photography are also usually sold in the same style of rotating mounts as used for CPLs - typically so are star filters and most other types where rotating changes the effect.
 
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AgentOrange76 said:
its on the camera all the time but may be turned to have no effect, it does act like an ND filter - mines about 2/3 of a stop so comes off if I need more light and dont need the effect
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There is no position in which a polariser has no effect. At 45 degrees to the horizontal it should have no effect on reflections from vertical or horizontal surfaces, but it will have significant effect on reflection from similarly sloping glass etc. and may darken blue skies in places...
 
Petrochemist said:
A CPL isa different than just a filter mount polariser, as that would be a linear polariser. I
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Engraving to identify items often uses codes but those codes mean nothing, if you don't have the key.

Far too often, acronyms are used to exclude paricipation or to pretend the user has special knowledge. On a public website, it makes far more sense to use language that includes and explains. Why not use English to ensure that the maximum number of readers can benefit from the discussion?
 
AndrewFlannigan said:
Engraving to identify items often uses codes but those codes mean nothing, if you don't have the key.

Far too often, acronyms are used to exclude paricipation or to pretend the user has special knowledge. On a public website, it makes far more sense to use language that includes and explains. Why not use English to ensure that the maximum number of readers can benefit from the discussion?
Click to expand...

You are the only one that seems to have the problem with it though?

Rather than adding to the discussion and supporting the original poster you are just trying to turn it into an argument.

Perhaps offer some positive input through your “50 years of experience”?
 
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AndrewFlannigan said:
Engraving to identify items often uses codes but those codes mean nothing, if you don't have the key.

Far too often, acronyms are used to exclude paricipation or to pretend the user has special knowledge. On a public website, it makes far more sense to use language that includes and explains. Why not use English to ensure that the maximum number of readers can benefit from the discussion?
Click to expand...

Best stay indoors and keep off the Internet then in that case because acronyms are everywhere.

I was even pricing up some timber last week and that was the same as a recent example. I didn't feel excluded from the timber merchants though.
 
I’ll always pack the cpl. I use it when needed, quite a often for landscape with water or otherwise controlling reflections.
 
LeeRatters said:
I was even pricing up some timber last week and that was the same as a recent example. I didn't feel excluded from the timber merchants though.
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Acronyms are, of course, useful when understood by all concerned.

That's why I wrote (above) "If you feel you must use acronyms, why not use the term in full when you first use it, upper casing the letters you want to use in the acronym?"

If your purpose is to communicate, then you'll go the extra mile to ensure your readers understand you. If your purpose is to posture, of course you won't.
 
I have my polariser on all the time on my DLSR with the walk around lens.

I really like the polarised effect for the pictures I take, and having the polariser always on allows me to take pics with and without the effect quickly, and so is always an option. It can sometime make a huge difference, depending on conditions, positioning and subject.

When the light gets low, and/or the conditions means it is having minimal effect, I remove it, because even having no 'effect' it is reducing the light and may force me to raise the ISO for a comfortable hand-holding shutter speed when without the polariser it may not need to do that.

BTW, it pays to get a good quality polariser. Many year ago I got a cheap Cokin polariser, and because it also fitted my 70-300mm lens I tried it on that, and the autofocus stopped working with that lens. :oops: :$ The shop I bought the polariser from said there was something wrong with the lens, but a higher quality polariser made the AF work again. :rolleyes: I decided not to reward the shop for not knowing what they were talking about, and got my money back and bought I think a Sigma Pro 1, somewhere else.
 
A_S said:
You are the only one that seems to have the problem with it though?
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Probably, most people just click away when they find something impenetrable.

Isn't it equally likely that I'm the only one who wishes to make a point about communicating clearly?
 
After reading a few of you that leave them on all the time I might try one again I have an Urth one. From memory I especially didn't like how awkward they are with a lens hood fitted.
 
redhed17 said:
I have my polariser on all the time on my DLSR with the walk around lens.

I really like the polarised effect for the pictures I take, and having the polariser always on allows me to take pics with and without the effect quickly, and so is always an option. It can sometime make a huge difference, depending on conditions, positioning and subject.

When the light gets low, and/or the conditions means it is having minimal effect, I remove it, because even having no 'effect' it is reducing the light and may force me to raise the ISO for a comfortable hand-holding shutter speed when without the polariser it may not need to do that.

BTW, it pays to get a good quality polariser. Many year ago I got a cheap Cokin polariser, and because it also fitted my 70-300mm lens I tried it on that, and the autofocus stopped working with that lens. :oops: :$ The shop I bought the polariser from said there was something wrong with the lens, but a higher quality polariser made the AF work again. :rolleyes: I decided not to reward the shop for not knowing what they were talking about, and got my money back and bought I think a Sigma Pro 1, somewhere else.
Click to expand...
Are you sure you didn't mount the Cokin CPL backwards? that would kill AF from many cameras. Screw on filters are hard to mount backwards but slot in types are very easy!
 
robj20 said:
After reading a few of you that leave them on all the time I might try one again I have an Urth one. From memory I especially didn't like how awkward they are with a lens hood fitted.
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Lens hoods on both Pentax & Panasonic lenses have a removable section to allow adjustment of filters. If your hoods don't allow this you may be better or using a hood that screws into the filter threads. With either of these options you can align the filter even with the hood on.
A CPL thats not aligned for the desired result is sometimes worse than useless. One aligned for use in landscape framing will be completely wrong for portrait framing (completely as is blocking all the light polarised as wanted & passing all the rest). Polarisers have NEVER been fit & forget filters.
 
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