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Author Topic: Polarizer, still needed?  (Read 2730 times)

kevs

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Polarizer, still needed?
« on: September 30, 2012, 05:58:21 PM »

I'm thinking of buying a new polarizer for my Canon 24 - 105. It's not cheap, so I have to ask, is this still needed in the digital filter age? thanks.
The purpose is to make the sky blue while shooting upwards at trees. 
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JeanMichel

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Re: Polarizer, still needed?
« Reply #1 on: September 30, 2012, 06:30:31 PM »

Hi,
A polarizing filter is a worthwhile purchase, it is only around $100. It really is the only way to control reflections and colour saturation in a scene. Of course, the effect is strongest at 90 degrees from the light source, and can be quite ugly when used with wide angle lenses such as a washed our sky at on end and a deep blue at the other. If all you want to do is darken blue skies then you can probably manage that in LR or PS. but with a filter you would be able to also control the amount of reflection/saturation in the foliage, a feat that would not be possible in LR or PS.
Jean-Michel
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Tony Jay

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Re: Polarizer, still needed?
« Reply #2 on: September 30, 2012, 07:14:26 PM »

The effects of a polarizing filter cannot be mimicked in digital post-processing.
It is the most (potentially) useful filter in digital photography.

Polarizers do have their issues: need to be used at 90 degrees to the incident light source, problems if used with wide-angle lenses, and 2-stop reduction in light - hence longer exposures required often needing a tripod or higher ISO or both.

However, used wisely, polarizing filters achieve effects unobtainable in ANY other way.

Regards

Tony Jay
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RFPhotography

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Re: Polarizer, still needed?
« Reply #3 on: September 30, 2012, 07:53:26 PM »

The effects of a polarizing filter cannot be mimicked in digital post-processing.
It is the most (potentially) useful filter in digital photography.

Polarizers do have their issues: need to be used at 90 degrees to the incident light source, problems if used with wide-angle lenses, and 2-stop reduction in light - hence longer exposures required often needing a tripod or higher ISO or both.

However, used wisely, polarizing filters achieve effects unobtainable in ANY other way.

Regards

Tony Jay

90 degrees is the optimal but the filter will still have effect at other angles, just less so.
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BernardLanguillier

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Re: Polarizer, still needed?
« Reply #4 on: September 30, 2012, 08:08:20 PM »

Adding to the previous comments, I have been using the latest EX series PL filter from Kenko, the light loss is now around one stop.

You should be aware that the AWB of some DSLRs don't deal that well with PL filters, it may become useful to shoot a reference grey in the scene.

Speaking about filters, you may also want to consider a variable neutral density filter, they help with water movement and to remove crowds from little densely populated scenes.

Cheers,
Bernard
« Last Edit: September 30, 2012, 08:10:34 PM by BernardLanguillier »
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kevs

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Re: Polarizer, still needed?
« Reply #5 on: September 30, 2012, 11:02:02 PM »

Great post guys. I usually get BW filters, very pricey though.
for Canon 24-105, what do you recommend?
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BJL

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To add to the arguments for a polarizing filter as the one filter that still matters a lot with digital cameras: another benefit is improving color saturation with subjects like foliage, by cutting some glare reflected by leaves.

A followup question: Are circular polarizers (as opposed to linear) still needed with non-reflex cameras, which do both AF and metering from the main sensor, without any reflection of the light onto auxilliary sensors? I am wondering, because light gets polarized when reflected of non-conducting surfaces.

But I suspect that all high quality multi-coated polarisers are of circular type anyway, so it might not matter much in practice.
« Last Edit: October 01, 2012, 10:09:43 AM by BJL »
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PierreVandevenne

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Re: Polarizer, still needed?
« Reply #7 on: October 01, 2012, 10:29:40 AM »

Also very useful with reflections off shiny buildings, through glass (stores, musuem, etc...),
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Ken Bennett

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Re: Polarizer, still needed?
« Reply #8 on: October 01, 2012, 12:39:24 PM »

Great post guys. I usually get BW filters, very pricey though.
for Canon 24-105, what do you recommend?

That's a great lens, why put a cheap filter on the front? The B+W Kaeseman 77mm is only $140.
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ErikKaffehr

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Re: Polarizer, still needed?
« Reply #9 on: October 01, 2012, 05:12:00 PM »

Hi,

I have little enthusiasm for polarizing filters, unless there is a need to reduce reflections, or possibly using with cross polarisation.Cross polarization is when you have polarizer on both light source and lens eliminating all non specular reflections.

If you need to reduce reflection polarizer is the only solution and works well, except on metal surfaces.

The highlights slider in Lightroom 4 is an excellent tool to darken sky. Try the grad filter with the settings below.

You may also check this page: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/46-fixing-sky-with-luminosity-mask

There are two reasons I am less than enthusiastic about polarizers:

- On my best lenses two Zeiss zooms for Sony you need thin filters and the filter ring is incredibly close to the front element. So putting on filters is no great fun.

- I have seen little benefits (except reducing reflections) compared with postprocessing.

Variable ND filter is something I use a lot more.

Best regards
Erik







I'm thinking of buying a new polarizer for my Canon 24 - 105. It's not cheap, so I have to ask, is this still needed in the digital filter age? thanks.
The purpose is to make the sky blue while shooting upwards at trees.  
« Last Edit: October 01, 2012, 10:53:41 PM by ErikKaffehr »
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Glenn NK

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Re: Polarizer, still needed?
« Reply #10 on: October 01, 2012, 08:35:49 PM »

I find CPL's are incredibly useful in closeup botanical images - even when I use a diffuser.  But here, angles are very narrow (100 macro with extender) so the polarization is virtually constant across the image.  The colour saturation of petals and leaves makes their nuisance worthwhile to me (if I don't forget I have it on  :-[).

On landscapes with wide lenses their use is somewhat questionable with part of the sky dark, and part light.

Glenn
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