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Author Topic: CPL + Wide Angle = Sadness  (Read 3881 times)

ahsanford

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CPL + Wide Angle = Sadness
« on: January 22, 2013, 12:02:44 AM »

Hello team,

I had a question regarding a certain frustration I've had with landscape shooting:  wide angle + circular polarizers.

The CPL has been a staple for me -- principally for contrast management with the sky in landscape work.  But as I am sure you all know, the effect is variable depending upon your angle to the sun.  Couple that with a wide angle lens, and whammo, you induce that ever-so-nasty local darkening/brightening in the sky -- I've been calling it 'CPL-pseudo vignetting.'  (It didn't really need a term, to be fair.)

Boring examples attached.  One with the maximum polarization, one with minimum.  Shot on a 5D3 with the 24-70 F/2.8L I on the 24mm end.  Straight JPG off the camera (I usually shoot RAW), re-sized only.

From a composition perspective, it seems like I only have four convenient choices to choose between:

  • Accept the pseudo-vignetting and take the shot.  Some dark blue sky is better than none.  I usually take this option.
  • Below a certain focal length, don't use the CPL and accept a glaring cyan sky.
  • Zoom in until the effect is minimized (on FF:  at least 35, more like 50 to me).
  • Move my feet, turn, etc. to cleverly reframe to put the darkness in a shady spot (if you can).

I have, of course, left out things impractical options like waiting for better / more even light, assembling multiple exposures or completely editing the sky down in post.

Physics are what they are, I'm looking less for a solution so much as a *convenient* thought process to net solid shots in these situations without a large post-processing task.  I strongly would like to get this right in-camera if possible.

Thoughts?  I appreciate your insights!

- A

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CPL + Wide Angle = Sadness
« on: January 22, 2013, 12:02:44 AM »

Ricku

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Re: CPL + Wide Angle = Sadness
« Reply #1 on: January 22, 2013, 12:13:36 AM »
Yes this is very annoying. The CPL-filters really needs an update for wide angle lenses.  ;D

I never use my CPL-filter below 35mm. When I want to take a UWA-photo with lots of blue sky in it, I often take two shots! One shot exposed for the ground / foreground, and one shot for the sky. I always underexpose the sky shot a little bit, to bring out more of the blue color.

When I get home, I fuse the two shots together in Photomatix.

This is not typical HDR, and the results looks very realistic.

Try it!
« Last Edit: January 22, 2013, 12:18:15 AM by Ricku »

Ricku

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Re: CPL + Wide Angle = Sadness
« Reply #2 on: January 22, 2013, 12:16:46 AM »
   
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That graduated effect doesn't always work. It is not very good for a shot like this. You need a straight horizon, or else you'll burn the tree / trees. :D

RMC33

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Re: CPL + Wide Angle = Sadness
« Reply #3 on: January 22, 2013, 12:37:21 AM »
Possibly use a Graduated ND filter during the shoot? A drop in style may work where you take one shot with and one without? Drop in would prevent most of the screw in issues with Wide Angle.

DynaMike

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Re: CPL + Wide Angle = Sadness
« Reply #4 on: January 22, 2013, 12:38:06 AM »
Plenty of people use CPL on wide angles with great success.  If on a zoom, best option is to just zoom in a little, and take a few steps back to recompose.  2nd option is to just turn down the effect some.  Smaller amount of polarization will help even things out, and you still get some effect.  I can use my CPL down to around 25mm at full power without major unevenness.

ahab1372

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Re: CPL + Wide Angle = Sadness
« Reply #5 on: January 22, 2013, 12:40:31 AM »
It is what it is. You can do the multiple exposure or HDR approach (without CPL), or frame tighter and stitch multiple shots with CPL

neuroanatomist

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Re: CPL + Wide Angle = Sadness
« Reply #6 on: January 22, 2013, 01:46:29 AM »
...you induce that ever-so-nasty local darkening/brightening in the sky -- I've been calling it 'CPL-pseudo vignetting.'  (It didn't really need a term, to be fair.)

Need one or not, the phenomenon is usually referred to as 'uneven polarization'.  :)
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Re: CPL + Wide Angle = Sadness
« Reply #6 on: January 22, 2013, 01:46:29 AM »

John Thomas

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Re: CPL + Wide Angle = Sadness
« Reply #7 on: January 22, 2013, 05:25:24 AM »

Usually I use CPL with good results till 24 mm, but I need to be careful (position wrt to sun, frame composition). If the thing doesn't work then I do the following math:

tripod + low ISO + big Av + in-camera HDR natural mode =  ;D

You can change the last therm of the recipe by changing it to 'Art Standard', or 'Art Vivid', as you like. If you want to add more spices then you can bracket more shoots and blend them in a HDR in PP.

Have fun!

ilkersen

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Re: CPL + Wide Angle = Sadness
« Reply #8 on: January 22, 2013, 01:24:45 PM »
The solution I employ:  Don't use CPL at UWA for the purpose of saturating the sky.  Use it to reduce reflections from leaves, rocks, water, and to bring out details from distant objects.  For the sky, either use GND filter or take multiple exposures and blend in post.

crasher8

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Re: CPL + Wide Angle = Sadness
« Reply #9 on: January 22, 2013, 02:34:43 PM »
Funny how the marketing behind CPL's is generally aimed at wide angle/landscape shooters with examples of before and after of wide expanse of open sky. I will not be buying one for my 16-35, the effect on my 24 is enough.
I just use it sparingly on the softest setting.

wickidwombat

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Re: CPL + Wide Angle = Sadness
« Reply #10 on: January 22, 2013, 10:34:33 PM »
Taking the earlier comment about my grad filter darkening the tree, I gave myself 60 seconds to do a better edit, this version has not touched the tree's luminance, colour, or hue to a level you can notice, but has given an even darkening of the sky.

If your images are not worth 60 seconds in post then I can't help.

how did you do that in 60 seconds?

only apply the gradient to the blue channel?
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Re: CPL + Wide Angle = Sadness
« Reply #10 on: January 22, 2013, 10:34:33 PM »