Panorama; what have I done wrong

Lurch · 05-25-2011, 03:50 AM

I managed to find some time this afternoon, just as the sun was setting, to try again at taking a panorama of Lake Burley Griffin.
I was fairly happy with my previous attempt, however with that being such a dreary day - the shot ended up getting the B/W treatment.
So I ran some simple PP on the series of images, and pumped them into Arcsoft Panorama Maker.
Now the prob is simple; why do I have a big blue bit in the middle?

twitch · 05-25-2011, 04:00 AM

Which shooting mode did you use? Perhaps Av?

Lurch · 05-25-2011, 04:11 AM

Manual
ISO 200
F 1.7
1/20th sec

twitch · 05-25-2011, 04:18 AM

CPL?
Exposure adjusted for that frame in PP?

Lurch · 05-25-2011, 04:25 AM

Ah... CPL yes.
Exposure was set across the range equally in LR

twitch · 05-25-2011, 04:28 AM

Cpl -> bingo!

Lurch · 05-25-2011, 04:48 AM

Gotchya

mtansley · 05-25-2011, 04:48 AM

CPL? What is it please?

Lurch · 05-25-2011, 04:54 AM

Its a polarizing filter

mtansley · 05-25-2011, 04:56 AM

Originally posted by Lurch

Its a polarizing filter

Ahh, the circular polarizer. I use one at times, I just hadn't heard them called that before.

In other words, if doing a panorama, don't use it.

**Just1MoreDave** · 05-25-2011, 09:05 AM

You can see a similar effect with some photos taken with a super wide angle lens and a polarizer filter. The shot is wide enough that you're getting light rays from very different angles. The filter is effectively blocking light rays at the angle it was set for, but not at the other angles. The sky is naturally polarized too, so this effect occurs even without a polarizing filter. The filter just enhanced the effect a lot.

newarts · 05-25-2011, 09:45 AM

It is a great example of how polarization is distributed across the sky and why one doesn't want to use a polarizer for wide angle landscapes that include the sky.

RioRico · 05-25-2011, 09:45 AM

A linear polarizing filter is usually designated PL.
A circular polarizing filter is usually labeled CPL.
Porarizers ain't Polish. PL (filter) is not .PL (nation).
Just more confusing photographic technical jargon...

Some photographic terminology is contradictory.
A UV filter blocks UV; that's straightforward. BUT...
An IR filter passes IR and blocks everything else.
Yellow, Orange, Red, Green filters are cut-offs also.

Closeup adapters are lenses but may be called filters.
Dim eBay sellers may refer to filters as lenses. Duh.
Decoding all this is a non-trivial endeavour. Bother.

mtansley · 05-25-2011, 10:21 AM

Ahh, but isn't it great that we have this website where even fairly experienced amateurs like me can safely ask a question WITHOUT being jumped on by 1000 users claiming you're an idiot!!

Thanks for all the info, I use an IR sometimes and my Dad used to use colour filters in his B & W days, I'd just never heard the term before.

Hmmm, begs the questions: PL - Polarizing linear, CPL, Circular polarizing what?, not linear again.

newarts · 05-25-2011, 10:36 AM

Originally posted by mtansley

Ahh, but isn't it great that we have this website where even fairly experienced amateurs like me can safely ask a question WITHOUT being jumped on by 1000 users claiming you're an idiot!!

Thanks for all the info, I use an IR sometimes and my Dad used to use colour filters in his B & W days, I'd just never heard the term before.

Hmmm, begs the questions: PL - Polarizing linear, CPL, Circular polarizing what?, not linear again.

I think it is closer to PL as an abbreviation for "polarizer" or "polarized light" not "polarizer, linear".

The "Circular" part is inherited from optics people and refers to "Circularly Polarized light".

For practical purposes a CPL can be thought of as a linear polarizer followed by a de-polarizer. They are used with cameras that use mirrors and prisms because polarized light interacts with those elements in ways that depend on the direction of the polarization & can mess up metering, etc.

05-25-2011, 03:50 AM	#1
Lurch Veteran Member Join Date: Apr 2011 Location: Canberra, Australia Photos: Gallery \| Albums Posts: 582	Panorama; what have I done wrong I managed to find some time this afternoon, just as the sun was setting, to try again at taking a panorama of Lake Burley Griffin. I was fairly happy with my previous attempt, however with that being such a dreary day - the shot ended up getting the B/W treatment. So I ran some simple PP on the series of images, and pumped them into Arcsoft Panorama Maker. Now the prob is simple; why do I have a big blue bit in the middle?

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05-25-2011, 04:00 AM	#2
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	Which shooting mode did you use? Perhaps Av?

05-25-2011, 04:11 AM	#3
Lurch Veteran Member Join Date: Apr 2011 Location: Canberra, Australia Photos: Gallery \| Albums Posts: 582 Original Poster	Manual ISO 200 F 1.7 1/20th sec

05-25-2011, 04:18 AM	#4
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	CPL? Exposure adjusted for that frame in PP?

05-25-2011, 04:25 AM	#5
Lurch Veteran Member Join Date: Apr 2011 Location: Canberra, Australia Photos: Gallery \| Albums Posts: 582 Original Poster	Ah... CPL yes. Exposure was set across the range equally in LR

05-25-2011, 04:28 AM	#6
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	Cpl -> bingo!

05-25-2011, 04:48 AM	#7
Lurch Veteran Member Join Date: Apr 2011 Location: Canberra, Australia Photos: Gallery \| Albums Posts: 582 Original Poster	Gotchya

05-25-2011, 04:48 AM	#8
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	CPL? What is it please?

05-25-2011, 04:54 AM	#9
Lurch Veteran Member Join Date: Apr 2011 Location: Canberra, Australia Photos: Gallery \| Albums Posts: 582 Original Poster	Its a polarizing filter

05-25-2011, 04:56 AM	#10
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	Originally posted by Lurch Its a polarizing filter Ahh, the circular polarizer. I use one at times, I just hadn't heard them called that before. In other words, if doing a panorama, don't use it.

05-25-2011, 09:05 AM	#11
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	You can see a similar effect with some photos taken with a super wide angle lens and a polarizer filter. The shot is wide enough that you're getting light rays from very different angles. The filter is effectively blocking light rays at the angle it was set for, but not at the other angles. The sky is naturally polarized too, so this effect occurs even without a polarizing filter. The filter just enhanced the effect a lot.

05-25-2011, 09:45 AM	#12
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	It is a great example of how polarization is distributed across the sky and why one doesn't want to use a polarizer for wide angle landscapes that include the sky.

05-25-2011, 09:45 AM	#13
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	A linear polarizing filter is usually designated PL. A circular polarizing filter is usually labeled CPL. Porarizers ain't Polish. PL (filter) is not .PL (nation). Just more confusing photographic technical jargon... Some photographic terminology is contradictory. A UV filter blocks UV; that's straightforward. BUT... An IR filter passes IR and blocks everything else. Yellow, Orange, Red, Green filters are cut-offs also. Closeup adapters are lenses but may be called filters. Dim eBay sellers may refer to filters as lenses. Duh. Decoding all this is a non-trivial endeavour. Bother.

05-25-2011, 10:21 AM	#14
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	Ahh, but isn't it great that we have this website where even fairly experienced amateurs like me can safely ask a question WITHOUT being jumped on by 1000 users claiming you're an idiot!! Thanks for all the info, I use an IR sometimes and my Dad used to use colour filters in his B & W days, I'd just never heard the term before. Hmmm, begs the questions: PL - Polarizing linear, CPL, Circular polarizing what?, not linear again.

05-25-2011, 10:36 AM	#15
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by mtansley Ahh, but isn't it great that we have this website where even fairly experienced amateurs like me can safely ask a question WITHOUT being jumped on by 1000 users claiming you're an idiot!! Thanks for all the info, I use an IR sometimes and my Dad used to use colour filters in his B & W days, I'd just never heard the term before. Hmmm, begs the questions: PL - Polarizing linear, CPL, Circular polarizing what?, not linear again. I think it is closer to PL as an abbreviation for "polarizer" or "polarized light" not "polarizer, linear". The "Circular" part is inherited from optics people and refers to "Circularly Polarized light". For practical purposes a CPL can be thought of as a linear polarizer followed by a de-polarizer. They are used with cameras that use mirrors and prisms because polarized light interacts with those elements in ways that depend on the direction of the polarization & can mess up metering, etc.