Polarizing Filters and Dark Skies

[John Mitchell]

Recently, I took some bright daylight photos using a polarizing filter in order to darken the sky and reduce some reflections. The resulting deep blue skies look a bit "blocky" at 100% -- i.e. the pixels appear clumped together in the darkest blue areas. Is this something that QC might be concerned about? I see no mention of it in the submission guidelines.

 

Thanks in advance.

 

P.S. I added a touch of noise reduction, which helped somewhat. The only other alternative that I can think of is to reduce the file size so that the skies appear smoother.

[Ed Rooney]

I would think Lightroom's noise reduction would clear up the problem. 

 

But I learned to avoid polarizing filters a long time ago working in travel marketing. Yes, a polarizer darkens the sky, but it also changes blue to a dark gray that does not project a positive message to a vacationer trying to select a destination. In PP it's easy to darken a sky and keep it blue. Using a polarizer to reduce refection is another matter. 

[John Mitchell]

I would think Lightroom's noise reduction would clear up the problem. 

 

But I learned to avoid polarizing filters a long time ago working in travel marketing. Yes, a polarizer darkens the sky, but it also changes blue to a dark gray that does not project a positive message to a vacationer trying to select a destination. In PP it's easy to darken a sky and keep it blue. Using a polarizer to reduce refection is another matter. 

 

Thanks, Ed. I also seldom use a polarizing filter except occasionally to reduce window reflections. Don't know what got into me. However, the results were pretty good this time, no grey skies (we already have plenty of those in Vancouver). Shall try applying a little more noise reduction as you suggested. These are shots that I should be able to more or less duplicate, so I might try retaking them this evening in softer light sans PL filter.

 

Still wondering what Alamy QC might think, though.

[David Kilpatrick]

Check the files on another monitor - quantizing (banding, blocking) is really common on dark blues on most monitors. Just check on a different one if you can, to be sure you are not trying to remove a problem which is not really there.

[Bryan]

Drifting a tad off topic here, but I have re-invigorated an old linear polarizing filter for use with the Sony NEX. Using manual focus glass, there is no problem in using this neat little 49mm thread filter, and it can give some lovely effects. I know that it is supposed to affect the metering, but I can't say that I have noticed any difficulty with that.

 

It might just be my imagination, but it appears to be more effective than my much larger circular polariser, that is less convenient to use and carry.

[John Mitchell]

Check the files on another monitor - quantizing (banding, blocking) is really common on dark blues on most monitors. Just check on a different one if you can, to be sure you are not trying to remove a problem which is not really there.

 

Thanks. Interesting that you should mention this. I just took an old monitor (which still worked OK but was taking up too much space in my cramped office) to the recycling centre yesterday, so I now only have one monitor. I've added a tad more NR as Ed suggested, and things are looking smoother. I'll probably also reduce the file size for good measure before submitting. Most editorial uses are small. In fact, even 4000 pixels on the long side is probably overkill in most cases.

[John Mitchell]

Drifting a tad off topic here, but I have re-invigorated an old linear polarizing filter for use with the Sony NEX. Using manual focus glass, there is no problem in using this neat little 49mm thread filter, and it can give some lovely effects. I know that it is supposed to affect the metering, but I can't say that I have noticed any difficulty with that.

 

It might just be my imagination, but it appears to be more effective than my much larger circular polariser, that is less convenient to use and carry.

 

Sounds like a good idea. I'm using an old 58 mm circular PL filter and a step-down ring on my NEX lenses. Seems to work fine, but it is a bit bulky.

[Duncan_Andison]

Drifting a tad off topic here, but I have re-invigorated an old linear polarizing filter for use with the Sony NEX. Using manual focus glass, there is no problem in using this neat little 49mm thread filter, and it can give some lovely effects. I know that it is supposed to affect the metering, but I can't say that I have noticed any difficulty with that.

 

It might just be my imagination, but it appears to be more effective than my much larger circular polariser, that is less convenient to use and carry.

 

Depending which Nex you are using you could also use it with autofocus lenses. Linear polarising filters work ok with contrast detection auto focus just not PDAF auto focusing ones. 

[Niels Quist]

I was stupid enough to buy a polarizing filter with my first Canon 5D - saw some of the disadvantages you mention above, and have not used it much since. However, I never forget to put on the lens hood / sunshade, which means a lot for a a blue sky together with the peripheral illumination settings (avoids the vignetting), but, of course, doesn't do much about the reflections.

[Gervais Montacute]

I've got a pretty good 77mm polarising filter by Sigma and I honestly don't use it that much anymore John. First of all, as everyone here knows, they are a waste of time going into  the sun and with your back to the sun. Effective at 90 degrees or other fairly obtuse angles. More effective for me on water rather than skies actually. For skies I would probably use my Lee filter varieties, but with a D800 for example, the dynamic range is pretty good so that's sometimes a lot of faffing around unnecessarily. IMO.

 

Also, if you have Lightroom, if your skies are not completely blown out, then the graduated filter tool (m) can be quite effective provided you don't overdo it. All these tools are great until they get overdone and start to look strange. Just by setting up the GF and reducing the exposure very slightly can improve things drastically. You can also use the dropper in Lightroom to take down the luminance, again, using moderation. I'm sure that's what you already do.

[John Mitchell]

I've got a pretty good 77mm polarising filter by Sigma and I honestly don't use it that much anymore John. First of all, as everyone here knows, they are a waste of time going into  the sun and with your back to the sun. Effective at 90 degrees or other fairly obtuse angles. More effective for me on water rather than skies actually. For skies I would probably use my Lee filter varieties, but with a D800 for example, the dynamic range is pretty good so that's sometimes a lot of faffing around unnecessarily. IMO.

 

Also, if you have Lightroom, if your skies are not completely blown out, then the graduated filter tool (m) can be quite effective provided you don't overdo it. All these tools are great until they get overdone and start to look strange. Just by setting up the GF and reducing the exposure very slightly can improve things drastically. You can also use the dropper in Lightroom to take down the luminance, again, using moderation. I'm sure that's what you already do.

 

Thanks for the response. Have you had any trouble passing QC with dark blue sky shots taken with your PL filter? I currently have two, a Tiffen and a B+W, both of which are good optically.

[Gervais Montacute]

B+W are great filters and I have just one. But for most photography I don't use them. The main issue for me is polarisers have a tendency to show up dust spots even more in blue sky than without. If you want dark blue skies without any issues, I would use the GF filter in Lightroom: but don't overdo it IMO.

[Bhandol]

Polarized shots shouldn't pose any problems with QC, I consider polarizers the most important filter to have and have a polarizer permanantly mounted on my most used lenses or at least in my pocket!

I like to use Hoya HD and Nikon polarizers which are both excellent as I find they transmit more light than most of the others I have used. Not just for blue'er skies but for making the colours jump at you, making foliage look more lush, reducing glare & reflection.

Just don't use them on too wide an angle as that will make the sky look wierd, i'd say no lower than 35mm on full frame or 24mm on APS-C/DX bodies

 

I sell a good deal of polarized shots such as this one which sold recently:

 

Parm

[John Mitchell]

Polarized shots shouldn't pose any problems with QC, I consider polarizers the most important filter to have and have a polarizer permanantly mounted on my most used lenses or at least in my pocket!

I like to use Hoya HD and Nikon polarizers which are both excellent as I find they transmit more light than most of the others I have used. Not just for blue'er skies but for making the colours jump at you, making foliage look more lush, reducing glare & reflection.

Just don't use them on too wide an angle as that will make the sky look wierd, i'd say no lower than 35mm on full frame or 24mm on APS-C/DX bodies

 

I sell a good deal of polarized shots such as this one which sold recently:

 

Parm

 

Your Denny's sign certainly does pop. By skies looking "weird," you mean...?

[Bhandol]

 

 

By skies looking "weird," you mean...?

Cheers John,

 

By skies looking wierd, I'm talking about that effect when you have part of the sky going  darker sandwiched between parts of the sky that are lighter (not a natural look).

 

Here's a not so servere example, but will get worse the wider you go (incidently it sold too, not so long ago, so i guess some buyers like that sort of thing). I can clearly see darker patch runing down diagonally from the top left to the center with lighter sky either side, was taken with an 18-55 +PL at its wider end, where as the shot of the "Denny's" sign was taken at the 55mm end:

 

Parm

[John Mitchell]

 

 

By skies looking "weird," you mean...?

Cheers John,

 

By skies looking wierd, I'm talking about that effect when you have part of the sky going  darker sandwiched between parts of the sky that are lighter (not a natural look).

 

Here's a not so servere example, but will get worse the wider you go (incidently it sold too, not so long ago, so i guess some buyers like that sort of thing). I can clearly see darker patch runing down diagonally from the top left to the center with lighter sky either side, was taken with an 18-55 +PL at its wider end, where as the shot of the "Denny's" sign was taken at the 55mm end:

 

Parm

 

Thanks for the example, it looks as if I'm probably safe to submit the shot I had in mind to Alamy. I used to use PL filters more often with my film cameras, but I stayed away from super wide angle shots for the reasons that you mentioned. I actually don't mind the "sandwiched" look. It can be quite dramatic, as in your photo above.

[dov makabaw]

I often use a polarising filter and have not had any QC problems. Don't use any other filters. Can't imagine that you will have a problem even if it seems a bit patchy.

 

dov

[John Mitchell]

I often use a polarising filter and have not had any QC problems. Don't use any other filters. Can't imagine that you will have a problem even if it seems a bit patchy.

 

dov

 

After reading the encouraging comments on this thread, I uploaded several PL images and they all passed. It's never fun to be surprised by an unexpected QC decision. Fortunately, I seem to be on a roll these days.