Polarizers and interiors...furniture glare

I am shooting some interiors, antique armoires to be specific, utilizing natural light. I am using natural light to give the look of what a visitor would see upon walking into a room, a "verite" appearance. I have been pleased with this approach and look except for one thing: glare on polished antique pieces. To get around that I have tried manipulating the ambient light with some success, but not always. I have researched shooting interiors techniques and those that have posted videos on technique agree with the use of natural lighting--and that includes normal room lighting, eg, from desk lamps, wall sconces, etc. They also agree that there is a problem with hot spots (from direct sunlight) and reflections and glare.

No one has described a magic bullet to address this (it is physics), but have various recommendations from "oh well, it looks natural and any viewer would accept it," to shoot multiple exposures, some for dark, some for the hot spots and glare, and some for overall and then stack them to combine to get a good exposure. I have also seen some mention of using polarizers, but not a lot.

 

The other day I was shooting one and had my 20mm 2.8 MF with a Nikon 62 mm polarizer on it. It helped the glare in some areas, but I could not get it to the affect the glare on the armoire door in every shot, even though the light was the same and camera position was the same. The glare on the portrait seemed to have a better response. The polarizer I used was probably 25 years old, but well kept. I had not used it in years prior to the other day. Do polarizers age?? Would getting a new polarizer help, or should I start thinking stacking of images?

Polarizers have very little effect at high angles of incidence, as in the photo above. The greatest effect is at the Brewster's Angle, typically about 55 deg from vertical.

 

You probably want to shade the window in some way.

Right, a polarizer may not be very effective from your position vs. the window. You may try using some curtain or dark cloth to block that window on the right, but that may affect the overall lighting of the image. You can also wait until it is night time so that there is no sunlight coming from the window, but then you need to figure out how to light this scene, and suddenly you may be using artificial lights instead of natural light.

 

Usually it is easier with artificial light so that you have full control of the lighting, but that doesn't seem to be what you want.

The pro who shoots my building projects uses a combination of highly manipulated artificial light, timing to avoid direct sunlight and specular reflections, and limited use of diffusers over windows and light fixtures. I've not seen him use a polarizer indoors, which would be ineffective across all possible angles of reflection (as noted above). In the first case, he sets his camera up with a remote control (CamRanger), and then walks the room with his hand-held, LED light panel, making multiple exposures with light locations and angles tailored for virtually every surface in the room. He then combines and adjusts the various exposures in PP to obtain a composite which is lit to very exacting specifications (and to remove himself from the images). BTW I don't find any of the reflected light offensive in your sample image.

 

Another thought: If you are getting good results with your polarizer, then try making multiple exposures with the polarizer in various positions, and then compositing the exposures, similar to what I described above for the light source. Your description suggests you are getting OK performance for some glare. Perhaps this will cover more of your bases with the available tools?

BTW I don't find any of the reflected light offensive in your sample image.

Interesting. I had assumed that we were talking about reducing the glare off the wooden door. While it is not a major issue, I too would like to reduce some of that.

 

Interesting. I had assumed that we were talking about reducing the glare off the wooden door. While it is not a major issue, I too would like to reduce some of that.

Some soft diffusion of the window would likely do wonders. I don't think the reflection is specular enough for a polarizer to be a solution. Still, the scene speaks of a light source off the right side of the frame (based on shadow patterns), and some lightness on that side feels right. Since the glare on the wardrobe door is clearly not direct, it might be as simple as blocking the brightly lit, exterior object outside the window, rather than making any changes inside the scene. I'm thinking it's likely a white-painted wall in direct sunlight, or some such, that we're seeing reflected in the wood. Sharp, point-source glare would be a different issue.

Edited April 26, 2019 by DavidTriplett

Do polarizers age?? Would getting a new polarizer help, or...

 

I can't really say how much this happens, but if you want to check your polarizer... Do you have a second one? If so hold them close together and look through. Now rotate to see if you can make the view black out. If so, this proves that both are ok. (If they are circular polarizers you'll need to reverse the front one).

 

If you only have one polarizer.. ok, do you also have something with an LCD display (flat screen tv, computer monitor, etc.)? Look at it through your polarizer while rotating. Again, if you can black it out this proves that your polarizer is working.

 

My guess is that your polarizer is fine, but you just don't thoroughly understand the conditions where it's effective. As Ed pointed out, it's all about this thing called Brewster's angle - the specific angle at which reflections from a non-metallic surface are fully polarized (if the light is not completely polarized then the polarizing filter can not completely block it).

Wow, thanks for the info...The image posted is greatly reduced from 9mb to 900 kb, so a lot of the rich detail is missing

@ Bill C said

but you just don't thoroughly understand the conditions where it's effective.

Brewster whaaa? You have that right! I thought, erroneously, that polarizers were effective for any "irregularly bounced" light, from any direction.

This was taken in the 2nd floor master bedroom of an old plantation house, so many Louisiana made 200 year old antiques that it was like being in a museum. The light coming in from the right was through closed french doors. There were sheer curtains which served to diffuse the light. Those doors led to a wide roofed veranda with probably an ENE exposure and it was mid afternoon, IOW, bright indirect light. IN addition there were wooden shutters outside the door. I tried it all ways, including with the shutters closed and still had glare. The angle of incidence is not high, but flat, ie, coming in from the horizon, not from above at all.

And yes, many who have addressed this on youtube have said: multiple exposures and stack, and just as many say the eye expects it and though noticing it, expects and accepts it.

 

 

@david Triplett

BTW I don't find any of the reflected light offensive in your sample image.

Right, I agree, but as Shun says, I'd just as soon not have it and the museum person I am working with on this would prefer not to have it also. Going there at night is not an option as the location is in another city about 80 miles away.

 

and finally @ Bill C, I rotated my polarizer in front of my MAC's screen and it went almost completely black, maybe a couple percent of light coming through. So, the 30 year old Nikon polarizer continues to work.

 

I mentioned that the people who addressed this issue had as a possible position "that is what your eye is seeing, so the viewer expects and accepts it." I am not ready to throw in the towel on this. I may have as many as another 20 to shoot---all with unknown lighting at this point

 

This is an outside shot of the place. The bedroom window is hidden by the fence post on the left. but it is identical to the visible others. And now I will look up Brewster's Angle,.

and finally @ Bill C, I rotated my polarizer in front of my MAC's screen and it went almost completely black, maybe a couple percent of light coming through.

 

If you want to have a little fun, hold a piece of clear plastic - maybe an empty CD case, or even a piece of crumpled cellophane - in front of the MAC screen when the polarizing filter has it blacked out. The loose explanation is that the plastic rotates the plane of polarization so that some of the light is now able to come through the camera's filter (which had formerly stopped it).

have a little fun, hold a piece of clear plastic - maybe an empty CD case

...and that is exactly the process used to 'see' stresses in structures. You make a transparent plastic analogue and push and poke it under polarized light and the stressed areas polarize the plastic's structure and produce (induce?) those lovely colours! Would have been very handy regarding DH Comet window shapes...!

 

Photoelasticity - Wikipedia

 

It's interesting how a certain amount of reflection, but not harsh 'hot-spots', is needed to convey surface type.

 

It's real easy to convert a shiny black patent leather boot into a dull rubber wellington by simply removing all reflection.

 

If it's a studio situation, or somewhere I can use a decent tripod, I take a set of images with different degrees of filter rotation and combine into what I like later.

 

Sometimes it's just 2 frames ALL and NON and layer them together in PS and either vary the layer opacity or erase through the 'upper' glare layer to expose the non-glare underneath..... again maybe varying the erasure opacity.

 

3D curved surfaces with multiple light sources can be a bit frustrating....:mad:.... but fixable.

 

Doing this with film requires a very different approach....:)

John, a large white translucent diffusion cloth that you can clothes pin over windows should do the trick and help make the light a little less directional. I have one that I made. B&H sells a 60X72 inch for about ten bucks and as well circular panels that fold up but are more expensive. Stores that sell fabric should carry what you need. The diffuser will bring out more detail in the cabinets. Good hunting.

John, a cheap alternative to a dedicated diffusion cloth would be an inexpensive polyester bed sheet sheet. My choice would be one that is white.

I am only talking about shooting the current scene and nothing else. There are certainly times when you want to take advantage greater directional lighting from windows and open doors.

Brewster whaaa? You have that right! I thought, erroneously, that polarizers were effective for any "irregularly bounced" light, from any direction.

An irregular surface, like moving water or wood, presents many angles of incidence. Use of a polarizer may cause a change in texture or appearance, but not eliminate all reflections. The book, "Light: Science and Magic" by Bivens, et. al., describes how to manipulate the angle of light to control specular reflections of this sort. In the OP's case, pulling the blinds would be the best solution. Another possibility is moving (e.g., to the left) until the window is no longer reflected in the cabinet. Bivens uses the analogy of billiards to manage reflections.

 

Reflections are not necessarily bad. Human skin, through a polarizer, looks dry and lifeless. Still water, especially lakes south of the Mason-Dixon line, look green or muddy. Specular surfaces like glass or metal reflect their surroundings, which can be manipulated to show texture and contours better than direct light.

Another trick wich sometimes works, stap on a ladder or something else to get yourself half a meter or so higher viewpoint, this often takes you high enough to avoid the reflection getting into the picture due to the slight downward angle of the camera.

Another trick wich sometimes works, stap on a ladder or something else to get yourself half a meter or so higher viewpoint, this often takes you high enough to avoid the reflection getting into the picture due to the slight downward angle of the camera.

right, but I was using a 20mm lens and it was very critical to have it positioned "just so" to keep lines straight.

 

John, a large white translucent diffusion cloth that you can clothes pin over windows should do the trick and help make the light a little less directional. I have one that I made. B&H sells a 60X72 inch for about ten bucks and as well circular panels that fold up but are more expensive. Stores that sell fabric should carry what you need. The diffuser will bring out more detail in the cabinets. Good hunting.

interesting...how is that different from a bedsheet? And what would I look for at a fabric store (though the B&H option sounds best)

I take a set of images with different degrees of filter rotation and combine into what I like later.

dont get the point, different degrees of rotation just make the polarizer work more or less.

Its very easy to understand a polarizer, just hold it in front of one of your eyes and turn it, if nothing changes you are outside the proper angle between looking direction and light direction, ^^

I would probably approach this in a different manner. I would only use artificial light (flash). In order to get a ”verite” look, I would use my 190 cm Elinchrom octa. Reflections could be controlled by moving the lightsource as well as by using a polarizer on the lightsource rather than on the lens.

Placing a bed sheet (or translucent cover) on the window would reflect an image of the backlighted sheet. You could use a large diffuser on a light, taking care that it cast no reflection on the cabinet. Polarizing the light would have the same effect as polarizing the lens. You could do both, but I've yet to see a polarizer large enough to cover a large soft box.

 

If you don't want the fuss of setting up lights and diffusers, a bounced flash, placed directly above the lens (to eliminate visible shadows, works. The entire room becomes the soft box. I would use a diffusing cap pointed straight up to further the effect. There would be some direct reflection from the cap, but probably minimal.

 

When moving the point of view, you can avoid convergence by keeping the camera parallel to the wall. You could use a tilt-shift lens, or a wider than necessary lens, then crop the results.

John, I am not sure if there is much difference. My older dedicated photoflex diffusers are polyester or some kind of hydrocarbon. They seem to be lighter and more translucent than cotton fabric I have for bed sheets though for some cases cotton may be better if you wanted less light to penetrate. I think a bed sheet is a good way to go if you already have one to use plus they already have a hem. The sheet style diffuser I own is polyester and was purchased at Walmart, no snickering please, years ago when they still had a fabric department. I paid someone to hem it. I recently just spent half a day trying to find some one to hem some pants so it may be easier just to go with a bed sheet. I have a small to large collection of diffusiers that I have acquired or purchased over 20 plus years. If your trying to show detail the difference between a directly lighted scene and one with diffuse lighting is very significant. I would love to have a diffuser the size of a house. But I will acknowledge it can come down to a matter of your clients taste. I had a very diffusely lighted monk seal image taken during overcast conditions on velvia many years ago that I showed to a well known professional who I paid to tell me it was harshly lit. Of course he was right. I think you can over tech things so I would go with what ever diffuser you have and make adjustments if you need. I would start with Eds suggestion about pulling the blinds if the windows have them. I don't assume you are using a tripod but I always will if I am working indoors without artificial light and want to use the lowest ISO allowable by law . I understand your trying to preserve the natural light ambience and the amoir was built at a time where natural light was a mainstay. The reflection might even be acceptable but I think diffusing the light will help disapate the glare without adding problems. You might try it on the outside of the window. Please let us know how you tackled the problem when you get the chance. Good hunting.

different degrees of rotation just make the polarizer work more or less

Indeed, that's the point! You can have as much reflection as you want, and you can either do it by layer blending later or in-camera by varying the filter 'strength'.

 

I also tend to keep them all so I can look at them closely on a big screen later, but yes, stacking with different rotations

 

Is there room to use a longer focal length?

 

I wonder if a polarizer will work well at such wide angles?, same problem as using a polarizer on a UWA for a sky shot, it only seems to work in the middle, 'cos of the Brewster angle.

The sky is polarized for the same reason it's blue, due to atmospheric scattering, with a maximum in a band 90 degrees from the sun. Brewster's Angle applies to reflection from a dielectric surface.

Ah, OK, thanks Ed. Different principles at work,,,:)

I noticed, out west, that a polarizer can greatly reduce the dry haze you see in the distance. That's scattered light and it's polarized when the light is mostly overhead.

A lot of good advice here. But in this particular situation I think I'd be less inclined to use a diffuser than I would a relatively dark fabric sheet to block some of the light source causing the reflection and also absorb some of the remaining reflected light from the surface.

Coming to this belatedly and with no personal experience of doing it, but two thoughts:

• Forgive me if I'm failing to notice this being suggested already, but... can you buy a plastic polarizer sheet and hang it over your window? (Googling suggests they exist for stage lighting; certainly a fair number of offices have polarised windows). Then if you have a polarizer on the lens as well at 90 degrees, you should cut out the specular reflection. I believe (and I could be talking rubbish) that the Brewster Angle thing is about the degree of polarisation of the light bouncing off the surface due to the incident angle; if you're effectively bouncing off a mirror, presumably what's polarised stays polarised? I defer to someone who's experimented or knows more basic optics than I can remember. Anyway, if you can kill the specular reflection that way, you should still presumably get the diffuse reflection.
  
• A traditional hack for this kind of thing is to use a (tilt-)shift lens, so you can give the impression of being head-on to the furniture but actually be off to the side. It's pretty much the same effect as correcting the distortion from shooting sideways in post, only with a bit more resolution (and better focal plane control). It'd still look funny, because you'd be able to see the side of the furniture as well as the front, but it'd give you control over where the reflection was going; it's a hack that's often used when shooting mirrors, I believe.
  

HTH.