Friday, February 21, 2014

A 2014 guide to camera filters and their accessories


    Neutral Density Filters:
  A neutral grey filter that limits the amount of light transmission to the sensor in your camera. Depending in the density of the filter, your camera may not be able to autofocus with the ND filter in place (3.0 ND for instance). A 10 stop or higher (3.0 ND) allows so little light into the lense that they call it black glass, there are ND filters that allow up to 20-30 stops of light filtering. Anything above 10 stops is custom made (welders glass).
Example of a home-brew high stop DIY
Welding Glass lense filter.
There is some debate over whether this is true or not but CPL and ND allegedly have a color cast that is semi unique to each manufacturer. These range from gold, brown, blue or even pink, these are all easily correctable in post if it does happen.
There are multiple types of ND; Variable, Hard and Soft Graded (Graduated), and standard ND.


     Polarized light filters and their practical applications:
  There are many possible uses for this type of filtering but let me define the two filters used for photography. These two types are Linear Polarizer (LPL) and Circular Polarizer (CPL), they are used for controlling the amount of polarized light that the lense picks up off of reflective surfaces, twisting the lense mounted filter changes the phasing the of light as it enters the lense.

LPL filters are meant for film cameras, CPL is meant for majority of modern DSLR due to the way the light is split by a beam splitting sensor inside the camera.

Manufacturers warn that the use of an LPL filter on an autofocus D-SLR may damage the camera, consult your manual if you are not sure but most of them will say do not use LPL.

One important factor to remember in particular, regardless of which filter you use, these filters are only effective when you are composing your shot at a right angle from light source.
It is possible to use them at lesser angles but as you turn the lense closer to the light source the filter loses it's ability to compensate.

Depending on the direction you rotate the filter, the result is more or less of the reflected light remaining in the shot when you take the picture as seen below in the shot of the water. You can optionally apply CPL and ND filters as software plug-ins using Lightroom and Photoshop during post processing but you may not be able to rescue the details that were blown out in after the fact. The water shot illustrated below was filtered entirely using post processing techniques.

Polarized light on a reflective surface.
The filter can make blue skies pop when the unfiltered shot may look washed out, it can also add a warming effects to portraits taken in bright sunlight.
Polarizing filters are similar to ND filters, they add contrast, in addition
to that they can enhance certain
parts of the color spectrum on reflective and non-reflective surfaces.
There are pro's and cons to CPL on a very wide lenses like the Nikkor 14-24. The most noteworthy con is pointed out by Ken Rockwell, there may be some issues with certain shots where the filter causes some banding or vignette in the shot. I'll talk more about the vignette issue later on in this article.
My own hands on experience using a Zeiss 21mm Distagon & 82mm B+W CPL mounted on a Nikon D800E; while shooting landscapes near water have not shown the aberrations that Ken mentions.


      UV & IR Filters:
   I have yet to find an application where a UV filter was useful for more than protecting the front element on a lense. That's an expensive use for a filter that you will invariably end up removing to accommodate a CPL or ND (approx. $80). I don't know of any benefit to stacking a UV/IR filter with the other filters.
If there is any justification for using them in a protective fashion, putting it on the end of your multi thousand dollar prime lenses while they are transported to and from your photography work sites is the only viable use I could think of.
The majority of modern DSLR's have UV and IR filters built into the sensor already.
These filters may have some niche application in astrophotography, however for day to day photography applications you are much better off with no filter, or using combinations of CPL & ND. There is one Leica camera that I know of that has no UV filter integrated into it's sensor, the Leica M8.

There are individuals out there who offer camera modification services such as removal of the IR and UV spectrum filtering on the sensor in your camera that enable enhanced imagery of deep space objects.

     Specialty Filters:
   
   1. Underwater Photography
   - Guidelines suggest your subject be no more than 10 to 60 feet from your camera, the loss of visible light is very pronounced underwater, the deeper you get. I have no experience in this area so I will link to a wiki page that explains it much better than I could, Here.
 
Underwater Filter for Salt Water & Blue Light
  2. Astrophotography
  - This is not my forte but definitely an area of interest for me. There are at least 3 types worth mentioning here, OIII and UHC, known as LPR's (Light Pollution Reduction Filters) but only 1 of them I have been able to find fits anything larger than the viewport adapter of a Telescope. These are Lumicon Hydrogen Alpha filters, probably not the best filter for this purpose but oh well. The LPR's that are best do not go above 46mm.


  3. Color Effects
 - This one is not particularly complex, hybrid CPL's with warming effects, and special ND's with a color banding in the middle to enhance skyline shots when your view is depressing but you want to take a picture anyways. Various color effects filters for artistic rendering of a scene such as enhancing water, foliage, and sky. Specialized filters for black and white photography. These are mostly for pre-processing effects and not mandatory since you could do all this in post processing if you really wanted to.

    Specialized Plate Filter Adapters:
  These were created for photographers that work with Wide (24-70mm) & UltraWide (1-24mm) lenses that have such large frontal elements that it cannot accommodate front mounted threaded lense filters. The Nikkor 14-24 in addition to some Tokina & Sigma lenses have this handicap. It caused a great deal of angst to myself and others who own these kinds of lenses due to the scarcity of the options available for filtering that the other lenses enjoy. Carl Zeiss makes very high end manual UltraWide lenses that can fit normal threaded filters (Distagon).
The Zeiss 15mm Distagon may require a plate adapter but I don't think so.

I will explore the available options if you don't own one and considered buying it or just bought one and you are having similar thoughts to what I had, "ok I own it, now what?!".
Hopefully after reading this you'll be armed with the information to help you decide which format is most useful to you. Camera choices and lense performance aside, the filtering options should always be a deciding factor in you're purchasing considerations unless you intend to shoot unfiltered all the time. Most plate filters are made of the same optical grade polymers used in glasses and contact lenses, others are still made of optical grade glass.

  1. 150mm & 100mm Lee Holder Kit

  The build quality is very good, they are a small company in the UK where the majority of items are made by hand or finished by hand on site. All the units are custom made, so if you order one you will have to wait for them to build it.

The drawback for a foreign customer of Lee is if you have a problem with their products you will be waiting a while for a replacement if it's covered by warrantee.

The 150 and the 100 are totally separate bracket systems but since I don't own the latter I am offering a visual representation of the 150. If you go to the Lee website to look at the 150 system, all they do is show you in a promotional video of the 100 system. I was VERY annoyed about that!

I wanted to see the 150 in action, all I got was a vid with a photographer walking around interesting country side with a 100mm bracket system, small lense and a camera I don't use. 
I was a new customer and somewhat naive about filters in general, I expected them to properly represent the item they were promoting, they did not.

The Lee website for what it's worth is a veritable treasure trove of information about their products and suggestions on how to use them properly, great for a new photographer.

Support is generally only available by email, they usually get back to you in a few days or less. Lee does not make a high stop filter (10 stop/3.0 ND) for the 150 bracket system so if you were hoping for that, think again. They do offer enough of the other filtering options that almost make it a worthwhile.

A word on the actual setup of the system, it's fairly sturdy but it would be very cumbersome to change this out to another lense in the field so my advice to you is find a lense you intend to keep it on most of the time if not full time, and leave it on. If you are really in love with this thing, buy more for the other lenses you use a lot. 

There is very little chance of vignette with this system if you use it properly, however be aware of the possibility of stray light bouncing back into the lense particularly with a super wide lense like the Nikkor 14-24.

The baffles that are used on the bracket system are not very good, the petal style baffles of the Nikkor didn't really do much to restrict stray light either but that is more of a design issue with Nikon. It does leave you with the urge to go buy some type of barn yard door style setup sometimes you may find on cinematography rigs, those are very expensive.. 

The Nikkor lense by the very nature of it's design, with a massive frontal element like this means you're choices are limited on what you are able to do with it. Night time sky shots are awesome, i've seen many photographers use it for this purpose with great success.
    Lee 150 Holder Kit & Nikkor 14-24 (click for enlarge)
    Lee 150 mounted on the Nikkor 14-24 (click for enlarge)
    The plate holder itself rotates freely 360 degrees.
  2. 145mm & 66mm - PhotoDiox 
 The Wonderpana system seems to me to be the most well rounded and designed system out of all the plate systems, due to the fact you can accommodate a threaded filter in addition to 1 plate or use 2 plate filters. It handles lenses as large as the Nikkor 14-24 in addition to smaller lenses since the Wonderpana system uses a step up ring to fit the 145mm plate. According to the pro's who use plate based filtering systems on a regular basis the attraction for them is the ability to slide in and out various plates on the fly without dealing with the cumbersome threaded filters. All the reviews not only from the professional review sites, but from customers that I have found are all positive with no indications of light leaking or refracting.

PhotoDiox WonderPana

  3. 170mm Coken and 165mm Hitech  
  Customer feedback about both companies from last year is mixed, majority of it indicating quality control issues. I recall one person commenting that any lense wider than 17mm will have vignette problems caused by the adapter made by Coken. Hitech customers have commented about light refracting or leaking back into lenses of cameras that have the Hitech filter system in place using the 3.0 ND plate made by Hitech. If Hitech can solve it's Q.C. problems it looks as if they have a fairly complete system with a large amount of filters on hand that fit their ultra-wide system. This is something of a problem where Lee is concerned if paying 400 dollars for a bracket system and being told we don't support blah blah filter type is a cause for concern for the buyer.
165mm Lucroit Hitech Holder Kit

Cokin's 170mm X-pro

 A short list of facts regarding filtering, and camera setup:
  The chances of vignette and various other issues increase drastically when you stack filters, especially ND filters. Very few camera's can perform autofocus operations with certain ND filters mounted, the D4 from Nikon is supposed to be able to handle autofocus with a 3.0 ND on it in some conditions. The D800E does not handle it well, I have not had any serious issues with vignette using the plate system so far. Generally you don't want to use more than 2 filters at once or you are almost guaranteed a bad result when you take the photo. If you use a 3.0 ND you're probably going to need to focus the camera before you mount the filter on it.

For the new people to photography, what is vignette you ask? Good question!

Vignette is a noticeable darkening around the corners and edges of a photo, sometimes this is done for artistic purposes.

Here is a list of potential unintended vignette causes:

  -The camera operator had too many filters stacked or the lense adapters were getting in the way of the camera as they widened their zoom.
  -FX camera with a crop sensor lense was not set correctly for the lense or in the case of an AI sensing camera body, it had a crop lense mounted that it could not figure out what it was.
 - One other possibility I can think of that someone may mistake for vignette is when the camera is set for TTL operation and the shutter is not synced up with the flash unit. (shutter obscures part of the shot)
Most camera and flash units don't allow TTL sync above 250 or 320. Some really expensive cameras will allow sync at speeds up to 1600.
 -Vignette can occur in post processing from improper or excessive processing of the shot.

The general consensus for stacking priority of filters is CPL first, ND second, stacking is not always necessary to achieve the result you want.

This is not part of the article but it pertains to filter usage, some pro's recommend a few tweaks to for handling photographing scenes in the alpines where it's loaded with beautiful powder and bright skies.
Up your EV compensation in the camera by up to +2 EV depending on conditions, and try using an ND filter. It's easier to subtract light in post than it is to add it later, just be careful not to push it too much or there will be unrecoverable details from the scenery. The white stuff is death to your camera's sensor since all it see's is dead space, so it tries to overcompensate for it thinks is blown out highlights by making the entire shot gray and under exposed. Other suggestions on the composition end of things, keep the sky out of your shot as much as possible. Break up all that powdery goodness with people or animals, and darker geographical features.

A list of filter and filter kit Manufacturers:
Bottom line about picking your filters by brand, majority of them are all good enough quality you won't see any difference between the 70 dollar filter and the 300 dollar filter in all but the most extreme situations. The top dogs in the filter business are B+W, Tiffen and Hoya. Beyond a certain point it's purely subjective.

Tiffen, B+W, Coken, Hoya, Hellion, Equinox, Zeiss, Lee Filters, Hi-Tech, Sing-Ray, PhotoDiox, Lumicon.


Disclaimers: I receive no remuneration for mentioning products here, all products and their respective trademarks are property of the aforementioned companies in this article. 

(I am not a web developer or an english major, I will not spend a lot of time obsessing over formatting and diction so if I make mistakes.. just deal with it!)