Stacking Filters -- Best Practices ?

B

blafarm

Active member
From an optical point of view, is there a "best practice" regarding how to stack multiple filters?

More specifically, let's say I have 4 lenses having varying thread diameters (16-35, 24-70, 70-200 and a Macro).

In order to protect the front elements, I decide to buy a Clear UV filter for each lens.

Then, recognizing that I might also need a Variable ND and Polarizing Filter for each lens, but not wanting to buy 8 additional redundant filters, I decide to use Step-Up rings for each lens to "equalize" the lenses to a common larger thread size -- let's say to 72mm.

The question is:

Should the Clear UV filters be directly connected to each lens -- or should they be attached to the Step-Up filter of each lens?

In other words, should the order be:

Lens > Clear UV > Step-Up Ring >Variable ND or Polarizing​


Or should it be:

Lens > Step-Up Ring > Clear UV > Variable ND or Polarizing
​


And, if I were to consider buying some magnetic Xume Quick Release Adapters to allow for quicker ND/Polarizing lens changes, would that change the equation?

In other words, with Xume adapters, should the order be:

Lens > Clear UV > Step-Up Ring > Xume Adapter > Variable ND or Polarizing

​


Or should it be:

Lens > Step-Up Ring > Clear UV > Xume Adapter > Variable ND or Polarizing
​


Thanks in advance for any advice.
 
I dropped the UV a long time ago. Definitely a good idea for beginners using expensive lenses, but not for me anymore. Now I just take care.

So, for me, that would be:
Lens > step up ring (glued) > ND

(the glued step up ring was a really good decision for me; it makes changing filters A LOT easier, since now it's always the filter that comes off when you spin) (I don't plan on selling any my current lenses, ever; they are all made of pure love)
 
Thanks for your response.


So, I guess the next question would be:


In terms of using step-up rings to standardize the thread sizes of all of my lenses, is there an optical difference (or disadvantage) to mounting a filter (Variable ND, Polarizer or UV) on a step-up ring -- as opposed to directly onto the lens?
 
I honestly have no idea. There's no way I'm going to buy a filter set for every lens I own, so I guess it was the only alternative... short of a matte box, which btw will usually put the filters even farther away from the lens.
 
In most cases the closer a filter is to the len's front element the better, but for practical reasons it's often moved farther away (ie many matte box setups).

Typically I only use clear (ie Clear, UV, Sky) filters when the front element needs protection (ie flying gravel, smashing glass, etc) but often use UV/IR filters if a particular camera (such as Blackmagic's) is especially susceptible to those wavelengths.
 
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blafarm said:
Thanks to both of you.
Click to expand...



Here's the rundown from a my point of view, and this is from my experience using cine lenses but maybe it can help with your situation:

There is protocol with filters and the order you stack them....But first, I want to talk about protective filters... Any piece of glass in front of a lens is reducing the optical quality of a lens. By laws of physics, there will be some minor light loss, loss in resolving power, and the increased possibility of internal reflections creating a loss in contrast and possible ghosting. In most cases, it's very slight. But that said, I always remove any unnecessary 'safety glass' in front of a lens for optimum quality.

In the film and television world of cinema lenses, we almost never use protective filters except in appropriate situations, thus I find it hilarious that we, under normal circumstances, use very expensive optics without any protection and when we get a $600 photography lens for a particular application, it comes with a protective UV filter! I mean, really? Master Primes don't come with protective filters... So the first thing that goes is the screw on UV filter, unless it's specifically needed for UV protection, which is rare. The only exceptions for front protective filter, in my opinion, are when using extremely rare optics and when in situations where you need protection from possible hazards. An example of the former would be for some unique super wide modern anamorphic elements. I believe I left a Hawk 20mm Anamorphic protective filter on, only because the anamorphic front element is just too rare to replace. An example of the latter would be when shooting low to the road for some leading or following car to car shooting or when shooting explosions, or other activities where debris could be sent towards the camera. We normally use optical flat filters versus screw-in UV filters, fwiw.) Other than that, I can say after years of using lenses with lofty price tags, we don't use clear protective filters unless the lens is in specific danger of damage. Lenses are always insured and always taken care of by professionals. After 200+ productions working with cine lenses, I can safely say I have never had to replace a front element from any sort of scratch, ding or other type of damage.

So my advice is to not sweat protective filters. Take care of your lenses with proper care and they will stay clean and clear!



Ok, regarding other filters....

IR Filters (Hot Mirror, IR CUT, IRND combo, etc) always are the first filter in the MB, (first being they are the first filter upon which entering light must first pass through.) Make sure the filter is facing the proper orientation outward. Typically if the engraved labeling of the filter is facing outward (the assistant looking into the MB can read it properly) than it's the right orientation. If no engraved filter label, look carefully at both sides of the filter and the side with the greater 'mirror finish' is the one that faces outward.

Diffusion filters can go in many places, but their effectiveness changes slightly depending if they are immediately in front of the front lens element or positioned further away. The same goes for Grad-ND filters. The edge of the grad filter can be made more or less pronounced depending on the spacing distance from the lens. Further away will have a harder transition and closer will be a softer more subtle transition.

Pola's are typically last in the filter order (nearest to lens) mainly because matteboxes have the 138mm round stage in the back.

To answer your question, putting a step-up or step-down ring between your lens and the filters is often necessary but it also creates a small distance, or gap, between them. This will have a very small impact on the filters function if diffusion filter, grad filter, and etc. There is also increased potential for optical reflections/ghosting if the spacing ring or stacked filters are not perfectly parallel or well coated. For this reason I would aim to have as little space/gaps between lens and filters (and filters and filters) as possible. I wouldn't worry too much about it, but the more parellel and compact your filters are to each other and to the lens elements, the less of a chance of internal reflections.


PS: maybe you should invest in a MB system. These allow you to switch lenses quickly and keep your filter pack ready to go, not having to waste time changing filters or buying multiple sets of filters so all lenses have the filters already on, like it seems you are doing.

PPS: I will continue my crusade against Vari-ND's. There's no such thing as a free lunch and in my opinion, they really aren't worth the convenience. :)
 
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Ryan Patrick O'Hara said:
Pola's are typically last in the filter order (nearest to lens) mainly because matteboxes have the 138mm round stage in the back.
Click to expand...

I agree, but for a different reason (I don't use a mattebox): pola's can act as an ND, so it is better to find the pola's sweet spot first and then screw on additional NDs if required.

And if you throw diffusion (that can also rob you of light) into the mix, you still add the ND last, if required.

Lens -- Pola -- (Diffusion) -- ND
 
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