The Big 4 "night filters" comparison

Attention please: as others my comparisons between other brands, I've try to realize this review without preferences in a specific brand. I'm expecting the same from you as interested reader:
are you a fanboy, a promoter, a sympatizer for a specific brand? Please close this page with the X on the upper part of the screen in the right... or... just scroll to see if your convinction is really founded or not, but please: don't give suggestions or opinions if you are not in right, thank you.

Hi! Finally my tests with this 4 brands about night filters are finished. Actually I've compare 4 brands but 6 filters because two of that night LP filters are squares, the others are circular filters.

I've got to remark this aspect because the most evident result is which, in almost all cases, there is difference between the circulars and the squares filters... we will see in which terms.

Meantime let me show you, in specs, which brands and filters I've analyzed for this comparison:
 

Haida circular "Clear Night" filter
Kase circular "Neutral Night" filter
H&Y circular "PureNight" filter
NiSi circular "Natural Night" filter
Kase square Wolverine "Neutral Night" filter
H&Y square "PureNight" filter, with magnetic frame


 

Ok, so, first of all let me explain what is a "LP" filter and how should be used. 

A "Light Pollution" filter is, generally, a filter made of Neodymium (a film of it between the glass or a glass made of Neodymium inside, added in as "dopant" of the material).

The applications spacing from nice furnishing accessories (as lamps) to specific scientific applications as to build the most powerful pulse lasers in the world... and, yes: also in photography as night filter.

Why? How could be useful?
Well, this chemical element (which is not available in nature as native state) is a metal with a lot of property: one of them is the capacity to assume different colors if different kind of light pass through it (starting from cyan, crossing the nuances of blue - violet, until the  magenta).
this means which it could not be the same experience about using one old "colored filter" like the blue one, because the sensor capture the result of the reaction between the light and the Neodimium glass and this aspect can be change starting by the light position respect to the snap position.
This is very important because helps you to understand some differences between products and their applications!
Indeed, because of the Neodymium reaction, I've see which some filters works significantly different if you change the place of your snaps respect of the light pollution: that's because of the thickness of the neodymium glass!

But let me explain better: as we will see, some brand has choose to build the same identical filter glass for square and circular filters but the others not: this looks like a different approach to the market but also the possibility to give some internal selections between circular and square filter type.
So, the NiSi brand has build the circular at same thickness glass of the squared filter (or maybe very closely to that): it's, most probably, a marketing choice for persons which want to snap cityscapes and which own a last generation camera.
The other circulars are different, much more thin glass = less filtration but also much more respect of the rest of color spectre: this means, In my opinion, a different application and I think is a good thing because sometime is not need have too much filtration, especially if you want to apply the filter in some astrophotography snaps. But means also which the other brands has realize different "LP lines" thinking about people which don't have more than pro-apsc cameras, so they don't have the same possibility to arrange the file as the others which possess ultimate full frame cameras.

Well, let's go deep in details
I've made a lot of comparisons in different situations but, the fact is that I've decided to use the white balance of the snap without filter and keep this value also with filter installed, for each one: in one session I've also decided to measure the WB using the card, then keep the measurement for all snaps, with and without filter.
Let's see also how this aspect change if we will put the same white balance in camera raw, for postprocessing.

First, we will start to check the snaps realized near the city but not inside of that: will be some peripheral snaps, in wideangle.
In this snaps we will see how the filters can handle the glow of the city.

Checking the histogram we can absolutely see that all circulars are, more or less, similar except the NiSi which is very similar to the square filter versions. I sincerly don't like and don't think that the effect of the Nisi Circular, Kase square and H&Y square is good for this application... if I've to choose one I sincerly prefere the H&Y square because of the good color spectre in yellows but also the nice cut in the green part of the spectre, helpful to cut "hoxigen" glow but, also, a bit of the led light spectre. 

Talking about the rest of the filters, it is evidently which, this ones are much "light" (than the squares and the NiSi one) about the result of the filter effect. Probably also because of the coatings applyed, I recommend the H&Y for the same reason, the cut of the green-light spectre, followed closely by the Kase. The Haida looks like a "middle way" between the Kase and the NiSi circulars.Let's see what's happen adjusting the white balance of the first snap, without filter. 

Well, as normal is, we can try to set the white balance after the snap (because of "instable" color cast of the filter... as I've explain in the introduction of the article) also to obtain amuch more "normal" - unaltered colors. So, starting from this, we are much able to choose the right filter.
The more rich about signal is, again, the H&Y circular (which shows clearly the cut in yellow frequences but in green - cyan too), followed by Kase circular aaaaand also the NiSi give a very good result! Then we have the H&Y Square and, more or less, the same result for Haida circular & Kase square.

Conclusions: which one is better?

- H&Y Circular PureNight Filter


Let's continue checking the snaps of this "night filters" used into a very yellow small town, because of old tungsten bulbs. We will compare result checking also the sky but, most of all, the color temperature result.

What say... this was a very hard condition: I've search the flare with a very super yellow light of this ancient village with a complication: the houses are yellow, the stone of the church too, so it is an extreme situation which help us to understand also how filters can handle the color of the things, not just the "hot lights". At first impact is almost impossible to reach a good setup for white balance on camera, however I've also propose the same snaps with WB modified for all, in the same point with same values aaaaand, if circulars are "more or less" the same good option, the best one looks the H&Y Square filter, the worst one the NiSi and the Kase square (because of the too many red tones especially in the shadows of the stairs).
Best control of the flares? The Kase square seems pretty good!

And, finally, an astrofollowed snaps-session of the sky near a big city with, also, clouds in the middle.

Let's check the capacity of each single filter to handle the light pollution refracted by the clouds in the sky

Well, I was returning to home and... FINALLY, after months I've the chance to do this final comparison which is, IMHO, the most important and interesting aspect of this filters: they have effect for some astroscape - astrofollowed snap?


YES...BUT...

right: there's some differences that confirm my guessings about the "way" which some brand has follow and some other not.
If circulars as Kase, H&Y, Haida too are very good to filter the  glow of the distant cities, in astrophotography are not so good especially if the sky is clear and the subject is not the milky way core (because of the nuances which this part have).

By the way we have, as histograms shows, a very good actions of all filters in the frame. Impossible to establish with accuracy which is the better, generally the Haida circular and the H&Y square filters looks as the best way IMHO, because of the cut not so aggressive about the cyan - green color spectre and also because of the reaction of the Neodimium glass if not directly exposed to the citylights.


That filters are closely followed by the NiSi and the Kase square which is pretty good to handle light pollution but I certainly say which is not the best for milky way snaps (returns too much violet cast and is not very the best for nightpics of the sky because of, more or less, -1 stop in light transmission)

But let's check in detail...
I've isolated a specific corner of this snaps and...

it's VERY interesting to see which the filters give not the same result at all!!!
Best result is the one of H&Y square filter which influence not so much the spectre, including the reds, followed very closely to the Haida which has some difference of spectre in reds, so could be a problem with a lot of subjects in the sky like some nebulae...
then we have a good result of the NiSi, followed by the two Kase and the H&Y circular.

OOK, I MADE IT! :D
It was hard and, I know, it's very complicated to try to find the perfect filter for our pics. I sincerly hope to have explain better how it works and, give you some material to help you to made a choice! Feel free to share,  ask me in comments or contact me HERE.
CIAO!!!