Hoya Ra54 Red Enhancer (Intensifier) Review

For some photographers, filters are not required for astrophotography or night photography in general. This is in general partially true, but with the exception of Light Pollution Filters.

Light pollution filters were well known for astronomers and deep sky astrophotographers for quite some time now. Night sky enthusiasts started using them back in the 80s when they realised that they could gain more contrast and detail for the faint deep sky objects when using them in front of their telescopes.

In our days, where the biggest percentage of our planet is heavily light polluted with lights of every kind, Light Pollution Filters is a must-have for night (sky) photographers as the most us lives near big cities.

As for the filters, there are plenty of choices in the market, with the cost ranging between a logical amount of euros and reaching nearly the cost.. of a lens..

HOYA Ra54 Red Enhancer (Intensifier) filter

The HOYA Ra54 is made from a rare earth element called Didymium and it is ideal for landscape photography because it primarly enhances red, orange and brown colors, giving them more contrast and saturation while not altering other colors of the spectrum.

It can also filter out the yellow and orange part of the spectrum from 575nm to 600nm, the colors of sodium vapor lamps which are mainly used in big cities, making it an excellent light pollution filter.

It looks like a common clear uv style filter, only having a faint purple tint and it comes in ranges from 49mm to 82mm.

Testing HOYA Ra54 Red Enhancer on the field

All my tests were made with : Nikon D800 and Sony A7s cameras and the lenses I used were : Nikon 20mm f/1.8, Sony 28mm f/2, Sigma 35mm f/1.4 Art and Nikon 180mm f/2.8 (only for deep sky). All the lenses had the HOYA Ra54 filter on.

All the images are straight out of camera raw files, with no editing.

My first test was made in my house. In the street below my house there is a lamp with a strong yellowish glow so it was the most obvious thing to do.

(Sony A7s, 28mm, f/4.0, 2 sec, ISO 1000, Daylight WB)

The image on the left is without filter while the image on the right is with the filter on.

As you can see there is a clear difference.

One minor issue though is that some unwanted flaring may be seen on the right (lamp) probably because the filter does not seem have any anti-reflective coating so beware for any light facing directly into the lens when shooting.

But lets see how it performs in clear dark skies, far away from light pollution.

(Nikon D800, 35mm, f/1.4, 10sec, ISO 3200, Daylight WB)
(Nikon D800, 35mm, f/1.4, 10sec, ISO 3200, Daylight WB)
(Sony A7s, 35mm, f/1.4, 10sec, ISO 3200, Daylight WB)

As you can clearly see in the last image, there is again some unwanted flaring near the galactic core, which I assume it was created by the intense light of the Syrp Genie which was directly in front of the lens. In my opinion it’s not something to worry about as it can be removed easily in most cases.

From my tests I measured that the filter also reduces a little more than a half a stop of light transmission (0.60 – 0.75 stop) so be sure to manually focus before attaching it in the lens (live view and/or focus peaking) and also beware before using it that you should alter your final exposure a bit either in shooting or in post. It is an insignificant loss as todays cameras are capable of producing great quality raw files that helps equalise the exposure flawlessly.

One other thing to keep in mind is that the filter works better under dark skies although it can be used in light polluted areas. Just dont expect to capture the Milky Way galaxy from a city just by attaching the filter on your lens.

 

An excellent filter, in a very affordable price compared to other options, with an immidiate effect in your night sky images !

 


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