Working With HOYA R72 Filter (Infrared) on a Full Spectrum Modified Camera

REVIEW: Long-time Usage by a Photographer, tutor, and Fine-art Artist



Important to know before reading:

Some of the photos in this review are made with the very same composition or subject. That is done in order to illuminate the issue better. Other photos are already finished artworks on which I have manipulated some quick blemishes ("photobomb") etc. All artworks here were done with the help of the Hoya R72 filter on a full-spectrum camera. Where I used a non-modified camera, I mentioned that in the writing. Happy reading!



I have always been loving to use new, exciting materials in my art and professional work with clients. Most of all, I have loved to use trusty materials and tools. As people already came to know me, I started my artistic route some 2.5 decades ago with a Black & White art (B&W). Since then I have always honed up my eclectic style and implemented B&W art even in the coloured work that came along the years.

Shooting in B&W is not simply taking a photo and desaturate the colours off it. When I talk about B&W I, in particular, mean the symbolic differences between Black and White. One thing is the opposite of another. That is what most of my work touches with. To being able to create such a body of work, in addition to my composition making process, I required special cameras, filters, lenses, and accessories.

Taking different camera bodies to a location, I tended to always take some special ones in addition to the "regular" full-frame bodies, just in case, I would think that a special photo opportunity could come by. One of those special camera bodies that I just mentioned is a full-spectrum modified camera. Having had a few from a few known converters in the past, I got my current full-frame one from a skilled and efficient sensor conversion service called "Infrared Camera Conversion". It is located in Europe and run by a specialised camera technician. As it appears, the service gets orders from all around the globe. Luckily, New Zealand, where I am usually based in, is still part of the world...



An Issue You Need to Know About Modified Cameras

I am not affiliated to the latter service but have been shooting with their converted camera for quite a while now, I would recommend for their good job in converting my piece. A very good point to mention is that they do not use silly scare-tactics on their website! As many of my readers and followers know, this is not my very first converted/modified camera. I have read so many scare-tactics on the websites of the other conversion-service competitors, and to be honest I was fed up with those brutal marketing tactics. They promise auto-focusing alignment after changing the sensor filter, however, up to today, I have never gotten a perfect auto-focusing full spectrum camera, and that is due to a few possible reasons that are not necessarily related to the bad practice of any of the conversion services I used. Sometimes the lens is simply not the right one to use! One needs to understand that the camera bodies are originally engineered to work with a specific spectrum of light, filters and lenses. Changing either one of those and you may get issues in focus. If you have not gotten any issue, then you're lucky. Otherwise, prepare yourself for a manual focus shooting, and believe me, this is not that hard to master it!

Focusing with Infrared filters, for example, is totally different from focusing with cameras that have "regular", visible light, and this is related to optics and how the projection reaches the sensor. Different wavelengths of light (different light colours) reach the sensor differently, and for instance, even in visible light you get diffraction, don't you? Hence, basically, I tend to be using MANUAL FOCUS when I shoot with those cameras. If to add one more thing about auto-focusing, then only the Hoya UV/IR filter assisted in the autofocus following the conversion of previous modifications, but that turned the camera back to only visible light wavelengths capable. The latter filter was also reviewed by myself previously. You can read the review HERE.




What's the Big Deal?

So, what does a full spectrum camera do that a "regular" camera does not? A full-spectrum opens up more wavelengths of light to your sensor. Originally, the sensor is set to receive only the mankind eye's visible colours (visible light). On one side, the infrared is the energy on the electromagnetic radiation line that stands beyond the 700nm. This puts the energy past the visible RED colour, and since its magnitude (strength) is lower than the visible red, it got the name infra-red (infra means "lower").


On the other side, another energy go past the visible violet colour. Since the violet colour already has the strongest magnitude in our visible light, all of the wavelengths beyond the visible violet are called "ultra" violet.


Both Infrared and Ultra-violet energies are invisible without special devices. Luckily, the camera sensors are very sensitive to all (, actually to most) of the spectrum from Ultra-violet to Infrared. That large stretch of the spectrum is called "full-spectrum". Now, one may ask the question "why should I modify my camera if I already have a full spectrum sensor?". The answer is that the absolute majority of the digital consumer and professional cameras go out of the factories with special filters that are put on top of the sensors. That filter is nicknamed "hot mirror", but many usually call it "infrared filter". The purpose of the filter is to allow the sensor to gather ONLY the light energy that stands in the margins of the mankind visible light/visible colours. Hence, when taking off that sensor filter (and replacing it with a transparent glass) allows the sensor to use all of its capability and therefore to gather the full-spectrum.


Those who are not sure what colours a pure full-spectrum shot can yield, straight from the camera, I created the below examples. The image shows a shot where the right-hand side is full-spectrum, while the left-hand side gets the "regular" visible colours. Please note, in this image I have let the white-balanced to be on "Auto". To get such effect I held the camera in my right hand, and the Hoya UV/IR filter on the left hand while covering with it half of the camera lens. As described above, the Hoya UV-IR filter turns any full-spectrum modified camera back to a "regular" only visible light camera.






HOYA R72 Filter

Today I give my notes regarding the use of the Hoya R72 filter. I have used this filter on both full-spectrum converted and non-converted bodies. Previously, I wrote a review on that filter; that earlier review was aimed to mainly the beginners' audience among you, who still have not put your feet down in the waters of camera conversion. You can read that earlier preview HERE. This review that you read here, however, is aimed for those of you who seriously consider modifying your camera bodies to full spectrum. Another review that is related to the ultra-violet area of the spectrum will be given in a separate article.


What wavelengths does the R72 relate to?

The Hoya R72 is a filter that blocks all of the wavelengths that are located on the stretch between the ultra-violet light (300nm) and the visible light (700nm). It allows light to pass only from around 720nm and then almost all light from 750nm upwards. In those wavelengths, the modified camera would yield a washed-out pinkish/reddish colour over all of the areas of the image.


Once we touch on the White Balance topic, we can refer to the real magic we can do with the filter. The below image was taken with an "Auto" White Balance. As you can find, the entire shot is washed with a faint red. (Do NOT be put off by the washout! The good stuff is further ahead!)




Pay attention that the closer tree (the one at the centre of the image) is sharp. The shot was taken in a low ISO (125) and relatively faster shutter speed (1/400sec), and on an aperture of f/5. Such exposures can capture sharp subjects due to the ability to gain a broader spectrum above the 700nm.

In comparison, cameras that are not modified are unable to gain that large stretch of infrared wavelengths, and actually, gain only 1% of the light that is achieved without the filter on the lens. The fact that the non-modified cameras cannot gain too much light requires those cameras to use substantially longer shutter speeds. This inevitably creates much blurry objects or background in the images when one shoots trees, clouds, cars, or anything that has even the slightest of movement. Another matter to remember when using non-modified cameras is that the colour of the images is usually much deeper when using similar exposure settings to the above image. You can find in the previous review what I wrote about non-modified cameras (HERE is the link).


The image below gives you the idea of how you may find your images on a non-modified camera (auto White Balance)






From here on we will not touch anymore on non-modified cameras.



Back to Full Spectrum Modified Cameras:

I have to mention another effect in infrared images; this is the contrast. This effect varies in different images, and it depends on the ability of the sensor to gain wavelengths past the 900nm or 1000nm. This is NOT related to the Hoya R72 filter but solely to the sensor. In such higher wavelength levels of the spectrum, the light anyways seems totally colourless. The higher we go in with the wavelengths - the stronger contrast we gain. If your camera sensor is manufactured as being unable to gain very high wavelengths (beyond 1100nm, for example) then the contrast would be lower to a sensor that does gain beyond the 1100nm. This is simple math, right?


To be truly honest, and I say it as a photographer that was nicknamed as "the B&W artist", the contrast that those newer cameras' sensors of this era can get does not play a great role, and only those who have extremely bitter personalities may bother to pay attention to the slight differences in the contrast. After having both DSLR and Mirrorless cameras modified onboard, taking thousands of photos with them, I honestly do not feel any real difference between the sensors, let alone that some camera manufacturers use the same sensors made by one of their rivals. So, I had to give that 'contrast' issue the stage, but this is not a big deal with this filter!


Below you can find the spectral (the wavelengths) that the R72 filter blocks, and those it passes through. The image was taken directly from Hoya's website.




White Balance:

White balance is a very important part of ANY image, and in infrared images, it takes a huge role! As we saw above, when shooting with the R72 filter on the lens, the image gets washed out with reddish/pinkish stain. When shooting your files in RAW, that may not be a substantial matter; however, in JPEG shooting the details of the image are already "baked" into the file and even in post-processing software, there is an immense data that is lost. The white balance is hence an important part of the shot, let alone the composition.


Furthermore, even when shooting in RAW, setting the white balance right through the camera is advantageous to you, the photographer. The composition can be corrected on the spot if you find that the shades are not as you desire. Post-processing may not get you the best result, especially when you look for getting smooth and clear results.


Sometimes, setting the white balance on different areas of the shot can yield different feel to the shot. The images below illuminate this matter.



Full Spectrum Modified Camera with HOYA R72: White balance on the greenery

Full Spectrum Modified Camera with HOYA R72: White balance on a Grey Card

Those two shots were taken in very similar weather conditions and were about ten seconds apart in sequence. As one may notice, the white balance on the greenery created a much visible contrast and separation than the second shot that was white balanced on a grey card. The chlorophyll of the grass and the trees' leaves is substantially brighter when white balancing the shot on greenery.


For black and white artworks, I would recommend white balancing on the area where you would like to let the beholders perceive as white. Afterwards, through a post-processing software, shifting the image to B&W would allow you to play better with the contrast.

This is genuinely your preferences that play the game in here. There is no good and bad, no right and wrong. As a B&W artist, I personally prefer a stronger contrast.


The below images illustrate the difference in the contrast that white balancing on different colours leads to:



White balacing on the greenery. Before and after turning to Black and White

White balacing on a Grey card. Before and after turning to Black and White


For those photographers who prefer to concentrate on coloured images, as opposed to B&W, the Hoya R72 can create fabulous artworks! When combining with other filters as a composite artwork, the wonderful qualities of the contrasty images are adding up a character to the shots. This eases the work when working on the artwork in the post-processing software. The examples below illustrate this matter:









Should I recommend the Hoya R72 filter?

Gosh, I am a Global Brand Ambassador for Hoya filters, so I am clearly representing Hoya around the world. But beyond the known affiliation to Hoya that I am known to have, those who have come in contact with me and my work along the years know well that I stand for my word. No matter what manufacturer made my tools, what service I used, or what product I buy, I never give any good word for a product that does not deserve it. Hoya knows very well that my reviews are genuine and if there is any issue with any product then I do reveal it in my reviews.


Having said this, I do recommend the Hoya R72 filter for both B&W and coloured infrared creations. The filter is made by the biggest optics company in the world, and it does not leave brighter areas on the image like those fake, cheap and unknown sourced filters. I have used the R72 for quite a lot, and I do wish that more infrared filters in additional spectral be created by Hoya.


Lastly, despite not being affiliated to, I have to recommend for the camera conversion service that I used lately, http://www.infraredcameraconversion.com/ . Based on my own experience with other service providers' cameras in the past, I feel that there is a great product that I get for the money spent. Conversion of cameras can definitely be tricky work, especially when it involves dust in the sensor; I have already seen in other conversion providers' cameras dust located in between the sensor and the new transparent glass. I returned the product immediately. Instead of paying to the roof or the moon with other providers, check out that service above, and I am more than certain that you get shooting full spectrum or infrared in no time.


Hoya R72 can be seen on Hoya's website on this address: https://hoyafilter.com/product/r72_infrared/


Please feel free to comment or make a contact with me regarding any of my reviews or services. I'd be more than happy to assist.





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Collins Ryàn - L'artiste is a professional photographer, tutor, reviewer, and artist. Collins is a global brand ambassador for Hoya, Tokina, and Kenko, Japan