Vis UV IR Flower Photography Guide

The images on this site consist of 3 photos of a flower - one in visible light, one in ultraviolet light, and one in infrared light. On this page I'll share the equipment and techniques I use to get these photos.

Vis UV IR Flower photography gear

Camera

First of all, you need a camera that can record infrared and ultraviolet light. The image sensors used in digital cameras are sensitive to IR and UV light. But people normally only want to record images taken in visible light.

So camera manufacturers install a filter that sits on top of the image sensor in their cameras. This filter blocks ultraviolet and infrared light, so that only visible light will be recorded by the camera.

Therefore, to take ultraviolet and infrared photos, you require a camera that is missing the UV and IR blocking filter. The camera I use is the Fuji IS Pro, which is manufactured without the blocking filter. However, you can also have the blocking filter removed from any standard camera using a service such as LifePixel.

I would recommend getting a camera converted through a company such as LifePixel over the Fuji IS Pro camera that I use. A reasonably modern camera will have better image quality and a decent liveview implementation compared to the Fuji IS Pro. You want to go for the full spectrum conversion.

Once you have a full spectrum camera, the camera will take photos that are a mixture of UV, visible, and infrared light. To create a photo that consists of only ultraviolet light, or only visible light, or only infrared light, you then need to use blocking (or cut) filters that cut the wavelengths of light you don't want recorded.

You'll need one filter for visible light photography, one for ultraviolet photography, and one for infrared photography. These are detailed below.

Visible light photography

For visible light photography I use a B+W 486 UVIR cut filter. This cuts ultraviolet and infrared light, so the camera only records visible light. Just like the filter installed in a standard camera does.

Note that with wide-angle lenses this filter can cause a cyan vignetting effect, but you are unlikely to use a wide-angle lens for these sort of flower photos.

Ultraviolet light photography

UV photography is trickier and more expensive than visible light and infrared photography. It is quite specialist, so a filter that passes UV light while cutting visible and infrared light is expensive. I use the Baader U (Venus) filter, which is designed for astronomy use.

Next, you need a lens that passes UV light. Most modern lenses have coatings that block UV light, and even the glass in the lens itself can block UV. Lenses also tend to focus ultraviolet (and infrared) light at different points to visible light. This creates a focus shift, so when focusing a lens under visible light, you then need to focus closer for a UV or IR image.

You can purchase specialist lenses that will pass UV and also exhibit no focus shift. They are extremely expensive though. For example, the Coastal Optics UV-VIS-IR 60mm f/4 Apo Macro, the Pentax Quartz-Takumar 85mm f/3.5 Macro, and the Nikon UV-Nikkor 105mm f/4.5 lenses.

Thankfully, so long as you are willing to deal with a small bit of focus shift, you can get along with much cheaper enlarging lenses. The EL-Nikkor lenses are generally regarded as pretty good for ultraviolet photography.

An enlarging lens has no way of focusing, so you will either need a bellows or a focusing helical. This enables you to change the distance of the lens from the camera, thus modifying the focus.

I use a combination of extension tubes and an M42 focusing helical. The EL-Nikkors are M39 mount, so I also use an M39 - M42 adapter, and an M42 - Nikon F mount adapter.

I have the EL-Nikkor 50mm f/2.8 N, EL-Nikkor 75mm f/4 N, and EL-Nikkor 80mm f/5.6. The EL-Nikkor 80mm f/5.6 I own is the old (non N) edition, and has a filter thread you can't buy filter adapters for. So I had to glue a step-up ring to the lens to allow mounting filters on it. It has quite a small amount of focus shift.

The EL-Nikkor 75mm f/4 N has a larger amount of focus shift and doesn't seem to pass quite as much light as the 80mm (when both set to the same aperture). The 50mm has a very short flange distance, and would need to sit inside the camera for infinity focus. It is useful for close-ups of smaller flowers, or used reversed for macro work.

Two websites that have reviews of lenses for UV photography (as well as lots of other useful info) are EL-Nikkor lenses in UV photograph and [UV] EL-Nikkor 75mm - 80mm - 105mm for UV?.

Finally, you also need a UV light source. Although the sun does output UV, there is not enough for a good expsoure without the flower blurring from blowing about in the wind. (If you photograph cut flowers indoors you won't have this problem though).

I use a Vivitar 283 flash with the fresnel lens (which blocks UV light) removed and replaced with clear plastic. This flash can be had quite cheaply on eBay.

Infrared light photography

Infrared photography is a lot more popular (and cheaper and easier) than ultraviolet photography, so there are quite a few different infrared filters available. I use a Hitech Infrared Cokin P resin filter. But the Hoya R72 seems to be the most popular infrared filter.

As with ultraviolet photography, most lenses exhibit focus shift between visible and infrared light. So you may need to adjust focus slightly. Most of the time I find when a lens is focused OK in UV, then it will also be OK (or just a small adjustment needed) in IR.

Checking focus in infrared can be very tricky as infrared images are typically very low contrast, with all parts of the flower (and foliage in the background) appearing much the same tone. Working in my garden, I sometimes take the memory card into the house, and preview the image on my computer with a strong contrast adjustment to check whether focus is okay or needs adjusting.

Keeping the framing and perspective similar

To keep the three images comparable, care has to be taken to photograph the flower with the same perspective for each shot. This, plus the fact that you can't see what the camera sees when shooting UV and IR, means that a tripod is a necessity. This keeps the camera locked down so that all three photos will look the same in terms of composition.

I use a carbon fibre Benro tripod with a Manfrotto 410 geared head and a set of cheap eBay focusing rails.

The geared head allows for precise adjustments, useful in close-up work, and very useful in macro work.

The focusing rails similarly allow for precise adjustments. They are particularly useful for moving the camera further back from the subject to compensate for focus shift in ultraviolet and infrared photography.

I don't recommend the cheap eBay ones I have, the cogs keep slipping on the rails. Instead I would suggest the Novoflex Castel-Q, which seems to get plenty of good reviews.

For low shots, you can reverse the centre column of your tripod and shoot with the camera upside down. With my camera this is quite a pain as you can't see the ISO etc. buttons, and it only displays ISO etc. in the the viewfinder and the top LCD, not on the rear LCD.

Alternatively, I sometimes use a Manfrotto super clamp clamped to the bottom of a tripod leg. With a 3/8" stud in the super clamp, I can then mount the head to the clamp to shoot lower than my tripod would let me otherwise.

If you don't already have a tripod, consider one of the special tripods that will lower completely to ground level. Mine will do this in theory, but has quite a tall centre column that means the head will always be at least a foot of the ground when mounted normally.

The Manfrotto 410 plus focusing rails is still quite tall even when mounted right close to the ground. So sometimes I opt to use a Markins ball head instead. This head is very good as far as ball heads go, but lacks the precision adjustments possible with a geared head.

Lighting

Ideally lighting would be kept the same for each shot. However, due to the relatively low sensitivity of my camera to ultraviolet light, I find that I have to use different lighting for my UV photos than that to the infrared and visible light photos.

For infrared and visible light photography, I sometimes use natural light. Sometimes I will use a small diffusion panel to diffuse the light.

Other times I will use flash, often shooting the flash through the small diffusion panel for a softer light. I use a Vivitar 283 flash with a log scaled 100k potentiometer (variable resistor) to control the power output.

For lighting the ultraviolet image, I use the same flash, but remove the potentiometer. This means that the flash fires at full power. I often add another Vivitar 283 also at full power. And I place the flashes as close to the flower as possible, with no diffusion. I want as much light on the flower as I can get.

Despite all the extra light, I still have to turn up the sensitivity on my camera to ISO 400 - 800 (typically ISO 800). Remember that only a small proportion of the flash output is UV.

Lighting for infrared is the same as for visible light. I am more likely to use undiffused light for infrared though as it adds a bit of contrast to the otherwise flat infrared image.

The Vivitar 283 flashes I use have a very high trigger voltage that would kill a digital camera. So I use a cheap eBay radio trigger to trigger them. I have adapted my trigger so it has a PC sync socket that can plug into one flash, and a long PC sync cord that can plug into another flash, meaning I can trigger two flashes from the one receiver.

I don't recommend the radio triggers I use, the connections inside the unit are always breaking and needing to be re-soldered. Check the Strobist flickr group for reviews of cheap radio triggers to find the ones that represent good value for money.

Other gear

An LCD magnifier / hood is useful for reviewing images on the camera's LCD on sunny days. Otherwise the sun on the LCD can make it very difficult to see properly.

A bulb blower and Lens pen are useful for cleaning lenses and filters. I wouldn't want to try using the pen part of the lens pen for cleaning the Baader U filter though. It might work well for all I know, but that filter is expensive to risk damaging.

Remote shutter release cable lets me trigger the shutter while holding two flashes or a flash and a diffusion panel.

Extra batteries for the flash. I use PowerEX and Eneloops, I prefer the Eneloops.

Nikon AF-1 or AF-2 gelatin filter holder is not essential by any means. It screws onto your lens like a normal filter, but can open up. This allows you to screw an opaque filter (like the Baader U) onto the AF-2, then open the AF-2 to see through the camera viewfinder. Then close it back up to take the photo. This is most beneficial if you are doing only UV photography, and so don't want to change filters.

An L plate bracket is something that would be very useful but I don't own. It lets you mount the camera in portrait or landscape orientation without having to adjust the tripod's head at all.

Various stepping rings are used due to the different sizes of the filters I have. The Nikon AF-2 gelatin filter holder has a large filter size, so I have to use step-up rings on the rear of it, and step down rings on the front.

A Plamp can sometimes come in handy for holding a plant still so it doesn't blow about in the wind so much. It isn't useful in all situations, since you need some way of attaching the plamp to the plant while also keeping it out of the frame.

Another issue with the plamp is that with larger flowers, the tripod may need to be positioned too far from the camera for the plamp to be able to reach the flower. Sometimes I use it to hold a diffusion panel up over the plant.

Image processing

How I process the images is quite variable. Typically for the visible light image I will adjust white balance and exposure.

For the ultraviolet image, I like to experiment. Probably the settings I use most though are to set the white balance so that tint is at 0 and the colour temperature is set to around 5000-6000k. I then open the image as a smart object in Photoshop.

In Photoshop I will create a channel mixer adjustment layer. I set Red to 100 blue, Green to 50 blue and 50 red, and Blue to 100 red.

After making this adjustment, I open the smart object and adjust exposure to taste.

For the infrared photo, lately I am just applying split toning with a warm colour for the highlights and a cool colour for the shadows. I adjust exposure, white balance, and saturation as well. These settings are quite different to what I use for infrared landscape photography.

After processing the three images separately, I put them together in a Photoshop template file I created. This ensures the images are spaced evenly and gives a consistent look between the different images.

More information

There are quite a few websites with good resources on multispectral photography:

Enrico Savazzi

information on scientific, UV, IR, macro, and micro photography.

Photography of the Invisible World - Dr. Klaus Schmitt

Lots of information on UV photography, lens tests for UV, and UV flower photos.

Beyond Visible - Shane Elen

Information on filters and flash for UV photography, plus other related info.

Bjørn Rørslett

Information on UV and IR photography, lens suitability, and a large number of UV flower photos.

Beneath the Waves - Ben Lincoln

Information and photos on UV and multispectral photography

My own website is www.davidkennardphotography.com, where I sometimes post information relating to multispectral photography on the blog. If you have any questions, please leave a comment below, or you can contact me through my website.