Jonathan's blog

Background

I’ve dabbled in infrared photography a few times, originally using Maco 820c. The results were varied and I didn’t shoot it often enough to get a good feel for it. More recently, I bought some Efke IR820. If you’re reading this post, you presumably know vaguely about the film already, so I won’t go on about it.

I decided to make a renewed attempt to understand how to expose the film reliably so I can start taking decent shots with it. I don’t have a proper light meter. If I can be bothered to carry my DSLR, it makes an excellent spot and average meter. If not, I use an iPhone app called Pocket Light Meter, which is surprisingly good.

There are various methods of metering for infrared film. The light meters in some SLRs can meter infrared accurately through the filter; unfortunately the one in my Canon AE-1 Program doesn’t. Some photographers work out an “effective ISO speed” for their combination of film and filter, and use this with an unfiltered light meter. Different forums recommend different effective speeds and it’s hard to compare filters. The only way to work out what’s best for you is to sacrifice a couple of rolls to trial and error.

Filters

I am using a generic 720nm filter, which is a little stronger than a Hoya R72. The most comparable branded filter is a Wratten #88A. Refer to this comparison of infrared filters if you need to work out which type you’ve got.

Using Efke IR820 with an #88A filter, I decided to start with a speed of roughly 1.5 ISO. If using my DSLR’s light meter, this means metering at 100 ISO and then adding 6 stops of exposure. If using my iPhone light meter, I can meter as low as 6 ISO and then add 2 stops. I bracketed my exposures by varying amounts, and recorded the exposure information, and the way I arrived at it.

Procedure

I decided not to “waste” the film by risking taking badly-exposed artistic shots, but instead to take technically interesting shots that included foliage, sky, clouds, concrete, water, and other materials as a learning exercise. Once I’ve learnt the right effective film speed and the right amount of compensation for my meter readings, it’ll be easy to go out and take well-exposed shots almost every time. Then I can focus on taking artistic photos for publication.

My procedure was like this:

• Take one frame without the IR filter, using the camera’s meter set to ISO100. This is to rule out development errors later on.
• With the filter on, take infrared photos using any method you like for metering. This might include using the camera’s meter, a handheld meter, intuition, the sunny-16 rule, or something else.
• Bracket the exposures by ±2 stops, so you have a choice of exposures to study later.
• Record what each exposure was of, the aperture, the shutter speed, and importantly, how you arrived at the exposure. I kept a table like the one below (and these examples are a selection of my actual data).
• After developing, and making sure the unfiltered exposure is correctly exposed and developed, I inspected each negative and decided which were under- or over-exposed, and which ones were OK. Then I have a handy reference of which metering methods gave the best results.

My results

From studying the data I gained from these 39 exposures, the best-exposed images were achieved with a handheld meter set to ISO6, and then adding 2 or occasionally 3 extra stops of exposure. This indicates that the effective film speed of Efke IR180 with an #88A filter is ISO1.5 – ISO0.75.

The reason that the exposure compensation varied between 2-3 stops is probably due to the makeup of the composition of each scene. Foliage comes out near-white in the infrared region, but is relatively dull in the visible spectrum. The handheld light meter wouldn’t take account of this, so scenes with a lot of foliage probably need +2 stops added. Scenes that include a lot of sky, which is rendered black in infrared, will probably need +3 stops.

To see all of my favourite shot from the roll, see my photo blog.

A while ago I shot some pseudo-infrared film: Ilford SFX 200. Unfortunately, being the impatient 6 year old that I really am, I didn’t fully read the data sheet.

The film is only sensitive up to 740 nm on a good day, while my filter only allows through wavelengths greater than 720 nm. Therefore, the film was almost guaranteed to be blank as hardly any light would get through.

Armed with this knowledge, I bought two rolls of Maco 820c which, as its name suggests, is sensitive up to 820 nm.

I also read a bit about how to meter properly when using an infrared filter. I set the ISO to 12 (the lowest my AE-1 will go). I attempted most of the photos 2 or 3 times, sometimes using the camera’s TTL meter with the filter on, and sometimes metering without the filter, then adding the filter and adding anywhere between 4 and 8 stops of exposure. In most cases the TTL light meter seemed to suggest about +7 stops, so I figured I was doing it about right.

I developed the film a couple of nights ago, and was disappointed to find it totally blank except for the one frame I’d shot without the filter. I hung it up to dry anyway, but then noticed that some ghostly images were appearing! I guess this means that I didn’t fix the film properly. Nonetheless, about half a dozen of the frames are showing underexposed images – which is progress. After about ten minutes the images stopped darkening so I moved them to a dimly-lit room to dry. I scanned them as quickly as possible, in case they disappeared again.

The negatives are massively underexposed, but the scanner was able to help a bit and I also used GIMP to boost the contrast massively. They look pretty awful and the grain is very coarse, but you can make out what the pictures are supposed to be if you look carefully. You can also see that much of the foliage is white, so I guess it worked

Some of the pictures also have fingerprints or creases, where the film got jammed while I loaded it onto my developing reel. It buckled and pinged out, and I had to poke it back in.

Here are some samples (published on this, my geek blog, rather than my photo blog, since I reserve the photo blog for pictures I actually like; and I consider these photos very much a scientific experiment!)

The Institute for Advanced Studies

Royal Fort House

Centenary Sculpture, Royal Fort Garden

Nathan in Royal Fort Garden

Incidentally, it’s now been a couple of days since I developed the film, and the images are showing no signs of fading further. Goodness knows what caused the magic appearing effect, then.

I still have one roll of Maco 820c remaining. Next time I will increase exposure by many, many stops. 15, perhaps. The camera’s longest shutter speed is 2″ so this will almost certainly put me in the region of bulb exposures and stopwatches.

If this doesn’t yield decent results I’ll stop buying infrared film, because it’s not cheap!

When I first started getting into photography a couple of years ago, I wanted to have a go at everything. I bought the cheapest infrared (IR) filter I could find on eBay and was delighted to find that my then camera, a Fuji S9600, was slightly sensitive to very deep red, and IR. I don’t think it was supposed to be, but it enabled me to take IR photos of outdoor scenes, and very hot objects, such as this light bulb.

When I traded in the S9600 for a Canon 450D, I was slightly disappointed to find that it wasn’t at all sensitive to the same range of IR and/or deep red. There are companies that will do an IR conversion, which involves taking the camera apart and removing its internal IR filter. It’s expensive, and it’s pretty much a one-way conversion.

Then I realised there was a cheap and practical alternative that had been staring me in the face the whole time. My 35mm SLR.

IR film is several times more expensive than regular film, but still vastly cheaper than digital IR photography. I bought a roll of Ilford SFX200 and it was about £8.

I read about how to correctly expose IR film and frankly it sounds confusing. Lots of people recommend using a light meter, but then you have to take into account the filter which is present on the camera but not on the light meter. It’s anybody’s guess how many stops you need to compensate for the IR filter.

It’s also a shot in the dark (no pun intended!) as to the ratio of visible light to invisible IR light. This varies with the time of day, what the light is falling upon, and about a million other things.

I wanted to shoot one or two frames, see the results, and then make sure I was doing it properly before shooting a whole film. Unfortunately that’s not easily possible, so I’m just going ahead and shooting a whole 36-exposure roll. As I write, I’m about halfway through the film.

The good news is that my Canon AE-1′s light meter appears to be sensitive to IR light. That is, with the IR filter on, the internal meter appears to work properly so I can simply use the camera as normal. I verified this with a quick back-of-the-envelope calculation to compare the meter’s behaviour with and without the IR filter. It seems about right.

So here’s hoping that this fantastic little camera will produce me 36 interesting IR photos. We will see – watch this space!