As I keep saying almost every day - I'm running out of things to shoot during my lunch break. Today I took my Zeiss 50 mm Planar and put a 760nm Infrared filter on it. The maker of the IR filter is Zomei. It's incredibly cheap and is plenty available on eBay in all forms and shapes. The tricky part is actually getting any light to the sensor, as it has an IR cutoff filter on it. The IR filter on the lens cuts off all visible light below 760nm, which makes only infrared wavelengths leak into the lens. The sensor's filter, on the other hand, tries to prevent IR getting through and only cares about visible spectrum. Hence, you end up with almost no light actually getting through. In order to actually shoot IR you'd need to convert your camera by removing IR/UV coating from the sensor.
Another tricky part is focusing the lens. On MM246, and perhaps any Leica rangefinder camera, the rangefinder itself becomes useless. I found that I need to use the Live View function to get my pictures in focus. Focusing on infinity is much simpler. Most lenses should have IR infinity mark on the depth of field scale. On the Zeiss 50 mm Planar, there is a special red mark that shows where infinity should be if you're shooting infrared. You can also use rangefinder to focus and then move the focus by the difference between the center of the DOF scale and the IR mark.
If you want to shoot infrared handheld, MM246 is not the best camera. My Planar was constantly at 2f, ISO was at 10000 to allow for a shutter speed of 1/60. In some places, I stepped up to 1/125. Below is what I ended up with after today's lunch. Note, that some pictures are displayed in a form of a gallery to show the difference between an IR and a regular picture I took previously of the same subject with roughly similar lighting.
The first thing you notice when you go IR is a nice black sky. I like the sky to be black when I shoot during harsh sunlight. I usually use #46 dark red B+W filter to darken up the sky.
The second most noticeable thing (if not the first) is the brightness of the vegetation. Most leaves, despite their natural color, become white. Even shadow areas become bright white color. Apparently, most leaves are translucent and transmit IR wavelength through. This makes them attractive to insects. What's interesting is that not all of the leaves turn white. Below is a good example in the range of "whiteness" you can get.
This picture shows the pitch black sky with some white grass and tree leaves.
This plant, on the other hand, looks quite normal under IR filter. Perhaps it doesn't need any help from flying insect and likes to be ignored.
Most trees would light up white in IR. Palm trees are especially bright. Below you'll see pictures of the great contrast between palm trees and other plants.
This is a small tangerine tree. The tangerine itself is white as well. You can also see a big flare, that would not be there under normal conditions. Most lenses have a special coating to prevent such reflection. However, most of the time, the coating does not take into account IR spectrum. This makes some lenses to perform much poorly under IR conditions.
Look closely at the crawling plants on the wall. Even in shadow it lights up a bit. These would be otherwise dark black leaves.
This picture clearly shows the contrast between palm trees and other trees. They're significantly brighter.
You don't have to have leaves in frame to get the desired effect. Even bark exhibits small glow from the IR.
Below is the comparison of the picture I took today with an IR filter and yesterday with an orange filter.