art, landscape, photography, seasons, technic, travel, world

Throwback Thursday: photographing the invisible lights


I took this image about 6 years ago with an old DSLR (introduced to the markets in 2004). That camera only has a very weak high-pass filter in front of the sensor, so it is able to capture invisible parts of the light, too. The high-pass filter is designed to prevent the invisible portions of the light from reaching the sensor for getting better images.

To get sharp images in IR you have to adjust the focus. IR has a different behaviour when it comes to sharpness, then the visible light. Each wavelength has its own behaviour. In IR the sharpness point is a bit to the left. I.e. when focussing on an object 5 m in front of you, you have to shift the focus back a bit i.e. to 3.50m. You have to find out the correct setting by try-and-error. Back in film days nearly every lens has had these extra marks on the distance control for IR. Thus, I recommend using an old lens for IR photography. Anyway, use your display and check your images carefully for sharpness – despite it is very hard to recognise sharpness in all the reds on the small screen. 🙂

For the above image I put an 720nm IR filter on front of my lens for blocking all rays with a wave-length shorter than 720nm. I also have a 760nm IR filter for monochrome images. These filters extends the exposure time enormously. I have to use exposure times of about 1 second and above in full sun during the day. Thus I have to put my camera on top of a tripod, despite the sun 😦 To make things even harder, the filter in front of the lens won’t let visible light coming through. That makes the viewfinder dark. You can’t choose the right angle of view. Either you guess it, or you’re constantly detach and re-attach the filter to your lens for every image. Have fun 🙂

I like to let the filter in front of my lens and guess the right angle. It’s more fun and more interesting seeing the results. First of all, I do a manual white balance on green grass in full sun. Next, I dial in f8, ISO 400 (to shorten the exposure time a bit) and 1 second as a starting point. Photographing in raw is my default, so I don’t have to change this setting for IR.

I don’t have modified my camera to remove the highpass filter. That’s about 400€ depending on the exact kind of camera. On the other hand, you will not only get the filter removed (you get back short exposure times), but also the focus justified permanently. So, you don’t have to worry about the focus correction I mentioned above. You also usually get back a bright view finder. But the camera now has a certain filter inside: the camera is defined! And you’re not able to switch the filter i.e. to check out other wave-lengths.

For the above image I’ve used a filter, that didn’t block all visible light. So, I can get these color IR images.

I used an old APS-C DSLR, an old 28-70mm lens (qualified for capturing IR images), a tripod, a remote shutter release and much of sun 🙂 That’s not very wide (like 42mm on a FX camera). I wish, I’d have a wider lens. But, in film days they didn’t have had APC-C SLRs. So, such lenses aren’t available. 😦 I also won’t use a more modern DX lens, because they aren not tested under IR light. So, you probably see flares inside the lens resulting in ugly hotspots.

Take care!

P.S. it’s also possible to photograph in ultraviolet. But, in that part of the spectrum I don’t have any experiences – sorry guys.

architecture, art, photography, travel, world

Monochrome Madness 2-23

Btw. as always: click on the photo to see it in a higher resolution

For a calm summer day I was at the river Wupper a few weeks ago. Enjoy the silence and the slowly running river. This is my contribution for Leanne Cole’s Monochrome Madness.
Take care!

Btw. as always: click on the photo to see it in a higher resolution

history, landscape, nature, photography, seasons, travel, world

Short weekend trip

610_9541-e_wOn Saturday we have had a quite summerly day. Sunny and warm.

My son’s girlfriend just bought her first DSLR with a kit lens. Before she bought it, she has asked me to show her how to use it properly.

Our first lesson was two or three weeks ago, when I introduced her to the basic functions and terms: aperture, ISO, shutter time, magic triangle, white balance, image stabilizer, focal length, field of depth and so on. This time, we went outside to a park. Here we tried some of the settings in practice lessons. A third lesson, a feedback session with reviewing her images, will be held soon.

I certainly brought back some images on my own. Our Sunday was cold and wet again. Thus, I developed the images, instead of being outside again 😦

You can see the river Wupper, a side river of the river Rhine. The Wupper is about 116 km long and crosses the town Wuppertal. Wuppertal was founded in 1929 by combining the older towns Elberfeld and Barmen, now quarters of Wuppertal. Instead of choosing one of the old names for the new town for several reasons, they created “Wuppertal” (= Wupper valley), because of their location in the valley of river Wupper. Nowadays Wuppertal has about 350.000 citizens, a university and some industry. Only few houses survived the massive attacks with aircraft bombs during WW2, thus Wuppertal is not really attractive from a photographers perspective. Although, there are still a few interesting houses around.

Wuppertal is famous for the Schwebebahn. Also, Aspirin was developed in the Bayer laboratory in Wuppertal. Once, Wuppertal was important for producing textiles in weaving mills (often home weaver) and dyeing yarns. But, these industries died. The last weaving mill was closed more then 40 years ago.

In the 1970s the peek of water pollution was reached. Many companies used the river as a cheap and easy way to get rid of their liquid remains from their production. Lots of chemicals from weaving mills, dyeing mills, groundwood mills and forges were channeled in the river. Locals told me, schools beside the river often got “stink free” in summer. In those times, the water got a different color nearly each day, depending on the different chemicals used for dyeing yearns in different colors.

Now, the river is clean again. Pew! Rare bird are back. You can see dippers, kingfishers and grey herons finishing for larvae and small fishes. Renaturation was successful!

This park has a secret. It’s not hidden. Rather it’s very large. It’s built more than 100 years ago. So, it’s worth its own post. But, not today.

Stay tuned!

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