Recently I was given a Braun Paxette. After running a couple of rolls of film through it, I’ve decided that the focus isn’t quite calibrated correctly according to the focus ring.
Fortunately, you can loosen three grub screws around the snout of the lens and rotate the focus ring without moving the lens, line it up properly, and tighten it up again.
To calibrate the focus, you will need:
- a bright and high-contrast object a known distance from the camera
- some tracing paper or other diffuse translucent material
And here’s how we do it.
- Set up the camera on a tripod with the back open/removed. Attach the tracing paper where the film would usually go, like so:
Calibrating a Paxette
- Put your bright object a known distance from the camera, and measure it. Call this distance X. If working indoors, try using something like a desk lamp or a TV screen (both are bright, with strong edges). If working outdoors, you could use a building with strong features (and pace out the distance from your camera).
- You might need to cast a shadow over the paper to see your image, but it should be there, albeit upside down.
- Focus the image so it is sharp. It can be hard to tell if the image is sharp, so you could use a magnifying glass to inspect it.
- When you’re happy that the image is in focus, you know that whatever your focus is set to now is X. Loosen the focus ring, readjust to that value, and tighten.
You’re done! Happy shooting.
I hadn’t realised how important it is to calibrate a monitor correctly.
My former method of “calibration” was simply to set the monitor’s contrast to maximum, and set the monitor’s brightness to a value that looked comfortable to me. I didn’t bother changing any settings in software.
But I got caught out.
Last night I took some photos and tweaked them on my PC so they looked OK. I published them and thought nothing of it. But several of my friends commented that they looked a bit dark, and when I checked the pictures out on two of the computers at work, they were indeed too dark.
My badly-calibrated monitors at home caused me to wrongly edit an image. So I read up on how to calibrate a monitor. There are many ways, but the method I’m writing about here is nice and simple.
- If you have TFTs, they are sensitive to the angle you look at them. Tilt them so they face directly at you.
- Turn the lights off in the room you are working in.
- On the monitor, set the colour temperature to 6500K
- On the monitor, set the contrast to 100%
- Look at the gamma black chart below. Adjust the brightness on the monitor until:
- Bar A is just visible at the bottom
- Bar B is visible from the bottom to about halfway up the chart
Gamma black chart
- Absolute black on your monitor is now calibrated.
- Find how to adjust the gamma on your computer. For example, I am running the proprietary nVidia X driver on Fedora and it comes with a convenient control panel. You can use Adobe Photo Shop to adjust the gamma, or xgamma under X Windows on Unix/Linux systems.
- Now look at the gamma chart below. Sit as far as possible from the monitor and squint so the lines blur together.
Gamma chart
- Adjust the gamma on your computer so the shade of grey completely across the gamma column is the same at 2.2.
- The monitor is now calibrated.
References
