Apr 29 2007

Making a sighting tube for a digital camera

Published by at 12:54 pm under DIY,photography

Many otherwise good point and shoot digital cameras do not have viewfinders. This is okay when you’re inside or under shaded lighting conditions, but in the full glare of the sun it can be extremely annoying. Most of the pictures I take are at the beach under the aforesaid bright conditions and so I’ve long thought how handy it would be to have a simple optical viewfinder that one could somehow attach to a point and shoot camera.

In the absence of a proper one, here is my bodged up sighting tube idea…camera with pen cap sighting tube

As you can see, I’ve taken the cap from a pen and taped it on to the top of the camera.

Here’s what it looks like from head on…

head on shot of pen cap sighting tube

Several things to note. First, you obviously need a cap with holes at both ends. This cap had a nicely centered small hole on one end, so I put it facing forward and then started playing around with the alignment to get it right for my telephoto at full magnification.

Second, you need to align your tube/cap with the central axis of the lens. The picture shows that I haven’t quite got the position right. It really should be nudged across to the right a bit more.

Third, be aware of parallax error. What looks centered through the finder close up, will not be centered at full zoom. You may need to deflect the tube slightly up or down to get it to match the centre of the image at the zoom setting you want to use. As a practical matter, this isn’t that important because you’re generally in the ballpark to begin with. This is not about framing stuff precisely, it’s about ensuring that your subject is definitely in the picture when you’re using the telephoto under bright conditions.

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