Focus assist for rangefinders

I had a bit of a moan about struggling to focus some cameras with my old eyes. It came home to me when I was trying to shoot some leaves caught in a wire fence in deep shade. I was turning and twisting the camera to find an edge that I could see move in the rangefinder patch. And then I had an idea. What I needed was a bright but small spot on the subject, so it would be really obvious and easy to bring two of them together. What I needed was a cheap laser pointer.

As usual, everyone else already seems to know this. Or at least it seems to be common knowledge to astrophotographers.

My first thought was to use a magnet to stick the pointer to the top of the camera. Then it occurred to me that camera top plates are probably made of brass, not steel. A quick test proved that my various rangefinders are not magnetic.

What the clever astro people are using is a hot shoe microphone adapter. Roughly £2 on eBay. On the other hand I don’t want to walk around with a weird gadget on the camera. So what I’ll be trying is the three-handed trick – one to hold the camera, one to focus and one to point the laser.

At this point I need to state what should be obvious – never point a laser in someone’s eyes. Also, never point a laser at a passing aircraft. It’s probably a bad idea to shine one into the lens of a digital camera too.

I had a trial go with the laser pointer we use to send the dog chasing itself dizzy and it’s easy to get the focus. It’s also easy to focus on things that are impossible with a normal rangefinder, like a smooth surface with no pattern. So it looks like a plan.

Off to eBay we go and a little laser pointer arrives in the post. It has a ring to attach it to a keyring, which I thought to use to hang it from one of the camera’s strap rings. What I found I could do though is to both support the camera and hold the pointer with my right hand. It meant holding the pointer like I was throwing a dart and pinching the camera between my little and ring fingers and the heel of my palm. It helps that I have big hands but it works. My left hand is under the camera, with my fingers focusing the lens. It sounds awkward but it works. The ‘dart’ grip lets me move the laser point around to put it on the focus patch. I’ve got a working focus assist.

Use of a laser pointer for focusing a rangefinder

I did try pointing the laser through the viewfinder to see if I could project two dots on the image, but that didn’t seem to work. It might do if I could line it up perfectly, but this is a quick and dirty tool, not a perfect one.

It’s also a good way to test that your rangefinder is calibrated. Shoot down the length of a long ruler or tape measure. Set up a matchbox part way down. Focus on it using the laser spot. Enlarge the negative to see if the lens focuses where it should. Russian rangefinders can mostly be adjusted and others probably can too. You don’t want to be shooting and developing a role of film after each adjustment though, so you will need to find a way of laying a focus screen on the film gate and locking the shutter open on B. I did do this once using Sellotape and a magnifier, but it took some careful cleaning to get rid of the stickiness afterwards.

Even without trying to adjust your camera, using a pointer to provide a focusing mark actually works and costs a couple of pounds.

Hurrah!

Author: fupduckphoto

Still wishing I knew what was going on.

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