Category: Uncategorized

Back Button Focus

One of the more controversial subjects in photography, at least for me, is the use of back button focus.

The premise is that, on cameras that allow this level of configuration, you can separate the ‘focus’ and ‘shoot’ operations, so one button under the thumb on the back of the camera becomes the ‘focus’ button, and the half-press of the shutter button no-longer changes the AF setting.

I’ve tried it, admittedly fairly briefly, and I can’t see the point. I don’t want the camera focussed on something that isn’t what I’m taking a picture of.  My two most used cameras have 49 and 65 autofocus points.  Recompose and shoot doesn’t happen very often, and I’m usually working with moving subjects, so the camera is permanently in AI-Servo mode.  Why would I NOT want to focus at the same time as taking the shot?

Shooting with the 7Dii, I’m usually steering the autofocus point in use as I’m shooting (and using a single AF point), so my thumb is busy elsewhere.  I’m still learning the finer points of the M6, and usually I’m using the touch shutter if I want to take more control over where the camera focusses. With the EVF, you can at least see where it’s aiming so can correct if needed. 

However, the thing that really, really winds me up is the assertion made that BBF will improve your photography, or even worse that you’re somehow not a ‘proper’ photographer if you don’t use it.  By all means give it a try.  If it works for you, the carry on.  But please don’t suggest I’m not as good a photographer just because I don’t use it.   Thanks.


WG0AT at Cape Cod

It was great to see that Steve WG0AT visited Eastham Lighthouse, as shown in this video.


Visiting these guys was one of my formative experiences in Amateur Radio (back when the ink was barely dry on my Foundation license).  Congratulations to Barbara on her new call as well! 

QRM on 70cms

After suffering QRM on the Bracknell 70cms repeater, GB3BN, for several months now, it was interesting to note that within several days of us finding the cause, a similar case was reported elsewhere.

The interference is noticed as a regular “chuffing” sound whenever the repeater is open but isn’t being overriden by a stronger signal.  Thanks to the excellent efforts of the TVRG, the QRM was been traced to a building site in Harrow on the Hill, where the 10mW transmitters on top of the cranes there have a direct line of sight to the GB3BN antenna high above Coppid Beech roundabout.  The transmitters appear to be linked to a crane collision avoidance system, tranmitting in this case on the GB3BN input frequency of 434.6MHz.

It was interesting, therefore, to read this report from G4UVJ about a similar problem affecting 433.5MHz in the Thames estuary area.  I wonder if it’s the same system in both cases?