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Monday 11 July 2022

Lenses and Tubes

I’ve been in the loft again. This time it was old photographic stuff.

The lens on my present digital camera (a 7.1 megamixels Canon Digital Ixus 70 bought in 2007 for £170) has a 3x optical zoom and a 12x digital zoom if one is happy with loss of image quality. That, of course, is nowhere near as good as more recent digital cameras where 20 megapixels and a 25x optical zoom (or more) would not be uncommon, and even many camera phones would now better it. Even so, I still find it adequate for everyday purposes (note to family: it may be time I had a new one).

But in the old days of film cameras, lenses were usually of fixed focal length. You could get zoom but they tended to be expensive, so people usually used interchangeable fixed lenses, typically a standard lens, a wide-angle lens and a telephoto lens.

My Zenith E came with a standard 58mm lens which was a little long, a bit like always being on 1.2x zoom. It also had quite a narrow field of view, so I bought a 35mm wide-angle lens for indoor shots, and also a 135mm lens for distance. My understanding is that the 135mm lens is equivalent to 2.7x zoom. For 4x zoom I would have needed a 200mm lens, and for 8x zoom a 400mm lens. As well as being  expensive, they would have been very heavy to carry around when out walking.

Here, captured from mid-auditorium by the 135mm lens, is my brother receiving his degree at the University of Bradford from “that old man with a dirty hanky” as my aunt put it (he was younger than I am now). I stood up to take the picture, the Zenith gave off its customary loud “clunk”, and I managed to sit down again before people on the rows in front turned round to see what the noise was.

But what did we do for close-ups? My digital camera has quite a useful close-up ‘macro’ feature, but lenses were not so straightforward. They could be near-focused to some  extent, but true close-ups required a set of extension tubes (sometimes called extension rings) which screwed between the lens and camera body.

I had a set of three tubes of 7mm, 14mm and 28mm, which, in combination, gave seven different levels of magnification. They screwed together with such satisfying precision. I took this close-up of Southern Iceland from a map of Scandinavia in an atlas in 1977.

Here are the lenses and tubes down from the loft. They are destined for the charity shop, although whether they are worth anything when these days you can pick up top of the range Leica, Canon and Nikon stuff for next to nothing, I don’t know.

 
 
 

And for the true nerds, here is the instruction leaflet for the extension tubes.

Tuesday 5 July 2022

Nice Little Earner

Fixed-term Indexed-linked Savings Certificates, once nicknamed “Granny Bonds”. 9.0% interest this year. Not bad! And it’s tax-tree.

They are no longer on sale. National Savings and Investments withdrew them in 2011. However, if you already owned some, you have been allowed to renew them for another period at the end of their fixed term. These are now two years into their fourth five-year term. They started off at £10,000 in 2005 and were last renewed in 2020.

They used to be linked to the Retail Price Index (RPI) but NS&I switched then to the poorer Consumer Price Index (CPI) in 2019. Even so, interest of 9% (8.99 + 0.01) is good. I doubt I’ve ever had as much as that before on anything. But we have endured years of low interest because inflation has been low. More than once I’ve considered cashing them in.

To calculate the average compound interest over 17 years the formula is (no doubt Mr. Brague will correct me if wrong):

    £10,000 x interest17 = £15,287 
    therefore, interest = 17 √ 1.5287  (the seventeenth root of 1.5287) = 1.02528
    In other words around 2.528%

Which I guess is probably about what you would have received over that period in a Building Society account.

It’s swings and roundabouts. High inflation was inevitable. It affects everything. So perhaps we should not be trying to take seats off swings and rides off roundabouts. It puts things out of balance and makes us dissatisfied.