Tag Archives: how to

DIY Lens

This is an excerpt from my Personal Investigation Project for Photography A Level

  1. Introduction

In this essay I will describe the process and outcomes as well as the reasons for building a camera lens. We live in a time where it’s possible to get digital camera setup for under £20, and a working quality film SLR (second hand) for under £10. On the other end of the spectrum some lenses for the epic red film cameras run at over £30,000. This begs the question: is it still possible to make a working lens from easily available parts. And produce quality prints? Well that depends on the definition of quality print. If to you a high quality print is a razor sharp, high contrast and undistorted image of a sporting event, then this is unlikely, as the technology required to make a lens that is sharp at wide apertures with little distortion is very precise. But it is certainly possible to get a very distinctive style of image with easily available lenses. Images taking with non-achromatic glass will result in chromatic aberrations (more on that later). And lenses that aren’t very precisely ground will not focus properly, and produce spherical aberration in images. The other simple method to make a lens is to use camera filters and adapters mounted in sequence onto a camera mount. This has the advantage of consisting of mostly achromatic lenses and will be securely and accurately mounted (via screw thread). It is very possible to create very high magnification images using this technique.

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Project: Battery pack

I recently rediscovered my air rifle and as such have been thinking about how to improve it. I have already made one small addition to keep a small amount of ammunition handy whenever I grab the gun.

When I first bought the gun I also went out and bought a cheap gunlight to use for lamping/ratting at night (I bought a second hand version of this). This search should yield something useful. the particular torch I bought came with a normal torch cap and a momentary remote switch. which was great because I could use it as a nnormal torch when i wasnt out hunting. the only proble is is that it only takes two CR123A batteries which are extremely expensive considering that they only last about 6 hours before the light starts to fade and flicker.

So I hit ebay for a quick shopping spree and after some searching and comparing (every little helps 😉 ) I found these battery holders to be the best value for money. Although you could try this search instead: battery holders.

Because rechargeable AA batteries only put out 1.2 v instead of 1.5 I will have to conduct some prelimiary test on the birghtness of the torch runnign at 4.8v (4×1.2). the chances are that it will work just not be as bright(single battery holders are on the way as I write and I will test at a full 6v too).

The plan is to connect a 4 cell holder and a 1 cell in series, and then test the duration, then as necessary add more of these combos in parallel, until a sensible amount of battery life is reached or the pack gets too heavy.

I you’re interested this is where I get my pellets from as my gun is very fussy about which pellets I force down it…:

The ebay store where I get my pellets from although at the time of posting they seam to be all out. (they shipped 2000 RWS superdomes for around £30 which I thought was pretty good value for money)