The other two I took were slightly blurry but I'm more than happy with how sharp this one is. And then this morning I went out and had a look and there's another pile of spawn, though no sign of frog or frogs. Our pond is just a plastic garden tub sunk in the ground with gravel, aquatic compost and plants added. It's not big or fancy - in fact it's probably only about 50cm across - but year after year it gets spawned in. That's quite flattering when you're trying to make your garden wildlife friendly. As far as I know none of the tadpoles matured last year, but this year I managed to clear some of the old sludge and weed out of the water before the frog returned so there's a bit more space and I hope that will help. Although I read somewhere that frogs like shallow water and will even lay their spawn in puddles, which seems staggeringly short-sighted of them!
It turns out my blog-composing issue is in Firefox (probably an outdated version, though to be honest I can never see why something that always has worked should suddenly not work) but not in Chrome so I've used Chrome for this. It's very much easier than trying to post from my tablet, so I'm glad I figured it out.