Another depressing week in which the task was to take photographs with different ISO settings and compare the results. And I would have to use the fully manual mode. I decided it was time to get to grips with AV mode, one of the two semi-automatic settings on the camera, and at least understand what this could achieve.
This stands for ‘Aperture Value’, or the size of the aperture which allows light further into the camera. Counter-intuitively for me, a small number, f/4.5, f/5.6, is a large aperture which f/16, f/22 is a small aperture. (Helpful article on Wikipedia.)
The appropriate aperture value allows you to blur the background, or bring everything into focus, i.e. the aperture will control the depth of field, or the area which is in sharp focus. So, a low f/number brings the foreground into focus and blurs the background, and a high f/number allows for sharp focus deep into the ‘field’, or foreground and background. OK, got that, but what do I set for a half-decent photograph?! The rule-of-thumb, says Wikipedia, is Sunny 16, i.e. f/16 on a bright, sunny day with sharp shadows, and then change upwards for blinding sunshine and downwards for gloom.
And just for fun, the fir tree in the same churchyard had the most amazing cones.
The actual task for the Week 2 was to take photographs with different ISO settings. ISO settings? This concerns sensitivity to light and the higher the setting, the greater the ‘sensitivity’, resulting in a less clear (or more grainy image). But it isn’t quite so simple. The rule-of-thumb says ISO 100 will give crisp images in sunny conditions. If it is darker or there is less light you need more sensitivity and therefore a higher ISO setting, ISO 400-800 on a gloomy day. I realised I would have to use the Manual mode and set aperture, ISO, and shutter speed to achieve a picture – panic!
And even more obvious..
That was enough for me for one week – I press on!
You may be interested in
PhotoNotes – why as well as how; useful!
F-Stops – Wikipedia is both helpful and way above my head!
Understanding Aperture – a beginner’s guide – very helpful!
ISO Settings – helpful
Candy Blackham
Lesson 3 taught us about the zone system, and ‘middle grey’ – how the lens meter will take the dominant tone and set it as the benchmark for ‘middle grey’, the average tone for the photograph. White will therefore become grey (darker than it really is) and black will also become grey (lighter than it actually is). Assuming the aperture is correct, one therefore adjusts the shutter speed. I think I have got this right…! This will be the subject of the next post.
Graham West
I’m not sure I entirely agree with the “Sunny 16” rule these days. It’s ok if you don’t have light meter, but these days cameras come with built-in light meters, so it’s pretty easy to get the correct exposure. f16 is a little small for most purposes for my liking, because the smaller the aperture the more the effects of diffraction start to creep in. f8 (“f don’t care”), is fine for most purposes (and is usually the “sweet spot” of a lens), and go wider if I want a shallower DOF, or narrow if I need a more extreme DOF.
BTW you should be adjusting your shutter speed before you touch the ISO, making sure to keep to the reciprocal rule.
Most of the time there’s absolutely no need to go full manual; one of the semi-auto modes will do.
BTW a good place to learn the basics of photography is the videos made by Mike Browne on his YouTube channel. It’s how learnt, and he’s a great teacher.
Candy Blackham
Well, you are of course correct on all counts! We had another lesson tonight and I learned about the Reciprocity Rule. And I will follow up re YouTube. Thank you so much for taking the time and trouble to respond. Another post will follow as I try to digest this week’s lesson!
Graham West
Thanks. 🙂
Technically, with the Sunny 16 rule you’re supposed to recalculate the shutter speed if you want to use a different sized aperture other than f16, but I really cannot be bothered – the light meter does fine most of the time. Having said that though, it can get it wrong from time to time, say if there is a massive difference in brightness between your subject and the rest of the scene (that’s where spot metering comes in handy), or if you are shooting something dark black or bright white. Classic example of this is snow. Left to its own devices your camera will make the snow look grey, so you need to make adjustments to compensate.