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We all know that the triumvirate of exposure are shutter speeds, aperture, and ISO. It’s this dastardly trio that operates like security guards to photons, standing there, ear-piece in their ears, saying “Oi, if you’re name’s not down, you ain’t coming in”.
The head security guard, Mr Aperture, is restricting the flow of how many photons can come in at the same time. Dr Shutter Speed is opening and closing the doors to the club for various amounts of times — if he opens the door for a long time, lots of people get in. If he throws the door open and kicks it shut again, only a few people get in. Professor ISO is the allegory-wrecker who just stands there, scratching his head, wondering how the hell he fits into this whole ‘club’ scenario.
The point I was going to make, however, is that something has changed over the past ten years, and ISO has taken over power impressively quickly…
Shutter speed has remained stable; typical shutter speeds on a SLR camera range from 30 seconds to 1/4000th of a second. That’s 17 stops of difference.
Apertures remain unchanged; typical aperture ranges for a standard prime lens go from f/1.8 to around f/19 or thereabouts. That’s about 7 stops of difference.
However, the biggest change comes from ISO-land. Only 10 years ago, you’d be nuts to use films slower than 3200 or so (don’t get me wrong, I loved my ISO 3200 T-Max… But that bad boy was grainy). On digital cameras, ISO 1,000 was merely ‘manageable’ in 2002… That’s only ~4.5 stops; a lot less than the range of light adjustments you get out of your ISO settings.
Compare that with the shots that are coming out of the current generation cameras. The Sony NEX-7, for example, was determined to have “quite useable results”at ISOs up to 6400, and the same verdict fell for the Nikon D3 camera:
That, ladies and gentlemen, is huge. It means that whilst the aperture and shutter speed range has essentially stood still for ten years, useful ISO ranges have increased from 1000 to 6400 — or from about 4.5 stops to 7 stops of useable range, which means that ISO now matches your aperture control when it comes to being able to control the brightness of your photos.
It might sound pretty subtle, but if you think about it, it’s quite the revolution: It means that ISO, which used to merely be a fine-adjustment tool only 10 years ago, can now be used as a major component in your exposure decisions…
Photo credit: picture by Haje Jan Kamps – taken at ISO 1600.
Haje Jan Kamps is a prolific photography blogger who has written a small stack of books about photography. He also developed the recently-launched Triggertrap camera trigger and has been known to travel the world a bit. If you’re of the tweeting kind, try him on @Photocritic!
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I’m not really sure what the point of this article is.
First off, most D-SLRs will now go up to shutter speeds of 1/8000th of a second, so that’s doubled since your 2002 reading. Also you could also include ‘bulb’ mode where the shutter can stay open for several minutes.
Max Aperture has also moved on a bit, Leica do a very nice and expensive F0.95.
You’re trying to say that these things haven’t moved on and back it up using ‘average’ values. You should be looking at the limits of the technology. To that point ISO now regularly hits 128,000 on some of the high end D-SLRs.
The point of this article? Well, it’s kind of explained in the headline
The f/0.95 is, indeed, a lovely lens. Canon have had those for a good long while as well. Take a look at the minimum apertures on those lenses, though, and you may find yourself surprised…
As for using the extremes: You have to look at ‘useable’ values. ISO 128,000 is all good and well, but they do have an incredible amount of noise in them. In addition, that’s not even the extreme. You could shoot at 128,000 and then under-expose your shots by two stops, followed by amplifying the signal further in post-production by two stops, giving you ISO 512,000. The photos would be completely beyond useless, but you could do this.
Shutter speeds on high-end cameras can, indeed, go to 1/8000, but this has been true for a long time. I had a Canon EOS 1N HS in the mid-1990‘s that had a 1/8000 maximum shutter speed.
The main point stands, I feel: Aperture range and shutter speed range haven’t changed much. Useable ISO range, however? That’s a completely different story – and it’s the most rapid field of development, too, which makes things even more interesting.