Learning when to change your ISO

In the interest of building my habit of writing daily (and to wind down from 5 hours of studying for a Corp Finance exam) I am going to share some quick info on some technical jargon, lingo, etc.

My previous entries discussed things such as ISO, F-Stop, Shutter Speed, EV (exposure value) without going into too much detail about what they all mean.

I discussed a couple days ago about utilizing some under appreciated modes (read about AV and TV modes Here).  Today we will go more in depth to some backing knowledge about ISO to lend support to mastering these.

ISO is a measurement that actually stems from actual film's sensitivity to light, commonly referred to as the 'Speed' of the film.  Vaguely how car engines themselves are not made of literal horses, the sensors of modern Digital Single Lens Reflex (DSLR) cameras continue this standard of measurement.

Standard consumer cameras typically have an ISO range of 100-1600, some as low as 50 and as high as 3200.  Professional series cameras, such as the Canon 1D, 5D or Nikon D300, D700, D3, etc. commonly have ISO as low as 50 and as ridiculously high as 25,600.

To typically achieve the best clarity (some would argue here also color quality) and least amount of noise in your shots, you want to keep the ISO as low as is possible.  When the light meter on your camera tells you a bound (depending on your mode) is not favorable for a proper exposure through blinking that number (if you have seen your F-Stop or shutter speed blinking) then you should then adjust your ISO to get a more proper exposure at the cost of adding noise to the photo.  Most modern DSLR cameras within the last year or two are very good at handling and reducing noise, you will typically only see very poor noise quality at 800 -1600 ISO and higher.

ISO 200 - 400 you can see little to no difference, at 800 you can see some noise begin to appear at the top of the stairs and along the walls.  (click to see full size in a new window)

At 1600 and especially 3200 ISO the noise increases dramatically, proving these settings should only be used when necessary.  

 

Of course, take some test shots of your own at the earliest opportunity of different types of settings and subjects, you may very well find your camera manages noise to your liking to handle a higher ISO, though, it will never look quite as good as a lower ISO.

As with all things manual on your camera body, regardless of what you are shooting with, practice now and practice often getting in the habit of double checking your settings every time you change your conditions.  If you have the ISO high indoors and step outside into the sunlight, make sure you dial that back down to get the best shots possible! 

Note: Those test shots turned out kind of crummy, I will get some better ones up soon.