What is ISO?

I am all about sharing the love of photography!  I love to help others take better photos whether it be simply using their cell phones, point and shoot cameras or answering DSLR questions for aspiring photographers!  I love to help others succeed!  I’ve been receiving quite a few questions lately so I thought I would start a “How To” blog section to help others.  Feel free to jump in and ask questions as well!  I will do my best to answer them for you.

What is ISO?  I currently have it on auto, what would be some recommendations when choosing the ISO?

The technical answer for this question is that ISO is the camera’s sensitivity to light.   The lower the ISO (for example 100), the less sensitive your camera is to light.  A a higher ISO (3600+ for example) increases the sensitivity of your camera making it easier to get quality images in lower light.

I use both manual and AUTO ISO.  For me (and I’m about to date myself) I think in terms of film and back in the 35mm days (I’m not THAT old ya’ll really) and which roll of film I’d have grabbed for what I was shooting at the time.  

If shooting a portrait session or wedding or anytime I have been commissioned for photographs I always shoot manual ISO.  The only setting that I do not set manually is the white balance as it’s a quick Lightroom adjustment.  I try to start as low as possible and when I read my meter and I can maintain a shutter speed of at least 1/60 with my chosen aperture then the ISO is correct for me.

Why 1/60th of a second?  This is totally personal.  This shutter speed produces the sharpest image for me.  When I go lower than that my images are not as sharp and in focus as I like them to be.  I have no idea why it’s just something I’ve learned over time.  Practice, practice and get to know yourself and your settings.  I recently heard a photographer speak that said in order to improve your skills you should be shooting 100,000 images a year whether it be on your camera or your cell phone.  That seems like a big number but it’s really not that many when you think about it.

I like to shoot as wide open as possible (at an aperture of 2.0 or less) if I can.  If I set my ISO on 100 and my aperture on 2.0 and my in-camera meter tells me for that setting my shutter speed should be 30 to balance the image (provided it’s not backlit, etc) then I increase my ISO up to 200 (just where I jump to next) and go from there.

If I can get a 60th of a second that way then I’m golden and ready to go.  I tend to be more aperture focused.  I know what depth of field I want for an image and then work the ISO/shutterspeed to make it happen.  ISO, aperture and shutter speed are your exposure triangle and everyone works their triangle differently.

Larger ISO’s are useful for darker settings and night photography, etc.  They used to scare me because I was afraid of grain but as long as you are using the lowest possible for the situation with the your aperture and shutter speed you shouldn’t be afraid of them.  I’ve learned to be confident in these situations but it came with lots and lots of practice.

I use AUTO ISO only on when I am on vacation.  There is just not time from the top of a tour bus to change your settings and snap a photo.  

Here are 2 images at different ISO’s.  Don’t be scared of playing as high as 3600 and up depending on your lighting.  As long as the light is there and the image is properly exposed you will be fine.


Manual, 1/1000, 2.0, ISO 400


Manual, 1/1000, 2.0, ISO 800

I hope this helps make more sense of ISO.  Please don’t hesitate to ask questions or offer more input!  



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