ISO test

Posted by on Jul 20, 2013 in Articles | No Comments

 

Well, I’ve done it again and I’ve gotten another camera – the little Nikon Coolpix A. One of the main reasons I got it was that it has the largest sensor of any of the small, compact cameras. The sensor is the same sensor that is in the adult-sized Nikon DSLR Dx cameras (the ones with the 1.5 crop factor).

But I am not going to write about the camera just yet. I am going to write about what we all should do as soon as you get a new camera- test the quality range of the ISO. Every camera in the world takes great pictures at their low ISO settings- usually 200 to 400. But almost every little compact camera also takes very mediocre pictures at higher ISOs. I have found that anything over ISO 800 is unusable for any of my needs.

How do I know this? I take a test series of pictures at varying ISOs and then I take a look at them on my computer at 1/1 and check for noise. Noise is what we used to call grain in the days of film. Noise are those colorful speckles that become increasingly obvious at ever higher ISO. Every camera has a threshold ISO beyond which the noise is so bad the picture is ruined and is of no use. The question is, where is that threshold? Hence the ISO quality range test.

I walked outside at twilight and shot a series of shots of the same subject at different ISOs. I started at ISO 200 and then shot the composition at ISO 400, 640, 800, 1200, 1600, 2000, 3200, 4000 and 6400. ISO 6400 is the highest my camera will go as ISO 200 is the lowest it will go. Here are the results:

Here is the composition I photographed. Not very exciting, I know, I just wanted an image with some dark tones in it (noise is easiest to see in the dark areas of the image). Both of these pictures are unprocessed in Lightroom. They are just as they were imported, no processing was done when downloading either.

 

ISO 6400

ISO 6400

iso6400

ISO 3200

 

 

 

 

 

 

 

Here are the pictures cropped to 4/1 which is a pretty small piece of the overall image. This allows you to clearly see the noise. Look at the blade of grass and see how it is so speckled? that is noise. I had to blow up these images to such extremes to be able to see the noise in a blog post. If you were looking at these images on your computer at normal size you would easily be able to see the image deteriorate as the ISO increased and the noise got worse.

 

 

ISO 3200

ISO 3200

ISO 6400

ISO 6400

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

And finally, here are the two images with some slight processing- I adjusted the color temperature to get the rosiness out of the image and then a touch of noise reduction and clarity. This was all done in Lightroom and it was done quickly. I’m not much of a tinkerer when it comes to processing.

 

ISO 3200

ISO 3200

ISO 6400

ISO 6400

 

 

 

 

 

 

 

Everyone should know the ISO threshold of each of their cameras. Why? Because I promise there will come a time (probably many times) when the light will be absolutely crummy but the subject you are trying to capture absolutely fabulous. When this happens you need to know how far you can push the ISO and still get acceptable results. If you don’t know this threshold then you will be either shooting at too low an ISO and thus have too low a shutter speed, ruining the shot or you will be shooting at too high an ISO and you will get a shot that is fabulously horrible. Knowing your threshold will give you the best chance to get your best image.

ISO 1600 Processed

ISO 1600 Processed

So what did I figure out about my new little Coolpix A? I can shoot up to ISO 1600 comfortably and up to 3200 with a bit of noise reduction processing. Now remember, this is for my needs. I am not making large prints. I am shooting for books, magazine and websites. for someone with more demanding needs their threshold will be different than mine.

So get off your couch and go outside and shoot a quick series of pictures at different ISOs and then take a look at them on your computer. You will thank me eventually.

Leave a Reply