ISO stands for International Organization for Standardization which isn’t terribly helpful in letting us know what it means. ISO was used to describe film “speeds” in the days of film. Films were graded by how “fast” they could expose for light. If you wanted a different ISO or speed film, you had to finish a roll and put in a new roll of film with a different ISO number.
Today in Digital photography as with most things, ISO is much easier, you (or the camera) can change it on the fly depending on conditions.
The best way to think of ISO is as the sensitivity of your camera’s sensor to light. The lower the number, the less sensitive to light your sensor is, the higher, the more sensitive.
So on a sunny day, you would want a very low ISO (most DSLRs bottom out at 100), while in a dark room, you might want a higher ISO.
How high an ISO is too high? As with most things, it depends. At very high ISOs, the camera introduces noise into the picture visible as extra dark pixels on your shot. This varies based on the camera sensor’s capability. Lower end camera’s may start to encounter noise at relatively low ISOs like 600-800, while higher end cameras may show little to no noise at much higher ISOs up to 12,500 and above.
Experimentation is the key.
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I get this question quite a bit, so I thought I would write a post to answer this FAQ. A couple disclaimers right from the start. I shoot Nikon cameras, that means I’m going to talk about Nikon DSLRs. Canon, Pentax, Sony and others make some fantastic cameras, I just don’t use them, so I can’t give you advice on those. Second disclaimer, I’m still an amateur/enthusiast photographer, I’ve learned a lot in the last couple years, most of it self-taught, but I’m not a professional.
Now on to the details. The Nikon DSLR universe is broken up into roughly 4 categories (by me): amateur, advanced amateur, enthusiast and professional. The amateur lines are the 3xxx series and the 5xxx series. the advanced amateur is the 7xxx series, the enthusiast is the 6xx, 7xx series and 8xx series and the professional is the Dxx series. Confused yet? Stick with me.
Amateur: The current models in this category are the D3300 and the D5500. They are Dx cameras which means they have a smaller digital sensor than Nikon’s larger DSLR. They can auto-focus on any compatible lens that has its own focusing motor (the cameras don’t have an internal focusing motor). This can limit which lenses can be used to full effect on the camera. These are great camera’s to start out in DSLR, especially if you aren’t sure how much you will use them. You will pay roughly $500 for the D3300 and roughly $750 for the D5500. My first DSLR was the D3100, the predecessor to the D3300. With these cameras you can take some amazing pictures.
Advanced Amateur: The D7200 is the current model in this category. With this category, you have the same sized sensor (Dx or APS-C also called a “cropped” sensor) as the amateur cameras, but you get two memory card slots, an internal drive focus-motor which dramatically increases the number of lenses your camera can fully use. There is also a big increase in the low-light capability of these cameras over the amateur ones. The D7200 is roughly $1100.
Enthusiast: The D610, D750 and the D810 are the current models in this category. These have an Fx or Full-frame sensor. This is a larger sensor than in the amateur and advanced amateur. All three have great low-light capability. The D610 and D750 have a 24 megapixel sensor and the D810 has a 36 megapixel sensor. The D610 retails for $1500, the D750 retails for roughly $1900 and the D810 for $2800. Of these three, I bought the D750 as it has the best low-light capability and has virtually all the capability of the more expensive D810. It does have a smaller sensor at 24 vice 36Mp but that isn’t terribly important unless you are cropping photos and then viewing/printing them at very large sizes.
Professional: The D4s is roughly $6000. For this dramatic increase in price you get a very well-built camera with incredibly detailed photos, great low-light capability and double the frames per second of other DSLRs. These cameras are built like tanks with metal bodies designed to survive years of harsh use and conditions.
So where am I? I used my D3100 for a couple years on automatic and once I started shooting manual I got the bug for a more capable camera. I moved up to the D7100 (which I still use) and added a full frame D750 to my lineup. I am very happy with my D750 and won’t be buying a new camera for some time.
Next article we will talk about lenses and how they are in some ways the more important investment than the camera body.
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