f5.6 1/1250 ISO 800 – 105mm macro – Mid-November Bee 2012
I guess the question is why use a high ISO?
Did I say it loud enough, lol?
Our last macro post two days ago dealt with aperture and shutter speed. It talked about how I blur the background of my critter shots.
So this leads us to the third choice in our arsenal of camera settings. Why change it at all when your camera selects the ISO automatically? There are a couple of good reasons for making a change.
f5 1/1250 ISO 800 – 105mm macro – Mid-November
The lower ISO, like 100, needs more light to get a proper exposure. ISO 100 might be what your camera is set for if you do not make a change and is good for sunny daylight conditions.
f7.1 1/1600 ISO 1000 – 60mm macro – Mid Summer Wasp
What goes with picking an ISO? Well, shutter speed and aperture do. There are other things to change like white balance for instance, but no need for more complications for now. Let’s stick with just the ISO, something that can be changed even on many compact cameras. I will show this in an upcoming post using my compact camera.
With the higher ISO, like my images at 800 and above with the Nikon D7000 camera, less light is needed to make a decent exposure.
Well, we can always use more light, right?
It is most useful when you have black insects as shown in this post. Without good even light, you can’t see the detail on a black subject. So to compensate, we raise the ISO.
Sure, we can use flash if it is more light that is desired. Often with macro shots I will use flash, but not today in these images. I will save flash for a later post, because there is a few tricks to know when using flash, and like I said, one thing at a time.
I find when people are first beginning to use manual settings, it is easier to try something different one at a time. Then the light bulb of understanding goes off. When this happens, they say, “Hey, why didn’t I try this before?”
And with many cameras, you can change the ISO and still let the camera auto pick the shutter speed and/or the aperture. Check your manual, or just try it on an auto mode. You might find this a great help.
f6.3 1/1600 ISO 1000 – 60mm macro Honeybee or fly, tiny antennae, hum? Mid-Summer
You might assume raising the ISO is a no brainer, always keep the ISO high. Light is good, no? Well, it is not light the camera is giving you, but greater sensor sensitivity to light.
Always when you get something good, there is a trade-off to pay. We pay by losing some color saturation and gaining some noise at a high ISO. With cameras today though, higher ISO is less of an issue.
My Nikon does quite well at ISO 800, even at 1250 like below in the photo taken indoors. But another trade-off is if printing them quite large, the loss in quality is really noticed. The greens are a slight bit less vibrant below, but it really is a nice subtle image of the Kalanchoe. Let’s look at this image even closer.
f5 1/200 ISO 1250 – 105 mm macro – Interior shot taken last week.
Everybody always talks about avoiding noise and never tells you what it means. So I will show you. See all the many patterned dots throughout the photo below? This is the noise. It appears in wide expanses of the same color, mostly noticeable in backgrounds.
This image above is a 200 percent increase. It would be a printed image 32 inches by 20 inches, like what would be a nicely sized wall hanging. See how the quality decreases, not so great huh? If I shot with flash, the ISO would be lower and I would have a higher quality image for reproduction.
Now look at 600 times its size, see the grayish dots now? There is other factors that play in this, but this is enough for you to see what happens.
How many would care about this at the original size on the web? None really because it is not noticeable at the paltry 72ppi. It only comes to light when I increase the size for comparison. So, for web use images, high ISO really is negligible.
So Besides Low Light, What Else is it Really, Really Good For?
If you don’t have a lot of light and need a fast shutter speed to dodge camera shake, you likely would raise the ISO. Shots at dusk are an example. You don’t want to ruin them by using flash.
In the bee image below, it was a case of raising the shutter speed. With bees I like to have the advantage if they take flight. You will see more bees in flight coming up with a post on focus. There are some tricks to getting the shots, more than raising the ISO.
Even a blind squirrel can find nuts on occasion, but no need to be like the sightless squirrel. It is not too hard to up your percentage of snapping those bees in flight.
f10 1/2000 second ISO 1250 – 55-300mm zoom Autumn
So here are some specifics on ISO:
- Doubling means we need half as much light or halving the ISO means twice as much light is needed. Example ISO 100 doubled to 200 or ISO 800 to 400
- If you don’t have a lot of light, or need a fast shutter speed, raise the ISO. I raise it when shooting birds or bees in flight for example. It allows a very fast shutter speed needed to stop action on the subjects. You can lower the shutter speed if you want motion of the wings.
- Many nature photographers will raise the ISO to get high shutter speeds for fast-moving subjects. You can compare the images to the last post on the grasshopper. I used ISO 200 because he was not moving very much at all. The bee was in constant motion.
f5.6 1/600 ISO 800 – 105 mm macro – Mid-November image
To manage exposure to get the sharp, clear photos we need to balance the three main elements—aperture, shutter speed and ISO. The choices we make change our resulting photo. Not too hard to remember, right?
f5 1/200 ISO 1250 – 105mm macro – Interior shot taken last week.