VISUAL TECHNOLOGY PRODUCTION( MPT 1843)
3 MARCH 2014
Week 4 already....Today, Dr. J lectured about EXPOSURE, APERTURE and SHUTTER SPEED. He also talk about PRIME LENS....
What is a prime lens? Well, it's a lens that isn't a zoom. A prime lens has a fixed focal length which means it has only one focal length. Examples of NIKKOR prime lenses are the AF-S NIKKOR 35mm f/1.4G and AF-S NIKKOR 200mm f/2G ED VR II, and the new AF-S NIKKOR 50mm f/1.8G. Some prime lenses are designed for specific uses, such as the Micro-NIKKOR (AF-S Micro-NIKKOR 85mm f/3.5G ED VR), Perspective Control (PC-E Micro NIKKOR 45mm f/2.8D), and Fisheye (AF DX Fisheye-NIKKOR 10.5mm f/2.8D ED) lenses.
If a prime lens gives you only one focal length, but a zoom gives you a range of focal lengths, what are the benefits to using a prime lens?
Prime lenses, are smaller, lighter and more compact than zoom lenses and tend to be faster, offering wide apertures of f/2.8, f/1.8 or even f/1.4. The large apertures let in more light, which benefits the photographer in a number of ways. First, you can use fast shutter speeds with large apertures to freeze motion. This becomes important when you're shooting in low light. By using a high ISO, and wide aperture, you'll be able to use high enough shutter speeds so you can hand-hold the camera.
Secondly, because fast lenses let in lots of light, the viewfinder will be brighter, and so it will be easier to confirm focus, ensuring your images will be sharp.
One of the most sought after benefits of using a prime lens is for the Bokeh achievable by photographers, especially portrait shooters. Bokeh refers to the pleasing diffused softness of the blurred background in an image with shallow depth-of-field.According to many photographers, a byproduct of using a prime lens is that you physically have to walk into- or step back from your subject(s) when shooting—since you can't zoom in and out. This will often cause them to be more creative in their picture making.
Using a Prime Lens for VideoWhen shooting HD video, prime lenses are ideal to use. They give you the ability to achieve the same shallow depth-of-field at wide open apertures for your video footage as you already get with your still photography. This is something that is generally difficult to do using a traditional video camera. Many photographers who are shooting HD video with their Nikon D-SLRs will appreciate the prime lenses ability to autofocus precisely and quickly when AF-F (Full-time AF) is selected or even to manually focus, which will lessen the occurrence of noise from the lens being picked up by the camera's internal microphone.
Prime lenses are well suited to a variety of subjects including; portraits, architecture, nature, landscape, sports and action, flora and low light. Nikon offers a range of prime or fixed focal length lenses. Click here to view the full line of NIKKOR prime / fixed focal length lenses.
Understanding Exposure
Whether you are shooting film or digital, the principle of exposure remains the same. Exposure is the result of a three-way balancing act between three controllable camera settings: shutter speed, aperture, and ISO. I call it a three-way balancing act because when one factor shifts one way, at least one of the other two has to shift the other way to counterbalance the change.
I will go into each component in the next few articles, but for now, here is what you need to know about the three factors:
· Shutter Speed: How long the camera shutter stays open to let light in
· Aperture: How wide is the opening of your lens when the light passes through
· ISO: How sensitive is your sensor to the light
Visualizing the Exposure Relationship
One of the best ways that I have learned in visualizing the relationship between shutter speed, aperture, and ISO is to picture water pouring from a faucet into a cup. The water itself is the light and a full cup of water is considered the “correct” exposure.
Your aperture is going to be how wide you open the faucet. How long you leave the water running is your shutter speed. So let’s take a look at these two things in regards to filling the cup to the brim. If you have the faucet wide open (large aperture), it won’t take long to fill the cup up (short shutter speed). If you close down the faucet to only allow a small stream of water, it will take longer to fill the cup (long shutter speed).
That’s essentially how the aperture to shutter speed relationship works. The larger the aperture opening, the less time it takes for enough light to “fill up” a cup of exposure. The smaller the aperture opening, the longer it takes for the light to fill the same cup.
3 MARCH 2014
Week 4 already....Today, Dr. J lectured about EXPOSURE, APERTURE and SHUTTER SPEED. He also talk about PRIME LENS....
What is a prime lens? Well, it's a lens that isn't a zoom. A prime lens has a fixed focal length which means it has only one focal length. Examples of NIKKOR prime lenses are the AF-S NIKKOR 35mm f/1.4G and AF-S NIKKOR 200mm f/2G ED VR II, and the new AF-S NIKKOR 50mm f/1.8G. Some prime lenses are designed for specific uses, such as the Micro-NIKKOR (AF-S Micro-NIKKOR 85mm f/3.5G ED VR), Perspective Control (PC-E Micro NIKKOR 45mm f/2.8D), and Fisheye (AF DX Fisheye-NIKKOR 10.5mm f/2.8D ED) lenses.
If a prime lens gives you only one focal length, but a zoom gives you a range of focal lengths, what are the benefits to using a prime lens?
Prime lenses, are smaller, lighter and more compact than zoom lenses and tend to be faster, offering wide apertures of f/2.8, f/1.8 or even f/1.4. The large apertures let in more light, which benefits the photographer in a number of ways. First, you can use fast shutter speeds with large apertures to freeze motion. This becomes important when you're shooting in low light. By using a high ISO, and wide aperture, you'll be able to use high enough shutter speeds so you can hand-hold the camera.
Secondly, because fast lenses let in lots of light, the viewfinder will be brighter, and so it will be easier to confirm focus, ensuring your images will be sharp.
One of the most sought after benefits of using a prime lens is for the Bokeh achievable by photographers, especially portrait shooters. Bokeh refers to the pleasing diffused softness of the blurred background in an image with shallow depth-of-field.According to many photographers, a byproduct of using a prime lens is that you physically have to walk into- or step back from your subject(s) when shooting—since you can't zoom in and out. This will often cause them to be more creative in their picture making.
Using a Prime Lens for VideoWhen shooting HD video, prime lenses are ideal to use. They give you the ability to achieve the same shallow depth-of-field at wide open apertures for your video footage as you already get with your still photography. This is something that is generally difficult to do using a traditional video camera. Many photographers who are shooting HD video with their Nikon D-SLRs will appreciate the prime lenses ability to autofocus precisely and quickly when AF-F (Full-time AF) is selected or even to manually focus, which will lessen the occurrence of noise from the lens being picked up by the camera's internal microphone.
Prime lenses are well suited to a variety of subjects including; portraits, architecture, nature, landscape, sports and action, flora and low light. Nikon offers a range of prime or fixed focal length lenses. Click here to view the full line of NIKKOR prime / fixed focal length lenses.
Understanding Exposure
Whether you are shooting film or digital, the principle of exposure remains the same. Exposure is the result of a three-way balancing act between three controllable camera settings: shutter speed, aperture, and ISO. I call it a three-way balancing act because when one factor shifts one way, at least one of the other two has to shift the other way to counterbalance the change.
I will go into each component in the next few articles, but for now, here is what you need to know about the three factors:
· Shutter Speed: How long the camera shutter stays open to let light in
· Aperture: How wide is the opening of your lens when the light passes through
· ISO: How sensitive is your sensor to the light
Visualizing the Exposure Relationship
One of the best ways that I have learned in visualizing the relationship between shutter speed, aperture, and ISO is to picture water pouring from a faucet into a cup. The water itself is the light and a full cup of water is considered the “correct” exposure.
Your aperture is going to be how wide you open the faucet. How long you leave the water running is your shutter speed. So let’s take a look at these two things in regards to filling the cup to the brim. If you have the faucet wide open (large aperture), it won’t take long to fill the cup up (short shutter speed). If you close down the faucet to only allow a small stream of water, it will take longer to fill the cup (long shutter speed).
That’s essentially how the aperture to shutter speed relationship works. The larger the aperture opening, the less time it takes for enough light to “fill up” a cup of exposure. The smaller the aperture opening, the longer it takes for the light to fill the same cup.
Now to visualize ISO, imagine adding a pump to the faucet’s plumbing to force the water out faster. Just by increasing the flow rate of the water, you can fill the cup faster without having to adjust the opening of the faucet or extending the time to fill the cup. ISO is similar in that you are artificially “pushing” more light on the sensor by making the sensor more sensitive to the light.
Underexposure and Overexposure
Underexposure and Overexposure
When an image is underexposed, that means that it is darker than a properly exposed image. Going back to our water faucet analogy, that means that you did not allow enough water to fill the cup all the way to the top. To correct this, you either have to open the faucet wider, give more time for the water to fill the cup, or force the water out faster. In camera terms, this means either opening up the aperture, having a longer shutter speed, or increasing the ISO.
If an image is overexposed, that means that it is way too bright. With our water faucet, that means letting too much water flow into the cup and having the excess water spill out into the sink. To adjust for this, simply close the faucet down a bit, shorten the amount of time allotted for the water, or slow the water’s flow rate. The camera equivalence would be closing down the aperture, having a shorter shutter speed, or lowering the ISO.
If an image is overexposed, that means that it is way too bright. With our water faucet, that means letting too much water flow into the cup and having the excess water spill out into the sink. To adjust for this, simply close the faucet down a bit, shorten the amount of time allotted for the water, or slow the water’s flow rate. The camera equivalence would be closing down the aperture, having a shorter shutter speed, or lowering the ISO.
So, keeping things simple for now, exposure is simply a three-way balancing act between three controllable camera settings: shutter speed, aperture, and ISO. The right combination of the three leads to a “proper” exposure where the image looks like it has the right amount of brightness. If you change one of the three settings, then you have to change at least one of the other two settings to maintain the balance.
Until then, stay creative!
References:
http://www.slrlounge.com/school/the-basics-of-shooting-a-dslr-explaining-exposure
http://www.nikonusa.com/en/Learn-And-Explore/Article/gmtndkds/prime-lenses.html
http://www.hongkiat.com/blog/levitation-photography/