As you may have noticed, I’ve added a timeline page to ATG, which is turning out to be an exciting project.
I’ve wanted to add historical information for some time now, but writing an account of how photography came to be as we know it today proved a daunting task. I decided instead to put it in the form of a timeline, which works quite well on an endless scrolling web page. The only difference is, it goes from top to bottom instead of left to right.
Today, I decided to add blank lines to represent the years between events. It seems to provide a more accurate graphic portrayal of the passage of time.
It’s a good start, but by no means even near complete. I’ll be adding new facts as I come across them, so it will get more and more dense as time progresses. Perhaps at the end of it all, I’ll use it to write that historical account.
Until then…
News, Muse and Reviews for Aspiring Lensmen.
Thursday, December 30, 2010
Wednesday, December 29, 2010
The Sensor
The Sensor is the light-sensitive electronic component of a digital camera which captures the image to be stored in memory. The information gathered by the sensor is passed on to the imaging engine and subsequently stored in binary format on a flash memory card.
The Film
Film is the light-sensitve media on which captured images are stored. Image information is stored as “latent” images which must be processed in order to be made visible.
Film comes in many different formats, that is sizes and aspect ratios. The most common format of film is 135 or simply 35mm, whose dimensions are 36mm x 24mm. It is said to have a 3:2 aspect ratio; that is its height is two-thirds of its width (or, its width is three-halfs of its height). The second most common type of film is 120 which can have several formats, the most common of which is 6cm x 6cm, a square format with an aspect ratio of 1:1. Square formats have the advantage of not requiring any rotation of the camera. Other 120 formats are 7cm x 6cm, and 6cm x 4.5cm and 9cm x 6 cm. There are many other film formats as well.
Film formats are divided into three classes based of film size; Small format (135), Medium (120, 220), and large (4x5, 5x7, 8x10). There can be many “formats” in terms of aspect ratio within a give film size.
Film is supplied in light-tight cartridges (110, APS and 135), rolls (120), or sheets (4x5, 5x7, 8x10).
Film comes in many different emulsions with different color, saturation, contrast and grain characteristics. The most common emulsion produces a negative image which becomes a master for producing prints. The next most common emulsion produces a positive image which can be viewed directly or projected, as well as being printed through a more complicated process. Most emulsions are balanced for daylight, although some are available for tungsten.
Film comes in many different sensitivities or “speeds” ranging from ISO 3200 (fast, coarse grain) to ISO 25 (slow, fine grain), the most common being ISO 200. The acronym ISO is used to denote film speed, but it is actually the logotype designation for the International Organization for Standardization. Prior to ISO, ASA/DIN was used, the acronym for American Standards Association and German Institute for Standardization (Deutsches Institut für Normung). Most cameras have an ISO setting to tell the metering system which speed of film you’re using. You can set it to match the speed of the film, or set it one to two stops higher to “push” the film, or one to two stops lower to “pull” the film. If you do this, you must process the film at the ISO the camera was set to in order to compensate. Some films respond to this technique better than others.
Which film speed you use depends on the lens speed, aperture range, shutter speed range, and lighting conditions. Fast speed film is used in conjunction with faster shutter speeds to capture action, or subjects in low light. Slow film is used in conjunction with slower shutter speed to increase resolution in still subjects, or in bright light.
Formats at a glance:
(Dimensions are width x height in the natural orientation of the camera)
110
110, 17mm x 13mm, 4:3 aspect ratio, landscape orientation
APS
half-frame, 18mm x 24mm, 3:4 aspect ratio, portrait orientation
square, 24mm x 24mm, 1:1 aspect ratio, universal orientation
sprocket hole, dimensions, aspect ratio and orientation governed by camera’s mask.
120, 220
6x6 (square, 2-1/4"), 6cm x 6cm, 1:1 aspect ratio, universal orientation
6x7, 7cm x 6 cm, 7:6 aspect ratio, landscape orientation
6x4.5, 4.5cm x 6cm, 6:4.5 aspect ratio, portrait orientation
6x9, 9cm x 6cm, 3:2 aspect ration, landscape orientation
Sheet Film
4x5, 12.7cm x 10.2cm, 5:4 aspect ratio, portrait or landscape orientation
5x7, 17.8cm x 12.7cm, 7:5 aspect ratio, portrait or landscape orientation
8x10, 25.4cm x 20.3cm, 5:4 aspect ratio, portrait or landscape orientation
Film comes in many different formats, that is sizes and aspect ratios. The most common format of film is 135 or simply 35mm, whose dimensions are 36mm x 24mm. It is said to have a 3:2 aspect ratio; that is its height is two-thirds of its width (or, its width is three-halfs of its height). The second most common type of film is 120 which can have several formats, the most common of which is 6cm x 6cm, a square format with an aspect ratio of 1:1. Square formats have the advantage of not requiring any rotation of the camera. Other 120 formats are 7cm x 6cm, and 6cm x 4.5cm and 9cm x 6 cm. There are many other film formats as well.
Film formats are divided into three classes based of film size; Small format (135), Medium (120, 220), and large (4x5, 5x7, 8x10). There can be many “formats” in terms of aspect ratio within a give film size.
Film is supplied in light-tight cartridges (110, APS and 135), rolls (120), or sheets (4x5, 5x7, 8x10).
Film comes in many different emulsions with different color, saturation, contrast and grain characteristics. The most common emulsion produces a negative image which becomes a master for producing prints. The next most common emulsion produces a positive image which can be viewed directly or projected, as well as being printed through a more complicated process. Most emulsions are balanced for daylight, although some are available for tungsten.
Film comes in many different sensitivities or “speeds” ranging from ISO 3200 (fast, coarse grain) to ISO 25 (slow, fine grain), the most common being ISO 200. The acronym ISO is used to denote film speed, but it is actually the logotype designation for the International Organization for Standardization. Prior to ISO, ASA/DIN was used, the acronym for American Standards Association and German Institute for Standardization (Deutsches Institut für Normung). Most cameras have an ISO setting to tell the metering system which speed of film you’re using. You can set it to match the speed of the film, or set it one to two stops higher to “push” the film, or one to two stops lower to “pull” the film. If you do this, you must process the film at the ISO the camera was set to in order to compensate. Some films respond to this technique better than others.
Which film speed you use depends on the lens speed, aperture range, shutter speed range, and lighting conditions. Fast speed film is used in conjunction with faster shutter speeds to capture action, or subjects in low light. Slow film is used in conjunction with slower shutter speed to increase resolution in still subjects, or in bright light.
Formats at a glance:
(Dimensions are width x height in the natural orientation of the camera)
110
110, 17mm x 13mm, 4:3 aspect ratio, landscape orientation
APS
APS-C (Classic), 25.1mm x 16.7mm, 3:2 aspect ratio, landscape orientation
APS-H (High Definition), 30.2mm x 16.7mm, 16:9 aspect ratio, landscape orientation
APS-P (Panoramic) 30.2mm x 9.5mm, 3:1 aspect ratio, landscape orientation
135
full-frame, 36mm x 24mm, 3:2 aspect ratio, landscape orientation135
half-frame, 18mm x 24mm, 3:4 aspect ratio, portrait orientation
square, 24mm x 24mm, 1:1 aspect ratio, universal orientation
sprocket hole, dimensions, aspect ratio and orientation governed by camera’s mask.
120, 220
6x6 (square, 2-1/4"), 6cm x 6cm, 1:1 aspect ratio, universal orientation
6x7, 7cm x 6 cm, 7:6 aspect ratio, landscape orientation
6x4.5, 4.5cm x 6cm, 6:4.5 aspect ratio, portrait orientation
6x9, 9cm x 6cm, 3:2 aspect ration, landscape orientation
Sheet Film
4x5, 12.7cm x 10.2cm, 5:4 aspect ratio, portrait or landscape orientation
5x7, 17.8cm x 12.7cm, 7:5 aspect ratio, portrait or landscape orientation
8x10, 25.4cm x 20.3cm, 5:4 aspect ratio, portrait or landscape orientation
The Shutter
The shutter of a camera is a device which controls the period of time light enters the camera. It blocks the light and prevents exposure until the picture is to be taken. On demand, it slides out of the way for a period of time, and then slides back to stop the exposure.
Shutter speeds are designated in fractions of a second, and can be set with a variety of different controls. On most film cameras, a dial is located on the top of the camera which sets the the shutter speed mechanically. On digital cameras the shutter may be controlled electronically through a thumbwheel or command dial, or through a menu.
Every camera has a range of shutters speeds from about 2 seconds up to 1/4000 of a second, depending on the performance characteristics of the shutter. Which of the available shutter speeds you can use depends on several other factors; the range of available apertures, the ISO setting of the camera, and the available light.
Which shutter speed you should use depends on the effect you are trying to achieve, which will vary depending on the movement of the camera, the subject or both.
Motion blur is an effective means of expressing movement in a photo. It occurs when the movement of the camera or subject is recorded over time by using a slow shutter speed. You can pan on a moving subject, keeping it relatively sharp while blurring the background for separation, or you can hold the camera stationary and let the subject’s movement tell the story. You can photograph a moving stream or a body of water and soften it with a longer than necessary exposure.
The ability to freeze motion can be a powerful way of capturing the moment. It also assures the sharpest possible image, which relies on the ability of the shutter to eliminate any movement of the camera.
Shutter speeds are designated in fractions of a second, and can be set with a variety of different controls. On most film cameras, a dial is located on the top of the camera which sets the the shutter speed mechanically. On digital cameras the shutter may be controlled electronically through a thumbwheel or command dial, or through a menu.
Every camera has a range of shutters speeds from about 2 seconds up to 1/4000 of a second, depending on the performance characteristics of the shutter. Which of the available shutter speeds you can use depends on several other factors; the range of available apertures, the ISO setting of the camera, and the available light.
Which shutter speed you should use depends on the effect you are trying to achieve, which will vary depending on the movement of the camera, the subject or both.
Motion blur is an effective means of expressing movement in a photo. It occurs when the movement of the camera or subject is recorded over time by using a slow shutter speed. You can pan on a moving subject, keeping it relatively sharp while blurring the background for separation, or you can hold the camera stationary and let the subject’s movement tell the story. You can photograph a moving stream or a body of water and soften it with a longer than necessary exposure.
The ability to freeze motion can be a powerful way of capturing the moment. It also assures the sharpest possible image, which relies on the ability of the shutter to eliminate any movement of the camera.
- 30 seconds — The lower limit of typical Digital SLRs. Usable for digital pinhole or infrared work.
- 4-15 seconds — The lower limit of typical compact or bridge digital cameras. Usable for digital pinhole or infrared work.
- 1-2 seconds — The lower limit of most mechanical shutter 35mm SLRs. Useable for 35mm or digital pinhole photography under bright lighting conditions. Usable for digital infrared work.
- 1/15-1/2 second — These speeds allow existing light photography under dim lighting conditions. They also allow you to soften the flow of a moving stream or waterfall. Usable for digital infrared work under bright conditions.
- 1/30 second — About the slowest shutter speed for hand-held use with a wide-angle lens. Usable for digital infrared work under bright conditions.
- 1/60 second — This is a good general purpose shutter speed, usually the lower limit for handheld use with a normal lens, and a setting most often associated with indoor or flash photography.
- 1/125 second — This is a fairly worry-free speed when using standard zoom lenses.
- 1/250 second — This is usually the maximum speed at which you can sync to a flash.
- 1/500 second — Good for use in bright sunlight, or with most telephoto lenses.
- 1/1000-1/4000 second — These speeds allow the photographer to freeze motion, such as in sports.
Automatic exposure cameras that have a Shutter Priority mode allow the user to select a shutter speed, while the camera selects the corresponding aperture speed for the proper or desired exposure. This allows for more predictable results when shooting in low light.
The Aperture
The aperture of a lens is a variable size opening which controls how much light enters the camera. It is one of two elements of exposure, the other being shutter speed. But the aperture doesn’t only affect the exposure; it also affects sharpness and depth of field, two important aspects of creative control within the scope of photography.
Apertures are designated by “f-stops”, and written as a ratio (1:2.8) or as an f-number (f/2.8) The smaller the number, the larger the opening and the more light enters the camera. The larger the number, the smaller the opening and the less light enters the camera. Starting from the widest aperture, each successive full stop lets in half the light of the previous stop. Some lenses have half-stop clicks, others only full stops. Digital cameras can typically select between half stops and one third stops through the camera’s software.
Apertures can be set with a variety of different controls. On most cameras, a ring or lever is located on the lens that rotates or moves to increase or decrease the aperture size mechanically. In the case of a digital SLR, a dial or thumbwheel is used to set the aperture electronically, while compact digital cameras may do this through a system of menus.
Every lens has a range of apertures, from one (for a simple, fixed-lens camera) to many (seven or more for a typical interchangeable SLR lens). Normal lenses typically have apertures ranging from f/1.4 to f/22. However, a compact digital camera may have a range of only f/2.8 to f/5.6. Simple or “toy” cameras might have two or three apertures, while “fixed-focus” cameras typically use smaller apertures for greater depth of field.
Depth of field is the width of the plane of sharp focus, from front to back. Narrow or shallow depth of field means that if you focus on the eyes, the nose and ears might be out of focus. Wide or deep depth of field means that not only will the nose and ears be in sharp focus, but elements both in front of and behind the face, within a reasonable proximity. Control over depth of field means that when taking a portrait, a distracting background can be thrown out of focus. It gives you the ability to isolate or separate your subject from its surroundings.
Sharpness is the maximum resolving power of the lens. With a truly sharp image, the greater you magnify the film negative or digital image, the more detail you will see, up to the limit of the pixels or film grain. Maximum sharpness is limited by the design and quality of the optics, and also by the effects of diffraction.
Diffraction is the tendency of parallel light rays to disperse when passing through an aperture. Normally the amount of dispersion is negligible. But beyond a certain point, the amount of diffraction exceeds the circle of light projected on the film or sensor, softening the image. The only way to overcome this is to increase the size of the film or sensor. Diffraction is the reason compact digital cameras with smaller sensors are limited to about f/5.6. Smaller than that, and image resolution would suffer greatly.
Different apertures produce different effects, based on degrees of depth of field and sharpness, and it’s important to know what these effects are. Which of the available apertures the photographer can use depends on several other factors; the shutter speed range of the camera, the ISO setting of the camera, and the available light.
The shape of the aperture is a consideration, as it has a direct affect on the bokeh. Some apertures use an iris with rounded blades which create a more circular bokeh. Others use a higher number of blades to create a smoother circle. Lenses with apertures consisting of “waterhouse stops” (interchangeable disks with varying-sized openings) can use custom shapes which will determine the shape of the highlights.
Automatic exposure cameras that have an Aperture Priority mode allow the user to select an aperture, while the camera selects the corresponding shutter speed for the proper or desired exposure. Aperture priority is the most popular auto exposure mode due to its ability to allow the user to control depth of field.
Apertures are designated by “f-stops”, and written as a ratio (1:2.8) or as an f-number (f/2.8) The smaller the number, the larger the opening and the more light enters the camera. The larger the number, the smaller the opening and the less light enters the camera. Starting from the widest aperture, each successive full stop lets in half the light of the previous stop. Some lenses have half-stop clicks, others only full stops. Digital cameras can typically select between half stops and one third stops through the camera’s software.
Apertures can be set with a variety of different controls. On most cameras, a ring or lever is located on the lens that rotates or moves to increase or decrease the aperture size mechanically. In the case of a digital SLR, a dial or thumbwheel is used to set the aperture electronically, while compact digital cameras may do this through a system of menus.
Every lens has a range of apertures, from one (for a simple, fixed-lens camera) to many (seven or more for a typical interchangeable SLR lens). Normal lenses typically have apertures ranging from f/1.4 to f/22. However, a compact digital camera may have a range of only f/2.8 to f/5.6. Simple or “toy” cameras might have two or three apertures, while “fixed-focus” cameras typically use smaller apertures for greater depth of field.
Depth of field is the width of the plane of sharp focus, from front to back. Narrow or shallow depth of field means that if you focus on the eyes, the nose and ears might be out of focus. Wide or deep depth of field means that not only will the nose and ears be in sharp focus, but elements both in front of and behind the face, within a reasonable proximity. Control over depth of field means that when taking a portrait, a distracting background can be thrown out of focus. It gives you the ability to isolate or separate your subject from its surroundings.
Sharpness is the maximum resolving power of the lens. With a truly sharp image, the greater you magnify the film negative or digital image, the more detail you will see, up to the limit of the pixels or film grain. Maximum sharpness is limited by the design and quality of the optics, and also by the effects of diffraction.
Diffraction is the tendency of parallel light rays to disperse when passing through an aperture. Normally the amount of dispersion is negligible. But beyond a certain point, the amount of diffraction exceeds the circle of light projected on the film or sensor, softening the image. The only way to overcome this is to increase the size of the film or sensor. Diffraction is the reason compact digital cameras with smaller sensors are limited to about f/5.6. Smaller than that, and image resolution would suffer greatly.
- f/1.2, f/1.4, f/1.8 — These apertures allow you to take photos in existing light without the use of flash, while minimizing motion blur. However, while they may not yield the sharpest images, their narrow depth of field affords you the greatest ability to isolate your subject from the foreground and background.
- f/2.0, f/2.8, f/4.0 — These apertures provide a good combination of sharpness and speed, with the ability to isolate your subject within the narrow plane of sharp focus. They require precise focusing.
- f/5.6 — An aperture available on most cameras and lenses, offering a good combination of speed and depth of field. Often the aperture at which most lenses are their sharpest. Focusing is less critical.
- f/8.0, f/11 — When there is adequate light, these are ideal apertures to use, giving high degrees of both sharpness and depth of field. f/11 is about the smallest aperture you can use before the effects of diffraction begin to degrade sharpness. A single focus setting will cover a wide range of distances. Many fixed-focus cameras use f/11.
- f/16, f/22 — When extreme sharpness is not a priority, but the need to avoid critical focusing is, these are the apertures to use. Everything from about 4ft. to infinity will be in focus, although not at maximum sharpness.
The shape of the aperture is a consideration, as it has a direct affect on the bokeh. Some apertures use an iris with rounded blades which create a more circular bokeh. Others use a higher number of blades to create a smoother circle. Lenses with apertures consisting of “waterhouse stops” (interchangeable disks with varying-sized openings) can use custom shapes which will determine the shape of the highlights.
Automatic exposure cameras that have an Aperture Priority mode allow the user to select an aperture, while the camera selects the corresponding shutter speed for the proper or desired exposure. Aperture priority is the most popular auto exposure mode due to its ability to allow the user to control depth of field.
Aperture Guide
A quick guide to apertures available on the Nikon D90, in 1/3 stop and 1/2 stop increments:
f/1.0
| These values, for the most part, have been taken directly from the camera. Some of the 1/2 stop values, when rounded by the camera, are the same as the 1/3 stop values. Using this chart, we can see for example, that an f/1.2 lens is a full stop faster than an f/1.8 lens, but an f/1.8 lens is only 1/3 stop faster than f/2.0. However an f/1.8 lens is a significant 1-1/3 stops faster than an f/2.8 lens, a common aperture value. The holy grail of speed, the f/0.95 lens, is just slightly over a full stop faster than an f/1.4. Using Nikon’s claim of a 4-stop advantage using VR, the 16-85mm f/3.5-5.6 would behave similarly to an f/0.95-2.0 lens in cases where it was not used to stop action. In reality however, it would be closer to f/1.2, a three-stop advantage. Not too shabby. On the other hand, the 70-300mm f/4.5-5.6 would be the equivalent of f/1.6-2.0. Still not shabby. So, unless you are shooting sports or other action, purchasing a fast f/2.8 telephoto may not be entirely necessary. It will however cut down significantly on flash recycle times, which may be a consideration. |
Thursday, December 23, 2010
Wednesday, December 22, 2010
Video on the Canon Powershot SD780 IS
I’ll level with you; I’m not a video person. It’s never held that much of an attraction for me. But even I have to admit that I’m fascinated by the fact that pretty much all still digital cameras come with some form of video. And the Canon SD780 is pretty amazing in this regard. In fact, it was a deciding factor in its purchase.
Wednesday, December 15, 2010
Restoring Lost Images
Every once in a while, the situation arises when your images seem to be gone. Or, you accidentally delete images that you meant to keep. Or, You accidentally format a memory card without offloading all the images. Here’s how to restore them.
The Pitfalls of Pixel Peeping
Pixel peeping is often used as a derogatory term to described those obsessed with zooming into digital images to scrutinize them on a pixel-by-pixel level. While pixel-peeping can be useful in evaluating lenses, no good can come of it when done as a matter of course.
Monday, December 13, 2010
First Impressions: AF Nikkor 20mm f/2.8D
I finally received my Nikkor Ultrawide prime today. I’ve been debating this purchase for a while now, but if I’m going to have at least one AF-D lens in my collection, it might as well be the most compact of them all and be compatible with a wide variety of bodies and uses.
It seems that, for a lens of this price range, a pouch should have been included. It was conspicuously absent from the box, as was the bayonet lens hood. But then, this is a different class of lens altogether.
First off, this lens is made in Japan. Not that I feel that products manufactured in Thailand, Korea or China are of poor quality. But this lens is made in Japan.
Secondly, it’s fully mechanical, not electronic. Yes, it has a chip to tell the camera what type of lens it is, and to relay the focus distance information for 3D matrix metering, but that’s it. When you look inside the focus scale window, you see a metal focus scale with etched, paint-filled numbers, directly coupled to the rubber-covered focus ring. This direct coupling makes all the difference. It gives the focus a silky-smooth feel with hard stops at 0 and infinity. Silky smooth, but not damped. Damping the lens would interfere with its autofocus operation, so it’s the first thing to go. But this lens is, for all intents and purposes, a traditional lens.
I like the simplicity of the older autofocus system. A simple mechanical linkage, driven by the camera, simplifying the lens. I can see now why this lens is as compact as it is. But, I can also hear the case for the built-in Silent-Wave motor. This lens is L-O-U-D. Fast, but loud. When traveling from one extreme to another, you can really hear it go. But, that’s not particularly field-relevant, because in actual use, the travel is usually quite short, emitting just a brief chirp.
This lens give new purpose to the two-position AF-M switch at the base of the lens. Doesn’t do much with a G lens. But with a D lens, it decouples the focus linkage, allowing fully manual focusing, as well as electronically disabling the motor.
Sadly, this is the worst mounting of all my lenses. It goes on with all sorts of grinding sensations, although I can find no physical evidence as to why. But, once it’s on, it fits nice and tight, with no play whatsoever. The body of the lens just barely provides enough surface area to grip it while mounting. I would definitely NOT recommend using the focus ring’s infinity stop to aid in this operation, although I would think the f/22 lock on the aperture ring would be OK. The additional surface area of the aperture ring definitely helps.
It’s a good idea to decouple the focus linkage using the AF-M switch before mounting any D lens. If you do accidentally slip and turn the focus ring, it won’t turn the motor and gearing in the camera.
On the D90, it looks and feels great. Proportionally it’s just right, although it would dwarf a D40 or D60, and on a D3 it would just about hold its own. Its outward taper gives it a solid, professional look, and its short focal length makes it compact and easy to focus. A lens you don’t mind keeping on your camera at all times. Tricky to keep your hand off the focus ring in autofocus mode, but the body is long enough to grip if you like to steady the camera that way.
The field of view is perfect on the D90. At a full-frame equivalent of 30mm, it falls between that golden 35mm, and the superwide 24mm, very usable indeed. Actually, the diagonal measurement of the APS-C sensor is 30.5mm making this a true “normal” lens, just as 43mm is on a full-frame camera. The DX crop factor uses the most accurate part of the lens’ field of view, so the edges are sharp and free of any noticeable aberrations.
To be honest, I don’t see myself owning a lot of D lenses, so If I only have one, this seems to be a good choice. If the impeccable Nikkor AF-S DX 35mm f/1.8G wasn’t 1-1/3 stops faster and so darn cheap, I’d probably forgo it for this lens.
Tech Notes:
It seems that, for a lens of this price range, a pouch should have been included. It was conspicuously absent from the box, as was the bayonet lens hood. But then, this is a different class of lens altogether.
First off, this lens is made in Japan. Not that I feel that products manufactured in Thailand, Korea or China are of poor quality. But this lens is made in Japan.
Secondly, it’s fully mechanical, not electronic. Yes, it has a chip to tell the camera what type of lens it is, and to relay the focus distance information for 3D matrix metering, but that’s it. When you look inside the focus scale window, you see a metal focus scale with etched, paint-filled numbers, directly coupled to the rubber-covered focus ring. This direct coupling makes all the difference. It gives the focus a silky-smooth feel with hard stops at 0 and infinity. Silky smooth, but not damped. Damping the lens would interfere with its autofocus operation, so it’s the first thing to go. But this lens is, for all intents and purposes, a traditional lens.
I like the simplicity of the older autofocus system. A simple mechanical linkage, driven by the camera, simplifying the lens. I can see now why this lens is as compact as it is. But, I can also hear the case for the built-in Silent-Wave motor. This lens is L-O-U-D. Fast, but loud. When traveling from one extreme to another, you can really hear it go. But, that’s not particularly field-relevant, because in actual use, the travel is usually quite short, emitting just a brief chirp.
This lens give new purpose to the two-position AF-M switch at the base of the lens. Doesn’t do much with a G lens. But with a D lens, it decouples the focus linkage, allowing fully manual focusing, as well as electronically disabling the motor.
Sadly, this is the worst mounting of all my lenses. It goes on with all sorts of grinding sensations, although I can find no physical evidence as to why. But, once it’s on, it fits nice and tight, with no play whatsoever. The body of the lens just barely provides enough surface area to grip it while mounting. I would definitely NOT recommend using the focus ring’s infinity stop to aid in this operation, although I would think the f/22 lock on the aperture ring would be OK. The additional surface area of the aperture ring definitely helps.
It’s a good idea to decouple the focus linkage using the AF-M switch before mounting any D lens. If you do accidentally slip and turn the focus ring, it won’t turn the motor and gearing in the camera.
On the D90, it looks and feels great. Proportionally it’s just right, although it would dwarf a D40 or D60, and on a D3 it would just about hold its own. Its outward taper gives it a solid, professional look, and its short focal length makes it compact and easy to focus. A lens you don’t mind keeping on your camera at all times. Tricky to keep your hand off the focus ring in autofocus mode, but the body is long enough to grip if you like to steady the camera that way.
The field of view is perfect on the D90. At a full-frame equivalent of 30mm, it falls between that golden 35mm, and the superwide 24mm, very usable indeed. Actually, the diagonal measurement of the APS-C sensor is 30.5mm making this a true “normal” lens, just as 43mm is on a full-frame camera. The DX crop factor uses the most accurate part of the lens’ field of view, so the edges are sharp and free of any noticeable aberrations.
To be honest, I don’t see myself owning a lot of D lenses, so If I only have one, this seems to be a good choice. If the impeccable Nikkor AF-S DX 35mm f/1.8G wasn’t 1-1/3 stops faster and so darn cheap, I’d probably forgo it for this lens.
Tech Notes:
- The 20mm f/2.8D has a bayonet lens hood mount, which accepts the Nikon HB-4 Bayonet Lens Hood.
- On the D90, the Hoya 67mm adjustable lens hood can be used in its intermediate position with a 62-67mm step-up ring.
- On a full-frame camera such as the N80, neither the 67mm nor the larger 72mm Hoya adjustable hood can be used even at their widest settings without minor vignetting.
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