I get a lot of questions from customers, workshop attendees, and even random strangers when I’m out shooting. Most folks ask about basic photography techniques or ask for equipment suggestions and, since these questions usually have broad appeal, I thought I would share my answers each Friday here on the blog.
This week, an attendee from last month’s Canon Live Learning seminar in Los Angeles asks:
I have it on my list to buy a neutral density filter. Should I get a regular one or a graduated one? What are your thoughts on the matter?
I enjoy taking close up images, such as insects on or in flowers. Is a macro lens the way to go, or is there a different lens with a tripod that works just as well?
OK, that’s two questions. A bonus this week…
Neutral density filters are a valuable accessory when you need to restrict the amount of light entering the lens. This is necessary when the photographer finds there is too much ambient light and requires a slow shutter speed to record motion blur. A shutter speed of 1/2 second or slower is a very effective means of blurring streams, waterfalls, or ocean waves for a dramatic and ethereal effect that illustrates the motion and flow of water.
Another application is when a photographer desires minimum depth-of-field for portraits or selective focus and must use the lens’ widest aperture to obtain that degree of isolation. In normal daylight this might not be possible without filtering some of that light from entering the lens.
Neutral density filters are classified by their optical density and transmission values.
The most widely used are:
ND2 (-1 stop)
ND4 (-2 stops)
ND8 (-3 stops)
These three filters can be used separately or together to produce the desired amount of light transmittance. A more convenient and precise, but costly, option is to consider a so-called “black glass” variable neutral density filter. This type of filter is offered by several manufacturers and is a single ND filter that offers varying degrees of density within a 9-10 stop range. By simply turning the front filter element, the photographer can dial in the precise amount of neutral density needed.
A gradual neutral density filter is a rectangle or square filter that has a gradient tone ranging from dark to clear and is offered with the same optical values listed above. It is commonly used to maintain detail in the sky when exposing for the foreground detail (or vice versa). For still photographers, Photoshop not only eliminates the need for gradient filters, but it also enables photographers to selectively darken or lighten specific areas of their image in a very precise manner. That being said, neutral density gradient filters are still widely used by videographers who wish to achieve the same effect while filming, but want to avoid spending long hours correcting tonal values in post processing.
Macro photography is a subject that requires much more than a single blog entry to discuss comprehensively, but the short answer to Pascal’s question is;
“Yes, a macro lens is the way to go”.
The simple reason is that macro is widely regarded as images captured at 1:1 life size or larger. Most lenses are incapable of achieving that degree of magnification unless they are a true “macro” lens. I’m a Canon shooter and my favorite macro lens is the Canon 100mm f/2.8L Macro. It is incredibly sharp and the “L” series glass produces excellent color, contrast, and tonal values. For Nikon shooters, the Nikon AF-S 105mmVR Micro f/2.8 is a comparable choice for macro.
There’s a couple of alternatives if you’re not quite ready to invest in a macro lens. One affordable option is a set of close-up filters. These filters are simple diopters that come in magnification powers of +1, +2, and +3 and screw on to the front of the lens. These filters magnify the subject and decrease the lens-to-subject distance which enables close-up focusing.
Finally, a set of extension tubes might be all you need for getting closer to your subject. They are typically sold in sets of three tubes with different lengths (12mm, 24mm, & 36mm) and can be used separately or together between the lens and camera body. By extending the distance of the rear lens element from the camera’s imaging sensor, you shorten the camera’s minimum focusing distance. Again, this allows you to leverage the magnification properties of a long focal length at very short distances.
When shooting close-ups of flowers, my favorite technique is to attach the 36mm extension tube onto my 200mm lens, then compose by filling the frame with the flower, and exposing with a wide aperture to blur the background. This isolates the flower and eliminates any distracting background elements.
I hope you find these answers useful. If you have a question you would like answered on the Omega Photo Blog, email me at email@example.com and I’ll give it my best shot…
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