|Ferns in the mountains of Molokai, Hawaii, taken with a Canon EOS-1Ds internally converted to IR photography and a 24mm Tilt/Shift lens set to ƒ/16 and 1/45 sec. with ISO 200. The image was optimized in Photoshop.|
Infrared, Inside Out
Q What are the advantages, if any, of having a digital camera converted solely to infrared capture versus using the B+W 093 IR filter on my DSLR?
Via the Internet
A All digital cameras are extremely sensitive to infrared (IR) light, and since 2002 the manufacturers of digital cameras have placed an IR cut-off filter (sometimes referred to as a hot-mirror filter) in front of the sensor to minimize the amount of infrared light that reaches it; infrared affects the color rendition, so manufacturers want to eliminate it.
The IR cut-off filter improves the sensor’s visible-light imaging performance. Both DSLRs and compact digital cameras, therefore, severely restrict the amount of infrared light that hits the sensor. So you have three options for shooting IR with a digital camera: adding an IR filter over the lens, replacing the cut-off filter with a clear filter or replacing the cut-off filter with an IR filter. The latter two options require special intervention by a professional; don’t try this at home.
There are several external IR filters available at varying intensities: the Hoya R72, the B+W Digital Pro Infrared #093, the Singh-Ray I-Ray infrared filter and the Wratten Gelatin IR filters, among others. Achieving a significant IR effect with a filter over the lens of an unmodified digital camera requires a very long exposure, with all the negative effects that brings: subject movement and camera movement are emphasized. The exposure will vary among camera models, depending upon the sensitivity of the sensor and the effectiveness of the IR cut-off filter. Fortunately, with digital imaging, the correct exposure can be gauged by looking at the LCD and the histogram.
Replacing the IR cut-off filter with a clear filter may affect the color rendition in normal use, but will increase the effectiveness of an external IR filter. One interesting application of this conversion is the ability to shoot an image twice (from a tripod), once with the IR filter in place and once without. In Photoshop, you can combine the two images and selectively include color in your IR photograph.
If you replace the IR cut-off filter with an internal IR filter, you can achieve either partial or total IR capture. A less powerful IR filter will allow both visible light and infrared light to pass through. The result is an unusual color rendition. A pure IR filter will allow only IR light to record on the sensor; this option gives the truest black-and-white IR capture possible with current technology.
From CRT To LCD, And Even LED
Q I’m seeking to replace my CRT monitor with a big, flat LCD model. Is “hi-def” for viewing Photoshop on my computer as big an improvement as it is for football on my TV? How will I know if my “old” computer (Dell Dimension 8300) with a 128 MB DDR ATI Radeon 9800 Pro video card can deliver hi-def images to the monitor? How do I know which monitors I can successfully use? (A Dell 30-inch Ultra Sharp requires, according to the Dell website, “dual link DVI-D compatible graphics card supporting 2560x1600 resolution.”)
Via the Internet A Most photographers have already replaced the old TV-type CRT monitors with flat-screen LCD models. They offer substantial improvements in color, resolution and contrast that will change the way you see your images; it takes some getting used to, but trust me, it’s better, much better. The resolution of an LCD computer monitor is considerably higher than the flat screen you’re watching football on.
The age of your computer will possibly constrain your options for a new high-resolution LCD monitor, but the most limiting factor is your graphics card. The ATI Radeon card in your computer was introduced in 2003. My research was unable to turn up the precise capabilities of that card, but based on my experience (I replace computers about every two years), your card is probably not compatible with a new LCD monitor’s DVI connection (which carries a full digital signal versus the analog signal you’re currently using). You can put an adapter on the computer/card to receive the cable from the monitor, but your computer still won’t be transmitting all the information the new monitor is capable of receiving and displaying. So you’re going to need to replace your graphics card with an option that will work with your computer and support the size and resolution of the monitor you have in mind.
The things to look for when buying a new LCD monitor are size, resolution and contrast ratio. An LCD monitor maintains its color far better than a CRT, but it can be helpful to purchase one with the controls that allow you to make color corrections; not all of them do. My Apple displays have few controls and work very well. A higher contrast ratio gives deeper blacks and a sharper-looking image, but each manufacturer seems to express this differently, so make these comparisons within brands.
For photographers, the size of the monitor really matters because you want to see as much of the image as possible when you’re zoomed in to the details. On my Mac system, I use an Apple 30-inch monitor to display the image and a second 24-inch monitor to hold my Photoshop palettes. But if you want to use two LCD monitors, you’ll need a graphics card that supports dual DVI outputs. I’m still maintaining a Dell Precision 670 computer and 30-inch Dell Ultra Sharp monitor from my Windows days. Both 30-inch monitors have a native resolution of 2560x1600.
A few LCD manufacturers (especially Apple) are now using LEDs for backlighting in their monitors versus the fluorescents that are more typically used. They use less power, render better color and offer more consistent brightness evenly displayed across the screen. Expect a higher price.
So, get the most capable graphics card your computer can handle. Then, choose the largest compatible monitor you can afford with the highest resolution and contrast available for that size. Then, sit back and gaze in amazement at your brighter, sharper images.
2X Or Not 2X
Q I use mostly Nikon equipment and one other lens, a Sigma, and now I’d like to get a 1.4X or 2X tele-extender to use with my Nikon D200 and my Nikon ED 70-300mm f/4-5.6 D lens that will also work with my Sigma AF 170-500mm f/5-6.3 D APO lens. What do you recommend?
Via the Internet
A Most zoom lenses significantly lose sharpness, especially in the corners, when paired with a tele-extender. Zoom lenses with greater range experience greater loss. Hence, neither of the lenses you mention works well with tele-extenders. Also keep in mind that with a 1.4X tele-extender attached, your ƒ/5.6 lens will become an ƒ/8 lens, and your ƒ/6.3 lens will become an ƒ/9, mandating slower shutter speeds or higher ISOs, which could exacerbate the loss of quality.
That said, the Sigma, Tamron or Tokina 1.4X tele-extender will fit on both lenses (I wouldn’t recommend a 2X extender on any zoom other than an 80-200mm ƒ/2.8). If you want to try the 1.4X, test it with a number of focal lengths at the lens’ widest aperture, as well as one to two stops less. If the quality level is to your needs, you have a match.
Separate The Pros From The Cons
Q In your December 2009 column, you commented about what is a "pro" camera. You then mention a Canon "pro" printer. What makes a printer "pro" quality? Also, I’ve read mention of "pro" lenses. Are "pro" lenses a separate line of glass or just high-end "regular" lenses?
Via the Internet
A A professional photo printer typically uses a full set of archival pigment inks in large cartridges or tanks and handles a wide variety of media, including fine-art papers, in larger sizes and rolls. The Canon professional printers I use are large-format; they start at 17 inches wide (the imagePROGRAF 5100), up to 60 inches wide (the imagePROGRAF 9100). These printers use 12 inks (four are blacks and grays) for a larger color gamut and include sophisticated software that allows you to customize the ink pattern to the particular media, and to make fine color and exposure adjustments for the print without adjusting your image file. Canon’s professional printers are major investments (the imagePROGRAF 9100 runs about $16,000) for businesses that make prints for pro photographers or for those photographers who insist on managing every image themselves from capture to print and/or want to make really big prints (that would be me).
Other printer companies have different criteria for their professional lines and may start them at the 13-inch level, but they also offer the brilliance and longevity of pigment inks, larger ink cartridges and the ability to print on fine-art papers.
The simplest definition of a pro lens is that it attaches to a DSLR manufacturer’s pro camera bodies. But it’s really more than that; pro lenses are higher quality and more specialized, providing a higher level of precision and greater range. They typically have highly engineered optics and more extreme focal lengths, and offer a sharper and more contrasty image. Most of Canon’s pro lenses have an “L” designation and Nikon’s are designated ED, but I would include highly specialized lenses such as fish-eye, macro and tilt/shift lenses in the “pro” category.
For information about upcoming seminars and digital-imaging workshops, visit www.georgelepp.com. If you have any tips or questions, address them to: OUTDOOR PHOTOGRAPHER, Dept. TT, George Lepp, 12121 Wilshire Blvd., Suite 1200, Los Angeles, CA 90025-1176 or online at www.georgelepp.com.