Condensation And The Camera
Q) I recently was photographing in the tropics with air-conditioning inside and hot, humid conditions outside. I had to let the camera and lenses "thaw" for 45 minutes before I was able to shoot because of condensation. All was well after that, but I wondered if this practice was doing any long-term damage to my lenses or camera.
Salem, South Carolina
A) Condensation isn't a problem for the newer high-end cameras and lenses, such as the Canon EOS-1D MKIIn, the Canon EOS-1Ds MKII and the Nikon D2x, D2Hs and D200. These pro cameras have sealing gaskets on all external controls and the lens mount. Some lenses also are sealed at the points where moisture might enter; check your manufacturer's list of lenses for more information.
For most other cameras and lenses, moisture will cause damage as it seeps into the mechanisms; in fact, a common problem in the tropics is the growth of fungus on the surface of lens elements! To avoid these hazards, seal the body and lenses, along with a desiccant canister, into plastic bags as soon as you enter the air-conditioned space. When you take the gear outside again, let it warm up while sealed inside the bag. Condensation will form on the outside of the bag, rather than on the equipment, and the desiccant will take care of any moisture that might be inside the bag.
Note that desiccants do, after a time, reach their maximum absorption capability, so periodically warm them up to dry them out again. Look under "silica gel" on the web to find numerous sources of desiccant products.
Keep in mind that the same dynamics can take place in the opposite conditions. In cold weather, we take our cameras into a heated enclosure and then later return to the cold outside, only to have our equipment fog up and condensation form on the warm camera parts. Then the moisture can freeze inside the camera, causing any number of problems.
I've struggled with these conditions while photographing in the winter in Yellowstone National Park and around Churchill, Canada, where polar bears are active. As in the tropics, use the sealed bag, and wait for the temperature of the gear to equalize with the air temperature before you begin to use it.
Save, And Save Again
Q) In OP, you said that every time you open and resave a JPEG image, photo quality is lost. I did an experiment in Photoshop and opened and resaved a file 10 times. The file size didn't decrease (although it varied slightly each time). Doesn't the fact that the file didn't get smaller mean that the JPEG didn't lose image quality?
Via the Internet
A) Every time you save the image, the program recalculates and restructures the pixels. The file didn't get noticeably smaller because you didn't change the compression rate from one save to another. But the slight variances in file size mean that the file was changed slightly each time you saved your test image.
If you always save at a low compression level, you would probably need to open and resave many more than 10 times before you'd see a change in image quality due to the cumulative effect of the slight restructuring of the pixels that occurs in each save. If you're saving at a high compression level, however, the degradation of the image will reveal itself more quickly in the form of artifacts and banding that cannot be corrected.
A) If the images are important to you, scan them and store them in TIFF, preferably on a backed-up external hard drive. The TIFF format is "lossless," meaning that no matter how many times you open, work on and resave the image, it's preserved exactly the same way.
Yes, TIFF images are large, but storage space is cheap these days—less than a dollar a gigabyte. If you're going to go to all the effort of scanning and organizing these old images, you should preserve them at the highest possible level of quality, and you can enhance or optimize the images on your computer. As to your already saved images, just don't open and resave them as JPEG files (see the previous question) and you'll be okay.
When you copy the files to CD-R or DVD-R for the kids, consider using archival-quality disks that can't be overwritten, such as the Delkin Archival Gold (www.Delkin.com); these are more stable and scratch-resistant. Write the files to the disk in JPEG form here, though. The quality will still be excellent for viewing and printing, and the file size will be more manageable.
Are LCDs Worth Their Color?
Q) I've heard for so long that the Sony Artisan is the ultimate monitor for accurate color representation, so I have in my Mac G5 system a 23" Cinema display and the Artisan to the side. Do you believe LCD monitor quality with the Cinema display is capable of accurate reproduction? I'd have a tendency to replace the Artisan with another LCD.
A) Like everything else in the computer world, the quality of displays is advancing rapidly. The main advantage of the Sony Artisan monitor is that it's capable of calibrating and profiling itself. LCD displays require some attention to calibration, but they have other advantages: a larger display area, a smaller footprint and longer-lasting color.
Unless testing color is your profession, there's really no reason to keep a clunky CRT display on your worktable anymore. Your Cinema display could easily be your main desktop, with a second LCD serving to hold your Photoshop tools and palettes. Many pros, especially those using Macs, are using LCD displays exclusively. The Apple Cinema HD displays in 20, 23 and 30 inches are among the best available. Because of their color fidelity and resolution, they're used by top graphic artists and photographers around the world. See www.apple.com/displays for more information.
Q) I'm finding that dust on my imaging sensor is becoming a real problem. Are there any new tools to make sensor cleaning any easier and, especially, safer for the camera? When I first bought my digital SLR, I was told to never touch the sensor and to send it in for cleaning. The time and expense that requires means that I must clean it myself. Dust seems to get on the sensor on every trip into the field!
San Bernardino, California
A) There are several new tools, along with a number of tools that have been around for awhile, that can clean your imaging sensor efficiently and safely. The cover over your sensor is actually a glass filter, and it's more robust than you might have been led to believe. It's wise to be extremely careful when cleaning the sensor, but this task shouldn't cause your heart to race.
VisibleDust has come up with the "Arctic Butterfly," a sensor brush that's twirled by an electric motor to spin off the dust on the brush and recharge the static electricity that captures the dust particles on the sensor. VisibleDust also has an improved swab that's used with Sensor Clean solution.
LensPen has brought out a new cleaning tool for imaging sensors called the "SensorKlear." Its unique shape gets into the corners of the sensor. These and many more sensor-cleaning tools can be found at www.micro-tools.com. The site even has tutorials on cleaning your sensor.
|Just Blowin' In The Wind
Here's a tip: In a recent issue of OP, you discussed various ways to reduce vibrations during an exposure. I'd like to point out an often-overlooked problem: the camera strap. Many times while shooting, I'll go to the extra effort of locking up a mirror and using the timer. As I'm standing waiting for the shutter to close, I realize that my camera strap is blowing in the wind, negating all the effort I went through to get a sharp image. It doesn't take much of a breeze to blow the strap around! I usually just wrap the strap around the handles of my tripod, and this is enough to mitigate any strap movement. Another solution is to use a camera strap with a quick release, such as those from OP/TECH and remove it when the camera is on the tripod.