ISO & Digital Image Quality

Lowest ISOs • Blowin' In The Wind • Stacking Tele-Extenders • Performance In Cold Environments
An ISO of 50 allowed a shutter speed of 1‚ÅÑ8 sec. at ƒ/32 to give the desired effect on these waterfalls in the surf on Molokai, Hawaii. A Canon EOS-1Ds Mark II was used with a 100-400mm lens set to 180mm
An ISO of 50 allowed a shutter speed of 1/8 sec. at ƒ/32 to give the desired effect on these waterfalls in the surf on Molokai, Hawaii. A Canon EOS-1Ds Mark II was used with a 100-400mm lens set to 180mm.

Lowest ISOs

I’ve noticed that many of the Nikon cameras, such as the D100, have a starting ISO of 200, while Canon digital cameras start at ISO 100. Is there a difference?
Via the Internet

A number of the early Nikon digital cameras had a lowest ISO reading of 200, but the current cameras start at ISO 100. The ISO of 200 was a function of the interface between the image sensor and the camera's processor. The camera was optimized to this ISO and attained excellent quality, even though it had an increased sensitivity of one stop over the Canon cameras. This tended to be problematic for photographers wanting to use slow shutter speeds in midday to render blurred water, however. It was then, and still is, necessary to use neutral-density filters to achieve the equivalent of lower ISOs.

Canon has standardized from the beginning to an ISO of 100 minimum, with the possibility of setting an ISO of 50 on some camera bodies. This ISO of 50 doesn’t increase quality; it simply lowers the sensitivity of the image sensor. Again, it’s necessary to use neutral-density filters to accomplish special techniques where long exposures are needed under bright lighting conditions.

Blowin’ In The Wind

How do you get sharp images when photographing in a stiff wind? I get so much vibration through the tripod that few images are sharp.
G. Hansen
Baltimore, Maryland

There are a few conditions that keep me out of the field, but photographing in a driving wind is nearly impossible for the very reason you mention: The tripod transmits the wind to the image. But there are some techniques that can work to minimize the problem. Collapse the tripod so that it’s as low to the ground as possible. Hang extra weight from the center of the tripod. It helps to have a hook at the base of the center column where you can attach your camera bag, a bag of sand or water, or even a rope that you step on to increase the tripod’s rigidity. When shooting close to the road near my vehicle, I’ve often positioned myself so that the van creates a wind break for me. The answer sometimes is to photograph early in the morning or later in the day when it’s usually less windy.

Stacking Tele-Extenders
I remember seeing details on how to stack the 1.4x and 2x Canon extenders, but I can’t find a copy of the procedure. I have both converters and a Canon 12mm extension tube. In what order should they be stacked?
Via the Internet

You’re referring to the older Canon 1.4x and 2x extenders. The order for these to be stacked and still focus to infinity is to place the 1.4x on the camera body, the 12mm extension tube and then the 2x extender. With the newer EF II extenders, a 12mm extension tube isn’t necessary for the two extenders to mate and to focus to infinity. Again, place the 1.4x on the camera body first. The result will be an increase of 3.4 times the original focal length of the lens and a loss of three stops of light.

To fully achieve the potential of this combination, use excellent technique, including a quality tripod and ballhead, an if needed, a cable release and mirror lockup. There’s no room for error at these focal lengths. Increase ISOs to compensate for the three stops of light loss.

The extender combination should be used only on high-quality lenses that are extremely sharp because everything you put between the camera and the lens degrades the image. I wouldn’t try this with any of the telephoto zooms, such as the 70-200mm ƒ/2.8 and 70-200mm ƒ/4. The dual extender method can be best handled by the prime single-focal-length telephoto "L" lenses.

> Visit

Performance In Cold Environments

My husband and I are planning a trip to Antarctica this winter. I need advice regarding equipment, as well as the use of digital cameras in that cold climate. I’m a Canon user and have the 5D, the older D60, a PowerShot Pro 1 and a wide assortment of lenses—wide-angle to 400mm. I also have several film cameras. Would film perform better in that environment? I’d like to take as little as possible, but still have what’s needed.
V. Bradish
Via the Internet

Many people are visiting the colder climates while we still have them. The temperature extremes in Antarctica aren’t nearly as severe as you might think; expect ranges from the 20s to 30s, so the only real concern is battery life. Always carry extra charged batteries, generally several more than you’d expect to need. Keep them in a pocket close to your body so they stay warm, and recharge them each evening when you return to your accommodations.

In my opinion, there’s no advantage to either film or digital in this environment, but if you visit colder environments, at zero or below, different problems can be expected. The battery situation becomes more critical. LCDs on the back of digital cameras can become sluggish or nonresponsive, and film can become brittle and even shatter. With either kind of camera, be vigilant about keeping moisture off the equipment surfaces as you move between cold and warm environments. As far as Antarctica trips are concerned, I recommend you take along a dry bag to protect your camera equipment as you transfer from boats to land or for working in rain or snow.

As for essential equipment, I suggest taking your 5D, with the D60 as a backup, and leave the PowerShot at home. You’ll need the wide assortment of lenses, including a 40mm. Take along a light tripod and a flash for fill on bright days. I can’t see any advantage to taking both a film and a digital camera when you have the quality of the 5D. With digital, you also have the advantage of checking your results as you go. It’s hard to return to Antarctica for a reshoot.

The Right Size
Please give me some advice into the sizing of files, from capture to archiving, sending to publishers and e-mailing.
L. Will
Valdosta, Georgia

I always capture at the largest file size possible. Whether you choose JPEG or RAW format will depend on your own work habits and how you want to use your images. Keep the large file size, either in 8-bit or 16-bit, as you work in your image-processing program, even if you intend to make only small prints from the optimized file. You can always resize downward and maintain excellent quality, but enlarging a small file doesn’t give very good results. I usually send files to the printer at 300 dpi sized to the paper.

Be careful that you don’t save the print file with the same name as the master file for the image because the smaller print file will overwrite the larger one, and you’ll lose the full set of information. The full-sized, optimized file should be kept in a .psd format (assuming you’re using Photoshop) so that if you wish to make additional corrections later, all of the layers are still intact. In other words, don’t flatten your optimized file. If you’re shooting in RAW, you also may want to save the original RAW file as a backup to your archived optimized file.

Files should be e-mailed in JPEG format at 72 dpi in a size that will display on the receiver’s screen without scrolling. Use a JPEG-quality compression of about 8 to keep the file size small. If you have the option, it might be best to embed the image within the e-mail rather than to send it as an attachment. Many of us are cautious about opening attachments from anyone these days. When sending images to a publisher or to someone who will be printing from the received file, it's always best to check first to see what resolution and size are preferred.

Editing With LCD Monitors
My computer has a nice 19-inch LCD screen. I bracketed a set of images, but when I viewed them on the LCD, I couldn’t see any difference. When I viewed them on our old CRT monitor, I could definitely see the differences. Are CRTs better monitors for image editing?
L. Heckman
Via the Internet

For editing purposes, the two monitors should perform equally well. I suspect that when you got your new computer and monitor, you also installed new image-editing software and that you have a setting in Photoshop Bridge that’s automatically correcting all of your thumbnail images as they’re loaded for viewing. If so, the correction software is bringing all of the images to the same standard.

Control U in Photoshop CS2 turns off the automatic thumbnail correction. In CS3, open an image in the RAW converter and click on Control K (Command K); unclick "Apply autotone adjustments." This makes your thumbnails in Bridge reflect their true exposure characteristics, letting you choose from among your bracketed images. If this doesn’t solve the problem, your monitor could need repair or adjustment.

For information about upcoming seminars and digital-imaging workshops, visit

One of North America’s best-known contemporary outdoor and nature photographers and a leader in the field of digital imaging and photographic education, Lepp is the author of many books and the field editor of Outdoor Photographer magazine. One of Canon’s original Explorers of Light, Lepp finds inspiration in advancing technology that fuels creative innovation and expression of his life-long fascination with the natural world.

Leave a Reply

Main Menu