By Jeff Cable
A couple of years ago, I purchased my first digital SLR camera that had interchangeable lenses. Between then and now I have learned some valuable lessons that I would like to pass on, so that others don't make the same mistakes that I made.
After buying a Canon 20D SLR with the 18-55mm lens, I was anxious to purchase a zoom lens. I looked online and went to my local photo store and purchased a Canon 100-300mm f/4.5-5.6 zoom lens for about $350.
I was all set. At least, so I thought.
Three months later I was at a photo trade show and saw the Canon 70-300mm f/4-5.6 zoom lens, which had image stabilization (IS). I was so impressed with the IS that I immediately put my other lens on eBay (thank goodness for eBay) and purchased the Canon 70-300 IS lens for about $550.
Now I was all set. At least, so I thought.
Six months later I was trying to shoot pictures at an ice hockey game (in a reasonably lit ice rink) and realized that my zoom lens was not capturing clear images. As it turned out, when shooting at 300mm at f/5.6 there was not enough light coming into my lens and the fastest shutter speed that I could use was 1/250. I really needed two or three times that speed to get clear images. At this point, I had talked to enough people in the industry and had learned about "fast lenses". Once again, I was back to the Internet and researching 2.8 lenses and determined that the Canon 70-200mm 2.8 lens would be the perfect lens for shooting sports indoors. After losing some sleep I decided that having IS on this lens was worth the extra $500 so once again I put my lens on eBay and then made the big purchase for the Canon 70-200mm 2.8 lens for approx. $1900.
Now I was all set.
This time I ended up with a great lens. Expensive, but if you are going to shoot indoors and cannot (or prefer not to) shoot with a flash, this can deliver some great images.
Before going through this purchasing ordeal, I never understood what made the difference between a $300 zoom lens and a $2000 zoom lens. Now I know.
The image stabilization helps reduce any shaking of my hand when holding the camera and helps me get a better picture. It does not help when the camera is mounted on a tripod, but often I am shooting handheld and appreciate the extra help keeping my lens steady when shooting.
Most of the less expensive zoom lenses have a variable aperture, which means that the more you zoom in, the less light you get in the lens. When you see a lens which says "18-200mm f/4.5-6.3" that means that at 18mm you will have a maximum aperture of f/4.5 but when you zoom to 200mm you will have a maximum aperture of f/6.3. Again, when shooting indoor without a flash, this is not optimum. The more expensive zoom lenses have a fixed aperture, which means that you can shoot at the highest aperture at any focal length of the lens.
Not only can I take better pictures in dark environments but I can also get more control of my images in well-lit areas. The higher the aperture (in this case f/2.8) produces an image with less depth of field. As you can see from these two pictures, the background is much more diffused in the picture taken with at f/2.8 versus the image taken at f/6.3
Not everyone can justify a couple thousand dollars to spend on a lens, and not everyone needs this type of lens. For those people who are always taking pictures outside and do not need to capture fast moving objects, the quality of the glass may not be quite as good but, the less expensive lenses will work great.
We often hear that the stereo speakers make the sound system, not the amplifier and most professional photographers agree that the investment in lenses has more of an affect on image quality than the camera itself. Keeping this in mind, choose your lenses wisely, and have fun.