Here’s a great idea: Use a wide-angle auxiliary lens attachment to compensate for your digital SLR’s small sensor crop factor! Does it work?
Few digital SLRs have imaging chips that are the same size as the 24x36mm standard used in 35mm film photography. When using lenses designed for film photography, this difference shows up in a multiplication or “crop factor” that, oft times, is misinterpreted as being something it is not. Using a digital SLR that has a multiplication factor of 1.5x means that when you attach a 50mm lens it covers and area-of-view that’s equal to that of a 75mm lens.
It is not equivalent to a 75mm in that the lens still maintains all the optical characteristics, such as depth-of-field, of the 50mm and only covers the area shown with a 75mm lens. That’s why crop factor is a more accurate and useful term because that’s what really happens! Your 50mm image is cropped as if it were made with a 75mm lens, that’s all. Wouldn’t it be nice if you could re-balance that discrepancy? Here’s one possible solution.
The Pro Optic Auxiliary High Quality Wide Angle lens is the opposite of teleextender. Instead of multiplying the focal length in a positive way, it does the same thing in a negative direction. When attached to your lens it provides a wider angle of coverage (0.7x) for those times when you are shooting in a confined space or shooting landscape images.
The Pro Optic Auxiliary High Quality Wide Angle lens (right) works with prime focal length and zoom lenses and attaches to the front filter threads of any lens with a 58mm thread but also works with 62, 67 and 72mm threads with an optional and inexpensive stepping ring.
More importantly, depending on the crop factor for your specific digital SLR, it negates some or all of the focal length discrepancy. For cameras such as the Canon EOS 1D Mark III, with a 1.3 factor, that 50mm lens turns into 45.5mm. On a Nikon D90 with its 1.5 factor, a 50mm lens becomes 52.5mm. With a Canon EOS D50 that has a 1.6 factor, our 50mm lens acts like a 56mm lens when the Pro Optic Auxiliary High Quality wide angle lens is attached.
In any case, it puts you in the ballpark, focal length-wise.
Don’t gimme that crop! You can use the Pro Optic Auxiliary High Quality wide angle lens to overcome your digital SLR’s magnification factor or just forget about all the math and just use this precision device to make your lens’ angle-of-view wider and have fun shooting landscape images like this one! ©2008 Joe Farace
Joe Farace is the author, along with Pulitzer Prize-winning photographer Barry Staver, of a new book called “Better Available Light Digital Photography” published by Focal Press is available at Barnes & Noble and Amazon.com.
