Choosing Digital SLR Lenses



Left Image: Canon EOS D30, Tamron 70-210mm f-2.8 (equivalent to about 110-330mm f-2.8 in 35mm), 1/250 sec at f-8, ISO set to 200, aperture priority, autofocus. Bogen tripod and ball head.

If you currently have lenses for your 35mm camera that fit a certain digital SLR or plan on purchasing lenses, you have to keep in mind that each focal length is multiplied by a factor of 1.3X or more depending on the camera. Digital cameras use CCD chip instead of film to capture images. CCD size is smaller than a 35mm frame which is 24 x 36mm (1 x 1.5 inch). Except for Contax N1 which has a 24 x 36mm 35mm frame size CCD, all other digital SLRs multiply the focal length by 1.3x, 1.5x, or 1.6x. Canon EOS-1D multiplies the focal length by 1.3x while EOS D-30 multiplies by 1.6x. Nikon D1X and D1H multiply by 1.5x. A 100mm f-2 lens becomes 130mm f-2 on a Canon EOS-1D or 150mm f-2 on Nikon D1H. The maximum aperture is unchanged. This can work to your advantage most of the time. A 300mm f-2.8 lens costs between $2200 to $4500. On a digital camera the focal length is equivalent to about 450mm f-2.8. This is somewhere between a 400mm and 500mm lens in 35mm format. A 400mm f-2.8 costs over 7000 dollars and is much bigger and heavier than a 300mm f-2.8. A 500mm f-4 costs about 6000 dollars and is also a very big heavy lens. There is no such a thing as a 500mm f-2.8. If such a lens existed, it would cost you well over 30,000 dollars and you would need to join a gym to build up some mussels to carry this lens. So, a 300mm f-2.8 is definitely a great buy for use with digital SLRs. Add a 1.4X or 2X teleconverter and you have an equivalent 600mm f-4 and 900mm f-5.6 lenses. 300mm f-4 lenses are another great choice. This is about the same as 500mm f-4 lenses in 35mm format, except they cost from $600 to $1200. 300mm f-4 lenses are very sharp and compact. They also work well with 1.4X teleconverters. The popular 80-200mm f-2.8 zooms become even more useful when attached to digital SLRs. This zoom becomes 120-300mm f-2.8. This is a dream lens. Fast, very sharp, and excellent focal lengths for outdoor photography. All manufacturers make 80-200mm f-2.8 or 70-210mm f-2.8 zooms costing from $800 to $1800. The only draw back is the use of teleconverters on this type of zoom. Some zooms/teleconverter combinations work fine while some don't. You can select a fixed 200mm f-2.8 costing under $1000 and use matched teleconverters and get better results than a 300mm f-2.8 with matched teleconverters on a 35mm camera. A 200mm f-2.8 is optically superb and very light and compact. It provides the same magnification as a 300mm f-2.8 on 35mm which costs three to four times more.



12-24mm digital SLR lens

Even the 50mm lens (the forgotten lens) becomes an excellent choice once again. 50mm f-1.4 and 50mm f-1.8 lenses are the sharpest lenses ever made. They are also very affordable. A 50mm f-1.8 can be bought brand new for less than $100. 50mm f-1.4 cost around $250. I have seen many used 50mm f-1.4 lenses in new conditions for less than $100. 50mm is equivalent to about 80mm in 35mm. This is a great focal length for portraits. 85mm f-1.4 lenses cost around $500. You get the same magnification with 50mm lenses which are as fast and even sharper. Wide-angle lenses become a problem when used on digital SLRs. 28-85mm zooms are very popular for a wide variety of subjects. 28mm is about 40mm in 35mm. You'll need wider coverage for most situations. Even a 24mm which is equivalent to about 35mm in 35mm format is not wide enough. What about 20mm? Still not wide enough for some wide-angle photography. On Canon EOS-1D 20mm gives about the same coverage as 24mm which is very good. On the EOS-D30 coverage is a bit over 30mm. You'll need at least 17mm or better yet, a 14mm lens to get a very wide view for landscapes or building interiors. Zooms that cover 15-35mm or 17-35mm are becoming very popular and quality is very good.

Here is some suggestions for building a good working system for most type of photography. Avoid using very long lenses unless you need to. A 600mm f-4 lens with 1.4x teleconverter is about 1260mm f-4 in 35mm. Do you need this much power? I know I don't. You can substitute zoom lenses with fixed focal length equivalent.

What else do you need? All the things you've been using with your 35mm camera including a solid tripod, cable release, flash, filters, etc. You won't need film, but you will need a memory card to record your images. Once you get home, download your shots to your computer and use a good imaging software to edit them. Half the fun is playing with your pictures in the image editing software. Just add a little imagination.