Some Technical Jargon
The optics and optical performance of the EF 90-300mm f/4.5-5.6 USM is similar to that of the EF 75-300mm f/4-5.6 III USM. A new high-speed CPU produces an increased speed of communication between the lens and the camera along with the development of a new AF algorithm. This basically means that the focus and light readings will be quicker when you take a snap.
The manufacturer states that the lens elements are manufactured from environmentally-friendly lead-free glass though I would hardly say that this means it is an environmentally friendly lens. An improved out-of-focus background effect is attained via an electromagnetic diaphragm (EMD).
This lens makes less noise than my 200mm when zooming and focusing in automatic. The lens makes use of a micro USM (Ultrasonic Motor) motor which is almost silent when in operation. It's very useful therefore for sneaking up on enemy positions, unwary politicians or for stalking wild animals. I took a brilliant picture of a tiger last week.
My lens cost £220 at Jessops but if you're willing to risk an on-line purchase you should be able to pick this lens up just under £150.
Product Feature Summary
Product Description: Canon EF telephoto zoom lens - 90 mm - 300 mm
Lens System: Telephoto zoom lens
Mounting Type: Canon EF
Lens Aperture: F/4.5-5.6
Focal Length: 90 mm - 300 mm
Optical Zoom: 3.3 x
Min Focus Range: 1.5 m
Focus Adjustment: Automatic, manual
Lens Construction: 9 group(s) / 13 element(s)
Special Functions: Tele, zoom
Filter Size: 58 mm
Max diameter: 71mm dia
Length: 11.5 cm
Weight: 420 g