Better Lens...

[SanctuS]

I have a Canon EF 75-300mm II lens, and I was wondering what the difference was between that and a lens with USM or IS. I believe I read somewhere on here the the USM stands for Ultra-Sonic Motor, and I know that the IS stands for Image Stabilization. Are those two features the only reason the same size lens with those features is 400 bucks more then my lens. What is so good about the USM? The better lens isn't even faster...

 

[subimatt]

USM is a factor, however IS is a major factor when it comes to price increase. USM allows the lens to autofocus much faster and much quieter that any standard lens, allowing to you get the shot faster and not as loud. IS is a great function that will help eliminate hand shake blur that you sometimes get when the photograph is taken at a slower shutter speed. It is great on telephoto lenses where minute movements make all the difference. A great entry lens with both of these features is the 28-135 IS, it is less that $500 new, and plenty of people sell them bn or ln for around $300.

 

[keith204]

In shooting sports, I would never use a non-USM (or HSM for Sigma) lens. (since I am terrible at manual focusing)

 

[Big Mike]

Also, there is the optical quality of the lens to consider. I've heard that the 75-300 IS lens has better optical quality than the one you have. Maybe that's because they use more advanced glass/lens elements, or something like that.

Also, take note that Canon has two types of USM lenses...and it's not always clear which is which. For example, I have the 75-300 USM III. It does have a USM focus motor...but it's not a 'ring' USM motor. The 'ring' USM motor is the better kind and is practically silent and very fast. Lenses with ring USM also have a feature called FTM (full time manual focus). This means that you can adjust the focus, with the focusing ring, at any time, without switching the lens into manual focus. As you know, with your current lenses, you can't manually focus unless you actually click the switch.

 

[Garbz]

You won't ever find that IS / USM is the only difference. For one they need to change lens elements to add IS and thus change the optics of the lens. USM helps though I have not yet found a solid need for it. I shoot sports with an old non silent wave motor lens and for me the autofocus is acceptable. Only lost a few shots due to missfocusing and they sucked to begin with.