75-300mm canon dc vs. usm

[slimpickins70]

bought a rebel xt and seeing as the AF on my sigma 75-300mm doesn't work and plan on eventually (6 mos. to a year) getting a IS USM. for now the budget should be about 140 is the usm motor worth streching it to 200?
if i go with the DC motor is the canon much better than the sigma or tamron? i'll probably be using ebay.

Thanks

 

[Big Mike]

There are two types of Canon USM focus motors. The first one is not all that different from the standard focus motors on most lenses...maybe a little better. I can't remember what it's called.

The other type of USM, I think is called 'ring' USM...and it definitely worth spending more money on. It's fast and very quiet. Also, since there is no mechanical connection...you can manually adjust the focus without having to switch the lens into manual mode. This is often called FTM (full time Manual).

I don't think the Canon 75-300 lenses have the ring USM...so it may not be worth the extra cash...especially if you plan to upgrade later anyway.

 

[slimpickins70]

Thanks Big Mike. I guess i'll try and find one with the DC motor for a good price. and save up for the IS USM version.

 

[ShutteredEye]

Thanks Big Mike. I guess i'll try and find one with the DC motor for a good price. and save up for the IS USM version.

I've got a Quantaray 75-300 f4-5.6 I'll sell super cheap. The AF does work with the XT. It's not a great lens, but it will tide you over until you save up for the IS USM version. I'll let it go for $75.

 

[slimpickins70]

ShutteredEye,
thanks for the offer. i plan on using the lense for shooting friends surfing on longboards and not moving too fast. would this lense be capable of keeping them in focus. about 50-75 yards away. i have a sigma but the AF is broken so i wouldn't even know if it would work and have been manually focusing. also is it a 75-300 or a 70-300 i did a search to read some reviews and didn't come up with much.

 

[ShutteredEye]

The Quantaray is basically an off branded Tamron or Sigma. The AF is reasonably accurate, and if you used the A/I Servo setting on the camera you should be just fine. I'm not going to lie and say this is the best lense out there for sports, because it just isn't. But it would get the job done while you saved up for a nicer lense... I am only asking $75 for it. Here's a link to the lense in question. I mistyped, it is a 70-300. I wouldn't expect that this would be the last long zoom you buy, I just thought it might be a stop gap while you saved for a nicer lense. Ultimately I'd recommend this lens. Or this lense.

I've heard that the Quantary lenses are just rebranded Tamron's, but I don't know for sure. Let me know.