usm vs non usm. whats the difference
1246433
The difference is if you want the camera to focus an image for you or if you feel confident enough to do it yourself. When I bought this lens it said that it was not included but it was just turned off.
1246434
USM means that the lens has Ultra Sonic Motors which control the auto focus. Basically a USM lens will focus slightly faster, and make less noise than a non USM Lens. Also it will use slightly less battery power. However if you are using the lens for mainly static subjects, distant landscapes maybe, it won't make a lot of difference which you have. If on the other hand you are trying to photograph birds in flight, USM will be better. There is also a 70-300mm lens with image stabilisation if you have the money, that lens will effectively allow you to hand hold the lens at 300mm without blurring through camera shake. The optics are also much better. http://www.amazon.com/Canon-EF-70-300mm-4-5-6-USM/dp/B00DY94BUE/ref=sr_1_2?ie=UTF8&qid=1387173489&sr=8-2&keywords=canon+ef+70-300mm+f+4-5.6+is+usm
1265207
Sorry for the confusion, there is absolutely no difference. Thank you for question..
1806541
i don't think there is any difference between the numbers. the "U" on the end is primarily a region indicator (JP for japan, USM, U, US, and so forth). the primary difference may be the information sticker or imprint on the battery itself. the charger does work for both of these rather well.
110002
I believe the difference is only in packaging. Retail, boxed and wrapped in plastic with instructions vs. Minimal, aimed toward someone buying in bulk.
1150213
No difference. One just omits the mm and the other includes it. Same exact time size.
2114754
USM stands for UltraSonic Motor. It is a fast, quiet and accurate motor for the autofocus.
540814
no puedo comparar. no he usado las dos versiones. solo puedo decir que la internacional es la que estoy usando y me parece una maravilla. felicito a todo el personal que hiso posible la creacion de esta maravilla
941647
I have no idea why there's a difference. Maybe it matters if you're doing tournaments, but not at all if you're just playing for fun!
1825102
The "us" indicates that the computer is sold for the United States market. The "nr" is for a different country.
1260669
USM lenses uses a non motor to focus and it has less vibration. is it worth the difference, perhaps to a professional or a real dedicated photographer. I guess if I had the bucks I'd have many great lenses. The lense you have in question, this one sells for less then $150 in my opinion is not a great lense and has a short life span.
1495160
I agree with Wesley, for the most part. USM refers to Ultra Sonic Motor, which is a little bit quieter than the regular autofocus motor, but that's not its primary purpose. The USM is capable of Autofocusing a great deal faster than a regular lens. Side by side, you'll notice quite a difference in the amount of time the lens needs to focus. Now, I shoot wildlife photography of wild animals. For me, that time difference in crucial. You'll want that should you ever be shooting moving subjects, like animals or sports events, for example. You'll have to consider how you plan to use the lens, and decide if the additional speed is something you'll need. I agree with Wesley, for the most part. USM refers to Ultra Sonic Motor, which is a little bit quieter than the regular autofocus motor, but that's not its primary purpose. The USM is capable of Autofocusing a great deal faster than a regular lens. Side by side, you'll notice quite a difference in the amount of time the lens needs to focus. Now, I shoot wildlife photography of wild animals. For me, that time difference in crucial. You'll want that should you ever be shooting moving subjects, like animals or sports events, for example. You'll have to consider how you plan to use... » Read More I agree with Wesley, for the most part. USM refers to Ultra Sonic Motor, which is a little bit quieter than the regular autofocus motor, but that's not its primary purpose. The USM is capable of Autofocusing a great deal faster than a regular lens. Side by side, you'll notice quite a difference in the amount of time the lens needs to focus. Now, I shoot wildlife photography of wild animals. For me, that time difference in crucial. You'll want that should you ever be shooting moving subjects, like animals or sports events, for example. You'll have to consider how you plan to use the lens, and decide if the additional speed is something you'll need. « Show Less
537478
If I understood the description when I read about the comparison at the time I made my purchase, the Ultra disk downloads and records video faster than the 32gb. The Ultra is a class 10 which is a speed measurement and the regular 32gb is a class 4. How much difference is the actual speed I have no idea. This is the extent of my knowledge.
90032
There is no difference. Be sure to check overall cost. Look for free shipping.
1906803
They look like the same to me in functionality. I chose the one eligible to ship outside the US. More a practical choice than technical comparison.
1481554
In practical terms, there is very little difference except that I believe the USM version was discontinued some time ago. Both lenses are not the best performers. The USM version has an ultrasonic micro-motor for focusing while the non-USM uses a electric conventional motor. Micro-motor USM isn't much faster or quieter while focusing than a conventional motor. This is in contrast to Canon's professional lenses which use a very different type of USM ("ring USM") that focuses very fast and silently. Check out a used Canon 100-300mm (also discontinued) if you want the faster ring USM auto-focus and better optics for a reasonable price.
2204190
U429085 is better quality and thicker. It is also more expensive. The difference is not really noticeable to me as I've bought both. But some reviewers note there is less humidity with food staying good longer.
523816
sorry but I don't know the difference. If you have the time advise me please. Thanks