lens - IS - USM - DO ?

[bmer]

Sorry if this question look weird, but I wanna buy a new lens (im new at photo) ...

something like a EF 75-300mm f/4-5.6

but I was wondering what "IS" "usm" "non usm" or "DO" stand for.

Im prety sure by the price that the EF 75-300mm F4-5.6 IS USM is better than the EF 75-300mm F4-5.6 USM.

But is it ok for me, who's a newbie ?

thanks

-Mathieu

[karusel]

I'm not trying to be rude, but for ****************, can't you use the 'search' function? Or google? A simple copy paste of your "IS" "usm" "non usm" or "DO" into google's bar yields many useful pages and the first hit is coincidentally one pointing to POTN forums to a thread with the question - what is the difference between USM and non-USM.

[Deckyon]

IS - Image Stabalization
USM - UltraSonic Motor (for focus)
DO - Defractive Optics.

IS gives you between 2 and 3 stops (depending on the lens) more for handholding. Great for longer telephoto lenses. USM allows very fast and quiet autofocusing (AF) and DO helps in correcting chromatic abberations (false color and fringing caused by reflections and coatings on the glass.)

As to the lens mentioned above, the only difference is the Image Stabalization built into the more expensive one.

[Deckyon]

I'm not trying to be rude, but for *************, can't you use the 'search' function? Or google? A simple copy paste of your "IS" "usm" "non usm" or "DO" into google's bar yields many useful pages and the first hit is coincidentally one pointing to POTN forums to a thread with the question - what is the difference between USM and non-USM.

It took you longer to rant than to answer the question...:confused:

[karusel]

Yes but I was contributing something else - search before you ask. As for me, before I make a thread like this I always look around first.

[Deckyon]

Yes but I was contributing something else - search before you ask. As for me, before I make a thread like this I always look around first.

Well, not everyone is YOU, thankfully! Quite a warm welcome you give to new users here... :confused:

[bmer]

I did some search ... only think I can find is some info about the "L"

and google say that "is" is to common word

thats why I start whit a "sorry" and say Im new at this... I wanted to avoid that kind of post..

anyways



thank Deckyon, that help alot

-Mathieu

[Deckyon]

L, in Canon-Speak is "Luxury" - Top end lenses, nothing better, EXPENSIVE!

[PacAce]

Yes but I was contributing something else - search before you ask. As for me, before I make a thread like this I always look around first.
Maybe someone needs to check out this thread:

http://www.photography-on-the.net/forum/showthread.php?t=60756

[karusel]

Sure.

[rocknitz]

Just you know, not everybody is as RUDE as "karusel" 99.9 % of the people here are great and very helpfully to new people!! Welcome to the forum.

AL

[CyberDyneSystems]

Yes but I was contributing something else - search before you ask. As for me, before I make a thread like this I always look around first.

Didn't look to hard though,.. or you may have found the forums Rules, ;)
In particular Section 4-8;
If you know an answer to a question either answer it or say nothing. Giving newbies blunt answers like "search the forum" is not allowed - please use the typing effort to giving the answer instead. Or just give the link to that post you wished the newbie should have searched for. Respect newbies - you were a newbie once.

.... there are more than enough members here willing to steer newcomers towards the answers they seek or to answer there questions helpfully. If you chose not to,. then by all means excercise your right not to answer at all.
:)

[CyberDyneSystems]

Welcome to the Forum Mathieu,

Here's Canon UK's explanation of "IS"

http://www.canon.co.uk/for_home/product_finder/cameras/ef_lenses/image_stabilization_lenses/index.asp

http://photonotes.org/cgi-bin/entry.pl?id=Imagestabilization

[jeffherald]

Welcome, Mathieu!

I am also new to the forum, but not new to photography.

I own the 70-300 III USM lens, which most people seem to consider not good (to say the least). My advice is it is a good lens, especially for the money is costs (about $225US). I have gotten many good photos with it. Not perfect, but perfectly acceptable. It is good for outdoors, not really good in lower-light situations. If you don't have much money, it is OK to start cheap and practice with it (my opinion). If you do have money to spend, then you can buy better lenses. I will certianly be upgrading in the future, as soon as I can afford to do so. Meanwhile it has served me well for several years.

Feel free to ask any question you like. Most people are happy to answer.;)

[karusel]

Sorry, sorry, sorry, sorry. I go over the top sometimes. Please, don't debate this here any further, if you feel you need to, please go to the thread pasted by PacAce.

CDS, of course you're right.

rocknitz: we could debate about rudeness for a long time and the outcome would surprise you. But not here as the originators questions apparently have been answered, and your provocations aren't taking this any further....

[HJMinard]

Karusel apologized ... forgive and move on. Let this thread return to it's original programming.

[jeffherald]

Well, after all of that, did you get your question answered? :)

[Medic1]

As far as the usefulness and how much "better" a lens may be for you with specific features, you first have to ask yourself what you are going to be using it for.......IS might not be worth the money for you if you will always be shooting fast shutter speeds in bright light situations. Feel free to post your picture taking "habits" and get some opinions on how useful each feature may or may not be for you.....

Welcome to the forum!!

[dhbailey]

IS - Image Stabalization
USM - UltraSonic Motor (for focus)
DO - Defractive Optics.

IS gives you between 2 and 3 stops (depending on the lens) more for handholding. Great for longer telephoto lenses. USM allows very fast and quiet autofocusing (AF) and DO helps in correcting chromatic abberations (false color and fringing caused by reflections and coatings on the glass.)

As to the lens mentioned above, the only difference is the Image Stabalization built into the more expensive one.

USM is SUPPOSED to give very fast and quiet autofocusing. The 75-300 IS USM however only makes it quiet, it most definitely is NOT a fast-focusing lens.

[ilya]

There is a lot of misunderstanding around USM. Not all USM is the same.



Ring USM (good USM) - Beginning in 1987 with the 300/2.8, Canon has been equipping its best lenses with the ring ultrasonic motor, in which the rotor and stator are big circles around the optics. These are incredibly fast and silent. Even more important, they allow simultaneous use of autofocus and manual focus. You can leave the lens in AF mode all the time and override the camera's decision at any time.



Micro Ultrasonic Motor (cheap USM) - 1/3rd the cost but still sold under the same name, little motor that they stick in the lens and then connect with gears to the focus mechanism. A micro USM does not allow simultaneous AF and MF. Thus, the largest user-interface advantage of the ring USM is gone. Much of the noise of a standard motor is back too. The micro USM is noticeably quieter than a regular motor, but not silent like a ring USM.



An even cheaper and crummier motor is the "micro motor", available on the 100 macro, 50/1.8, and couple others.



all USM lens sold by Canon do have the "Ultrasonic" logo and trademark printed on it. But that does not mean there is a USM ring motor inside.
all USM ring motor do have a window were you can read the focusing distance. Some USM micro-motor have it too, like the 75-300 USM II (IS or not). no window, no USM.

true test - all USM ring motor lenses, when in AF mode allow focusing manually.

[RJSorensen]

Welcome Bmer . . .