what is the quality of lenses that are not manufactured by canon?

[Koen_S1]

And what would be the best alternative for a 18-135mm lens?

If you're not auto-focusing much, can I ask what you shoot the most? Cause that would give us a sense of what lenses to suggest. If you're shooting a lot of landscapes, then we'd suggest a wide lens....if you're shooting sports, it's something else.

Currently I´m not shooting a lot, but I´m planning to buy a new camera, probably the T3i, and I´d like to shoot landscapes, a little sport (karate, but really not that often) and I´m filming a lot.
Basicely I´m looking for an allround lens that has enough zoom but also is good for filming.
Oh, and do you guys think that as soon as the T4i is announced the price of the T3i will drop?

[kdsand]

And what would be the best alternative for a 18-135mm lens?

If you're not auto-focusing much, can I ask what you shoot the most? Cause that would give us a sense of what lenses to suggest. If you're shooting a lot of landscapes, then we'd suggest a wide lens....if you're shooting sports, it's something else.

Currently I´m not shooting a lot, but I´m planning to buy a new camera, probably the T3i, and I´d like to shoot landscapes, a little sport (karate, but really not that often) and I´m filming a lot.
Basicely I´m looking for an allround lens that has enough zoom but also is good for filming.
Oh, and do you guys think that as soon as the T4i is announced the price of the T3i will drop?

Wasn't the 18-135 supposed to get the new quiet / silent drive soon? If so you may want that for video use.

[Koen_S1]

[/quote]

Wasn't the 18-135 supposed to get the new quiet / silent drive soon? If so you may want that for video use.
[/quote]
yes, I thought so to, it should come with the new T4i right? But then again theres the price of such a sweet thing...

[wockawocka]

You get what you pay for.

[kdsand]

Wasn't the 18-135 supposed to get the new quiet / silent drive soon? If so you may want that for video use.
[/quote]
yes, I thought so to, it should come with the new T4i right? But then again theres the price of such a sweet thing...
[/quote]

Î expect a substantial jump in price  also  .
Video shooters will be happy but regular shooters not, unless there's some other improvements. 

[smirkypants]

You get what you pay for.

Maybe sometimes, but I would argue that sometimes (certainly not always) buying Canon lenses gets you better quality but with often diminishing returns. Your return on investment is almost never 1 to 1. For instance, you might get +10% quality for +200% price; or rather, small improvements for big prices.

It's funny. I think that people who shoot with Canon glass usually (usually!) produce better photos than those who shoot with third-party glass, but I think there's a selection bias going on as well. People who shoot with high-end glass are usually more into their photography, and generally more skilled and dedicated. Truly dedicated photographers choose invest in great gear to get them that little bit of an edge, but that doesn't mean if they had shot with slightly inferior glass most of their shots would have been different.

[AdamJ]

I mounted my Sigma 12-24mm II on Thursday for the first time since December and found that the AF was dead. Since it's something of a specialist lens on FF, I've only used it a handful of times so I'm very annoyed about it. The lens has gone back to Sigma UK so I'm now waiting to see how their after-sales service shapes up. It's a pity because in all other respects, I love this lens. I have huge respect for Sigma's optical design capabilities in the ultrawide zoom segment.

I'd like to think that my experience is a one-off but if you read lensrental.com's write-up on another well-respected Sigma lens, the 120-300mm OS, you'll see that the electrical failure rate on that lens is startlingly high. That's also a pity because this lens has had very good reviews.

I can't recall ever reading of such a failure in a Canon lens. [Edit: I stand corrected - I've just read another thread mentioning Canon AF motor failures].

[unruled]

You get what you pay for.

Maybe sometimes, but I would argue that sometimes (certainly not always) buying Canon lenses gets you better quality but with often diminishing returns. Your return on investment is almost never 1 to 1. For instance, you might get +10% quality for +200% price; or rather, small improvements for big prices.

It's funny. I think that people who shoot with Canon glass usually (usually!) produce better photos than those who shoot with third-party glass, but I think there's a selection bias going on as well. People who shoot with high-end glass are usually more into their photography, and generally more skilled and dedicated. Truly dedicated photographers choose invest in great gear to get them that little bit of an edge, but that doesn't mean if they had shot with slightly inferior glass most of their shots would have been different.

I agree with what you are saying, however the bias may well be due to the difference between doing photography as a profession, or as an amateur. It can account for the bigger budget allocation, as well as actually growing more quickly in your skills as you spend your time earning a living with it.

well, its all speculation anyhow I think that certainly there are some very nice 3rd party lenses, and especially as an unpaid photographer, its worth shopping around. Lets not forget cheap canon lenses can be just as full of duds as low end 3rd party lenses, its just that we often compare cheap 3rd party lenses to L glass, which is somewhat unfair.

[smirkypants]

Lets not forget cheap canon lenses can be just as full of duds as low end 3rd party lenses, its just that we often compare cheap 3rd party lenses to L glass, which is somewhat unfair.

You're so right. I forgot Canon made non L glass (not joking.... seriously didn't think about it).

[ScottyP]

Either there is a major difference in IQ and quality control, or the reviewing website I most often use (you know the one) is somehow biased toward Canon (and maybe Nikon, but I don't read that part of the site).  Every review I read of a Tamron or Sigma lens reads like a death sentence.   "My 2nd copy was better than the 1st, but my 3rd copy was so bad I wished I had the 1st copy back..." and so on.  Or  "I really wanted to like this lens, but..."  I think I have read every Sigma or Tamron review on the site and none of them reccomend any of the lenses.  In fact, they they kind of discourage you from buying non-Canon.

That said, I went to the one old-school camera store in my PA city today and tried out the Canon 70-200 2.8 IS II, (and also the non-IS f4 version) and compared them to the Tamron 2.8 equivalent.  Have to say, even just tracking the stuff on the store shelves, both the Canons were much faster to focus, and way smoother/quieter.