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Old Jan 31, 2007, 8:38 AM   #1
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I am so unhappy with this lens. The zoom was very stiff to begin with, it hasloosened up a bit so I kept it. Now I'm noticing I can't get MF to work at all with my 20D. This was a problem with the last Sigma I bought (70-200 2.8 I had to return). And the AF is so very slow and loud and inconsistent. Did I get a bad copy or is this typical? I'm fairly happy with the images, it's just a pain to operate. I bought it brand new three weeks ago, and I'm 4 days past the point of return. Kicking myself for not getting it back there sooner. Should I send it in to Sigma?

JohnG, i keep trying to give Sigmas a try because you rate them so highly, but I am prettydisappointed so far. I traded in my Canon 17-85 IS toward this and am afraid it was a very expensive mistake.
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Old Jan 31, 2007, 8:58 AM   #2
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The 24-70 unlike the 70-200 does not have HSM (ultrasonic) so you can't manually overide it
-> you have to switch it to MF before being able to manual focus (i.e. not full-time)

Also not having HSM the lens is also not as quiet because of the internal gear train - Only the ultrasonic lenses are silent
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Old Jan 31, 2007, 9:01 AM   #3
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The problem I am having is when the MF switch is enabled.The focus ring moves, but nothing TTL changes. It is most bizarre. Someone said not all Sigma lenses have digitalchips? But wouldn't that affect AF, not MF?

And yeah, I have HSM/USM and non lenses, and this is by far the loudest non-HSM lens I've seen! it's like one of those Castrol commercials when your engine runs without oil.
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Old Jan 31, 2007, 9:09 AM   #4
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urbanaries wrote:
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The problem I am having is when the MF switch is enabled.The focus ring moves, but nothing TTL changes. It is most bizarre.
Did you pull the focusing ring forward or back?
(to engage the mechanism)

-> This is done so you can't accidentally change it once you've set the manual focus on a tripod...



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Someone said not all Sigma lenses have digital chips? But wouldn't that affect AF, not MF?
All lenses (from any manufacturers) have chips in them... to serially communicate with the camera
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Old Jan 31, 2007, 9:14 AM   #5
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Am I missing something here? pull the ring toward the camera body or the end of the lens...as opposed to rotating it clockwise/counter like every other lens?
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Old Jan 31, 2007, 9:16 AM   #6
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there are 2 switches to get the lens to MF mode. 1st MF/AF switch. 2nd - the ring that goes back and forth to togle between the AF/MF

in theory , if you are in the AF mode, you press the shutter release half way down , it autofocuses , then you can toggle the ring position to switch the MF override mode on to be able to adjust the focus.

or you can switch to the MF , toggle the ring and work in MF only mode.
not extremely straight forward but you kinda get used to it.


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Old Jan 31, 2007, 9:20 AM   #7
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ok, i think i understand, i just have never encountered this before somehow? forgive my ignorance! I don't have the lens right here so I'll try it later. It sounds likeshoddy design, if you ask me. If I hate the loud/slow AF, I want to be able to MF as fast as possible, and this sounds like a lot of fidgeting.
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Old Jan 31, 2007, 9:27 AM   #8
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When I returned the 70-200 2.8, the KEH rep said it probably wasn't sharp wider than 5.6 because the chip wasn't "digital" compatible. Maybe he was talking out his @$$. Maybe I just can't seem touse Sigma lenses properly and should stick with Canons? :?
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Old Jan 31, 2007, 12:35 PM   #9
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urbanaries wrote:
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When I returned the 70-200 2.8, the KEH rep said it probably wasn't sharp wider than 5.6 because the chip wasn't "digital" compatible. Maybe he was talking out his @$$.
May be so - How does the camera get its EXIF info for the focal lenght/aperture to include with every image then? (even in 'MF')




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Maybe I just can't seem to use Sigma lenses properly and should stick with Canons? :?
Beauty is in the eyes of the beholder... (The left one is the Sigma 70-200 f/2.8 EX)

I already spent enough on Canon, may be I should add another Sigma 300-800 to complete the right side! :-) :lol: :G


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Old Jan 31, 2007, 12:46 PM   #10
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Oh yes you should!

But you know what would happen then? You'd just start thinking that you should get the Canon 1200mm to complete the right side with Canon.


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