So I just got the Sigma 24-70mm 2.8 HSM and

I'm having trouble with micro adjusting the lens on my 5dmkII. It def. needs adjusting and I got it sharp and on point at 24mm but at the long end, it's still missing by a little.

I set up a tripod and taped some printed text to the wall. I don't understand how it would be on point at 24mm but a little off at 70. Is that just what comes with owning a zoom? The only other zoom I have is the 24-105 and I never really tested it because it was a kit lens and I don't use it often (love my primes).

Anyway, not sure what I'm doing wrong or if it's wrong at all.

I'm also testing the lens against the Canon 24-105L and I'm seeing similar results in terms of sharpness and color.

I basically got this lens for an all purpose lens when I don't want to carry 2-3 primes and f/4 isn't cutting it. So far I'm leaning towards the Sigma.

Any advise with testing zoom lenses would be appreciated. Thanks!

Oh yea, here are some samples (sorry also posted these in lens sample thread). Is it safe to say I got a good copy?

70mm f/2.8

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i dont think the micro adjustment feature works on 3rd party/generic brand lenses, but should easily adjust for front/back focussing with the 24-105

bluefox9er wrote in post #8931776
i dont think the micro adjustment feature works on 3rd party/generic brand lenses, but should easily adjust for front/back focussing with the 24-105

Seems like i've read where they have been adjusting Sigma and other lens .

I take it you're just guessing , or do you know for sure ?

To the OP, just make sure you do your testing on a tripod. It will help you rule out any error on your part.

I am doing my testing on a tripod and at 24mm it's perfect but at 70 is a bit off so I'm wondering if that's just the characteristics of zoom lenses. I suppose I can do the same test on my 24-105L but I ran out of time.

And yes, micro adjustment works for non canon lenses and I wouldn't call Sigma generic. I own a Sigma 24mm f/1.8 macro and it's so good I use it often (and that's in a line up of an 85L II, 35L and 24-105L... was actually my only non L lens till this Sigma 24-70 hsm purchase)

How much off on the long end do you need to correct with the MA feature?

I would ma the lens on the long end wide open and see at the other focal length is its close enough of where you want the focus.

I have a Canon 28-135mm IS that from 28 to about 70mm would focus dead center of the dof. From 75-135mm it would slightly front focus. I had to send it in twice to canon to correct this.

I currently have a tamron 17-50mm F2.8 in for service. The lens would focus close dead center at F2.8 throught out the focal range but as distance increase after 3 feet it would front focus and eventaully need 12ma to correct.

Got it back the first time they align the lens and calibrated but it was the same. Should be getting that back this week.

I tested a Canon 24-70 f/2.8 L - tonight on my 5D and was not moved by its 70mm performance in the store.
However it's sweet spots near center of frame and from 30-50mm where it's best moments.

It was not as nice as my prime L's but that's a Zoom for ya.
It was still perfect for print or production work of any kind!
I decided to buy it as I need something flexible like this to compliment my prime lenses.
Low light AF was quirky too but not the worst, but better then the AF in low light of the 50 f/1.4 USM I tested tonight.
The Canon 16-45 f/4 L looked and felt like it was cut from the same cloth as the 24-70 L.
Same great color and contrast, still not prime sharpness, but still the best zoom I've used to date.

At 70mm F/2.8, looks like the same quality I get with the older NON-HSM version of the Sigma 24-70 F/2.8.

Same with you. At 24mm, it performs.