Sigma 17-70 backfocus?

[Aszental]

Hey i just shot this and i was wondering if the experts can take a look at it

Shot at 70mm, F4.5, 1/125s




What do you think, is it an issue?

Thank you!

[gstark]

Hey i just shot this and i was wondering if the experts can take a look at it

They'll be back in .... about three months. Can you wait?

What do you think, is it an issue?

My personal belief is that 99.9999% of so-called back-focus issues come down to just one cause - operator error.

Usually that translates to poor technique, which might mean a poor understanding of how the camera works, or how it might work in a given situation.

Ferinstance, I took my bright shiny new 30D out for a play last night - first time - and I'm not at all happy with the results. Focus is soft. Colours aren't how I like 'em. Exposure is all over the shop. I was shooting my D200 by its side, and results from that camera make an interesting comparison - super sharp, colour is great, exposure is where I like it ....

What's really interesting is that at first glance (chimping only - I've not yet moved the images to a calibrated system) the super-high ISO images from the Canon seem to be noiser than those from the Nikon.

Is any of this disappointing to me?

Not in the slightest - it's an expected outcome. Until I learn the nuances of the Canon, and how to take advantage of its features (and I'm still at the bottom of a very steep learning curve with the D200, mind you) then this is exactly what I believe I should be seeing.

I think that too many people take the learning curves for granted .....

But please feel free to disagree.

[sirhc55]

Not a problem

[Onyx]

Well I had BF issues with my D70, consistently replicated using every which means of focus testing available at the time, so I'm less inclined to agree with Gary. Though I do believe half the cases of backfocus is down to user error.

In this case, going from the sample posted, it seems to be only ~10mm off from 'ideal', which is within tolerance IMHO. Plus the fact that you've tested it now, and are aware of it - means you can then compensate for it shooting in real situations.

[Aszental]

Thanks guys, here is another shot i took.



If i bought the lens from HK, would i have to send it back to HK to get calibrated? IS there anywhere in Australia i could do it?

Thanks

[Onyx]

That second shot looks quite familiar - like how I remember my 18-70DX to look on the D70.

IIRC, Sigma's AU distro are PhotoContinental or some other outfit in the sunshine state...