Sigma 10-20 - Undecided - 100% crop pic

[paleblue]

You're right, it's bad karma to sell it on without letting the next owner know (hope the previous owner is suffering). I may just send it off anyway to see what Sigma say . Just tested other lenses quite thoroughly, all appear fine so that's a relief.

 

[dcash29]

Unsharpened

Sharpened

The colour balance seems to have altered when i saved the sharpened shot so please ignore. Noise in the water is evident , selective sharpening would have been used normally.

Edited sharpened picture

Any comments?

 

[coldpenguin]

One thing i will say is i am not a fan of the live view for it focus, i always feel it's off dont no why but i have noticed this in a few shots. I now only use it for family snap shots.

I don't understand this (not specifically your post).
As far as I understand it, the OP put the camera on the tripod, then used live-view to ensure that the manual focus was good.
I assume they zoomed in and confirmed the position.

With live view, my understanding is that the camera sensor is 'reading' the light, and then displaying it on the LCD [instead of writing it to card].

When the shutter is triggered, the curtain should rise, the aperture should move to position, then curtain 1 falls, then curtain 2 falls.
The light hits the sensor, then gets written to card.

How can the focus change? What can be causing the light that was in focus to now not be in focus?
Only the aperture change, but the camera would perform this anyway. Ok, so the shutter moves one extra time.

 

[dcash29]

Guess Elaine is just saying what she gets on the LiveView isnt what she gets for a final image?

 

[HoppyUK]

Any comments?

It makes the point really well. Post processing makes a huge difference, but it can't get image detail from nowhere, so it must have been there in the first place.

And 'sharpness' is not just resolution, but also 'contrast'. Actually, contrast, which is the flip side of resolution in optical terms, is arguably more important. I'll try and find a link in a minute, to a Canon page which shows this. In lens terms, when resoLution goes up, contrast goes down - you can't have both, well you can and really good lenses have a lot of both, but still one goes down as the other goes up.

Maybe not such a bad lens afterall, but we'll never know now as it's going back. Sara's getting the Canon.

And it shows that if meaningful conclusions are to be drawn on this kind of thing, then identically shot and processed images need to be shown side by side.

Edit: here's the link. It's a PDF from the book EF Lens Work III from Canon. Very good it is too. Flick through to page 203 (12) and enlarge the three pics of the cat top left. See how the hi-res but low-contrast image looks worst. http://software.canon-europe.com/files/documents/EF_Lens_Work_Book_10_EN.pdf

 

[swag72]

Thanks for all your help and advice folks - All sorted now - Happier with the Canon!!

Having a look at some similar shots now. I say similar as the weather is less sunny today, the shutter speeds are lower, still shot on a tripod with remote. The position is not the same as I can't see exactly where I was before and the mm is probably a little different - Not at all the same then really!!!

But, I am a happy bunny now, so problem solved for me anyways. Hope those of you with problems get them sorted.