[Rufus]

My 10D. Sigma 17-35 exdg: Results? Good. In fact consistently good for 18 months.

NN's 20D:
Works very well with her 24-105L, my 50mm, my 28-105..........

However, put my Sigma 17-35 exdg on NN's 20D, and the results are awful! :o

Any ideas?

[NT73]

10D 17/35
20D 34/70
Simple

[noisynoodle]

10D 17/35
20D 34/70
Simple

????????????????


--NN

[slejhamer]

the results are awful!

Awful in what way(s)?

[Rufus]

Messy. Lacking resolution. Cheap.

I'll post some examples in a bit.....



(Rummages in HD to find suitable bits)...........................

[Rufus]

Some time later,
Ok, here we go:

20D Sigma 17-35 EXDG HSM, 250s f6.3, ISO 100


Now a full sized crop:



Neither sharpened btw..........

[slejhamer]

1st guess: plane of focus was behind the lamppost. Tricky scene for AF.

[Rufus]

A perfectly reasonable evaluation........ But, I have 50 frames which ALL look like this. :o

[NT73]

10D 17/35
20D 34/70
Simple

????????????????


--NN

Poor attempt at humour. (1/2 the size 1/2 the quality)

[slejhamer]

A perfectly reasonable evaluation........ But, I have 50 frames which ALL look like this. :o

Open up the RAW files in Canon's software (I've forgotten what it's called - the garbage that came with the camera) and you can identify the focus point.

Also were all the scenes like this? Lots of contrasty lines for the AF sensor to grab onto? AF can be easily fooled.

[slejhamer]

Poor attempt at humour. (1/2 the size 1/2 the quality)

I thought it was quite funny.

[noisynoodle]

I thought it might be that but 10D to 20D would be twice the size and twice the quality

[Rufus]

................the garbage that came with the camera, said Slej.

Yes, good idea Slej. Now I just need to find it....

[slejhamer]

I'd be curious to see the section outlined in red at 100%. Might be able to get a better feel for the plane of focus in there, given the depth of the horizon. At this resolution, the little cross in the background looks sharper than the lamppost to me. I could be wrong.