Canon 100-400mm Soft ?

[crmcatee]

Been looking at some of my images recently taken with this lens at 400mm and don't think they're particularly sharp. I'm planning on testing it this weekend (assuming the weathers nice) but recommendations on checking softness would be appreciated.

My current plan is Solid tripod, well lit subject, IS off, combination of both manual and auto focus and using a scale alongside the subject to see what's in and whats out at various focal lengths.

Anything to add ?

[wyvern971]

try wide open, mid apature (around F8-11) and closed down F16+

[Mr Noble]

Vowed I'd never admit this to you guys, but all the hassle I had with my 70-200 f2.8VR that I saved long and hard for and found to be soft, and sent back to Nikon twice, was found to be caused by the $1 UV filter that the nice Hong Kong shop I bought it in threw in as "Special Prize. Sir!!"

It was such a poor quality filter that it made all the pictures soft and cocked up focussing. (and ruined half my mates wedding pics!)

Worth checking if you've got one on there.

G

[crmcatee]

Good point - I'll try it with both the filter and without.

[V6GTO]

Mr Noble said:

Vowed I'd never admit this to you guys, but all the hassle I had with my 70-200 f2.8VR that I saved long and hard for and found to be soft, and sent back to Nikon twice, was found to be caused by the $1 UV filter that the nice Hong Kong shop I bought it in threw in as "Special Prize. Sir!!"

It was such a poor quality filter that it made all the pictures soft and cocked up focussing. (and ruined half my mates wedding pics!)

Worth checking if you've got one on there.

G

Thanks for the banter ammunition Greg

Martin.