100-400 User opinons needed for faulty lens

Wow, thats amazing!!!

Yeah, I'm using a standard Hoya UV so I'll be taking it off...

EDIT: Just got my lens back from Canon and the results back up the filter theory.
"Checked and tested. No fault found. Up to standard/normal. Compared against other lenses."

It seems that to test a lens an engineer just shoots a few shots and compares them with other lenses. Not to knock the engineers skills but I would have thought that Canon would use a more hi-tech approach like shooting a test pattern and using computer analysis to measure deviations/problems.

So it does seem like the filter is the problem. I'll take it off and report back when I have some shots to compare.
Cheers,

Are you all using the Ebay "hoya" filters? Just wondering if it's all hoya or just the less expensvie ebay ones?

Peregrin wrote in post #2017371
Are you all using the Ebay "hoya" filters? Just wondering if it's all hoya or just the less expensvie ebay ones?

No I got it from a shop here in UK.
Order info says:
Hoya G series 77mm Skylight
It was only £11 so I guess its not really surprising...

I'll use it when I shoot in a bad environment

When I first got it I did test with and without shots. There didn't seem to be any difference so I guess it only has problems under certain conditions.

Wow, I just bought some hoyas for my husband...hmmm...I'll have to check them out.

The filter imperfection apparently gets more obviuos on longer lenses. I was using Hoya UV on 70-200 f2.8 for about 6 month and still could get sharp pictures most of the time, blaming every soft picture on myself and background artefacts on smaller aperture.

Bought couple B+W UV filters last week to replace Hoya. The camera shop where I bought them didn't even carry Hoya filters - no wonder why.

We've only ever used B&W as well but we were pressed for time and bought some locally (doesn't carry B&W in stock)....so I just wondered if he was going to have trouble...

Having this kind of distortions from filter I guess that either glass density is not even or glass surface is not perfectly flat. So you can still be lucky not getting any of those surprises.