What's the best way........

[taz]

to tell if any marks/scratches on a lens will affect the IQ?

 

[jpwone]

The following link may be a bit of a revelation when it comes to marks on the lens and picture quality

http://www.lensrentals.com/news/2008.10.30/front-element-scratches

John

 

[AndyB]

That is pretty amazing. I must kick an old lens around and try it for myself

 

[jgs001]

Oh Boy... That lens front element is toast... Yet, considering, those images are quite good...

 

[taz]

I probably won't bother testing then

 

[ukaskew]

Maybe I'm missing the point entirely, but if you have a good look at some images from it and they seem fine, isn't that enough? I had a 300mm f4 with a nice little chunk gouged out of the front element, but I never noticed it in the images and neither did anyone else.

 

[StewartR]

1. Take photos.
2. Look at photos.
3. If photos are good enough then lens is good enough.

 

[taz]

All I was trying to get at was that as there is a specific way to tell if there is dust on the sensor, is there a similar way to check a lens.