Question: I've heard claims ranging from *"higher-quality lenses only make a noticeable difference for scientific applications and super-huge prints,"* to *"even the difference between high-quality and uber-high-quality lenses can be seen with the naked eye on 6x10 prints"*

Before I sell my house so I can take amazing pictures from a cardboard box, I'd like to actually see the difference. However, all the examples I've found compare photos not only from different lens, but also with different cameras/scenes/photographers!

**Are there any examples of the same scene, with the exact same settings on the same camera, taken with multiple lenses (of differing quality/price)?** Multiple comparisons with different scenes/cameras *(especially cameras of different qualities)* would be preferable, to eliminate any variables. I'd also prefer a non-biased source *(so, not the lens-manufacturer)*.

I'd also be interested in comparing telephoto to zoom+teleconverter *(of the same quality, focal-length etc.)*, or comparing zoom to fixed-length... but perhaps those are asking too much :)

Answer: 
Sometimes I think I could sit and play with [The Digital Picture](http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx) all day staring and lens quality comparisons, along with different camera backs. It's a highly useful site.
The only relatively comprehensive comparison I know of is [The Digital Picture](http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Sample=0&FLI=0&API=0&LensComp=119&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=1). They are limited to mostly (only?) Canon, and use only one photo, a test chart.

Apart from that, there are a number of individual "shootout" reviews comparing a small number of lenses, like [this one](http://kenrockwell.com/nikon/comparisons/DX-super-zooms/index.htm). You'll have to hunt them down one by one.