Insofar as the amount of information contained in their reviews of various manufacturers and individual lenses.
And.. the fun and learning that can be done (interactive on the notes of comparing settings such as f-stop, focal lengths, et al) while checking out a lens that you might have under purchase consideration.
First off, though.. need to understand ... this stuff:
Now then, while on the above linked page, you can take a look at a comparison with the lens under review, namely that of the Tamron ... to that of:
i) Sigma 8-16mm f/4.5-5.6 DC HSM Lens ii) Sigma 10-20mm f/3.5 EX DC HSM Lens iii) Sigma 10-20mm f/4-5.6 EX DC HSM Lens iv) Tokina 11-16mm f/2.8 AT-X Pro DX Lens
... by simply hovering your cursor over the focal length (as but one example ... f-stops covered this way as well) noted and checking the image displayed to see how things change between lenses, or.. with the same lens at varying focal lengths.
There are also some additional tests/comparisons between lenses on "Vignetting Test Results Comparison", "Lens Flare Comparison", "Lens Distortion Comparison" and a couple of other comparative considerations.
Well, certain lenses that is.
The-Digital-Picture.com
This site is quite impressive.
Insofar as the amount of information contained in their reviews of various manufacturers and individual lenses.
And.. the fun and learning that can be done (interactive on the notes of comparing settings such as f-stop, focal lengths, et al) while checking out a lens that you might have under purchase consideration.
First off, though.. need to understand ... this stuff:
"Field of View Crop Factor (Focal Length Multiplier)"
Let's take a look at some of the site features via a lens review:
Tamron SP AF 10-24mm f/3.5-4.5 Di II LD Lens
Now then, while on the above linked page, you can take a look at a comparison with the lens under review, namely that of the Tamron ... to that of:
i) Sigma 8-16mm f/4.5-5.6 DC HSM Lens
ii) Sigma 10-20mm f/3.5 EX DC HSM Lens
iii) Sigma 10-20mm f/4-5.6 EX DC HSM Lens
iv) Tokina 11-16mm f/2.8 AT-X Pro DX Lens
... by simply hovering your cursor over the focal length (as but one example ... f-stops covered this way as well) noted and checking the image displayed to see how things change between lenses, or.. with the same lens at varying focal lengths.
There are also some additional tests/comparisons between lenses on "Vignetting Test Results Comparison", "Lens Flare Comparison", "Lens Distortion Comparison" and a couple of other comparative considerations.
Here is the page on the "Lens Distortion Comparison".
Select from the drop down menu the lens, or lenses you are comparing.. for a look see at the results and how they stand up.
I am bookmarking this one, how about you?