This is a great example of the most useful that an online review needs to be. Real world samples with shot by shot information. From this you should be able to see and judge distortion, contrast, bokeh, and image quality in general.
The thing is, lens reviews are hard to reconcile with simply because lenses are going to be used in so many different ways by different photographers. Any reviews by the likes of Ken Rockwell or even Thom Hogan can only come down to personal opinion.
For example: I love Kenneth's idea that I can throw away all of my lenses and just carry one body with the 28-300 planted on there and away I go, but it just doesn't work for me. I generally carry a two body/3 lens kit, and the lenses are all 2.8 or faster. I can't shoot the way I do with a maximum 5.6 aperture on the long end, so the 28-300 is out for me.
My point is that I'm a wedding photographer, and to shoot the way I want to I shoot I use fast lenses. If I were to review the 28-300 I'd probably conclude that it has a great range, but isn't fast enough. Therefore, not actually the second coming kit bag liberator. It's my opinion.
Ken's review is his opinion. Any review is the reviewer's opinion based on what is gonna work for him or her. It does appear that ByThom might have a grasp on the fact that there are different kinds of users out there where Rockwell will just assume that doing it his way is the way to salvation, but either way, these reviews shouldn't really mean anything to the person who's considering buying the lens.
There is a chance that catching up with these infamous reviewer's is actually just a comforting confirmation of what the reader wants to hear. Want to justify blowing next years holiday savings on a 'Pro' Lens? Drop in to Ken's. Want to marvel at your efficient and performance adjusted kit bag,
and know that you made the right choice for that Safari trip you keep planning? Swing ByThom's - and Nikon market strategies be dammed!
Perhaps the most reliable way to review a lens would be to hire one and take it out for the weekend and shoot what you like to shoot. Better still, get a client to pay for the hire. If it saves you, helps you, enables you to shoot like never before, then you can say "Yes! I'm going to buy one of these lenses" If it doesn't improve your current set up, or isn't necessary then you can save a lot of money and keep on shooting the way you like shooting.
In the mean time who gives a rat's tail what any of these reviewers have to say when it comes to lenses? It's all subjective, and generally of no use to the reader.
Here's a couple of things I'd like to say about the 50mm1.8:
I love this lens, it's cheap and fast (enough) and pretty sharp most of the time. I wish it could see a bit better in the dark, and was always in focus no matter where I pointed it all of the time, but it's generally pretty good. If you are in exactly the same situations as me and shoot in the same way as I do with the same cameras, it will probably work pretty much the same. You should buy one.
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examples of my photography at
http://www.alexanderleaman.co.uk