Congratulations on a great shot Scott, but not on the message you are promoting with it. Another member posted a few pages back that he and a friend took the identical shots with L and non-L lenses and could see a distinct difference in every photo. Sharpness is not the alpha and omega of images, you said, and we could add, neither is low light capability, but when they are needed, the images are either lost or compromised when the lens is not good enough. Even when the lesser lens can do the job, it often requires being set on a tripod and precise manual settings, all of which can be done handheld and only a shutter speed or aperture setting with a good lens and a good camera.

The UHH advocates and professional reviewers of the L series all say the same thing about them. Scott can create terrific images, but there are conditions under which the lesser equipment will fail, even in his hands. If it is a paid gig and the shot is vital, the client will not want to hear the excuse that the black ceiling absorbed too much of the bounced flash.

A pro lens gives the following advantages, whether or not Scott admits that these have any chance of creating better images:

1. Better Build. Pro lenses are made of top quality titanium and better glass, while the inexpensive ones are often have many plastic parts. I dropped the Canon 70-200mm F2.8 about four feet onto a hard tile floor some five years ago. It works perfectly to this day. The weather sealing makes them much less likely to allow fine dust particles, or water to leak into them.

2. Wider Apertures. Primes can go to F1.2, most zooms to a constant F2.8, and the incredibly wide zoom F28-300mm to F3.5-5.6. This makes a substantial difference when the lighting is not adequate and a speedlite is not allowed or useful. The cheap lens will miss the last few shots at the park as the Sun is going down, while the pro lens can take perfect images in the same circumstances. Dim light at a wedding, compounded by a black ceiling and a no direct flash rule will leave the cheap lens striking out, but the good lens performing adequately.

3. Pro lenses have faster, quieter focusing motors, which once again results in some shots that are lost with a cheaper lens that hunts for the focus, or dials it in at a leisurely pace. Images from an inexpensive telephoto lens will miss many sports shots, as well as sudden entertaining moments that arise at indoor social events.

4. Clearly Better Images. Pro lenses produce more saturated color, less chromatic aberration, better contrast, and less distortion.

If you are an artist with the time to work at your own leisure, you may get away with a lesser lens. If you are a serious pro, you will not take the kind of chances with other people's images that the inexpensive lenses impose. If you are not a pro and can afford the L lenses, I cannot understand why you would not buy them.

Final word: The most important equipment is the photographer, so the great ones will consistently produce great images with lesser equipment, but they would produce even better images more consistently and with less hassle if they had pro lenses.

I would like to disagree with your disadvantages. It is too generalized. There are several reasonably priced "L" lens such as the 24-105mm, the 70-200mm f/2.8L non IS, and the 70-200mm f/4 both the IS and non-IS versions.

As far as the weight goes, both of the 70-200mm f/4 lens are quite light. Having used "L" lens on a T2i, 7D, 6D, and 5D MK III, I have found them to be well balanced on these cameras. For me, the balance of the camera is of far more importance than the total weight.

Expensive is a relative term. ... People on fixed incomes may disagree as to what is affordable or not & I suspect many people on this site would consider the cost of the "L" lenses you listed as beyond what they would like to pay . I can't tell you how many posts I see where people are seeking out lenses costing no more than $500.... Granted, you pay for better quality, but , by the same token, you can overpay because of a brand name. The lenses you listed go from $650 or more on most sites ( I did find a "BGN" 24-105 on KEH for $546)... As for the weight, I do agree with you there as the F4 versions are considerably lighter than their F2.8 counterparts.