I would say an L Series lens from Canon is a pro lens and hardly mid-range and given that all of these are getting close to a grand these would be a serious purchase. Last year I bought the Canon EF 70-200mm f/4L IS USM and have been extremely pleased with it. I decided the additional size and weight of the f2.8 was something I could do without, after all one stop of ISO is hardly a deal breaker although if we were still shooting film I would have gone for the f2.8. In a similar vein I have just bought a Canon 6D. This is a full frame camera and a couple of megapixels smaller than the 5DMk3. I chose it because it is smaller and lighter but with really excellent low light focussing and ISO results. Since having it I prefer it to my 5DMk2, the shutter is so quiet and it fits the hand beautifully. If you are looking for a full frame Canon don’t be seduced by the rather spurious advantages of the Mk3 and have a good look at the 6D
From Digital Camera World
If you’re looking for an upgrade to your ‘budget’ telephoto but can’t stretch to a fully professional lens, there are some smart mid-range options to be had. We test 8 top optics to find out which is the best telephoto lens for your money. On test are:
Canon EF 70-200mm f/4L IS USM, £965
Nikon AF-S 70-200mm f/4G ED VR, £950
Panasonic G X 35-100mm f/2.8 Power OIS, £895
Pentax DA* 200mm f/2.8 ED IF SDM, £745
Sigma APO 70-200mm f/2.8 EX DG OS HSM, £800
Sigma APO Macro 180mm f/2.8 EX DG OS HSM, £1,300
Sony FE 70-200mm f/4 G OSS, £1,250
Tamron SP 70-200mm f/2.8 Di VC USD, £1,100

With prices ranging from abut £100 to £400, budget 70-300mm lenses can be a movable feast, especially in terms of physical length and aperture.
Indeed, as you move through the zoom range, these lenses stretch considerably in length, while the widest available aperture tends to shrink from f/4 to a fairly narrow f/5.6.
To keep shutter speeds fairly fast for minimizing camera-shake and motion blur, you can often find yourself having to combine the longest zoom setting with the widest aperture, which can really degrade image sharpness.
At the other end of the scale, fully professional telephoto zooms like the Canon EF 70-200mm f/2.8 L IS II USM, Nikon AF-S 70-200mm f/2.8G ED VR II and Sony 70-200mm f/2.8 G SSM II are much more refined.
The relatively wide f/2.8 aperture remains available throughout the zoom range, and the physical dimensions of the lenses remain fixed at all zoom and focus settings.
However, they can be heavyweights in two undesirable ways. Hefty price tags of nearly £2,000 for the Canon and £2,500 for the Sony put them beyond the reach of many photographers who aren’t taking pictures for a living.
Secondly, with their large front elements to enable an f/2.8 aperture, they have a big, heavy build, typically weighing in at around 1.5kg.
A popular compromise is to opt for a 70-200mm f/4 telephoto zoom, usually costing less than £1,000. These lenses are more compact, lighter in weight, yet still tend to have robust build quality and premium quality glass.
They also boast a constant-aperture design, albeit at one f/stop narrower than their f/2.8 counterparts. That’s less of a problem than it used to be.
The latest SLRs usually deliver excellent image quality at raised ISO settings, putting less of a priority on ‘fast glass’. You can also get a tight depth of field when shooting at 200mm at f/4. READ THE FULL REPORT HERE