I have an occasional need for long lenses. 100-300mm Canon zooms are available for $75-200.

The get what you pay for aspect is 1) slow 2) not too sharp 3) marginal auto focus 4) chromatic aberration 5) focus and aperture change during zoom.

If one were using the lens strictly for outdoors video, it seems only #4 of of concern. Am I missing something?

My experience with cheap lenses is that they can work well within certain ranges. Usually they fall apart at the extremes. In other words, shooting at the widest and longest focal lengths, shooting at the widest and smallest apertures. Stick in the mid ranges and you can often get buy with a cheap lens. Try to shoot at around a 5.6-8, and don't go all the way to 300mm. The only way to find out how it works is to get one and try it out under various conditions. If you order from B&H or Adorama or some reputable place like that, and if the lens is too soft, etc., you can send it back. I got a Sigma from B&H one time and it was soft at the wide angle, which is what I wanted it for. They took it back with no problem at all.

If you are looking for a great telephoto lens I would recommend an old M42 (screwmount) Pentax Takumar manual focus lens. There are a number of different focal lengths available: 105mm, 135mm, 200mm, 300mm and they are quite reasonably priced - $100 - $300 each on eBay. The catch is that these are manual focus lenses. For video this is desirable, but not so much for still work. The build quality of these lenses in incredible - not a single piece of plastic to be found - and the optics are top notch.

Good luck!

The 70-300 range isn't much of a challenge, and most of the cheaper lenses out there in this range are fine. The Sigma 70-300APO is probably the best of the bunch, the AF being of the leisurely type, but it's sharp. The weakness with all of the lenses in this category, is the 300mm end.

Amongst older manual focus 70-200 zooms, the Tamron 70-210/3.5 constant aperture zoom is likely the best without going to a much more expensive Nikon 80-200/2.8. Then go with a manual focus 300/4.5 or 300/4 from Nikon for the 300mm end if it's even needed.

I;ve got a Vivitar ( tokina made ) 400 / 5.6 in OM mount. what a great lens when you consider APS-C crop factor makes it a 600mm 5.6. go price one of those ! I got this lens on ebay for $80+shipping. get whatever you think will work. video is a LOT less demanding then stills

Video does not need the super sharpness that still photography requires, so my older Nikkor AI lenses, 200 f4 and 24mm f2.8 which are soft for stills at 100% are very good on the 7D for video.

I would add that IS feature is essential for video, especially for tele zoom lenses. Unfortunely, none of the old types come with IS (or VC, VR, OS etc).

I would add that IS feature is essential for video, especially for tele zoom lenses. Unfortunely, none of the old types come with IS (or VC, VR, OS etc).

Essential you say? Seems movies have been made for the past 100 years without it, and no current cinema lenses that I am aware of have IS either.

What do you mean by "essential"?

Well, the OP asked for "cheap consumer tele lenses", which I assumed to be non-"cinema lenses". Unless the OP is a professional cinematographer who films 100% time on a rig, being a steady cam or a tripod or a glidecam, etc, he may find IS very helpful in reducing shake in a zoom lens. So, "essential" means for "cheap consumer tele lenses" and for handheld outdoor videos/non-cinema works.