Old Timer Loc: Greenfield, In.

I had been wanting a good lens for wild life and finally got lucky yesterday and bought one locally. I found it locally and for some reason he was needing the money quick. I bought it for less than Keh offered for it because he could not wait for the money. I took a few pictures trying it before buying it and now I want to junk what I thought were some decent lens. I have one question, on side of lens there is button that has 2.5m and 6m. What is that for? Also this lens is supposed to work well with a tele-converter as I under stand it. Should that also be a Canon?
Even with out IS I was blown away with how clear the shots were at a distance hand held with just using some thing as a support or to lean against. I now know what good glass will do now. The party I bought if from said he used it with a mono-pod. It seems like it would be heavy and awkward to use that way and would take a heavy duty one. how does other use it when shooting in the rough areas and for quick shots?
Thanks for any advice and input.

seeSAW Loc: Western Mass

I use a monopod with a pistol grip ball head. I can connect & disconnect easily and the pistol grip with angling the monopod makes it easy enough to compose my shots.

AdkHiker Loc: Northeast

The 2.5 m and 6 m refer to how close you can focus ... With the switch in 2.5 m position allows you to get as close as 2.5 meters from your subject. No an extender does not need to be Canon only one that is compatible. I have a Pro Optics 2x I can but rarely use on my Canon lenses. I think entender compromises the image quality too much. Although the Canon 1.4 X III could be a future addition

clicktime Loc: Yucca Valley Ca.

The switch is for the distance range the lens looks for focus but if you narrow down the distance it locks focus faster. It is ether looking for focus from 2.5m to infinity or it is looking for focus between 6m to infinity. Set it for the distance range you are from the subject. A teleconverter for that lens will take away f-stops your f-4 lens will become f-5.6 with a 1x4 converter but it will bring the subject closer making the lens focal distance around 450mm. The 2x teleconverter will not auto focus on that lens I would stick to the 1x4. You will lose a little of that good glass effect with a converter. More expencive converters do a better job. Remember to set your shutter speed bigger then the focal distance of the lens { 300 or more}.

jeep_daddy Loc: Prescott AZ

You don't say exactly which model lens this is. There is a 300mm f4 and a 300mm f2.8 There's earlier models too. The teleconverters will work with both of these but the 2.0x will take a long time to focus so getting birds in flight is very hard to do. The 1.4x is fine. I wouldn't buy any other teleconverter than Canons. I've known others that own 3rd party with disappointing results. Most everyone I know that has the 300 f2.8 can hand hold this lens for birding but sports photographers all use monopods. Since you say it doesn't have IS, for those shutter speeds less than 1/600th you better use a monopod or tripod. If you're talking about the 300mm f4 - that is a light lens and you should have no problem hand holding this for 90% of your images.

Oh, the switch on the side is to limit the minimum focal distance in meters. If most of your subject matter is farther than 6 meters away, it's best to keep the switch there but if you need to get up close, you'll need to throw the switch to 2.5 meters. You're probably thinking, well why not just leave it in 2.5m? Well when you get off the subject i.e. bird in the sky, the autofocus will try to focus all the way to infinity, and then back all the way to 2.5m and then back out to infinity. This takes a long time and if the hunt is shortened from infinity to 6 meters it takes less time.

CamObs Loc: South America (Texas)

Shooting sports/action you need the monopod so you can pick up and run towards or away from the action. Handheld will wear your bu*t out.

Old Timer Loc: Greenfield, In.

Thanks for all the input and advice. I really like the lens even if it does not have the IS. I have got some good shots already and have not got try BIF yet.Gets great detail and chroma. Again thanks for the help

Michael O' Loc: Midwest right now

Assuming you have the f 2.8, the lens is rather heavy. yet is easily supported by a mono-pod, especially if you get a carbon fiber one --
maybe a 4 section one that extends to maybe 5 ' tall or a touch more.
That combo works well for sports or wildlife.