Hi .... I just recently acquired from online a Canon EF 70-300, 4- 5.6 IS USM lens. When rotating the focusing barrel I noticed it does have some end-play (backlash) when reducing or increasing the zoom range. I am guess the endplay is about 1-2mm. Is this typical for this lens? How much is too much? This lens was advertised as hardly used.
" This lens was advertised as hardly used."
It probably was hardly used! Its a low end lens not well built. Not a good candidate to buy used unless you can try before you buy. Is return an option? If not just use it if it works OK picture wise.
The lens is a 2005 design, sharper and better contrast than my 70-210mm F4 (1987) lens. Supposely is does have one UD element, from Canon > ("The UD lens element minimizes chromatic aberration throughout the zoom range and, compared to the previous lens, achieves higher image quality with high resolution and high contrast without any color bleeding on subject outlines).
I did some testing yesterday and was able to get a reasonably sharp image of a squirrely supprisinly at 1/60th of a sec at f8 and wide open at 300mm. Other pics were good but not as impressive as this one which I will insert in this reply. I bought the lens with original box, papers, manual etc, all in MINT condition for $200. Part of me thinks I should have saved up and waitied for a nice "L" lens, but I am not a pro but a picky amatuer when it comes to sharpness for outdoor photography. I only wish it did not have the funky backlash when rotating the zoom ring. Possibly it was this way when new....I belleive it sold new in the stores for about $450. I am currently ussing it with a Canon 30d cropped sensor body.
Here is the link below of the lens in question:
The backlash can occur anywhere within the rotation of the zoom ring. Example, when set to 135mm there is about 1-2mm side to side play while rotating the zoom ring.
Another example of this lens at 300mm, f9, 1/500. The viewer within this site may comprimise the image sharpness slightly.
"You always confuse the 75-300..."
Matter of opinion but I don't like either. That is why I down play them either or, or both. I know some guys get decent results with them and more power to'em. However, I will not recommend either. These lenses are designed to a price point. Because like the OP opined, buying an "L" would require more money and/or more saving up. Bottom line for what they are designed for they are fine. If I was the OP, I would just use it and not worry about it, until I needed to.