Used 24-105mm. What to look for?

Maybe a daft question but I'll be going to have a look at a local seller of a 24-105 in the coming days.

I know all lenses seem to have their issues but what to look for with this particular candidate. I've read the 24-105 has focusing issues. How do I test for such problems? Any tips?

Never had any focus issues with mine - and haven't heard stories from others either. Focus is fast, quiet and reliable. Some (including me) have some zoom creep, but it's not a big deal. Main things to check for, as with any used lens are:

- fungus
- signs of drop damage (check even sharpness across the frame)
- sticky or grinding actions on zoom or focussing rings

If it's a good example, go for it. I really like mine.

No focusing issues with mine either - The IS on this lens is pretty quiet, so it would pay to check this is working OK as well.

Thank you guys for the information, glad I asked the question. I didn't think to particularly check for a sticky zoom although perhaps I would've felt it.

Strange though, on the lens archive thread for the 24-105 I've read numerous members have a 'softness' issue. Not sure how to check for this on the tiny camera screen.

tman2782 wrote in post #12967243
Thank you guys for the information, glad I asked the question. I didn't think to particularly check for a sticky zoom although perhaps I would've felt it.

Strange though, on the lens archive thread for the 24-105 I've read numerous members have a 'softness' issue. Not sure how to check for this on the tiny camera screen.

For every one that says 'soft', there are probably ten that would say the opposite. Mine is very sharp...and like the other posters, no focusing issues either. If it had a 2.8 aperture, I wouldn't have the need for my 24-70L. Great all-around lens. The best that you can do, short of carrying a laptop with you, would be to take a few sample pics, zoom in on the LCD, and use the scroll button to check around the frame. Not the best, but you should be able to see any 'softness'...

I have rented this lens three times, three different lenses. the first two were tack sharp, the third was ok but not nearly as sharp. I would take a few shots before you buy. You will be able to see if its sharp right away. Good luck

Thanks for the feedback.

argyle, Very true, I just thought it was a given that lemons in the 24-105 form are common and didn't want to end up with one, but perhaps it's only as common a problem as could be with any lens. Don't have a laptop with me but will try and work with the seller to see full scale pics.

I've had this lens for a number of years.
It's sharp on my 40D, 7D and 5DII
The IS noise is nominal
I have not experienced lens creep (zooms out on its own)

Be sure to check the zoom. This lens is famous for self-zooming. Zoom in, point the lens down, shake the lens a little bit. See if the lens extends itself. It is an easy fix but something you should be aware of.

jmckayak wrote in post #12970280
Be sure to check the zoom. This lens is famous for self-zooming. Zoom in, point the lens down, shake the lens a little bit. See if the lens extends itself. It is an easy fix but something you should be aware of.

Yup, a lot have mentioned about zoom creep in well used lenses. Doesn't bother me too much, but what would be a good fix for such an issue? (other than Canon repair)

so what test do you do for checking for A problematic lens ?