Autofocus issues with sigma 150-500mm

Hi all, I bought a second hand 150-500 mm sigma lens to use with my d7200, was all fine but all of a sudden weird stuff is happening. The autofocus doesn't want to work, if I take it off and back on again sometimes it comes back to life but it might take several times before it works. I've looked at the mount and can't see anything that screams wrong or broken and basically I'm scratching my head and getting frustrated. Anybody have any ideas on what to do or shall I contact sigma and see if they can do anything?


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gunnerhedge said:

Hi all, I bought a second hand 150-500 mm sigma lens to use with my d7200, was all fine but all of a sudden weird stuff is happening. The autofocus doesn't want to work, if I take it off and back on again sometimes it comes back to life but it might take several times before it works. I've looked at the mount and can't see anything that screams wrong or broken and basically I'm scratching my head and getting frustrated. Anybody have any ideas on what to do or shall I contact sigma and see if they can do anything?


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Your post doesn't indicate what camera body you're using but some have a focus-lock switch on the back of the body that surrounds the "OK" button with a white dot and and an "L"; the "L" setting locks the auto-focus.

There is also a M/AF button near the lens mount release button. Have you tried making sure those switches aren't "stuck" or in between settings?

If those things check out I think it might be time to call Sigma.

I would try cleaning the lens contacts in accordance with this procedure from Nikon:

https://www.nikonimgsupport.com/eu/B...d=1&lang=en_GB

Horoscope Fish said:

Your post doesn't indicate what camera body you're using but some have a focus-lock switch on the back of the body that surrounds the "OK" button with a white dot and and an "L"; the "L" setting locks the auto-focus.

Click to expand...

If I'm not mistaken this doesn't lock the auto-focus, it only locks the focus point.

Sounds to me like this may be a contact issue. I had that lens and it's a heavy thing, so if it was allowed to merely hang from the body it could have disfigured the mounting ring slightly causing you to break contact. Doesn't have to be broken, only bent ever so slightly. Put the lens on a tripod and as you try and focus see if applying some mild pressure forward from the back of the body does anything to get it to focus more consistently. If so then you've got a ring problem. That said, I would try cleaning the contacts first as mentioned already.

Thanks for the replies, I'll try cleaning the contacts and update with that, if worse case scenario and its the mounting ring can that be repaired or will it be cheaper to get another camera? So far only appears to happen with this lens.

Like Jake said, try mounting it on a tripod (using the lens' tripod foot, not on the bottom of the camera) and see if pressing the lens and body together slightly will allow you to take a photo. It's possible the mount on the lens is slightly bowed...or the contacts need cleaning as was mentioned. And if there are any tiny screws on the lens' mount, make sure they are snug.

Most likely it isn't the fault of your camera so I doubt you'd need a new one. Problems can come up if people use long lenses mounted on a body AND if they carry the combo by holding the BODY. The mounts aren't designed for all that stress. Always carry any lens/body combo by whichever is heavier. And when a lens is heavier than the body, ALWAYS mount the combo on a tripod using the tripod foot...not the hole on the bottom of the body.

Thanks for the advice, I will try these things when i get in from work this evening. As for the carrying by the lens I'll make sure im doing that, I know i have allowed it to hang from strap on shoulder a couple of times when not thinking about it.

gunnerhedge said:

Thanks for the advice, I will try these things when i get in from work this evening. As for the carrying by the lens I'll make sure im doing that, I know i have allowed it to hang from strap on shoulder a couple of times when not thinking about it.

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You might want to look into one of the camera straps that fastens directly to the tripod foot. You'd need to make sure it is screwed in snugly each time when using it to ensure it doesn't come loose. Some people have damaged a camera and/or lens because of this. Previously I was opposed to these straps UNTIL I tried one myself. I bought whichever BlackRapid stap is the ambidextrous one--although I'm right-handed, I carry my camera on my left. I LOVE this strap when I use my 300mm f/4 mounted with a teleconverter on the camera. It beats carrying the combo by hand. By the way, my BlackRapid strap has some type of rubber disc that acts similar to a gasket when it is screwed into the tripod foot. It seems very secure, but I still check it each time I use it.

hark said:

You might want to look into one of the camera straps that fastens directly to the tripod foot. You'd need to make sure it is screwed in snugly each time when using it to ensure it doesn't come loose. Some people have damaged a camera and/or lens because of this. Previously I was opposed to these straps UNTIL I tried one myself. I bought whichever BlackRapid stap is the ambidextrous one--although I'm right-handed, I carry my camera on my left. I LOVE this strap when I use my 300mm f/4 mounted with a teleconverter on the camera. It beats carrying the combo by hand. By the way, my BlackRapid strap has some type of rubber disc that acts similar to a gasket when it is screwed into the tripod foot. It seems very secure, but I still check it each time I use it.

Click to expand...

Funny enough I've just bought a peak design slide which can connect to the tripod mount, might give it a go, at the moment it's just connected like a normal strap.



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Ok here's an update from this evening, I've cleaned the contacts and it appears a bit better but I have noticed that there is some play between the body and lens which is not evident on my other lenses. As long as it's turned a certain way it works. Is there anything that could improve this or am I safe to continue using it?


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If its lateral movement and not too much it can be normal on some lenses.

To avoid duplication and confusion, we really need to combine this thread with the Sigma 150-500 thread in Photography Q&A.