Horrible AF Performance with Sigma 150 - 600 Sports and Sony a7r III

Hey guys.

I bought a good as new Sigma 150 - 600 Sports.

I'm using it nearly daily for 1 month now and I constantly have horrible AF Performance.

When shooting with AF-C (no matter which AF-Field) out of 300 shots ~20 are sharp.
The rest is either completely out of focus or slightly out of focus, doesn't matter if I set the Focus-Range switch to <10m, >10m or full.
When shooting in AF-S or DMF its better.

Anyone else having these problems with exactly this setup (a7r III and Sigma Sports)?

I wrote Sigma and they told me "It's normal, use a tripod". Yeah, thanks for nothing.

It's really frustrating and I think about selling it again and check out some alternatives like the Sony 200-600. I never had such problems with any of my lenses.

If any of you got the same problem, did you find out some kind of workaround for it?
Or are there any in-camera-settings that help?

AF-S / DMF / manual Focus isn't the best practice with moving deer and birds.

Hopefully someone here who owns the same kit can help. What is DMF?

Mizzu wrote:

Hey guys.

I bought a good as new Sigma 150 - 600 Sports.

I'm using it nearly daily for 1 month now and I constantly have horrible AF Performance.

Mizzu,

You bought it "good as new".

Did you get a warranty with it from the seller.? If so let the seller take responsibility  for it.

It's possible that a fault had been caused to it from the previous user(s) and was sold on for that reason. AF is not known to be deficient in those lenses.

If you test it on a tripod as suggested make sure to turn off Steady Shot (IBIS) in the camera and also OS on the lens.

S

DMF is Basically AF-S with manual override for Manual Focus. So you can prefocus and then fine-adjust it manually.

The Customer Support guy was a German one, so I don't know if this helps you.

I bought it one some "private eBay", I don't know if something like this exists anywhere else except Germany. It's basically eBay but with direct contact to the people for private selling.

I have the original invoice of the Lens and everything, so warranty shouldn't be a problem.

I did already some tests on all Apetures on a tripod, IBIS on and off and so on, but only to check if the lens is sharp and if it's centered perfectly.
I will do some more tests later after sunrise and report back then. Thanks already for your responses.

Have a good start into the week.

Allright, so I tested it out a little more in the garden.

With and without OS on a tripod. There were no problems with focusing at all in terms of sharpness, but sometimes the AF simply completely "broke", like when I was half pressing the shutter button and changing the subject, it stopped trying to focus at all and didn't focus anylonger until I fully pressed the shutter button to take a photo.

Also releasing the shutter button and re-pressing half for focus didn't work. This happened multiple times, so maybe this also happens when I'm shooting outside and I just didn't realize it until now (?)

And sometimes it just pumped liked crazy until it got back to focus anything (like 4-5 seconds or so). But I think this happened when I used the full range of focus and didn't switch to 0-10m focus distance, so I think this was normal.

Also I have to say that the AF-C didn't have a lot to do in a test-scenario like this, since I had no moving subject to test (so that AF-C would have to fine-adjust / fine re-focus again like in real life with animals). Very often the pictures are just slightly out of focus, when shooting in nature.

Except that the AF completely broke as described, it worked as intended as you would see in every test-video on Youtube (and as I would wish for in real life) when switching from subject to background and vice versa. But it's a complete different story when focusing on something that's moving (like the head of a deer, a bird or stuff like that). I don't mean crazy flying birds or running deer (I wouldn't even bother trying to photograph these with this lens) but standing deer that move their heads and look around.

No idea. I'm a little baffled to be honest.

Hi, with the Sony 200-600 being so good for what it costs (especially used), I wouldn't bother with anything else, in particular if adapted.

I recall having the 150-600 C and never managed to focus with enough speed to make it usable for anything other that very slow moving targets.

If I were you, I'd try to sell the 150-600 and get a 200-600, it will be night and day in terms of AF and also the IQ at the longest end will be better (and still very good with a 1.4x TC).

Yeah. I'm also thinking a lot about trying out the Sony 200 - 600 just to have a comparison but what keeps me from buying is the size. I would have need to buy a new Backpack and I really want to avoid this, haha

Maybe I will give it a try though. The Sigma is really frustrating so far...

Well, the Sony is only 3 cm longer than the Sigma Sport (so probably equal including the MC-11 adapter) and more than 700gr lighter, so guess you will be better off even under that point of view

I think you're talking about an adapted Sigma. I mean the Sports version designed for Sony FE (Full Frame E-Mount).

Yeah, I measured my backpack and it's exactly these few cm that it is too small.

But still, I think there's no alternative than testing out the Sony and see if it's as horrible as the Sigma. Everyday I use the Sigma I'm getting more and more annoyed.

No joy for me to use it. And photographing should be a joy everytime.

Yes, if it’s the dedicated FE version, I find very strange that it behaves like described, it should be at least decent in that regard.

Anyway I would expect that the native 200-600 would be significantly snappier to AF.

OK. Thanks for the info. I ordered a Sony 200-600 now to test it and to see if it works better.

Starting to lose patience...

I got the Sony 200 - 600 today for testing purposes.

Man, this is day and night difference!

Out of 40 Shots, 38 were in focus and much much sharper (even wide open) as with the Sigma.

The AF is much faster and the keeper rate is just another level now.

I will definitely sell the Sigma and keep the Sony. I didn't expect this to be such a massive difference. Now photographing is a joy again.

Never again a Sigma Telephoto...

Told ya..

Happy you found “your” lens, in my experience Sigma long lenses are very good optically but not suitable for demanding AF-C work (maybe with the exception of the mighty 500 F4, but likely not adapted to Sony).

Mizzu wrote:

I got the Sony 200 - 600 today for testing purposes.

Man, this is day and night difference!

Out of 40 Shots, 38 were in focus and much much sharper (even wide open) as with the Sigma.

The AF is much faster and the keeper rate is just another level now.

I will definitely sell the Sigma and keep the Sony. I didn't expect this to be such a massive difference. Now photographing is a joy again.

Never again a Sigma Telephoto...

Mizzu,

I hope you get it repaired before you sell a dud to some unsuspecting victim.

S

to be honest, I don't think it's faulty. It's probably just the combination of crappy a7r III AF + crappy Sigma AF.