Sigma 100-400 return debate - front-focusing normal?

Started 2 months ago | Discussions thread
ForumParentFirstPrevious
Flat view
poipoipoi_2016 Contributing Member • Posts: 888
Sigma 100-400 return debate - front-focusing normal?

So I bought a Sigma 100-40 and I'm wondering if this is a bad copy or just expected on a cloudy day.

So it's a great little lens from about 100-250. Sharp, fast-ish for the weight on a 400mm, OSS gets me up to about 1/25 at 100mm and I have shaky hands so I'll absolutely accept that. And then out past 250mm or so, it starts to front-focus on a cloudy day. Not every time, but if 3 out of 4 photos don't focus right, I'm going to give in, return this, and wait to buy the GM instead.

Is that front-focusing expected, have other people seen that? I ask because I've now had my hands on two copies and they both front-focused in the Michigan weather

 poipoipoi_2016's gear list:poipoipoi_2016's gear list
Sony RX100 V Sony a7R III Sony FE 16-35mm F2.8 Sony FE 24-105mm F4 Sony FE 24mm F1.4 GM +3 more
ForumParentFirstPrevious
Flat view
ForumParentFirstPrevious
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow