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

Started 3 months ago | Discussions
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

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SQLGuy
SQLGuy Forum Pro • Posts: 10,368
Re: Sigma 100-400 return debate - front-focusing normal?

Do you have the dock for it? You may be able to adjust it.

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OP poipoipoi_2016 Contributing Member • Posts: 888
Re: Sigma 100-400 return debate - front-focusing normal?

SQLGuy wrote:

Do you have the dock for it? You may be able to adjust it.

Sadly no.

I take it there's no way to adjust it except the dock?

 poipoipoi_2016's gear list:poipoipoi_2016's gear list
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SQLGuy
SQLGuy Forum Pro • Posts: 10,368
Re: Sigma 100-400 return debate - front-focusing normal?

poipoipoi_2016 wrote:

SQLGuy wrote:

Do you have the dock for it? You may be able to adjust it.

Sadly no.

I take it there's no way to adjust it except the dock?

I don't believe so. Sony doesn't provide any focus adjustments in camera menus other than MFA (for use with the LA-EA4). I don't believe any other camera manufacturers allow such adjustments either. At least with the Sigma lenses you can adjust focus preferences at various focal lengths with the dock. For Sony's own lenses, no such option exists that I know of.

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A7R2 with SEL2470Z and a number of adapted lenses (Canon FD, Minolta AF, Canon EF, Leica, Nikon...); A7R converted to IR.

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PaulDr New Member • Posts: 22
Re: Sigma 100-400 return debate - front-focusing normal?

Though I may be stating the obvious, the dock is used with the Canon mount version of the lens (which I use with the MC-11) . Any updates for the E mount version would be done through the camera.

Not a Doctor, PaulD was taken, so I added the second letter of my last name.

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OP poipoipoi_2016 Contributing Member • Posts: 888
Re: Sigma 100-400 return debate - front-focusing normal?

PaulDr wrote:

Though I may be stating the obvious, the dock is used with the Canon mount version of the lens (which I use with the MC-11) . Any updates for the E mount version would be done through the camera.

Not a Doctor, PaulD was taken, so I added the second letter of my last name.

https://photo.stackexchange.com/questions/108165/sigmas-for-sony-can-be-calibrated-with-sigma-docker-what-about-sony-lenses

Stackexchange says Sigma says it's not their problem.

OK, let's return the 100-400 and the 28-200 that came in the same box, then loop back around in a couple years and grab the GM II.

 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
SQLGuy
SQLGuy Forum Pro • Posts: 10,368
Re: Sigma 100-400 return debate - front-focusing normal?

PaulDr wrote:

Though I may be stating the obvious, the dock is used with the Canon mount version of the lens (which I use with the MC-11) . Any updates for the E mount version would be done through the camera.

Not a Doctor, PaulD was taken, so I added the second letter of my last name.

Oh, hmm ... I thought it was already out. It was strongly rumored on many sites several months ago: https://www.sonyalpharumors.com/sigma-will-soon-announce-a-new-usb-dock-for-sony-e-mount-lenses/

Kind of annoying that they have one for L mount, but not for E mount. I wonder if they ran into trouble because of the E mount license agreement which also prevents them from offering E mount teleconverters. On the other hand, Samyang has an E mount dock. Maybe their terms are different?

BTW, I suggested this because there was a thread here previously with an MC-11 user who was able to correct misfocusing issues with his EF mount Sigma lens using the dock.

-- hide signature --

A7R2 with SEL2470Z and a number of adapted lenses (Canon FD, Minolta AF, Canon EF, Leica, Nikon...); A7R converted to IR.

 SQLGuy's gear list:SQLGuy's gear list
Canon PowerShot G9 Canon PowerShot S100 (2000) Canon EOS-1D Canon EOS 5D Fujifilm FinePix S5 Pro +24 more
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