So I’ve got this new Sigma 30mm f1.4 lens, and I’m not massively pleased with it after messing about in the living room. Focusing ring seems a bit rough, focus isn’t that quick despite having an ultrasonic motor.

But anyway, the puzzing thing is this. When I use the live view screen zoomed in for manual focus I can get some excellent definition on the screen, but when I press the button (in manual mode) the picture comes out pretty blurry, even if I leave it in MF mode to take the pic. The lens makes a few clicking noises which could be the cause of it.

When I take pictures in AF mode across the room it also seems to be missing focus badly too. Ok so it’s indoors under artificial light, but at f1.4 there should be enough. My kit lens manages fine.

Wondering if these things could be related. Perhaps the AF calibration is out?

Not unusual for Sigmas. You’ll have to send it off to get it calibrated.

My previous sigma lens (70-200mm f2.8, so very different from yours), exhibited similar issues and had quite a significant backfield issue. To do with how the lens talked to the camera relative to plane of the sensor V autofocus sensors.or something.

Used this to test http://regex.info/blog/photo-tech/focus-chart

Back focus ce
Sent both camera (Minolta 7D- old school!) and lens off to sigma UK and they turned it around really fast. Great customer service.

Kev

Right, interesting.

I have an AF adjustment setting on the camera, so for a particular lens you can set it to compensate on all the focus points. However it identifies the lens by serial number and it looks like it didn’t recognise it because it came up as 00000000

Lens was bought S/H from the US, dunno if Sigma UK will complain about that – should probably call them.

Oh and the clicking noise might’ve been because the lens was switched to MF but the camera was still in AF mode. Bit annoyed though – it’s an EX lens for expensive so I’d expect the damn thing to work 🙁

EDIT – that test chart looks pretty good, I think I’ll get that and test all my lenses just to make sure.

Don’t pay for any focus test charts, the original one online is free to print.

I had the same lens and has to send it back to sigma. good lenses but the qc is a bit cack.

Sigma have a habit of reverse engineering lens protcols for some (if not all) brands to avoid paying licence fees so their lens ids aren’t recognised (sounds like this is what you’re seeing).

Kudos was your ring all rough and groatey too? (fnarr 😉 )

Re license fees – Oly should be paying Sigma to make 4/3 lenses not the other way round 🙂

Oh btw.. the Oly 8mm fisheye is absolutely a wonderful thing.. in love already! Pics to follow after I’ve taken it out this weekend.

I’ve a Sigma 70-300 and have always found it a little soft, hoping to get a 70-200 f4L soon so it wont be a problem much longer. 😀

Re license fees – Oly should be paying Sigma to make 4/3 lenses not the other way round

Yes, it’s an odd business model.

If it’s any consolation, I had one of these and it was a cracking lens!