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10-06-2018, 08:43 PM   #1
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Help With Sigma 50 1.4 EX DG

I've been playing around with a Sigma 50mm f1.4 EX DG HSM I just got in and was disappointed in the performance at first. The pictures looked very soft and had a distinct glow or halo around the in-focus areas wide open. It also looked off-focused so I tested it and adjusted it to -9. I shot some more pictures wide open and there was still a strong glow and softness to the in-focus areas. This is completely different from some samples I've seen from other people taken with this lens at f1.4. I'm wondering if it's just me and my inexperience with the lens, if this is just how it's supposed to be, or if this is a dud lens and I should send it in for servicing and adjustment with the camera.


All pictures below taken at f1.4 unless noted. All are full sized jpegs.












Same as the second picture but at f1.6
f1.8


f2

And again at f1.4


10-06-2018, 09:17 PM   #2
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I would say calibrate it at the distance you will actually use it to shoot portraits, use single point focusing, use the hood, then go out and shoot real world portraits rather than test shots.

I kind of felt the same when I got mine, but after I dialed it in and really got to know it I really like it. In my book it is a toss up with the DA* 55.
10-07-2018, 02:39 AM   #3
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I have recently acquired one and I see the sharpness as good enough wide open on my copy.
I would suggest you try live view wide open to eliminate focus errors at source and see if that improves things.

When testing mine, in the field I found +7 worked on my K-3ii, and proper testing made that +8.

I found that focusing from MFD gave me a even spread around focal point, where the front and back zones where equal. When I focused from infinity the zone was off set a bit, but the target (about 5 feet away) was still in focus.

I tested it a dozen times and it was repeatable.

The first image below is on song from MFD, the second image is a crop from the first. The third image is focused from infinity and is front focused a bit. I can live with that for portraits.

---------- Post added 07-10-18 at 02:42 AM ----------

I should add, I have not applied any sharpening to these images.
Attached Images
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 

Last edited by Kevin B123; 10-07-2018 at 02:41 AM. Reason: Making better sense
10-16-2018, 05:15 PM   #4
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I think I now have the focus down well enough but I still get pretty strong haloing around in-focus objects wide-open. It occurs at minimum focus distance and further out indoors and outdoors in bright and slightly shadowed sunlight. I'm still unsure of what to do about this. The haloing is mostly gone by f1.6 and completely by f1.8 but I didn't buy this lens to only use it as a f1.6 or f1.8 lens.


Last edited by MikeyBugs95; 10-16-2018 at 05:26 PM.
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