Is 50mm Sigma that good?

[lexonio]

I'm only starting to work with fixed lenses, but it seems I can't get them to work properly.

T2i, 1/60, f/1.8, ISO 320

The focus was supposed to be on the centre of the nose, yet the "portrait" still got blurry. Is this an autofocus issue of my specific lens, or that's just the way it is supposed to be?
Thank you.

 

[foobar]

Focus on the eyes, not the nose – remember that depth-of-field is very shallow at these apertures.
f/1.8 will probably not be enough to get the whole face in focus. Try a smaller aperture (e.g. f/3.2) first and work your way down.

 

[jwong]

Try shooting a slanted surface like a ruler at a few apertures f/(1.8, 2.4, 4, 5.6) and at a few distances to see if the focus is consistently off. If the blurriness persists at f/4 and f/5.6, then you might have a bad lens, but if it's limited to f/1.8 to f/2.4, then you might consider having the lens calibrated to your camera body because your camera body does not have microfocus adjustments. The faster the lens, the shallower the DOF and the more critical that the body and lens be well-matched.

 

[rj79in]

At f/1.8 you hardly have any DOF to work with. Try dialing in a smaller aperture and shoot with that.

Also, as the earlier poster mentioned, don't focus on the nose. This will ruin almost all your portraits. Try using single focus points to focus on the eye and despite a shallow DOF, you may get good shots.

BTW, have you tried testing the AF on your lens using a tripod?

 

[Actionpix]

To me the focus looks spot on to the center of the nose. All in that distance is sharp, as far as I can see.

 

[Marsu42]

Also, as the earlier poster mentioned, don't focus on the nose. This will ruin almost all your portraits. Try using single focus points to focus on the eye and despite a shallow DOF, you may get good shots.

In a recent topic about f2.8 vs f4 lenses, someone said his customers would prefer f4+ portraits due to not so blurry bokeh (yes, this is hard to believe to some...) and larger dof. Personally, I would like a portrait of me to have my eyes *and* nose in focus at the same time, too - or it's a creative shot from an odd angle, but this might not your regular portrait shot.

 

[alipaulphotography]

All shot on the Sigma 50 on a 5D classic - No problems at all. Always focus on the eye. If you are struggling - stop the lens down a bit. Only use f/1.4 if you need to. You'll find the lens sharpens up quite a bit too.

EDIT - Just released you were shooting f/1.8. You probably just missed focus. Keep practicing and you'll get the hang of it.

 

[rj79in]

Also, as the earlier poster mentioned, don't focus on the nose. This will ruin almost all your portraits. Try using single focus points to focus on the eye and despite a shallow DOF, you may get good shots.

In a recent topic about f2.8 vs f4 lenses, someone said his customers would prefer f4+ portraits due to not so blurry bokeh (yes, this is hard to believe to some...) and larger dof. Personally, I would like a portrait of me to have my eyes *and* nose in focus at the same time, too - or it's a creative shot from an odd angle, but this might not your regular portrait shot.

My only point was that if shooting wide open, it is improbable to get everything in focus at the same time. I've found portraits where the eyes are in perfect focus (even though the nose and the ears are slightly blurred) the images are dead useful.

 

[Marsu42]

All shot on the Sigma 50 on a 5D classic

Some of your shots are very nice - so what aperture did you actually use on these (the exif is missing), or are these samples with f1.4?

 

[alipaulphotography]

All shot on the Sigma 50 on a 5D classic

Some of your shots are very nice - so what aperture did you actually use on these (the exif is missing), or are these samples with f1.4?

A couple of the really low light ones are 1.4, others mostly 1.6 or 1.8. Thanks.

 

[ddl_cgy]

Besides the small DOF for a prime at large aperature you are shooting borderline too slow if handheld which can also make the picture blurry.

For a crop camera you should be shooting at least 1/(Focal Length * 1.6 crop factor) which is 1/80s here.

 

[Silverstream]

I have this and I was very disappointed. I had read that some of them had focus issues but thought I would be the lucky one. Got it. Performed a myriad of tests. Called B&H(where I had bought it), ran more tests that they suggested. Returned it, got another lens. Almost exactly the same results. Wound up sending to Sigma. They fixed it under warranty and returned it. It was actually worse when I got it back. I now never use this lens.

I purchased an 85mm f1.4 locally and it is much better. I have a T2i fyi. I put the 85mm on a borrowed 5D mk II and it was noticeably better and pretty damn good.

If I had microadjustment for lenses on my camera, I might be able to get it closer. the 85 mm front focuses on my t2i so I sometimes deliberately focus lock on an area slightly behind my real point of focus. And take a bunch of pictures to help me get lucky. It also seems to do more hunting in low light than my EFS 17-55 f2.8 IS which is a superb lens for me BTW.

 

[lexonio]

Very good job Alipaul! That actually brought some faith in this Sigma back, I think I'll have to wait and try micro adjusting the focus when I get the 5dmkIII.

Also, very good advice about the shutter speed, I'm too used to shooting with IS on my 24-105L, I'll have to keep that in mind.

I was thinking about selling this lens and getting a Canon f/1.4 one, but I think I'll have to look into my issues deeper. Thank you.

 

[Mt Spokane Photography]

If focus is off, try AFMA. The 50mm Sigma is optimized for crop cameras and is excellent with them, if you can get the focus set accurately. For FF, the Canon is a little better than the Sigma.

The best 50mm I've owned, as far as sharpness is concerned was the 50mm f/1.8 MK I as made in Japan. It has a focus ring like the f/1.4 and just seemed to me to be a slight amount better. this was likely due to sampe variation, but the build and handling were just plain better. However, I bought the 50mm f/1.4 since I'm always needing more light.

I've come to avoid the 50mm range, since I can crop my 35mm L images, or maybe even use my 85mm f/1.8 with better results. Its not a bad lens, its just that the other primes are so much better.

 

[marekjoz]

I don't own one, but believe them (comparison of test shots against EF 50.14 and Zeiss): http://www.lenstip.com/177.4-Lens_review-Sigma_50_mm_f_1.4_EX_DG_HSM_Image_resolution.html

 

[Bennymiata]

If you're shooting at F1.4 and hand holding the camera, it's also quite likely that between half pressing the shutter, getting focus, then pressing it all the way, your body will sway ever so slightly and because of the very shallow DOF, you'll miss the focus either one way or the other.

As others have said, try using F4 or smaller.
You won't notice much difference in the DOF, but the chances are more of your shots will be sharp.

 

[koolman]

I have a canon 50mm 1.4 + t2i. For a good AF lock you need to focus on something with good contrast, like the eyes. The nose is not a good place. You need to use the center AF point only, and make sure the focus locks well on the eyes. Additionally you need good bright light.

Finally, I'm not sure f/1.4 is an ideal f stop if you want a super sharp portrait. I usually use f/2.8 as it is very tricky to nail exact focus with 1.4 - as the DOF is very shallow - any slight miss focus will cause blur.

This is especially true with a t2i rebel - who's AF points and system are not as developed as the higher bodies.

I've heard the 60d is much better.

 

[Jamesy]

Are you focusing and recomposing? That will change the focus point for sure. If you shoot in portrait orientation and your subjects eyes are on the top portion of the viewfinder try using a focus point in the top area of the viewfinder to avoid or minimize the 'focus/recompose' focus shift that may be occurring.

 

[Marsu42]

I've heard the 60d is much better.

My 50mm f/1.4 focusing on the 60D is usually spot on.

The 60d's center af point is extra sensitive for lenses of f2.8+, meaning it can adjust the focus to a fine degree. For this to work, your lens/body combination of course has to have no front/backfocus, but afma is missing from the 60d (thanks, Canon!) so this might be an issue with very fast lenses.

 

[Mt Spokane Photography]

I don't own one, but believe them (comparison of test shots against EF 50.14 and Zeiss): http://www.lenstip.com/177.4-Lens_review-Sigma_50_mm_f_1.4_EX_DG_HSM_Image_resolution.html

Be aware that combination lens-body tests only apply to that lens-body configuration, in the above case, a Canon 20D.

FF tests with a 5D MK II will be completely different with regards to edges, CA's, and vigineting