Sigma 85mm 1.4 - Is this OK ?

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Ben
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I've just run some tests on my new Sigma 85mm 1.4 and I want to get your opinions as I've got little to compare it with.... I know that Sigma don't have the best QA so I just want to make sure that I haven't got a "Friday Afternoon" copy.

I'm happy with the AF - seems reliable and predictable, I've dialled in a small amount of micro adjust but no more than for my other lenses.

CA seems good past F2.8 and starts to appear when the lens is wider than that:

Yes I am aware that it is all but impossible to get rid of CA on a 1.4 lens. And I'm happy with the sharpness.

All images out of camera and saved with a small amount of sharpening.

The harshest test (backlit tree at f1.4) shows the focus related fringing (100% crop from centre of image). Notice the purple/green fringing of branches in front and behind the branches in focus:

tree-crop.jpg


100% crop: Notice the purple colouration on the birds head between the metal plates. This is colouration caused by the focus point being in front of this.

f1-4-crop.jpg


By f4 it's gone:

f4-crop.jpg


I do love the bokeh though:

f1-4.jpg


Do these results seem OK ?
 
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Can't see the tree pic, but the bird head ones do look soft - I'd expect a lot more sharpness at f4 compared to f1.4 but there doesn't seem that much difference tbh.

Edit - having looked at the EXIF perhaps it's due to camera movement - shutter speed is only 1/60. I'd want at the very least 1/focal length before trying to judge sharpness.
 
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To be honest the shots above are aimed at showing CA rather than sharpness.

I did a test with flash and at F4 it is sharper than my 70-200F4 L (at 85mm). Equally at f2.8 it is sharper than my 24-70L so I have no reason to expect it would not also be performing OK at F1.4.
 
it's quite hard to tell from the centre crop only, but certainly, wide open, my lens also does suffer from similar CA.

it very much depends on the lighting conditions and the subject - on your bird ornament it's hardly noticeable whilst on the trees (and it has to be said, back lit, high contrast is a pretty tough test for any lens) more so.

seems fine to me.

enjoy your new lens.
 
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Can you show some wide open tests with flash, mate?
 
CA with fast lenses us always going to be a problem and even more so when you try to show it with harsh conditions. take a head shot with the flash and see if therefor any CA on the highlights in the eyes
 
Here are some more shots using centre focus point on a 5D2 (shot in raw and exported with a slight sharpen, I did not focus and recompose, I just cropped the full size images slightly before resize/export):

F1.4

bethan-1.jpg


100% crop:

bethan-crop-1.jpg


F4

bethan-2.jpg


100% crop:

bethan-crop-2.jpg
 
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Thanks for those, Ben. I'd say it's okay wide open, but not brilliant. Although saying that I'm not sure how sharp I'd expect it to be, tbh.

The biggest problem you have is putting it on a Canon. ;)
 
Ha ha v funny. Tell you what give me the AF from a D700 and the sensor from a 5D2 and I'll give you a kidney.

The 5D3 just needs better AF (kids move fast) and it will be all but perfect for me.
 
Ben, I agree pretty much. If the 5DII had decent AF I'd never have switched.
 
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