The "magical" Canon Nifty-Fifty 50mm f/1.8 II vs Sigma 50mm f/1.4 Art

Started Nov 1, 2015 | Discussions thread
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markodarko
markodarko Regular Member • Posts: 198
The "magical" Canon Nifty-Fifty 50mm f/1.8 II vs Sigma 50mm f/1.4 Art
8

I'm posting this because, quite frankly, I'm tired of every other photographer and their dog harping on about how amazing the Canon nifty-fifty is, or how it can out-resolve lenses costing 10x the price, etc. You've all heard the story.

For its day, perhaps (in the centre) it was kinda nifty, and possibly for the amount of money you have to pay for it (although to be honest, I personally wouldn't use it unless they were free with my cereal and I had no alternative), but none the less these stories of legend really need to dispel. The sooner they do, the sooner people will stop buying them and the sooner Canon will have to bring out a mk III (or update their other 50mm lenses).

My hope with this test is that anyone considering buying the nifty-fifty will think again (especially when they see the edges).

Here's the test scene:

D'ya like my big yellow ruler thing?

Items were placed directly behind the spirit level and then a piece of string which was looped around a hotshoe mount was used to make sure the camera was both centred and perpendicular to the spirit level so as to prevent focus errors at the edges. The camera was then set to be perpendicular to the scene. The focus point was the oval blob of the quaver on the book.

Images were focused manually using Live View (no mean feat with the nifty-fifty I can tell you!) and a 2 second timer was used. The subject was around 2.2 metres away from the camera. No image corrections (lens profiles etc) were applied. The images are as-is aside from exposure matching in LR4.

Test 1 at lowest common aperture of f/1.8:

Centre @ f/1.8 (Sigma is always left, Canon is always right)

Mid-left @ f/18

Edge-left @ f/1.8. A little soft there by the Sigma, but still useable, unlike the Canon.

Mid-right @ f/1.8

Edge-right @ f/1.8

Test 2 at f/2.2 and beyond:

OK, so let's now close the aperture to f/2.2 so that the nifty-fity is no longer wide-open, and let's leave the Sigma at f/2.2 for a while so that we can see at what aperture the nifty-fifty needs to be closed to until the edge sharpness is as sharp as the Sigma at f/2.2... (I'm not even going to be as cruel as do a corner test, just the edge as that's a useful portion for framing)

Centre @ f/2.2

Sigma @ f/2.2, Canon @ f/2.2

Sigma @ f/2.2, Canon @ f/2.8

Sigma @ f/2.2, Canon @ f/3.2. Still not as sharp so let's try f/4...

Sigma @ f/2.2, Canon @ f/4. Neeearly as sharp as the Sigma, but not quite...

Sigma @ f/2.2, Canon @ f/5.6. There we go.

At f/5.6 the Canon is now marginally sharper than the Sigma, but let's not forget that the Sigma is nearly 3 whole stops wider than the Canon. Let's see what the centre now looks like...

Centre. Sigma @ f/2.2, Canon @ f/5.6

Even with the Sigma nearly three whole stops wider than the Canon, the centre is still sharper even though the Canon is at f/5.6(!), albeit only by a small margin as they're both very sharp in the centre now... Well, until you set the Sigma to f/2.8 of course, whereby you can see that there's still more sharpness and contrast to be had...

Centre. Sigma @ f/2.8, Canon @ f/5.6

No point showing you the Sigma comparison at f/4 or smaller. I think you get the picture. So finally, to focus (no pun intended) on the Sigma for a second. Here's a screenshot to illustrate just how astonishing this lens's centre sharpness is wide open vs stopped down...

Centre. Sigma @ f/1.4 (left) and f/4 (right)

So there we are. What can we take from all of this aside from the fact that if you want to place anything in the edge of your frame with the nifty-fifty and you want it to be sharp, you have to close the aperture to f/5.6? Hmm. How about...

  • Can the nifty-fifty out resolve lenses costing 10x its price? No.
  • Is the nifty-fifty useful wide open? No. Even the centre is soft.
  • Should you buy one? No.
  • Is there a reason it's cheap? Yes.
  • Is it a bargain? No.
  • Should people stop telling people how great the Canon is? Yes!

Obviously, these are my opinions, no matter how strong they are, and no doubt some will reply saying that "it's not a fair test because the lenses don't cost the same!" etc., well duh, that's precisely the point of the test - to illustrate that the Canon doesn't out-resolve lenses that cost 10x its cost, and moreover, even at the cheap purchase price, unless you are going to use it at f/5.6 or smaller (but then why buy an f/1.8 lens in the first place if that's the case?) it's just not useable - especially at the edges, and as mentioned previously, these tests don't even touch on the corner sharpness (or lack of it for that matter), just the edges where things such as faces tend to go in certain compositions.

The ONLY time I'd consider using the nifty-fifty is for fairly close dead-centre subject matter at an aperture of f/2.8 or so where the background would be so blurred it would, as a byproduct, make the centre seem much sharper than it is - or of course, if you're just going to put the images on the internet at a small size, but if you're seriously in the market for a fast 50mm lens then I would look elsewhere.

Buy cheap, buy twice...

Cheers,

Mark.

Canon EF 50mm F1.8 II Canon EOS 5D Mark III Sigma 50mm F1.4 DG HSM | A
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