Sigma 50 mm f/1.4 Art

[neuroanatomist]

This is a departure from the norm for Bryan's lens tests:

"My evaluation lens was a short term loan from Sigma, as they offered the production-grade lens before it was commercially available."

Any time a manufacturer supplies a product to a well-known reviewer, a big unanswered question is whether the provided copy is truly representative of units purchased retail. Clearly, it would be in Sigma's best interest to pre-test a batch of them and pick the best copy they can find for review (in fact, they are supposed to generate measured MTFs for every lens they produce, so they have the data already).


I've always felt that one of the strengths of Bryan's reviews (in addition to their thoroughness and readability) is that he purchases review copies through standard retail channels (B&H may put him near the top of the preorder queue, but that's fine), and therefore avoids the potential confound of bias introduced by testing a 'hand-picked' lens from the manufacturer. I hope Bryan chooses to test one or more copies of the lens purchased retail to see if the results align with the copy provided by Sigma.

[Kayaker72]

I hope Bryan chooses to test one or more copies of the lens purchased retail to see if the results align with the copy provided by Sigma.

+1

I think that is the solution. I understand TDP having to get their review up in order to be competitive with other sites. SLRgear had a significant number of hits because they were the first review. But I absolutely agree. I trust Bryan's reviews more than most. I simply think he tries harder. If he is seeing copy variation, he tests multiple copies. The only other group I've seen do this is lensrentals, for obvious reasons. But it would be great to see the review results for the 50A verified with a true production copy.

That said, I think the picture is getting clearer with the "Art" series. Excellent optics, especially sharpness. Not the necessarily the old AF issues that Sigma had, but perhaps AF inconsistency issues. I suspect the level of light may affect the Sigma Art lenses more than it affects Canon lens. I'll try to test that tomorrow morning with the 35A.

Of course, the end result is important, can the "Art" lenses deliver the images you want. This may be why I am sensitive to the AF, but I "missed" several shots due to the AF issue in lower light. I've only tried the 35A in two events, so it deserves more of a chance, but one particular sequence with my niece and sister-in-law could have been great. But the 35A missed AF on consecutive shots. Usually with an EF lens, at least one shot would be sharp.

[neuroanatomist]

...but one particular sequence with my niece and sister-in-law could have been great. But the 35A missed AF on consecutive shots. Usually with an EF lens, at least one shot would be sharp.

That's what would worry me. In a controlled test (the butterfly/book series), where neither camera nor subject were moving, the 50A's AF clearly missed on 4 of the 10 shots shown, which Bryan states are representative of the more extensive series. I have a bit of trouble reconciling a 40% miss rate with 'occasional' AF inconsistency.

[Bryan Carnathan]

Thanks for the great discussion, everyone!

My review copy of the 50 Art was indeed manufacturer-provided (the only way to get one right now) and that of course leaves open the question of cherry picking. I will be very surprised if the copy I evaluated is noticeably better than the retail-purchased copies coming soon. If it is, Sigma's practice of selecting ultra-high performing models for evaluation purposes will quickly be called out. I'll try to get a retail copy of this lens in for testing. That way, we will all know. Sean will also be using this lens in more depth soon. We will advise on any inconsistencies we discover.

As for a 40% miss rate being high, I completely agree. My experience was not always that case. For example, I was probably getting a hit rate in high 80% range shooting runners at the track meet and probably in the mid-90% range during the long portrait session. Results with other subjects were mixed. Sometimes great. Sometimes not.

Let me know if you have any more questions!