Sigma 24-105mm F4 DG OS HSM Art or Cannon EF 24-105 f/4L IS USM

[I @ M]

The history of the ribbon breakage in the EF24 to 105 is a consideration.

As was the mirror box assembly of the EOS 5D.

As are many considerations with any brand.

The issue I mentioned is with the VR functionality of the Tamron 70 to 300: the lens's VR non-conformity with the expectation of how the VR and the Back Button Auto Focus should work.

As I understand the issue: specifically the expected functionality with a Canon EF Lens having Image Stabilization active and with the camera set to BBAF, the that the IS on the lens will be activated by either BBAF and/or Half-depress Shutter Release: however this is not so with the Tamron VR Lens. It appear that the VR is ONLY activated by BBAF - hence a specific advantages (or uses) of BBAF are void. For one example: to lock focus (by releasing BBAF) but allow VR/IS to remain active via the Half-depress Shutter Release is voided.

I came upon this issue by way of my responding to a specific question about BBAF and IS, (but I not knowing that the lens was not a Canon Lens and that we were actually discussing VR). I was most insistent as to how BBAF and IS would work; but it was only after a couple of days that it was revealed to me that the lens was not a Canon Lens but a Tamron Lens.

Subsequently I have sourced reports that this is so with other copies of the same lens and also some other Tamron Lenses.

Must have been a while ago because I bought that lens for a young lady with a 550D or 650D ( can't remember which ) about 16 or 17 months ago and the VR/IS/VC worked perfectly either on the shutter or back button. The lens is still going strong in far away Germany to this day and certainly represented a large saving with, from what I can see, no lack of quality when comparing the Canon equivalent.

but the OP (on another thread) indicated that he wanted the best and also indicated that there has been quite a lot of money spent and will be more money spent on quality glass for specific uses, whereby he wants to “buy once” and once only.
These facts lead me to believe that the OP might benefit from the disclosure of these minutia and nuances, which could possibly be considerations in his buying choice.

In this case he is probably better off buying the best which from all accounts I have seen taking into consideration the known fault with the Canon lens would be the Sigma ----

Seriously, "off brand" bashing based on hearsay is so 1990's.

[William W]

. . . Seriously, "off brand" bashing based on hearsay is so 1990's.. . .

The issue with the Tamron Lens was reported a few weeks ago.

The views I gave were my opinion and reasons for them. One doesn't expect everyone to agree and to do as one does - but a forum is a place where opinions are given for consideration.

***

To the particular comment that you make above - the example of the Tamron Lens, with much detail so that the OP and others might consider the relevance to their own buying considerations, was based on what I consider valid reports and as such are no more "hearsay" that your reporting of the lady using her lens.

And in these regards the readers make up their own minds as to what is relevant and what is not.

WW

[I @ M]

To the particular comment that you make above - the example of the Tamron Lens, with much detail so that the OP and others might consider the relevance to their own buying considerations, was based on what I consider valid reports and as such are no more "hearsay" that your reporting of the lady using her lens.

I define hearsay as when people repeat that which they have read or been told but have not actually experienced themselves. Maybe I didn't make it clear in my initial post but my observation of the Tamron lens was from my own hands and eyes when operating that lens on the camera and not from repeating what I had heard from "valid reports".