Sigma Video on their lenses adapted to the RF mount

[Tronhard]

Anyone following this site for any length of time will be aware of the controversy among some about the performance of Sigma lenses, and in particular the 150-600 Contemporary, working (or not) on the R-series bodies.

This has led to calls for Canon to modify their cameras to accommodate the perceived issues with third-party lenses.  As I have had to respond ad nauseam, no OEM camera maker takes any responsibility for 3rd party equipment attached to their bodies - be it Nikon, Canon or any other, whether it be lenses or flashes.

Well, about six months ago, SIGMA released the following video on using their current EF lenses on the R-series bodies. 

What is significant to me is their strong statement that their lenses perform well on the R-series  bodies - so obviously they see no issue to be fixed.  While I have faith that Sigma and Tamron are working on RF native lenses and will hopefully be able to release them in the foreseeable future, this video lends weight to the argument that it is more likely that it is how the cameras are set up, or operated. 

I observe that the bodies I have seen most people claim flawless operation are the full-frame bodies, for which the Sigma lenses were designed. Most issues seemed to happen with the APS-C R7 tracking system, which has also had issues reported with Canon EF legacy glass and even RF glass, so I wonder if the focusing system of that unit is worthy of consideration as a factor?  I don't have one so I am only speculating.

Another variable might be the firmware version of the Sigma lenses and their customization settings. There may also be issues with technique - using a tripod vs hand-held.  Finally (tongue in cheek) I observe that that presenter from Sigma is shooting gannets, where I have taken a lot of my shots of the same moving birds without any issue, so maybe someone will suggest that it's all about the subject! 🙂

[Tronhard]

To me the setup of the lenses is critical.  I found no issues on my own lenses when using the R5, R6 and R6II units - apart from the rare occasion when it could not find ANY focus, but that was essentially because I was shooting through screening objects, like trees - so I don't think that is a fair criticism for me to make.

The most issues seem to be with the R7, which has a very high pixel density at 32MP in an APS-C sensor, so that is equivalent to the pixel density of an 81MP FF sensor, which is pretty massive.  The R7 used a dumbed-down version of the R3 sensor, which is 23MP FF, so there could well be issues to do with that.  Finally, as we seem to agree, how the focus is configured and used is going to have a major impact on the success.  The  videos I saw seemed to indicate that the Sigma 150-600c was on a tripod with OIS active.  I shoot hand-held with OIS and have no issues, so I wonder if that is significant.

[Tronhard]

I got a response from writing to Duade Paton but a very vague one.

Settings:
I shoot using back button focus and back button exposure, with the shutter button purely there to trigger the shutter which is set at high speed continuous.   I use single-point focus located in the centre of the viewfinder, and exposure with servo but not continuous focus, and eye tracking for animals, humans and other -each assigned to a C1 - C3 mode setting.   I pretty well always shoot hand-held in available light.  I leave the focus tracking on the default with no tweaking.

Technique:
I point at the eye of the subject, and press BBF to lock on, if the focus prefers some other point, I use the centre button on the rear wheel to force the focus to centre.  From there it tracks,  Similarly, I point to whatever object I consider mid-tonal, and lock exposure on that.  It is how I have shot for a long, long time, so I can do it very quickly without having to think - it will take a while for someone starting to make it subconscious.

I shoot mechanical shutter always and therein may lie another issue.  The electronic shutters are fast - the R7 can get to 30FPS, while the R6II can get to 40.  Personally, I have no need for such speed, and I don't want to wade through thousands of images later. Given that the R7 in particular seems to show issues with pulsing, I wonder if the shutter rate, combined with massive pixel count and what I consider is a deeply flawed digital bus - pushing 40FPS through a very dense sensor that is BSI/stacked, to an inadequate buffer and slow cards is not a good balance.  So, since the sensor and data transfer are so integral in these R-series bodies, I wonder if there are delay factors also impacting the focusing process.

Conclusion:
I think the issue is a very complex one, involving the technology, configuration and operation of a much more complex array of factors impacting focus and throughput.  Thus, I think much more, carefully planned testing needs to be done if one is going to pinpoint where an issue lies.

I would also say that this has been, to a degree taken on as a cause celebre by those who are trying to pressure Canon to allow third party RF lenses - it makes grist to their mills to point to otherwise respected lenses not apparently functioning on the R-series bodies, and that Canon is the evil empire in denying open access to their R mount technology.

[ctitanic]

I don't understand what do you mean by "exposure with servo but not continuous focus".

[Tronhard]

This feature may not  be available on your camera model - it's on the R5 and R6 MkI but not on the R6II.  On the cameras that do, on the first focus screen there is an option for Servo mode and another for continuous focus.  It was very confusing to everyone, so Canon removed it.  Servo would allow focus to follow moving objects if the button for focus was held down, but not if it was not.  Continuous would focus all the time whether the button was held or not - which is a great way to drain the battery!

[ctitanic]

Got it, Sony a7r III had something like that. I hate it.

[Waddizzle]

Trevor,

I am surprised and not surprised to hear the R7 seems to have issues with the Sigma 150-600mm.  As I noted earlier, my 7D2 could not perform as well with the lens as my full frame bodies, or even the APS-H 1D4.  The 7D2 was fine for One Shot AF, but not as stellar when it came to tracking in AI Servo mode.  Turing off the Sigma OS seemed to make the biggest improvement, which is true for both FF and APS-C bodies.

I am not saying APS-C bodies and the Sigma 150-600mm don’t play well together.  They just did play as well together as with my full frame bodies, 6D, 6D2, and now the R6 Mark II.  The latter is a great body with all my Canon L glass, especially the EF 135mm f/2 USM.