Lenses not supported on Scarlet - Sigma 20mm f/1.8

[Eugene Lehnert]

I have a Sigma 20mm f/1.8 EX DG RF lens that I have placed on my Scarlet camera but I am not getting access to the iris or auto focus options. Has anyone had trouble with this lens?

I also have a kit lens for my Rebel T2i that is 18mm-55mm. I do not have iris control for this lens either but it's not on the list of lenses even though I read that lenses on the list would get rudimentary support.

Is there an option in the camera that I need to check?

 

[Mike Pepin]

I'm having problems with iris control on my Canon 50mm macro. I would love to know what lenses are not supported also.

 

[Les C.]

Unless it's on the 'DSMC CANON MOUNT ELECTRONICAL LY SUPPORTED LENSES' page in the manual, it's not 'supported'.

Of course, what you're probably more interested in is whether it will work or not.

That seems to change with the firmware upgrades. The more recent upgrades break 'support' for some 'unsupported' lenses that previously worked.

I don't quite get this?

If it's a Canon mount' and it's been engineered correctly, it should read the lens data from the chip and work.

Iris should definitely work, and auto-focus should work - but not as fast as if the software had been customized for the lens.

This is what happens if I put a Sigma lens on my Canon DSLR. It just works - and I haven't heard of one not working.

Of course, the Canon lenses are going to focus faster on the Canon DSLR, as they've build this into the software and they 'know' about those lenses.

But, any lens should work if it's truly a 'Canon Mount', albeit not as fast for auto-focus, and I hope that RED takes this position in the future. Scarlet users are definitely going to bring valid lens choices into the picture that are not on the 'official' list.

BTW - RED seems to (with a few exceptions) get the Iris working quite well on non-supported lenses.

Certainly open a support tickets so that they are at least aware of the problem lenses.

Probably with a bit of tuning in RED's code (after all, Canon has had a very long time to perfect their code), RED cameras will work perfectly well with 'unsupported' lenses.

 

[Eugene Lehnert]

I can understand why the 17mm-55mm lens will not work but the SIGMA should be working. It's on their list.

 

[Malk Kamalko]

My Sigma 20mm 1/8 works perfectly on Scarlet & Epic ...

 

[Eugene Lehnert]

Firmware

Firmware

What firmware are you running?

 

[Robert Hart]

I have the 28mm 1:1.8D EX DG lens ( without the letters "RF" ). Mine is the Nikon version. There is no internal servo for control of the iris on this version. Lens focus is selectable between manual focus and internally actuated autofocus.


Assuming your lens and mine remain otherwise very similar, maybe check these two things with the lens DISmounted from the camera body.


1. Cycle the auto-manual selection by sliding the focus ring fully rearwards to manual. The rear of the ring then covers white print "AF" and a white line on the lens barrel, leaving only the letter "M" and a white line visible.

2. Rotate the focus ring to move the mechanical elements of the focus actuation. Something might have become baulky from being in storage. Manual focus movement may release it. These things sometimes happen. Now with a two-fingered grip, slide the focus ring fully forward decisively to the auto position but without being forceful or violent. Rotate the ring again. If the numbers in the focus window now move when you rotate the ring, the manual actuation may not have not declutched and you may have a faulty lens.


If you can find a camera shop which is prepared to let you test your lens on a Canon camera, this might best be done to eliminate the possibility the lens is faulty when correctly operated.


FOOTNOTE.

The auto-iris on my lens is camera-actuated by a mechanical lever on the Nikon version I have. For fully auto actuation by mechanical power from the Nikon camera, the iris ring must be rotated to f22 and a small slide lock on the iris ring clicked rearwards. This uncovers a small white telltale dot. The fully auto movement will occur without the ring being locked but it is then possible for the iris ring to be inadvertently rotated which prevents the iris lever from being moved by the camera over the entire range. The Sigma-for-Canon auto-iris management may be setup entirely differently but if your lens offers a manual iris ring, chances are there is a manual-auto select on the lens somewhere, which might be disabling the servo functions.


FINALLY.

I do not know bee from bull's foot when it comes to the RED camera family, so pay heed to established and more experienced operators on this forum. It may as suggested above be a firmware version issue.

 

[Larry Cheuk]

I have the same Sigma lens and it works fine.

 

[Eugene Lehnert]

There must be some kind of miscommunication error with the lens mount. I now have borrowed a 20mm EF 2.8 AF lens from a friend and it too does not have iris control. I am in communication with RED about this. They want me to reset the camera to factory settings but it does not allow me to go back to anything earlier than 3.0.7.