Sigma 35mm f/1.4 not working with metabones speedbooster xl ef-m4/3

[A Furry Peanut]

The aperture seems to only go as far as 1.4, but with the speedbooster xl, this should be larger by 1.3 stops. I checked the metabones website and the lens was not listed in their compatibility list, but they did mention that their speedbooster should work with most ef lenses. Does anyone know if the speedbooster just doesn't work with the sigma 35 or if there is something wrong with my speedbooster?

[jonpais]

3 hours ago, A Furry Peanut said:

The aperture seems to only go as far as 1.4, but with the speedbooster xl, this should be larger by 1.3 stops. I checked the metabones website and the lens was not listed in their compatibility list, but they did mention that their speedbooster should work with most ef lenses. Does anyone know if the speedbooster just doesn't work with the sigma 35 or if there is something wrong with my speedbooster?

It may be that the GH5 is unable to register .95 or whatever in the EVF (same as other G and GH cameras I've owned) but for sure the lens is faster with the XL, and your metering should work correctly as well. Hope that helps.

[A Furry Peanut]

5 hours ago, jonpais said:

It may be that the GH5 is unable to register .95 or whatever in the EVF (same as other G and GH cameras I've owned) but for sure the lens is faster with the XL, and your metering should work correctly as well. Hope that helps.

I am not too sure by what you mean by "unable to register". Are you saying it is going over 1.4 but just displaying it as 1.4? Because there is a distinct noise and shift in light when I change the aperture, this suddenly stops when I hit 1.4 so I am sure my camera is unable to go any higher. Also the lowest aperture my camera displays is still 16 so I don't think it's doing anything funny with the numbers either. 

[jonpais]

It is unable to display .95 on the EVF. I'm quite certain there is nothing wrong with either your camera or lens. 

[A Furry Peanut]

8 hours ago, jonpais said:

It is unable to display .95 on the EVF. I'm quite certain there is nothing wrong with either your camera or lens. 

Is there a way of knowing when it's at f/1.4 and when it's at 0.95 but just displaying 1.4?

[BTM_Pix]

Metabones have recently(-ish) upgraded the firmware.

Says it has 'detailed EXIF' so that suggests if you take a still it should show you in the EXIF what the aperture was.

http://www.metabones.com/article/of/Firmware_Adds_Cinema_EOS_Lens_and_GH5

[A Furry Peanut]

2 hours ago, BTM_Pix said:

Metabones have recently(-ish) upgraded the firmware.

Says it has 'detailed EXIF' so that suggests if you take a still it should show you in the EXIF what the aperture was.

http://www.metabones.com/article/of/Firmware_Adds_Cinema_EOS_Lens_and_GH5

So I took the still and checked and it does indeed say 1.4, an interesting thing I found though was there was a "Focal length" listed as 22mm and a "35mm focal length" listed at 44mm, not too sure why there were too but my focal length is 44.8mm (35mm x 1.28 crop)

[Jonathan Clifford Bergqvist]

Look into the lens when it is mounted on the speedbooster and GH5, open and close the Aperture. If you see that it is not stopped down a bit when you have it at the lowest value, then you get the extra light boost but the metabones fails to covert 1,4 to whatever it may be on a speed booster XL. 

My Canon lenses register "correctly" with the converted F-stop, my sigma does not. 

The lens acts as a 22 mm on the speedbooster so FF equivalent is 44

[jonpais]

If you place thes camera upside down on the sofa, then cover the LCD with the old sock, then place an sheet of white paper between the LCD screen and the camera body while lifting then camera up by the hot shoe, you should be able to notice as gentle tugging inn the left pant leg of your trousers.

[Jonathan Clifford Bergqvist]

17 minutes ago, jonpais said:

If you place thes camera upside down on the sofa, then cover the LCD with the old sock, then place an sheet of white paper between the LCD screen and the camera body while lifting then camera up by the hot shoe, you should be able to notice as gentle tugging inn the left pant leg of your trousers.

I think my way of doing it is easier, however you will end up with basically the same result. 

[A Furry Peanut]

7 hours ago, Jonathan Clifford Bergqvist said:

Look into the lens when it is mounted on the speedbooster and GH5, open and close the Aperture. If you see that it is not stopped down a bit when you have it at the lowest value, then you get the extra light boost but the metabones fails to covert 1,4 to whatever it may be on a speed booster XL. 

My Canon lenses register "correctly" with the converted F-stop, my sigma does not. 

The lens acts as a 22 mm on the speedbooster so FF equivalent is 44

So I looked into the lens and played with the Aperture, when I stop down to 1.4, the Aperture is completely wide open. 

I think my biggest concern is that I can hear a sound and see each individual light shift when stopping down from 16 to 1.4, but if I try to stop down one more time at 1.4, there is no visible light change or sound, if I am entering f/0.95 but the camera is not registering it, shouldn't there be another sound and visible light change? 

[Damien Théraulaz]

@A Furry PeanutHi! Just read your question about speedbooster and aperture. I own the same lens (sigma 35 ART), and I love it. I tested yesterday at the shop a speedbooster XL with my GH5. I went to the same question... first I saw on youtube a guy testing a canon 50 1.4 lens. He could go to 1.2 aperture, not below. 

On my test with the sigma I only could go to 1.4. it's disturbing me.

I have two choices... either buying a voigtlander 25mm or the speedbooster (I own other EF lenses). So here is my question: can you tell me if you think you are reaching 0.95 aperture or not. Because for the price of the speedbooster, it's not good for me if I can't use the full aperture. 

Sorry for my bad english.

and thank you for answering me.

Damien