Blackmagic Forum

Hey there,

I am thinking about using 1.4x or 2x teleconverters from Sigma or Canon or from other brands

https://www.bhphotovideo.com/c/search?q=ef%20teleconverters&filters=fct_brand_name%3Acanon%7Csigma

Sigma 50-100 with BMPCC6K Pro.
Does anyone used these teleconverters on S35 BM cameras? Will they work?
If yes, how was the image, it was sharp or not, is there any video tests or examples to share?
And can you calculate how much will become focal length of sigma 18-35 + sigma 50-100 with 1.4x and 2x at 6k?

Thank you

Pay attention that teleconverter should be used with lenses that are thought for teleconverter, check the compatibility list or you cannot mount together.
Canon is only for ef mount, ef-s not work be cause le see protrude inner the mount.
And not all ef can be connected.
I had canon x2 that work fine for sharpness (I use only with series L lenses) but remember that also multiply the iris, that mean I use it with 70-200 2.8 is II, now I had 140-400 5.6 lenses.
I had 18-35 sigma Ef-a and you cannot mount on multiplier.

You can see here sigma and canon mount, not possible with Ef-s lenses.


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I see what you mean about protrude inner the mount it won't work with sigma 18-35.
But i suppose 50-100 will work with canon's 2x and it will become 100-200 f3.6?

Not many lenses work with TC's the 70-200 zooms will and the TS-E shift lenses but anything that has it's rear element flat with the rear mount won't. Not sure why you need a TC with s35 as this is effectively a 1.5 crop anyway.

John Griffin wrote: Not sure why you need a TC with s35 as this is effectively a 1.5 crop anyway.

I need more zoom when shooting at 6k with my 50-100mm.

Does sigma say their TC will work with the 50-100?

John Griffin wrote:Does sigma say their TC will work with the 50-100?

I have send an email, but they didn't answered yet.
Also I've read in other forum that canon 2x teleconverter works with 50-100, but without autofocus, which I am ok.

bmpcc6k wrote:

John Griffin wrote:Does sigma say their TC will work with the 50-100?

I have send an email, but they didn't answered yet.
Also I've read in other forum that canon 2x teleconverter works with 50-100, but without autofocus, which I am ok.

Uhm I’m quite sketptical
Or you can connect well and all work, or not.
Wait the official answer, to avoid to waste money.
Unfortunately I not know anyone that have 50-100 sigma to test or verify it.
Also be cause if not is correct you risk to scratch rear lens of sigma.


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carlomacchiavello wrote:

bmpcc6k wrote:

John Griffin wrote:Does sigma say their TC will work with the 50-100?

I have send an email, but they didn't answered yet.
Also I've read in other forum that canon 2x teleconverter works with 50-100, but without autofocus, which I am ok.

Uhm I’m quite sketptical
Or you can connect well and all work, or not.
Wait the official answer, to avoid to waste money.
Unfortunately I not know anyone that have 50-100 sigma to test or verify it.
Also be cause if not is correct you risk to scratch rear lens of sigma.


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Sure i won't try it until I get official answer.

Besides that I had some research and find an extender which technically can work with both sigma's
https://bhpho.to/3H291RF

mmm kenko was not sharp just in '90, i not think is a good solution.

carlomacchiavello wrote:mmm kenko was not sharp just in '90, i not think is a good solution.

ok, got it

Or go fully manual, find a nice long lens from the Zeiss C/Y line and get a Mutar.

Personally, I will avoid any teleconverter. If you have a 150mm and you were planning to use a TC and need an extension barrel too, I will just buy a 300mm lens or even a 500mm mirror lens which will rather be about the same cost. With the S35 crop, you should have enough long focal length.

You can cheaply go with something like this:
https://www.amazon.com/Canon-75-300mm-4 ... 43&sr=8-35

If you done mind the 4-5.6 variable aperture at its widest. Anyway with a TC you’re likely to end up with about the same aperture.

In the official email it's says that it will work, but I need to rent it at first then decide to buy it.

Guys who can tell me how much is multiplier when using 6k pro - 6k braw or 4k braw and 4k prores?
I need to calculate how much will become focal length of my 50-100mm.

Kim Janson wrote:The question is why would you want to do that? it is a heavy class and you would be using only the centre part of the image. Maybe you would be better off just cropping the image when needed or getting a 70 to 200 mm lens.

I have both the lens and Canon 1.4x, tested it long time a go on full frame and the advantage is it makes the lens a full frame lens. not 100% sure, but as I remember there was some focusing issues.

Sometimes I need more focal lenght. I don't want to crop honestly.
And I am not interested to invest in a new FF 70-200mm lens for now, that's why teleconverter is optimal solution for me right now.

So you are using Canon 1.4x with Canon's FF 70-200 or with Sigma's 70-200?

Hi, did you end up trying the Sigma 50-100 f1.8 withthe Canon x2 teleconverter?
I want to try the same combo, own both, but concerned I'll break something if I do.
Really hope it will work.

OK everyone, a little late to this chat, but here is what I found (its good news)

I used the Sigma 50-100 f1.8 and the Canon 2x Extender iii on my Canon C200, it works like a dream. Autofocus works 100%, not as smooth as with all canon, but good enough. At f1.8 on the lens the DOF is so shallow that the AF takes a moment to settle, but surprisingly effective.

Super happy with the outcome.

HykCIne wrote:Hey there,

I am thinking about using 1.4x or 2x teleconverters from Sigma or Canon or from other brands

https://www.bhphotovideo.com/c/search?q=ef%20teleconverters&filters=fct_brand_name%3Acanon%7Csigma

Sigma 50-100 with BMPCC6K Pro.
Does anyone used these teleconverters on S35 BM cameras? Will they work?
If yes, how was the image, it was sharp or not, is there any video tests or examples to share?
And can you calculate how much will become focal length of sigma 18-35 + sigma 50-100 with 1.4x and 2x at 6k?

Thank you

It works 100% on my Canon C200, with AF. Super usable combo.