Canon EF 50mm f/1.2L USM converted to SA mount!!!!

Started Aug 13, 2007 | Discussions
Arky Regular Member • Posts: 433
Re: Manual focus?

Daiver wrote:

I haven't seen that lens in person but I assumed that rear lens
element would be bigger than it actually is, it actually looks to be
about the same size as the canon 50mm f/1.4.

The rear lens element diameter is 38 mm.

The rear lens element diameter is 37.4 mm on the 50mm f/1.4.

I have converted a few canon lenses to SA mount and those with
electronic manual focus lose the ability to manual focus with the SD9
and SD10, although auto-focus works well.
Does the electronic manual focus on that lens work with the SD14?

I dont know. Some people say me the same. But Canon 50 1.2 have not
electronic manual focus. When i move focus ring i lens inside moving.
It work without camera. It is real manual focusing lens. Electronic
manual focus have Canon 85 1.2 lens.

Thank you for that info on the 50mm f/1.2L and you are correct about the 85mm f/1.2L being an electronic manual focus lens, along with most of the "big whites". If the focus elements move when it isn't mounted on the camera it can't be an electronic manual focus lens. It's not the first time the specs listed on the B&H website are incorrect.

http://www.bhphotovideo.com/c/product/457680-USA/Canon_1257B002_Normal_EF_50mm_f_1_2L.html

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OP Daiver Regular Member • Posts: 130
Re: Manual focus?

DaSigmaGuy wrote:

The rear element of my Canon FL 55mm f1.2 is 40mm, 2mm bigger than
rear element of the Canon EF 50mm f1.2 and it still fits inside an SA
mounting plate with at least 2mm to spare all round, as long as you
remove the three internal bezal ring mounting lugs of course.

Sorry, little my mistake. I am went to home and measure with my callipers.
The rear element of Canon 50 1.2 is around 37mm. Not 38.

The maximum diameter inside sigma mount is 43 mm. Inside canon 48.6 mm. Canon is bigger, and it is easy to do modifications.

Thomas Ko Contributing Member • Posts: 685
Dum question

Um... sorry that i m actually don't quite understand the re-mount work, But one simple thing i want to ask:

Is the Canon 50mm/f1.2 lens "re-mount" to SD14 still have AF or it is just plainly MF?

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OP Daiver Regular Member • Posts: 130
EXIF also saved right
OP Daiver Regular Member • Posts: 130
Re: Dum question

Thomas Ko wrote:

Is the Canon 50mm/f1.2 lens "re-mount" to SD14 still have AF or it is
just plainly MF?

Canon 50 1.2 lens was remount to SD 14.
Still have AF, MF, aperture, infinity, exif, ALL WORK as in Canon.

Bacause Sigma and Canon have the same electronics, and little difference in lens to body programm protocol.

Gunter B Contributing Member • Posts: 951
Re: Manual focus?

Hi Arky,
haven´t you converted a 135/2L?
Is there anything special about that one to convert, I should know?

Thanks for help.

Arky Regular Member • Posts: 433
Re: Manual focus?

Hi Günter,

I have converted the 135 f/2, its a fairly easy conversion since it's rear optics are recessed into the lens instead of protruding into the mount like most lenses. 3 of the 4 screwholes will line up with the SA mount but the top screwhole will need to be drilled and counter-sunk just like Daiver has done with his 50mm. It will focus to infinity with the standard SA flange but the range scale on the lens will show the lens to be focused a little past infinity. If you want the range scale to be accurate you will need to shave the mount down a little thinner, especially around the outer edge.

The 135 is a "TC aware" lens so it has a 10 circuit electrical contact block, you will probably be replacing it with a standard (non-TC aware) 7 circuit sigma contact block. The extra 3 circuts in the 10 contact block are there solely to detect the presence of a TC. If you just leave these extra 3 wires unconnected (tape the ends to avoid shorting) the lens will not "see" a TC and the AF will operate at full speed, I have heard the SD14 AF works fine with this lens at full speed. The SD9 and SD10 however, cannot control this lens when it's AF is operating at full speed, for those cameras you will need to slow down the AF motor by fooling the lens into thinking it is attached to a 1.4x TC. To make the lens think it is attached to a 1.4x TC simply solder the extra 3 TC detection circuit wires together (again tape the end to avoid shorting) and tuck them away inside the lens.
Hope this helps, don't hesitate to ask if you have any more questions.
-Jerry

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Gunter B Contributing Member • Posts: 951
Re: Manual focus?

Thanks Jerry.

I have successfully converted a Canon 50/1.4, which I am very happy with.

Now that I know it works, I will probably get an 135/2. It is my dream lens, being tacksharp at f2.

Arky wrote:

Hi Günter,
I have converted the 135 f/2, its a fairly easy conversion since it's
rear optics are recessed into the lens instead of protruding into the
mount like most lenses. 3 of the 4 screwholes will line up with the
SA mount but the top screwhole will need to be drilled and
counter-sunk just like Daiver has done with his 50mm. It will focus
to infinity with the standard SA flange but the range scale on the
lens will show the lens to be focused a little past infinity. If you
want the range scale to be accurate you will need to shave the mount
down a little thinner, especially around the outer edge.
The 135 is a "TC aware" lens so it has a 10 circuit electrical
contact block, you will probably be replacing it with a standard
(non-TC aware) 7 circuit sigma contact block. The extra 3 circuts in
the 10 contact block are there solely to detect the presence of a TC.
If you just leave these extra 3 wires unconnected (tape the ends to
avoid shorting) the lens will not "see" a TC and the AF will operate
at full speed, I have heard the SD14 AF works fine with this lens at
full speed. The SD9 and SD10 however, cannot control this lens when
it's AF is operating at full speed, for those cameras you will need
to slow down the AF motor by fooling the lens into thinking it is
attached to a 1.4x TC. To make the lens think it is attached to a
1.4x TC simply solder the extra 3 TC detection circuit wires together
(again tape the end to avoid shorting) and tuck them away inside the
lens.
Hope this helps, don't hesitate to ask if you have any more questions.
-Jerry

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