[IMPOSSIBLE] Can magic light make Canon EOS-6D autofocus on F/8？

[archerhu]

I think 6D is a best equipment if it can make autofocus on F/8. But I think Canon never make 6D can do that, otherwise that's less people will buy 5D MarkIII. So I want to know whether Magic Light can make some research to make 6D's F/8 autofocus enable?
Thanks!

[Marsu42]

I think 6D is a best equipment if it can make autofocus on F/8. But I think Canon never make 6D can do that, otherwise that's less people will buy 5D MarkIII. So I want to know whether Magic Light can make some research to make 6D's F/8 autofocus enable?

+1 for this research request ... I never thought of that, and you can tape the pins of the Canon tc (or use the Kenko) but real "hacking" by memory/fw patching should force the Canon fw to af @f8 sind afaik it always works, it's just a lot slower and less precise than wider max. apertures.

[archerhu]

Thanks for your +1.
I think althought F/8 autofocus is slower than max. apertures, but it should faster and accurate than MF
I like F/4 lens, because they are more lighter, so I can bring them to all place include peak. According to my experience, it's difficult to bring some F/2.8 lens to walk long time when elevation over 3500m. My F/4 lens(for example 70-200/4 IS) plus 2X will lose autofocus, that make I will not sure the picture what I take is what I want, most times MF does precise enough.
So, I really really want Magic Light can enable my 6D autofocus on F/8.
Thank you very much!

[nanomad]

Unfortunately I don't have an F/8 lens to test (the closest is the 70-200 F4 but I have no x2 extender). Anyhow, I don't think that's possible since the AF chip is outside the ARM package.

Do you get any errors when you put your F/4 + 2x lens in AF mode?

[archerhu]

When I use 70-200/4+2X extender, the max aperture will become F/8, and the camera will not support autofocus.
I think maybe it's possible because it's disable F/8 autofocus on 5D MarkIII in previous firmware too, but at the lastest release support F/8 lens use center point to autofocus. So I guess focus chip is support many function, but Canon disable some according camera's market positioning.

[1%]

So this is for extenders only? Don't have one to test

[Marsu42]

So this is for extenders only? Don't have one to test

There are no f8 lenses (well, that I know of) :-) ... it's only for f5.6 + 1.4x extender or f4 + 2x extender. However, for the birding crowd and cheaper telephotography below $10000 this is a very important feature.

[archerhu]

So this is for extenders only? Don't have one to test

It's not only for extender, you can use to reflex lens(they are F/8 normally)
And It's very useful for photographer limit by buget(F4 lens +2X is cheaper than F/2.8 lens+2X) and weight(400 lens is heavier that 70-200/4 + 2X), is that right?

[archerhu]

Unfortunately I don't have an F/8 lens to test (the closest is the 70-200 F4 but I have no x2 extender). Anyhow, I don't think that's possible since the AF chip is outside the ARM package.

Do you get any errors when you put your F/4 + 2x lens in AF mode?

nanomad, I think maybe that's some clue in the 5DMarkIII firmware, they don't support F/8 autofocus before v1.2.1. Is there some way to decode and compare the 1.2.1 and 1.2.0 firmware, tha and this function to 6D's Magic Light function?

[Marsu42]

nanomad, I think maybe that's some clue in the 5DMarkIII firmware, they don't support F/8 autofocus before v1.2.1. Is there some way to decode and compare the 1.2.1 and 1.2.0 firmware, tha and this function to 6D's Magic Light function?

I'm pretty sure on 5d3 they did more than just "enable" it since the 5d3/1dx af system is much more complicated than other cameras, it has to be adapted for the lens groups. But on 6d, it is likely it's really nothing more than patching out the Canon fw disabling the af system @f8+

[archerhu]

I'm pretty sure on 5d3 they did more than just "enable" it since the 5d3/1dx af system is much more complicated than other cameras, it has to be adapted for the lens groups. But on 6d, it is likely it's really nothing more than patching out the Canon fw disabling the af system @f8+

Hi, Marsu42
I think I have different opinion, I check the data sheet of 5D3 and 6D. 5D3's focus system can work at -2EV to 18EV, 6D's focus system can work at -3EV! That means 6D's autofocus system maybe powferful than 5D3(maybe just autofocus function but focus speed, because focus speed maybe need othe chip support). At past, camera manufcturer said they can't support F/8 autofocus because the light accross lens is not enough, but now 5D3's -2EV focus system can do that, why 6D's -3EV focus system can't?
So I guess 6D can do that but Canon will not enable it for protect 5D3's market.

[aptass]

You can tape over/cover some of the contacts on the extender to allow AF but it is disable because it's very slow and Canon wants to provide usability.
It's not guaranteed to work. It is available on the 5D Mark III and 1DX because of a faster AF from start. 

http://photo.net/canon-eos-digital-camera-forum/00H102

[archerhu]

You can tape over/cover some of the contacts on the extender to allow AF but it is disable because it's very slow and Canon wants to provide usability.
It's not guaranteed to work. It is available on the 5D Mark III and 1DX because of a faster AF from start. 

http://photo.net/canon-eos-digital-camera-forum/00H102

According the link you posted, I think that might be use software to let camera miss the extender information, then focus system can work normally.

[Marsu42]

I think I have different opinion, I check the data sheet of 5D3 and 6D. 5D3's focus system can work at -2EV to 18EV, 6D's focus system can work at -3EV! That means 6D's autofocus system maybe powferful than 5D3

You've been fooled by Canon's marketing - the 6d's af system has only -3lv at the center point (other points are +0.5lv) and the outer points aren't cross points, even the center one isn't cross @f2.8. The 5d3's af system isn't only light years ahead of the 5d2/6d as it's faster and more precise, but it's also more complicated because it gets modified by the lens used (read the manual under "lens groups") - that's why I think f8 for 5d3 was more complicated than it would be for 6d.

[aptass]

According the link you posted, I think that might be use software to let camera miss the extender information, then focus system can work normally.

No it will not work like normal. It will be very slow. That's the reason it's disabled. I don't think ML will make it faster. It's in the design of the AF on the 6D.

[archerhu]

You've been fooled by Canon's marketing - the 6d's af system has only -3lv at the center point (other points are +0.5lv) and the outer points aren't cross points, even the center one isn't cross @f2.8. The 5d3's af system isn't only light years ahead of the 5d2/6d as it's faster and more precise, but it's also more complicated because it gets modified by the lens used (read the manual under "lens groups") - that's why I think f8 for 5d3 was more complicated than it would be for 6d.

I think it's bad news for 6D's users, but I still hope your team can do some research for it.
Thank you!

[archerhu]

No it will not work like normal. It will be very slow. That's the reason it's disabled. I don't think ML will make it faster. It's in the design of the AF on the 6D.

As the previous I post, I think enable the F/8 autofocus is useful for make focus more  accurater than MF(because DSLR not like the SLR, it's focusing screen is not suitable for MF), and I need the center point focus only, I don't need fast focus @F8, because it's not reality.

[RenatoPhoto]

Try this little trick I used on 7D and 5D3. 5D3 will now focus up to f11

I use the left or right focus points which are more sensitive than the center.  Enable all the focusing points and then just use all of the available on the left or right.
In my 5D3 I can autofoucs with a 300mm f4 + 1.5x canon + 2x kenko = 840 mm at f/11.