Official specs: Canon EOS-1D X Mark II

JeffreyG wrote in post #17908140
At 100mm, yes. But why are you shooting the zoom at the wide end with a 2x tc to get a 200mm f/9 when the lens can shoot 200mm without?

At the long end the zoom is f/11 with the tc.

I guess a simpler way to ask the question is: Regardless of the exposure settings, do variable aperture lenses always AF at the largest aperture (f/4.5 in this case)? From what I'm reading online, they do.

Edit:
For example, Sigma says you can add a 1.4x teleconverter to its 150-600 f/5 to f/6.3 and still get autofocus as long as the camera can AF at f/8.

http://www.sigmaphoto.​com …leconverter-compatibility

JeffreyG wrote in post #17907930
The 1Dx and 5D3 were both released in March, four years ago and so are (were) both due for an update. I think this time around Canon is going to wait until September or so to release the 5D4 so as to get as many 1Dx II orders through first. Canon has learned that they cannot cripple downmarket bodies so much any more if they plan to compete against Nikon and Sony, so instead they will work the release schedule and get higher end sales from the 'gotta have it now' customer.

People getting a 1dxmk2 wont be gettinga 5d4 regardless.

the only way a 5d4 will dip into 1dx sales is if it does 10+fps burst shots

TeamSpeed wrote in post #17882390
I have both types of lenses, and I see virtually no difference between the two types (and not all USM lenses are created equal either) when doing video. In any case, STM lense are great pieces of gear, especially for those on budgets.

idkdc wrote in post #17882412
I'm not sure what USM lenses you have, but a 24-70mm f/2.8 II is much faster and quieter at focusing than a 40 STM, which I also own but lend out to family in friends. Even an 85mm f/1.8 is much faster, even though it is a much older design.

That said, yes, they are great for the money, which is what I said in my previous post. Preaching to the choir on that note.

There are two different stm motors. A Gear type and lead-screw type. One is quieter than the other. I have noticed that my 55-250 stm was quieter than the 40. The 55-250 STM uses the Lead-screw STM motor. It is larger and quieter. The pancake lenses have to use the Gear type STM motor because it is smaller for their compact size.

The difference between the 2 motors is pretty noticeable when it comes to sound. When I first got the 55-250 stm I had to do a double take because I couldn't hear it focusing and I didn't think it was working. I was so used to hearing older lenses focus!

thenextguy wrote in post #17908162
I guess a simpler way to ask the question is: Regardless of the exposure settings, do variable aperture lenses always AF at the largest aperture (f/4.5 in this case)? From what I'm reading online, they do.

Edit:
For example, Sigma says you can add a 1.4x teleconverter to its 150-600 f/5 to f/6.3 and still get autofocus as long as the camera can AF at f/8.

Those f/6.3 lenses deceive the camera; that is the only reason that an f/5.6 camera will focus them, or an f/8 camera can with a 1.4x.

The minimum f-number depends on the zoom position. It is not possible for the f-number to be 5 when the zoom is set to 600mm.

[Edit]: There's also a limit to how far deception gets the lens; going too far beyond the camera's limitation may still allow the AF system to attempt AF, but that does not guarantee success, and it may interfere with attempts at manual focus override, going hunting after you have already manually focused.

John Sheehy wrote in post #17908196
[...] going hunting after you have already manually focused.

That's what back-button focus is for.

thenextguy wrote in post #17908162
I guess a simpler way to ask the question is: Regardless of the exposure settings, do variable aperture lenses always AF at the largest aperture (f/4.5 in this case)?

They focus at the largest allowed aperture at whatever focal length you are at. So f5.6 is as large as the aperture can go at 400mm on that lens.

we had this conversation the other day but it was about a 100-400 and I interjected my thoughts about this Sigma sport lens which is F 5-6.3 lens. Hoping a sigma 1.4 TC will work at these new F/8 spots. I was also talking to a lady who shoots wildlife with a 500F/4 and she puts an extension tube on the darn thing to get around some of the restrictions. have not checked into this yet.

My thoughts on the Sigma sport F 5-6.3 lens

I would say that the 150-600 Sigma sport lens is a consideration to the 100-400V2 - Its a killer lens. Fast focus, great images and its 600mm at same F/stops. My Opinion is 2 different animals.

100-400 definitely a lot easier to hand hold, pan,IS system is phenominal, just a great lens to 400MM

600MM is a new ballgame.

This update is huge for us that shoot wildlife.... Going to change the decision process for everyone. Its going to make you reconsider what you really need. F/4 glass is king of the hill. Hand hold F/4.0-6.3 glass is now a very desirable consideration in my opinion because I would gladly give up a 500 F/4 for the portability of these others lens and being able to get close and hand hold...Plus the $$ factor as well...factor 600MM into this...and the amount of $$$ your going to be able to save on glass...not a hard decision to me.... With ISO capabilities of these new sensors F/5.6-6.6 is not a big deal at all. I would rather hike in a 150-600 sport v/s a 500F4...any day of the week

Erik S. Klein wrote in post #17908229
That's what back-button focus is for.

I don't like the back button. Makes me lose my grip on the camera when holding a telephoto with my left hand. What I would like is two shutter buttons right next to each other with different settings. THAT would work for me.

John Sheehy wrote in post #17908371
I don't like the back button. Makes me lose my grip on the camera when holding a telephoto with my left hand. What I would like is two shutter buttons right next to each other with different settings. THAT would work for me.

So right. I find it annoying that the cameras are set up for bb focus (great!), but the buttons are badly placed for it. Of course that is a personal thing.

John Sheehy wrote in post #17908371
I don't like the back button. Makes me lose my grip on the camera when holding a telephoto with my left hand. What I would like is two shutter buttons right next to each other with different settings. THAT would work for me.

David Arbogast wrote in post #17908375
So right. I find it annoying that the cameras are set up for bb focus (great!), but the buttons are badly placed for it.

There's a front button that can be used for this purpose I think...at least AF lock on the 5D3, and I think the 1DX and 1DXII.

Very true. I have 400DOii and 500ISii and the 'wieldability' changes drastically with the 500.
Different tools different jobs. On lives on monopod one doesn't. Fully agreed about the 150-600.
I have that one on an a77ii and it is my pick up and go reach machine and not just for the weight
and wieldability; also in case I go crashing down and what I'd rather see hurt or not. Soon enough
the grab-n-go will be the GX8 when the Leica 100-400 gets here.
This may sound repugnant to some, maybe many, but sometimes ultimate IQ is not the goal. It's
taken me right at 60 years to reach that conclusion!

idkdc wrote in post #17908384
There's a front button that can be used for this purpose I think...at least AF lock on the 5D3, and I think the 1DX and 1DXII.

The AF lock button on the back (5DS R) is probably the best positioned button for me. I just need to train myself to use it and get over my discomfort.

Politely disagree to a point. Most Canon bodies allow a different button to be set up for BBF don't they?
Often one 'fits' better than the other.
Do agree that BBFP (back button focus pumping) is more difficult hand holding the big lenses but a non
issue on tripod/monopod and truth is at places like Conowingo/Haines/L&D14 many many use tripods.
If you want to experience weird back button placement pick up a Lumix GX8-that took me 2 weeks of
use to mental map to.
It's all good though. I remember the days when nary a button was programmable.

MedicineMan4040 wrote in post #17908396
Politely disagree to a point. Most Canon bodies allow a different button to be set up for BBF don't they?
Often one 'fits' better than the other.
Do agree that BBFP (back button focus pumping) is more difficult hand holding the big lenses but a non
issue on tripod/monopod and truth is at places like Conowingo/Haines/L&D14 many many use tripods.
If you want to experience weird back button placement pick up a Lumix GX8-that took me 2 weeks of
use to mental map to.
It's all good though. I remember the days when nary a button was programmable.

It would be "groovy" if I could be a bit clearer regarding what I would prefer (ergonomically). On the back of the camera there is a groove built right into the body for your thumb, yet the available buttons for bb focus are all to the right of that ergonomic groove. I want a button aligned with the groove at my thumb tip...so I can continuously keep my thumb in the groove where Canon designed it to be.

David Arbogast wrote in post #17908441
It would be "groovy" if I could be a bit clearer regarding what I would prefer (ergonomically). On the back of the camera there is a groove built right into the body for your thumb, yet the available buttons for bb focus are all to the right of that ergonomic groove. I want a button aligned with the groove at my thumb tip...so I can continuously keep my thumb in the groove where Canon designed it to be.

That would certainly be an improvement over what they have now, but I am not sure that I really ever want to have AF and shutter separated; hence, my two-shutter-button approach. The instant you realize that AF is not going to happen fast enough, you simply switch to the shutter button that isn't tied to AF. Very fast and intuitive. Much faster than turning the AF switch off on the lens, and then back on again when needed, or pressing the "AF stop button" on the lens which isn't near where I comfortably hold the lens, and only works until you press the shutter button again. There's no way that once you got used to the two-shutter-button approach that it wouldn't be faster and result in less wasted time. The choice will become transparent in no time; you don't have to remember if the AF is on or off because it is always both on and off. The AF switch on the camera leads to a lot of disaster, IME, which would never happen with two shutter buttons.

Of course, manual override that actually worked would be helpful, too. My 400 DO II IS does not have manual override until AF is already verified! What genius requested that feature from Canon, I wonder? At least on my classic 100-400, I had manual focus override until I released the half-shutter press. The 400 DO II IS immediately tries to AF again as soon as I find manual focus, when I try to override hunting.