November 26, 2014, 09:30:50 AM

Author Topic: another AF point selecton option I would like in future  (Read 6550 times)

sanj

  • 1D X
  • *******
  • Posts: 1646
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #15 on: June 21, 2012, 06:07:53 AM »
On the EOS 3, there's 45pt AF, same as the 1-series until the 1DX.
But, there's also the option to limit it to 11 points (with the plus of having spot-linked metering).
And it's this that I use most often, i'm never tracking birds with it so don't need all 45, and I don't mind a bit of focus+recompose if I really have to.

On my 7D, however, there's 19 points, or there's only options for 5 in a +, or 9 in a square.

If there was a way to limit it to centre+4 corners of the diamond, or even centre+8 (four corners of the diamond and 4 on the sides, like a 5D2), then yeah, i'd probably use that occasionally.


Seeing as this is the digital age, how about we just have a "custom AF selection" screen, so we can select/deselect any combination out of the 19/45/61 that we want?

Super good idea...

canon rumors FORUM

Re: another AF point selecton option I would like in future
« Reply #15 on: June 21, 2012, 06:07:53 AM »

Jettatore

  • Guest
Re: another AF point selecton option I would like in future
« Reply #16 on: June 21, 2012, 07:46:57 AM »
Great idea Wicked. 

SambalOelek

  • PowerShot G1 X II
  • ***
  • Posts: 53
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #17 on: June 21, 2012, 08:25:45 AM »
On the other hand, Canon, along with other Japanese electronic manufactures are too dumb to come up with intelligent firmware because they still run those firmwares under DOS! A real OS with multitasking kernel is the foundation to software intelligence. Look at smart phones, they run OSX (iphone), Linux Kernel (Android) and Window Kernel (Windows Mobile). The OS limits how complicated your software layer can ever be.

Most contemporary Canon DSLRs (and many compacts) run DryOS, a RTOS (completely unrelated to DOS, by the way). This limits costs compared to licensing another OS. None of the operating systems you list are real-time operating systems, and would not necessarily be suitable for Canon DSLRs. The DryOS kernel fits in 16kb of memory, the Android kernel is, what, 2MB?
« Last Edit: June 21, 2012, 08:29:11 AM by SambalOelek »
1D X, 1D IV, 5D III, 6D, 7D, M. Assorted lenses.

KevinAv4

  • Guest
Re: another AF point selecton option I would like in future
« Reply #18 on: June 21, 2012, 02:04:59 PM »
I don't Get why Canon doesn't improve they're features Via firmware or software tweaks, as something like Custom Af point selection and such could set them apart from the competition and create competitiveness with other companies, becoming a win-win for everyone.

kdsand

  • Canon 70D
  • ****
  • Posts: 276
  • Newt II a human stampede
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #19 on: June 21, 2012, 03:37:49 PM »
I could see the benifit of a touch screen for af selection especially in live view ( yes I know some hate touch screens but then again alot of people used to detest a screen of any type).

Perhaps we could use our noses while looking through the viewfinder :-) .

But in all seriousness why not allow full af customization? I can understand rebels menus options being kept simple but other than that it seems overly constrained.
60D, t2i, Magic Lantern, Manfrotto, Joby, Domke, SanDisk and excetera excetera

sarangiman

  • Canon 6D
  • *****
  • Posts: 375
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #20 on: June 21, 2012, 06:13:32 PM »
Customization would be huge, in general.

I personally use the 'all cross-type' option; however, having an option for 9 or 11 or whatever number would be great.

And while we're on the subject, if you look at the mapping of the 9 points --do we even know if those are all cross-type?

Also, for the 9 points, why don't they enable the top-most/bottom-most center sensors (which are cross-type)? Why have that rectangle shape when you could have more of a diamond spread (more AF spread... which is what more photographers, in my understanding, who custom select points typically want anyway)?

At any rate, full customization would just allow photographers to use what they need, which would offer an incredible advantage in terms of speed in fast-paced shooting scenarios.

briansquibb

  • Guest
Re: another AF point selecton option I would like in future
« Reply #21 on: June 21, 2012, 06:20:41 PM »
Customization would be huge, in general.

I personally use the 'all cross-type' option; however, having an option for 9 or 11 or whatever number would be great.

And while we're on the subject, if you look at the mapping of the 9 points --do we even know if those are all cross-type?

Also, for the 9 points, why don't they enable the top-most/bottom-most center sensors (which are cross-type)? Why have that rectangle shape when you could have more of a diamond spread (more AF spread... which is what more photographers, in my understanding, who custom select points typically want anyway)?

At any rate, full customization would just allow photographers to use what they need, which would offer an incredible advantage in terms of speed in fast-paced shooting scenarios.

1D4 9pts(outer) are 3 points in each of 3 rows

canon rumors FORUM

Re: another AF point selecton option I would like in future
« Reply #21 on: June 21, 2012, 06:20:41 PM »

sarangiman

  • Canon 6D
  • *****
  • Posts: 375
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #22 on: June 21, 2012, 07:13:02 PM »
Quote
1D4 9pts(outer) are 3 points in each of 3 rows

I see. My point is that the 5DIII has a cross-type AF point above the upper-most, center, selectable AF point in 9pt mode (and one below the lower-most, center, selectable AF point). Why not use these in the 9pt mode instead of ones closer to the center? You'd get more AF spread... and like I said, photographers are typically talking about more AF point spread, not less.

Enabling those (to create a diamond like spread of selectable AF points) gets you one step closer to an area of the frame that has no AF points at all. I don't really understand decisions such as these. Maybe I'm missing something.

Either way, customizability would solve issues like this in one gigantic sweep.

wickidwombat

  • Canon EF 400mm f/2.8L IS II
  • *******
  • Posts: 4542
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #23 on: June 21, 2012, 07:43:18 PM »
I'm not sure why they made the double cross sensors in a straight line like they did maybe for action or something but to me it would have made more sense to make the sensors nearest the rule of thirds intersections double cross type

the reason for having an option to limit selection to 5 is speed of changing points on the run, more point more time more chance of error
APS-H Fanboy

psolberg

  • Canon 7D MK II
  • *****
  • Posts: 483
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #24 on: June 21, 2012, 11:00:22 PM »
honestly, I just want full viewfinder spread on FF cameras. canon and nikon's points are all bunched up together. the 5DmkIII in some modes you can't even see what da hell you're shooting because it is like a fly infestation landed on your lens.
SPREAD THEM!

kdsand

  • Canon 70D
  • ****
  • Posts: 276
  • Newt II a human stampede
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #25 on: June 21, 2012, 11:17:45 PM »
honestly, I just want full viewfinder spread on FF cameras. canon and nikon's points are all bunched up together. the 5DmkIII in some modes you can't even see what da hell you're shooting because it is like a fly infestation landed on your lens.
SPREAD THEM!

 :o
SPREAD THEM!
  :o
Heard that before.  ;)
60D, t2i, Magic Lantern, Manfrotto, Joby, Domke, SanDisk and excetera excetera

wickidwombat

  • Canon EF 400mm f/2.8L IS II
  • *******
  • Posts: 4542
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #26 on: June 21, 2012, 11:23:29 PM »
interestingly on the fuji x10 AF point selection is an eve grid with full screen coverage only available in live view but its not fast perhaps it just uses a contrast detect system

neuros article explains well why AF points dont spread out in the phase detect AF system i'm sure he will post a link in here soon :D
APS-H Fanboy

sarangiman

  • Canon 6D
  • *****
  • Posts: 375
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #27 on: June 22, 2012, 01:17:28 AM »
Quote
honestly, I just want full viewfinder spread on FF cameras. canon and nikon's points are all bunched up together. the 5DmkIII in some modes you can't even see what da hell you're shooting because it is like a fly infestation landed on your lens.
SPREAD THEM!

+1. Keep preaching sense, psolberg. :)

canon rumors FORUM

Re: another AF point selecton option I would like in future
« Reply #27 on: June 22, 2012, 01:17:28 AM »

neuroanatomist

  • CR GEEK
  • **********
  • Posts: 14964
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #28 on: June 22, 2012, 04:22:40 AM »
neuros article explains well why AF points dont spread out in the phase detect AF system i'm sure he will post a link in here soon :D

Since you asked...   ;)  Canon EOS DSLR Autofocus Explained

The relevant part:

AF Point Coverage
 
For many people, this is a big issue in comparing cameras. While it would be wonderful to have AF points available over the entire extent of the frame, there are technical limitations on the spread of the AF points - at best, they can only occupy the middle area of the frame, because of simple geometry and optics. In a nutshell, there are four reasons for this limitation:

  • Size of the secondary mirror. Light for AF passes through the semi-transparent part of the main mirror (most is reflected up to the viewfinder), then is reflected off the secondary mirror down to the AF sensor. There is limited space behind the main mirror, based on the necessary geometry (i.e. the main mirror has to be at a 45° angle to the incoming light, and the secondary mirror has to be behind the main mirror and at an angle of 90° to the main mirror, so it's length is limited by the distance between the main mirror and the image sensor).
  • Distortion. With many lenses, the edges of the frame are subject to distortion (barrel/pincushion), and that reduces the accuracy of phase detect AF.
  • Vingetting. The AF system needs a certain amount of light to work. Almost all lenses vignette to some degree, meaning there might not be enough light at the edges of the frame. For example, the EF 17-40mm f/4L has >2 stops of vignetting wide open at the wide end - that means at the edges of the frame, you're below f/5.6 and AF sensors would not have enough light to operate (i.e. in dim light you'd be below the EV sensitivity of the sensor).
  • Temperature. Canon has stated that larger AF sensors are more susceptible to changes in temperature with the result that they change size, getting either larger or smaller as the temperature rises and falls. That reduces the accuracy of the AF system overall.

It's worth noting that none of these limitations apply to contrast detect AF, so using LiveView you can autofocus right out to the edge of the frame.
EOS 1D X, EOS M, and lots of lenses
______________________________
Flickr | TDP Profile/Gear List

sarangiman

  • Canon 6D
  • *****
  • Posts: 375
    • View Profile
Re: another AF point selecton option I would like in future
« Reply #29 on: June 22, 2012, 05:02:52 AM »
Thanks for the concise explanation, Neuro.

Quote
Temperature. Canon has stated that larger AF sensors are more susceptible to changes in temperature with the result that they change size, getting either larger or smaller as the temperature rises and falls. That reduces the accuracy of the AF system overall.

I myself have found varying optimal MA on different days. Haven't quantified it rigorously, but it's certainly believable based on my experience w/ the 85/1.2 on different days (now that it's warmed up in Seattle, I have a new temperature to compare to the performance throughout the winter).

canon rumors FORUM

Re: another AF point selecton option I would like in future
« Reply #29 on: June 22, 2012, 05:02:52 AM »