How good is non crosstype point? Share your thought :)

So instead of keep hijacking someone's thread, I've decided to open a new thread solely for discussing about non crosstype point on ANY Canon model in regards to speed, accuracy, hit rate etc.

Like Gabe said in the other thread, pictures worth a thousand words. So I actually went out this morning before work and re-enable (yes, I have them disabled!) my non crosstype points on my 5D3 and test their accuracy and speed.

All shots are SOOC JPEG, no processing or cropping, using my 70-200II @ f2.8 with al servo, mostly @ 200mm using various non crosstype points.

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I know when I had my XSI (yeah I know very different focus compared to a 5DIII) the non cross type sensors sucked on certain things. For most general use it came up ok but then other times depending on how much contrast or what not it just wouldn't hit.

Never used them before. I always shoot in center AF point. I focus and recompose.

Take Care,
Cheers, Patrick

rx7speed wrote in post #16422579
I know when I had my XSI (yeah I know very different focus compared to a 5DIII) the non cross type sensors sucked on certain things. For most general use it came up ok but then other times depending on how much contrast or what not it just wouldn't hit.

So do you find the outer crosstype on the 7D much better and more accurate?

Saint728 wrote in post #16422592
Never used them before. I always shoot in center AF point. I focus and recompose.

Take Care,
Cheers, Patrick

I see you have a 1DsIII, Is there any reason why or just a personal preference?

My old 5D, the peripheral (line-type) AF points worked fine IF the scene's contrast happened to be going the right direction for the selected AF point. As this was often not the case, using anything other then the center (cross-type) AF point was an exercise in frustration.

Since I upgraded to the 5DIII, I have the line-type AF points disabled. 41 cross-type points is such an upgrade over the 1 I had before, that I don't miss the extra 20 points. When I select an AF point, I want to know that it's going to focus regardless of the direction of contrast.

mike_d wrote in post #16422656
Since I upgraded to the 5DIII, I have the line-type AF points disabled. 41 cross-type points is such an upgrade over the 1 I had before, that I don't miss the extra 20 points. When I select an AF point, I want to know that it's going to focus regardless of the direction of contrast.

Thanks for your insight mike_d.

I also have the non crosstype disabled on my 5D3 and find 41 points aplenty for my need. However, I have to say I was pleasantly surprised when I went out and try them today, at least under good light and mostly static subjects anyway.

It's rather simple. Linear points have one distance measurment element, cross-type have two. Thus linear points are exactly 50% as good as cross-type.

Note that this is the general answer. Cameras combining a standard-precision linear point in one direction, at f/5.6, with a high-precision point in the other direction (from f/2.8) are of course a little more than 100% better when they become cross-type, compared to when you match a linear point with normal precision to a cross-type one, which also has normal precision in both directions.

Sounds like fun. I'll get my 5D and Sigma 70-200 out tomorrow. It is 3:30 am here, now.

kin2son wrote in post #16422668
Thanks for your insight mike_d.

I also have the non crosstype disabled on my 5D3 and find 41 points aplenty for my need. However, I have to say I was pleasantly surprised when I went out and try them today, at least under good light and mostly static subjects anyway.

I think this is an important point. Most of my subjects these days aren't still for more than a couple of seconds if I'm lucky so I need all the AF speed and reliability I can get.

An AF point is a line, really. It works best if the contrast it's trying to detect is perpendicular to the line. If the line is a line, then the angle can go all the way down to 0°, an angle where the AF point is useless. Below 30° it has lost half of the efficiency. But if the line is actually two, perpendicular to each other (a cross-type point, in other words), then the angle will never become worse than 45°. Which makes a big difference.

apersson850 wrote in post #16422758
An AF point is a line, really. It works best if the contrast it's trying to detect is perpendicular to the line. If the line is a line, then the angle can go all the way down to 0°, an angle where the AF point is useless. Below 30° it has lost half of the efficiency. But if the line is actually two, perpendicular to each other (a cross-type point, in other words), then the angle will never become worse than 45°. Which makes a big difference.

This^^^^^^ If you do a bit of searching, you can find out exactly which way the various focus points (lines) run on your particular camera, and then pick your focus target to suit. Makes a huge difference. Sometimes you only have to move your focus point on a subject a tiny amount, and it will lock near instantly, where it was previously hunting helplessly.

If you've got a bit of spare time, it's pretty easy to figure out with some pretty basic tests. A door frame inside in lowish light works brilliantly. Pick your focus point, then try to focus on the jamb (vertical part of the door frame) and then the lintel (horizontal part of door frame) It will very quickly become obvious which is which

Knowing how Canon AF works and its limitations is 99% of battle. Learning and understanding Canon's AF system is in every owners best interest.

http://www.youtube.com​/watch?v=iAx86nblZ2g
http://www.youtube.com​/watch?v=3_F7lCvp5DI
http://www.youtube.com​/watch?v=1WTWiN9kLts

In that light sure they are decent. Get to ISO 1600+ and/or w/ tracking. They suck. Main reason I got rid of my rebel and went 60D. I did take a step backward on AF from 7D to 6D

Talley wrote in post #16422837
In that light sure they are decent. Get to ISO 1600+ and/or w/ tracking. They suck. Main reason I got rid of my rebel and went 60D. I did take a step backward on AF from 7D to 6D

Hey Talley not sure if you've been following this other thread where Gabe show some animals and bifs tracking using 6D's outer point.

https://photography-on-the.net …?p=16421066&pos​tcount=378
https://photography-on-the.net …?p=16421072&pos​tcount=379