[causey]

It's just that people think more is better, fancier, if not absolutely necessary. (But usually they go with 'absolutely necessary'.) Which kills the joy of taking photos. 'Cause most of us aren't professionals, but amateurs and 'enthusiasts' whose ultimate purpose is the joy we tend to forget--and many accomplished professionals might not care a whole lot about the number of focus points. (AF performance is another thing.)

[uchinakuri]

As far as I understand it, the reason for more AF points isnt meaningless when you are trying to use AF to take a picture of something that is moving. If your cam has more AF points, then the cam will be able to effectively track that object as it moves across the frame.

So if you are taking pics of landscapes or birds perched on a branch, then you dont need more AF points.

Please note that I'm not saying that fewer AF points = cant take pics of moving stuff. (Just to avoid the slew of posts showing pics of moving objects taken with Pentaxes hehe )

[Pål Jensen]

I admit that I am just a lowly amateur, have little long term experience, and no desire to become famous and be a Pro........but I sure as heck can't understand why 11 focus points is not 10 more than I need 98% of the time?

Every Canon pro I've heard of turn off those 48 AF points and use only 11 for performance....

[opiedog]

Every Canon pro I've heard of turn off those 48 AF points and use only 11 for performance....

canon has 59? AF points?

yeah, the 39 af points have their use, but for most folks not needing any tracking, it'll not be fully utilized.

nevertheless, it IS a selling point

[pingflood]

Every Canon pro I've heard of turn off those 48 AF points and use only 11 for performance....

I don't think you quite know how it works.

First, the Canon pro bodies have 45 AF points.

Second, the 11 points is not "for performance" (believe me, 1 series AF is nothing but performance). What they have done is modify the manual selection (via a custom function) so that when they pick an AF point with the joystick (or wheel on the older ones) it only lets you pick from the center one and ten spread out in a ring around the center. It's for those who don't really want to spend time stepping around all 45 points, but still want to have some flexibility in manual selection. Note that this function is only active when manually selecting an auto point. In auto selection (AFPS) single shot mode or AI servo mode all 45 points remain active.

[GeneV]

It seems to me that having a gazillion focus points would be helpful for point and shoot modes where the camera picks the POF, but not particularly useful for speeding up the AF for the center point that I use 90% of the time.

[kinkindoll]

thanks guys,

of coz we know the various AF focus points may not be useful but it may be a milestone for Pentax. Anyway, I think the most Pentax users are attracted and addicted by Pentax own colour, especially in film, also CCD sensor...

looking forward for the official announcement...

[paperbag846]

Something tells me that a moderate number of focusing points is necessary to achieve an accuracy / speed ratio. If you have too few focusing points, it will be hard for the camera to find the subject. If you have too many, the CPU of the camera would have to be very powerful in order to process all of that information in real time. Therefore, a moderate number of AF points would be ideal for fast AF.

I'm not so sure that the number of AF points in the older Pentax bodies (k10 / 20d) was the real issue w.r.t. focus speed.

[Gimbal]

The thing with to few AF-points is that each point has to be relatively large in order to cover at least some area of the viewfinder when in auto-mode. So the center point is (for most people) surprisingly large, and that fact alone has caused many threads about Pentax miss-focusing. They aim for one detail and the camera finds focus on something else in the background.

More points equals smaller points equals higher precision when aiming.

[montoblan]

For a stationary subject there is actually no reason to use anything but 1. The multipoints are mostly used for tracking purposes.

Not true. If you have a lens with a flat focus plane and a normal to wide focal length, then the distance to the focal plane in the center is different than the distance to the focal plane nearer the edge of the frame. With, say, a 28mm at F1.8 or F2.4, if you do the focus-on-the-center-then-recompose thing, you're basically guaranteeing that your shot will be back-focused.

[youky63]

Anyway, 11 or 45 points, the main AF problem for Pentax is not in the body, but in the lenses. I don't know how many people here tried a high end Canon or Nikon body coupled to an ultrasonic lens. I played with a 5DmII and several lenses (24-105 f/4, 70-200 f/2.8 II, 135 f/2) and the focus speed of the lenses is awesome!!!! Another world compared to in-body screw motor or SDM. And completely silent...
So if you want to see a big improvement in K5 compared to K7 (excepted for track focussing), pray for a new ring motor lens line up.

It seems to me that having a gazillion focus points would be helpful for point and shoot modes where the camera picks the POF, but not particularly useful for speeding up the AF for the center point that I use 90% of the time.

well i think 11 large AF points might work the same as the 39 AF points on d7000, which someone pointed out are small, if they have the same amount of spread

[bats]

I second what Montoblan just said. If I had focused using centerpoint and then shifted the camera to recompose, I would have been in trouble here. The focal plane (at f/2.8) was narrow enough that shifting the camera would probably have pushed the right-hand arc out of focus.




While I am fine with the 11 focal points of my K10D. less would be a problem. More? That would be okay by me but not absolutely necessary.

[Pål Jensen]

Anyway, 11 or 45 points, the main AF problem for Pentax is not in the body, but in the lenses. I don't know how many people here tried a high end Canon or Nikon body coupled to an ultrasonic lens. .

I have. I used the Canon 1ds (or whatever it is called) with a 35-350 L lens. It is the slowest AF system I've ever tried!

[Winder]

I find that 3/2 format is too wide for most of what I do and end up cropping away 20-30% of the image. When using the 5D or the k-7 I simply use the center AF point and center my subject. I find that focusing and recomposing moves the subject out of the "sweet spot" in the center of the lens.

With my Contax 645 and film I don't have any issue because the 4/3 format is more natural for me and the Contax 645 glass is very sharp. The film is more forgiving. When I used the E-3 the Olympus glass give excellent edge to edge sharpness, and the 4/3 format is perfect for my taste.

The Sigma 30mm f/1.4 is a good example of a lens with excellent center sharpness, but if you move your subject to follow the rule of 3rds then you have moved them into a noticeably soft area.

99% of what I do with a 3/2 format will only require a center AF point.