Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-16-2010, 07:00 AM   #16
Veteran Member
causey's Avatar

Join Date: Feb 2009
Location: Arlington, VA
Photos: Albums
Posts: 3,758
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.)

09-16-2010, 07:13 AM   #17
Forum Member




Join Date: Mar 2010
Posts: 57
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 )
09-16-2010, 07:14 AM   #18
Pentaxian
Pål Jensen's Avatar

Join Date: Dec 2007
Location: Norway
Photos: Albums
Posts: 3,148
QuoteOriginally posted by Rupert Quote
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....
09-16-2010, 07:32 AM   #19
Site Supporter




Join Date: Jan 2008
Location: NC
Posts: 787
QuoteOriginally posted by Pål Jensen Quote
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

09-16-2010, 07:57 AM   #20
Veteran Member




Join Date: Jun 2008
Location: Borås, Sweden
Photos: Gallery
Posts: 3,165
QuoteOriginally posted by Pål Jensen Quote
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.
09-16-2010, 08:06 AM   #21
Site Supporter
GeneV's Avatar

Join Date: Oct 2008
Location: Albuquerque NM
Photos: Albums
Posts: 9,775
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.
09-16-2010, 08:11 AM   #22
New Member




Join Date: May 2008
Posts: 21
Original Poster
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...
09-16-2010, 08:14 AM   #23
Veteran Member
paperbag846's Avatar

Join Date: Jul 2010
Photos: Gallery
Posts: 2,396
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.

09-16-2010, 08:34 AM   #24
Pentaxian




Join Date: Apr 2007
Location: Sweden
Posts: 1,940
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.
09-16-2010, 08:39 AM   #25
Junior Member




Join Date: Mar 2010
Posts: 29
QuoteOriginally posted by ManuH Quote
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.
09-16-2010, 08:44 AM   #26
Senior Member




Join Date: Apr 2010
Location: Osaka
Posts: 144
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.
09-16-2010, 08:44 AM   #27
music_lover
Guest




QuoteOriginally posted by GeneV Quote
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
09-16-2010, 08:51 AM   #28
Senior Member




Join Date: Sep 2010
Location: San Francisco
Photos: Gallery
Posts: 103
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.
09-16-2010, 10:28 AM   #29
Pentaxian
Pål Jensen's Avatar

Join Date: Dec 2007
Location: Norway
Photos: Albums
Posts: 3,148
QuoteOriginally posted by youky63 Quote
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!
09-16-2010, 10:30 AM   #30
Loyal Site Supporter




Join Date: Apr 2010
Location: Tennessee
Posts: 5,797
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.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
af, k5, pentax news, pentax rumors
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
AF points....what are they? D4rknezz Pentax DSLR Discussion 10 09-12-2010 08:09 PM
Why different reputations for same points? GeneV Site Suggestions and Help 40 08-25-2010 12:34 PM
Kx AF Points tradixionales Troubleshooting and Beginner Help 11 07-18-2010 07:25 AM
More talking points Nesster General Talk 3 06-30-2010 10:26 AM
K-7 Focus Points jolinjo Pentax DSLR Discussion 3 11-11-2009 01:41 PM



All times are GMT -7. The time now is 08:15 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top