Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-14-2009, 03:17 PM   #2761
Senior Member




Join Date: Apr 2009
Location: Mississippi
Posts: 184
QuoteOriginally posted by PentaxPoke Quote
I still don't understand why we need more focus points than 1. Why let the camera decide where it wants to focus? I understand the need for multi-point metering, but multipoint focusing makes no sense to me.
Because focus-recompose with a large aperture prime at short distance is asking for trouble. It's not about letting the camera choose. It's about letting me choose the particular point I need for a particular shot.

05-14-2009, 03:17 PM   #2762
Pentaxian
Ratmagiclady's Avatar

Join Date: Nov 2008
Location: GA
Photos: Gallery | Albums
Posts: 13,464
QuoteOriginally posted by Asahiflex Quote
It's 980 shots on a single charge and as far as I know, the K-7 still has 11 focus points (phase detect AF) with nine cross-type sensors. The "15" is still unknown to me.
Nine cross-type sensors would actually be a good improvement if you want to use different focus points. I'm still unconvinced it's faster than just picking something at the right range for whatever off-curvature of field anyway. But it'd probably make those other points more useful.

Don't see the advantage in giving a camera more spots to get confused about. If what's there is better, yay.

Also, something I harp on: Screen for fast lenses, Pentax. We know what to do with it.
05-14-2009, 03:18 PM   #2763
Senior Member




Join Date: Jul 2008
Posts: 102
QuoteOriginally posted by PentaxPoke Quote
I still don't understand why we need more focus points than 1.
Because using the center point requires focus recompose, and in many cases this can cause the focus to be behind the subject. Using an AF point that's closer to the subject minimizes this problem. More here:

Why Focus-Recompose Sucks
Focus and Recompose Exposed - James Duncan Davidson - James Duncan Davidson
Focus and Recompose


QuoteQuote:
Why let the camera decide where it wants to focus?
In most cases it's best to manually select the AF point that's closest to the subject, not let the camera guess it. However, when shooting birds-in-flight (or other moving subjects) it's sometimes difficult to keep the AF point on the subject, this is where the auto AF point selection can be useful.

QuoteQuote:
I understand the need for multi-point metering, but multipoint focusing makes no sense to me.
Does it makes sense now?

Prog.
05-14-2009, 03:26 PM   #2764
Forum Member




Join Date: Oct 2008
Location: Croatia
Photos: Gallery
Posts: 64
QuoteOriginally posted by PentaxPoke Quote
I still don't understand why we need more focus points than 1. Why let the camera decide where it wants to focus? I understand the need for multi-point metering, but multipoint focusing makes no sense to me.
In addition to everything replied to this statement prior to my post, I find, when the camera is on a tripod, that it is much easier to focus by manually selecting a focus point.
Saves the hassle of readjusting the frame each time for focus.

05-14-2009, 03:31 PM   #2765
Pentaxian
Ratmagiclady's Avatar

Join Date: Nov 2008
Location: GA
Photos: Gallery | Albums
Posts: 13,464
QuoteOriginally posted by Prognathous Quote
Because using the center point requires focus recompose, and in many cases this can cause the focus to be behind the subject. Using an AF point that's closer to the subject minimizes this problem. More here:

[
Prog.
So... you compensate by choosing a focus point at the right range, like with an old-fashioned focus aid. Faster than selecting a focus point and *then* telling the camera to focus, and *then* adjusting your composition.

Never mind waggling around till AF point selection does something you agree with.
05-14-2009, 03:31 PM   #2766
Veteran Member




Join Date: Nov 2007
Location: Trinidad and Tobago
Posts: 421
QuoteOriginally posted by Desmond.young Quote
look at the flash on top of the body.... quite different from K10/20D.....
maybe....it's....
i just dont get it, its either Pentax has the most morons working in their marketing department or Pentax does not have a clue how to run a business
no where on Pentax site states about a K30D or a K7, but yet there is much talk going around

Dave
05-14-2009, 03:33 PM   #2767
Senior Member




Join Date: Apr 2009
Location: Mississippi
Posts: 184
QuoteOriginally posted by dafiryde Quote
i just dont get it, its either Pentax has the most morons working in their marketing department or Pentax does not have a clue how to run a business
no where on Pentax site states about a K30D or a K7, but yet there is much talk going around

Dave
You know the camera hasn't been officially announced, right?
05-14-2009, 03:38 PM   #2768
Senior Member




Join Date: Sep 2008
Location: Norway
Posts: 127
QuoteOriginally posted by PentaxPoke Quote
I still don't understand why we need more focus points than 1. Why let the camera decide where it wants to focus? I understand the need for multi-point metering, but multipoint focusing makes no sense to me.
QuoteOriginally posted by Caat Quote
You can't track an object moving across the frame with a single AF point
And you have to remember that one af point is just one tiny spot. It searches for the optimal contrast in that particular post. Let's say you're photographing an object with fairly flat and non-structural surface, you'll perhaps need a focus point that's a bit on the edge of that object to find a suitable contrast to adjust focus on.

As said by Caat it's also quite difficult to focus with just that tiny spot or even a few tiny spots spread around your frame if the subject is moving. For birds in flight you'll most probably go for auto/multipoint and hope for the best, or go all manual. The more af points the more chance you'll have that at least one of them will hit a suitable part of your subject. Of course this will also requires that the camera can detect "something interesting" instead of just the background.

05-14-2009, 03:42 PM   #2769
Veteran Member
RBellavance's Avatar

Join Date: Nov 2006
Location: Near Montréal, Canada
Photos: Gallery
Posts: 1,716
QuoteOriginally posted by Ratmagiclady Quote
Nine cross-type sensors would actually be a good improvement if you want to use different focus points.
Except the K10D and K20D already have 9 cross-type sensors

A really good improvement would be to have some points more sensitive than f/5.6.
05-14-2009, 03:43 PM   #2770
Veteran Member




Join Date: Jul 2008
Location: Sweden, Umea
Posts: 869
I can bet you can manualy focus much faster then changing your focus point.

And if your in a studio on a tripod and taking product shots. Why would you autofocus then?

L2Turnthefocusring
05-14-2009, 03:46 PM   #2771
Veteran Member
RBellavance's Avatar

Join Date: Nov 2006
Location: Near Montréal, Canada
Photos: Gallery
Posts: 1,716
QuoteOriginally posted by sveinmb Quote
And you have to remember that one af point is just one tiny spot.
That is a common misconception, at least on the Pentax AF systems we've seen so far. The AF "points" are actually quite large, larger than the red "square" we see in the viewfinder. For instance, the center AF sensor covers approximately the same area as the central "circle" in the K20D's viewfinder.

That can lead to problems because the camera will sometimes lock onto a high-contrast are you think is outside the AF sensor area, but in fact is not.
05-14-2009, 03:48 PM   #2772
Senior Member




Join Date: Jul 2008
Posts: 102
QuoteOriginally posted by Ratmagiclady Quote
So... you compensate by choosing a focus point at the right range, like with an old-fashioned focus aid.
If by "old-fashioned focus aid" you mean the split-image or microprism in old focusing screens, then no, it not the same. These aids were in the center of the frame, where as the focus points are spread over a much larger area.

QuoteQuote:
Faster than selecting a focus point and *then* telling the camera to focus, and *then* adjusting your composition.
Using the closest focusing point may save some time (in recomposing) compared to using the center point, but the main reason to use it is to avoid the focus-recompose out-of-focus issue described in the links I posted.

Prog.
05-14-2009, 03:48 PM   #2773
Junior Member




Join Date: Dec 2008
Posts: 26
To bad Wolfram|Alpha hasn't been released yet... the answer to all our K-7 questions.
05-14-2009, 04:13 PM   #2774
Pentaxian
Ratmagiclady's Avatar

Join Date: Nov 2008
Location: GA
Photos: Gallery | Albums
Posts: 13,464
QuoteOriginally posted by RBellavance Quote
Except the K10D and K20D already have 9 cross-type sensors

A really good improvement would be to have some points more sensitive than f/5.6.
Do they? I thought there were just three. Not that I know: I just use the middle one. And what you mean 'more sensitive than 5.6?' I don't buy expensive gear to use the kit lens.
05-14-2009, 04:15 PM   #2775
Pentaxian
Ratmagiclady's Avatar

Join Date: Nov 2008
Location: GA
Photos: Gallery | Albums
Posts: 13,464
QuoteOriginally posted by Prognathous Quote
If by "old-fashioned focus aid" you mean the split-image or microprism in old focusing screens, then no, it not the same. These aids were in the center of the frame, where as the focus points are spread over a much larger area.



Using the closest focusing point may save some time (in recomposing) compared to using the center point, but the main reason to use it is to avoid the focus-recompose out-of-focus issue described in the links I posted.

Prog.
If you use the *middle* one and pick your range, it *is* the same, more or less. Like I say, a screen for fast lenses without the artificial DOF to brighten up kit lenses in the shop, though, would be most welcome.

(I mean, if you're worried about DOF control with fast lenses wide open, it's not fancier computerized AF you need, to guess where in the frame Joe Amateur wants his focus interpolated: you need glass to focus on. )

Last edited by Ratmagiclady; 05-14-2009 at 04:21 PM.
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!
pentax news, pentax rumors
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
POST A PIC TO OWN THE PIC ABOVE! (Game) ll_coffee_lP Mini-Challenges, Games, and Photo Stories 788 08-01-2015 01:01 AM
Who out there would prefer a K30D? Ben Hunt Pentax DSLR Discussion 45 11-05-2010 06:48 AM
What would we want from the K30D? offertonhatter Pentax News and Rumors 102 04-22-2009 02:30 AM
So... is the K30D actually going to have autofocus? SupremeMoFo Pentax News and Rumors 88 01-03-2009 05:53 PM
Iso 1600 pic and a Butterfly Pic... Eastern Shore Charlie Post Your Photos! 5 07-06-2008 10:27 AM



All times are GMT -7. The time now is 06:05 PM. | See also: NikonForums.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