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04-26-2011, 11:46 AM   #16
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QuoteOriginally posted by UnknownVT Quote
Really?&lt;br /&gt;<br />
&lt;br /&gt;<br />
This is not my experience &lt;br /&gt;<br />
- neither from tests where they have compared:&lt;br /&gt;<br />
&lt;br /&gt;<br />
from: [URL=&amp;quot;http://www.imaging-resource.com/PRODS/KX/KXA6.HTM&amp;quot;]Pentax K-x Digital Camera Performance - Full Review - The Imaging Resource!
&lt;br /&gt;<br />
If you say so, im still getting many pics with focus behind person if the background is lighter with 5 point mode, and even with good light 10% of pics are focused at background as well, darker it gets more with focus on background, lighter background is even more, im doing mostly shots of my gf and c the results, if 5 point refuses to lock i use center af, but if its dark even that fails, also looks like it depends on lenses ( corect me if im wrong) but with sigma 17-50/2.8 im getting less bad ones than with kit, but for some reason fa50/1.4 is the worst, one time i tried to pic black can indoor with poor light with it, snd af refused to lock on him in any mode. So go figure, i got used to it, using af lock more often or pre focus with flash, tthats my experience, and whatever that review shows it does not reflects on camera in hands in most situations, plus different lenses gives you differns resulys about speed and at thr end i dont c any comparising to other cameras, so it looks like bunch of meaningless numbers,,&lt;br /&gt;<br />
&lt;br /&gt;<br />
<br />
<br />
forgot, shooting on stage even if it dark should be easier because u have lights on person and, not dark person and light backround, plus depends on zoom, if zoom closer camera have less options to focus on if you have just the person in view, correct me if im wrong<br />

example, this sunday i was taking pictures of my gf stanging of front of garden entrance, entrance was made of nice shinny metal pipes, and they were bright, 8 of 10 shots with 5 point af were focused at entrance, about 4 feet behind her, center piont did the job, but then on the way back i wanted more shots with lil close up, 6 vertical pics with 5p af and all came out focused on her, but she covered most of frame
sorry for quality and cpntinious sentences but using phone to reply gl


Last edited by fafo13; 04-26-2011 at 12:04 PM.
04-26-2011, 01:45 PM   #17
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QuoteOriginally posted by fafo13 Quote
&lt;br /&gt;<br />
If you say so, im still getting many pics with focus behind person if the background is lighter with 5 point mode, and even with good light 10% of pics are focused at background as well, darker it gets more with focus on background, lighter background is even more, im doing mostly shots of my gf and c the results, if 5 point refuses to lock i use center af, but if its dark even that fails, also looks like it depends on lenses ( corect me if im wrong) but with sigma 17-50/2.8 im getting less bad ones than with kit, but for some reason fa50/1.4 is the worst, one time i tried to pic black can indoor with poor light with it, snd af refused to lock on him in any mode. So go figure, i got used to it, using af lock more often or pre focus with flash, tthats my experience, and whatever that review shows it does not reflects on camera in hands in most situations, plus different lenses gives you differns resulys about speed and at thr end i dont c any comparising to other cameras, so it looks like bunch of meaningless numbers,,&lt;br /&gt;<br />
&lt;br /&gt;<br />
<br />
<br />
forgot, shooting on stage even if it dark should be easier because u have lights on person and, not dark person and light backround, plus depends on zoom, if zoom closer camera have less options to focus on if you have just the person in view, correct me if im wrong<br />

example, this sunday i was taking pictures of my gf stanging of front of garden entrance, entrance was made of nice shinny metal pipes, and they were bright, 8 of 10 shots with 5 point af were focused at entrance, about 4 feet behind her, center piont did the job, but then on the way back i wanted more shots with lil close up, 6 vertical pics with 5p af and all came out focused on her, but she covered most of frame
sorry for quality and cpntinious sentences but using phone to reply gl
Sorry, the formatting of your post is awful, so makes it hard to read....

I see....
I offered references of actual independent test results that show center focus no slower than 5 point -
it is entirely your prerogative to completely dismiss/ignore those -
however I would be grateful to please see independent test results that show otherwise,
that supports your initial assertion that 5 point is faster?

The simple fact you are having problems focusing, shows that 5 point for you is failing -
is there any other way of interpreting that?

I do not have problems mis-focusing with center point,
since I know where the camera is trying to focus.

You may think dark venues are easy -
have you actually tired it, to make such a claim, please?

I have plenty of shots where the point of focus is not in the spot light:


ISO5000, f/3.5, 1/4, 18-55 zoom @ 18mm


ISO5000, f/4, 1/5, 24mm -

just to set the scene:


the flugelhorn player in the background above -

both shots - ISO5000, f/3.5, 1/6, 18mm
the area in this shot is pretty dark, significantly below both the AF and metering spec limits - but the K-x still managed to focus.

The LV (light value) for these shots is ~ 0EV @ ISO100 this is about 1/4 foot-candle or 2.7 lux -
this is about 1/4 of night street lighting
and it is definitely below the K-x specs for both metering and AF for the lenses I used.

Final comment: I have very, very few (if any) shots on any night that are out of focus.

Last edited by UnknownVT; 04-26-2011 at 03:30 PM.
04-26-2011, 07:57 PM   #18
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my apologies for format of my post but it was created at work with a phone and i was pretty busy, but let me go over your reply.



"I offered references of actual independent test results that show center focus no slower than 5 point - it is entirely your prerogative to completely dismiss/ignore those " ---- i never said that 5 point is faster but ive said that im getting "many pics with focus behind person if the background is lighter with 5 point mode" ( examples from just last week, im deleting all except keepers but im getting enought of them that i can supply many any time)




done with tamron which ive returned cause i was getting 80% of pictures with focus anywhere but not on my girl



ny autoshow last weekend - not even dark enviroment, but enought that background was brighter and thats where the focus went




aquarium 2 weeks ago - damn light on tank and AF decided to go there, about 30% pictures went like this that day for me, but unfortunately, canon didnt manage to f**k up any like this, ofc those that came up good with kx were iq superior but f**k IQ when your subject isnt in focus





" I would be grateful to please see independent test results that show otherwise, that supports your initial assertion that 5 point is faster?" - what i said and mean is nice numbers means nothing of a focus is 0.456 of a sec or it is 0.345sec or 0.567 means nothing to 99% of users ? test that compare side to side different cameras in many situation can give any picture of its performance.


"The simple fact you are having problems focusing, shows that 5 point for you is failing - is there any other way of interpreting that?" --- maybe it is my fault, but by any means pointing camera and taking picture isnt so hard, dont have problem with off focus with canon but i do with kx, call it my failure, but why do i fail with only this particular camera ? i huess you gonna call bad unit, but i dont think its a case here.


"You may think dark venues are easy - have you actually tired it, to make such a claim, please?" ---- failed to focus even with much more light, and yes ofc, i bought kx with 50/1.4 cause i love sunlight and flashes, i bought this setup cause i love low light

and example of my low light trials:




EV-0, zero modifications to this picture, tooke few shots but i got it !






in addition im talking about dark person on lighter background, on those pictures, those people are same lighted as the wall.

as of your pictures at this size its impossible to determine few thing, please post 100% crop from center of 2nd and 3rd picture




and on very end, picture under shows an example where my KX failed to AF in any mode at the object, took me 20 shots to get it sharp with manual focus cause AF refused to lock on that cat, was pretty dark room single 40 watts bulb in enclosure above, btw with 50/1.4 lens





ok now mr UnkownVT please explain my points, hopefully someone will step up and write what i mean in english and you will get my point if you dont and please dont twist what i said.

and still even i do love my pentax i dont think its a good expensive p&s camera, its a camera to someone who is starting adventure with DSLRs not for one whos is ending with it.

thanx for patience,

fafo13, the noob

Last edited by fafo13; 04-26-2011 at 08:47 PM.
04-26-2011, 10:01 PM   #19
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QuoteOriginally posted by fafo13 Quote
ok now mr UnkownVT please explain my points, hopefully someone will step up and write what i mean in english and you will get my point if you dont and please dont twist what i said.
Let's just address your focusing issues - without resorting to any personal comments.

Please look at the K-x viewfinder view that vegabraveian posted previously:

I've highlighted the 5 AF points in red.

In that view one can see if the camera chose to use the lowest or the top focus points then the picture probably would be out of focus - but in this case since three sensor points along the middle cover better detail it hopefully would have chosen one of the points along the area of main interest.

So far hopefully this is easy to understand.

However the important point is that the camera cannot read our minds - so it does not know which point to use - merely locking on to the easiest to focus or the area with most detail.

Now if we look at your first and second pictures - because the main subjects, the people, are off center - there were probably more focus points on the car(s) behind - therefore the K-x is likely to have locked focus on the car(s) instead of what you wanted/intended - the person.
Does that make sense?

It may have a little to do with whether the main subject is darker or brighter - because with a brighter background there is more easily discerned detail, so the camera probably would pick the easier targets to focus on.

And in these cases if you used center focus - it would also make exactly the same mistake - because the center focus point would be on the car(s) right?

So how does one solve this problem?
It is in the manual -
it's to use pre-focus lock and hold, then recompose.

This is to focus on your subject by pointing the central area at the main part of interest - lightly half-depressing the shutter button to lock the focus (eg: on the face) look for the green hexagon focus confirmation icon - then holding that half depression lock - and recompose to get the whole car in the shot (keeping the green hexagon on) - then fully depressing the shutter - that way the camera had focused on your main subject - the person's face - while you hold that focus locked - then recompose to get the shot you want.

Hope you understood that - that is why a central focus point is more precise, if and only if, you pre-focus lock hold and recompose -
if all you do is point and shoot then center point focus will fail more often than not unless the main subject is always dead center.

For your shots perhaps using all the focus points may have helped doing only point and shoot - but it is still a gamble what the camera would have picked to focus on.

I strongly suggest you use the pre-focus lock and hold then recompose method as outlined in the manual - then decide whether you prefer 5 or center point.

From pages 119 and 120 in the K-x user's manual -



Hope that helps you?


Last edited by UnknownVT; 04-26-2011 at 10:12 PM.
04-26-2011, 11:05 PM   #20
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Yah...I usually using AF Lock with half press shutter. Focus and recompose. It's work too on my SF10 camera who hasn't AF Lock button.
04-27-2011, 06:50 AM   #21
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oh really, since when i had problems with af, i dont, read agsin, ive said and ill repeat it.

Kx af system isnt great, yes there are ways to work it out and achive fine photos, but its not my point

my point is if you wanna buy dslr, as casual shooter, you may be better off other cameras

like for example, i own canon which on same situations isnt failing and focusing better.

Many ppl buy dslrs to point and shoot, canons does the job, kx dont, for few reasons ive explained

which doesnt make me a noob or kx a bad camera, simply pros and cons
04-27-2011, 08:28 AM   #22
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QuoteOriginally posted by fafo13 Quote
oh really, since when i had problems with af, i dont, read agsin, ive said and ill repeat it.
Kx af system isnt great, yes there are ways to work it out and achive fine photos, but its not my point
my point is if you wanna buy dslr, as casual shooter, you may be better off other cameras
like for example, i own canon which on same situations isnt failing and focusing better.
Many ppl buy dslrs to point and shoot, canons does the job, kx dont, for few reasons ive explained
which doesnt make me a noob or kx a bad camera, simply pros and cons
I'll agree with you - K-x AF system is not really for point-and-shoot type of photography - especially not center point, and probably not 5 point -
using all the points - maybe.

All I did in the my previous post was to point out why the K-x "failed" and how one could get better focus.

Try turning on all the focus points - but as I have already said - using multiple focus points can be hit and miss - as the camera probably locks on to whatever it considers has the most detail/contrast - and in your two photos may not be the main subject you wanted the focus on.
(This is one of the reasons why many digicams now have face detection focusing - to focus on any faces it detects)

The K-r may be a better camera for you - as it will at least show in the viewfinder which points it is using to focus - but again it probably will do the same/similar thing as the K-x - but merely making its intentions visible.

Best bet is to try using the K-x with all the focus points turned on and see if it gives you any better results for point and shoot - if not, then probably the only real way of getting the majority of photos in focus on the subject you want, is to "direct" the camera to do so - that is to use the pre-focus lock hold and recompose as shown in the manual.

But I am agreeing with you that K-x is not really a point and shoot type camera - its auto focusing works well but not for p&s type of photography.

I think Canon dSLRs may have similar problems when merely used in the p&s type shooting - please look at this post in this thread it points to a series of videos by a official Canon representative on Canon dSLR AF in 3 parts
and several pages worth of posts that talk about Canon dSLRs mis-focus

Last edited by UnknownVT; 04-27-2011 at 08:36 AM.
04-27-2011, 09:34 AM   #23
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QuoteOriginally posted by fafo13 Quote
what ive learned with my kx is that center point focus is even harder to get in focus stuff than 5 point, so except few things and not even with low light situations i do use 5 point af cause it does perform lil better, and simply kx refuse to af on objects if u have light behind them even with center af even with f1.4 lenses
5 points might perform better speed wise because you give the camera chance to find something that it can more easily focus on. Below how your camera thinks
QuoteQuote:
Hey, I can't focus on the face, let's try the shirt. Also not, let's try the wall behind his grilfriend. Ah, bingo.
But you don't want to focus on that wall, you want to focus on your girlfriend It will e.g. focus on the background because it can and that is more than likely what happens in what I quoted below.

QuoteOriginally posted by fafo13 Quote
If you say so, im still getting many pics with focus behind person if the background is lighter with 5 point mode, and even with good light 10% of pics are focused at background as well, darker it gets more with focus on background, lighter background is even more, ...
And yes, this last quote states that you have AF problems.

I hope I understand your problem correctly.


Last edited by sterretje; 04-27-2011 at 09:41 AM.
04-27-2011, 10:30 AM   #24
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I've created 2 overlays based on the viewfinder image posted earlier. Keeping the original images in mind, for the first one (the dark street) I find it clear where it focused (left point). I'm a bit more in doubt about the second one, probably the center.
Attached Images
   

Last edited by sterretje; 04-27-2011 at 10:36 AM.
04-27-2011, 11:31 AM   #25
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As usual, great help from Pentaxians!

I am quite happy with the K-X and focusing.

As with ALL cameras, some shots will be off, and some individual cameras will be off.

I also think the back lighting of some of the pics may play a part in throwing off the focus.

As noted, the trick I use for quick on-the-go shots is to center focus on the subject, wait for the focus beep, then move off center as desired. Takes an extra second, but gets me more 'keepers'.

cheers
04-27-2011, 12:09 PM   #26
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QuoteOriginally posted by fafo13 Quote
oh really, since when i had problems with af, i dont, read agsin, ive said and ill repeat it.

Kx af system isnt great, yes there are ways to work it out and achive fine photos, but its not my point

my point is if you wanna buy dslr, as casual shooter, you may be better off other cameras

like for example, i own canon which on same situations isnt failing and focusing better.

Many ppl buy dslrs to point and shoot, canons does the job, kx dont, for few reasons ive explained

which doesnt make me a noob or kx a bad camera, simply pros and cons
K-x is not for P&S, that's what's your problem. It is for people who want to be serious about doing photography. And if you use the center AF point only, it's just a question of fraction of second to recompose. My friend's got a Canon DSLR for maybe 2 or 3 years and do you know how many times has he used other mode than autopicture or program? Never. He always sets everything to automatic, that's why his pictures are so shi*ty.
04-28-2011, 05:54 AM   #27
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sterretje - all 3 pics, target was withing 5 focusing points, but af chooses to focus on lighter backgound, thats what im trying to say, it iis NOT problem for me as its a annoying glitch for p&s users, about my picuters, its not i got 2 or 3, about 20-30% in similar situations are like this.

flawlessgraphics - its a way to do it, or just release and press half way shutter button, and move a little camera, most of the times kx is relocating focus, most of the time on target

freddykrueger - its not MY problem, please show me when i said its MY problem, i said it a draw back of kx, not my problem, just a annoying thing, read dont guess.

further, kx isnt p&s camera oh really ? every ( or majority) dslrs has auto mode, so you can point and shoot and out of 8 ppl i know with dslrs,5 are using it is as P&S ONLY.

"do you know how many times has he used other mode than auto picture or program? Never. He always sets everything to automatic, that's why his pictures are so shi*ty." ---- exactly and many many ppl do exactly like this, and if you one of them you will be annoyed and disappointed and you will hate pentax for reason im trying to explain, focusing at lighter background for some reason, canons are better in this matter for example and this is my ONLY point ffs

plz read, read twice if necessary cause im gonna get heart attack one day :d

tnx for input
04-28-2011, 10:29 AM   #28
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fafo13: He has a Canon and his pictures suck. It doesn't matter, what camera you have. Pictures taken in auto mode will always suck. DSLRs are simply not made for stupid people. They are made for people who want to do more than just "take pictures of something or someone". If you want a P&S with great image quality, you might want to get Nikon P7000 or something like that.
04-28-2011, 11:23 AM   #29
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QuoteOriginally posted by fafo13 Quote
plz read, read twice if necessary cause im gonna get heart attack one day :d
Let me try to clear the air a little -
because part of this is my fault.

fafo13's first post on this was in Post #5
QuoteOriginally posted by fafo13 Quote
what ive learned with my kx is that center point focus is even harder to get in focus stuff than 5 point, so except few things and not even with low light situations i do use 5 point af cause it does perform lil better, and simply kx refuse to af on objects if u have light behind them even with center af even with f1.4 lenses
I took 5 point being "better" than center point
as being "faster" and posted that it was not.

As it turned out being faster or not, was irrelevant -
I believe what fafo13 was trying to say was that in p&s type situations 5 point stood a better chance of focusing than center point.

Unfortunately his next post #16 was marred by very bad formatting as he posted from his phone - so it was hard to read - I think his gist in that was again 5 point was better for p&s - especially in situations when the main subject was dark with brighter background.

His post #18 was showing examples of the types of shots that posed difficulties - I assumed he was having problems - which he never said - and proceeded to outline how to use focus hold and recompose.

Then it finally dawned on me that all he was saying was that for p&s situations 5 point is better - and there are many who are more casual shooters and do use dSLRs in p&s mode.

So he is right, in that he never said he had a problem with the K-x, only that it can fail with p&s type shooting, especially with dark main subjects in front of brighter backgrounds.

As far as I know he may well use focus lock and recompose when encountering these situations - or just knows the K-x will not do well under p&s type shooting.

I hope I have not misread and misinterpreted fafo13 again.

So this is my contribution - hopefully defusing this situation
04-28-2011, 01:08 PM   #30
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QuoteOriginally posted by fafo13 Quote
sterretje - all 3 pics, target was withing 5 focusing points, but af chooses to focus on lighter backgound, thats what im trying to say, it iis NOT problem for me as its a annoying glitch for p&s users, about my picuters, its not i got 2 or 3, about 20-30% in similar situations are like this.
The overlay is quite accurate. What was the target in the 2 photos? For the first one I'm quite sure it was the lady (your girlfriend?). And she only covers three of the five focus points, not all five. So you still give the camera chance to focus on one of the other two focus points; and it picked the one with the lighter background. As you're saying. Reason in this specific one is probably that the bonnet and windshield have a nice contrast, not so much that it was brighter.

Would you have set the camera to center focus, it either would have gotten it right (probably with great difficulty in the photo with the lady) or it would not have been able to focus on the lady at all. But it would not have missed the focus as badly as it did in that photo.

Therefore I'm of the opinion that you should only use center focus or select a focus point yourself (and remember it), specifically with the K-x that does not tell you what it has focused on.

As I see it:
1)
you use 5 point focus and accept that the camera gets it wrong in a significant number of cases
2)
you use center focus and accept that the camera can not always focus
3)
you use center focus and make life easier for the camera by
3a)
pop the flash up so it can assist the camera in focusing; push it down again before taking the actual shot; inconvenient as it implies extra actions but a possible solution
3b)
get an external flash with focus assist light; some of them have a mode where they will not flash but only do the focus assist; inconvenient because you now need to carry a flash around.
3c)
get a camera with a focus assist light

A little story
I had a film SLR and bought my wife an advanced P&S. On a holiday, we decided to leave the film camera at home and only use the P&S; it even had the option to use center focus. One little problem: after going in sleep mode it forgot that it was previously set to center focus. As a result focusing was all over the show if we quickly wanted to take a photo and the keeper rate was about 20%.
That was for me the reason to buy a dSLR. And I have never ever allowed the camera to select a focus point. Most of the time center focus and recompose and sometimes I selected another point

And a note:
The (red) squares do not indicate the size of the focus point; the actual area is bigger. For the center focus point it is said to be slightly smaller than the rounded braces at the left and right of it (so about 2.5 times bigger)
And the camera will try to find something in that area (either far away or nearby) to focus on. So it can still focus on something that you don't expect (the bonnet and windshield is an example where the actual contrast is outside the red square).
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