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12-18-2010, 08:39 AM - 1 Like   #1
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who cares for bad AF under tungsten light ?

I cannot believe that only very few of the PENTAX Kr and K5 owners care about the disabillity to autofocus in dim and tungsten light conditions. I had my K5 callibrated, checked, replaced but with a fast lens (let`s say 2.8 or faster) and a 50 mm or wider lens attached the K5 is not capable to make a clean head shoulder portrait for example. Just give it a try under dim or tungsten light (artificial lit room) if you have a fast lens (70mm limited for example) . Just AF on the eyes of person with wide diafragma . You will find your Focus on the tip of the nose !! with or without flash .
In case you microadjust the front focus you will find yourself with the same problem in daylight again !
Why are hordes of people satisfied with a product that cannot focus correct and consistent in daylight and artificial light allike ?
It is not a 20 Dollar throw away cam but it is supposed to be a semi professional camera. Believe me NO professional will keep a camera with this issue for any longer than 1 hour and after testing bring it back to his dealer.
I did and I am very dissapointed that a camera that is built for fast fotograpy falls short in exactly this aspect.

Do the test yourself and you will find similar issues with your copy !
Take the 2.8 or faster aperture with your 35 or longer lens . AF on a short distance ( 50 cm till 1 metre) and you will get ZERO pictures in focus in artificial light conditions !
How about that from a guy that would do everything to keep the K5 because he likes it soo miuch for all other features but cannot because of this idiot shortfall . In case you don`t care about an inch or so out of focus or only shoot with the kitlenses you can consider this posting as non valid for you !

12-18-2010, 08:54 AM   #2
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That's strange. My K-5 is perfect with all my lenses under tungsten. The K-r is known to have problems, but I hadn't heard the K-5 had them.

Are you sure you're complaining about the right camera?
12-18-2010, 08:59 AM   #3
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OP, you sure are good at finding camera faults judging by your post history!
12-18-2010, 09:05 AM   #4
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QuoteOriginally posted by bjan Quote
Why are hordes of people satisfied with a product that cannot focus correct and consistent in daylight and artificial light alike ?
Probably because this "issue" is nothing new. AF systems tend to front focus a little bit under tungsten light, not just with Pentax bodies, but for other systems as well. Personally I think the K-7/K-5 does a better job handling this than some older bodies I've owned, but I would agree it's not quite perfect - but not to the point of crying foul over it.


Last edited by dgaies; 12-18-2010 at 09:37 AM.
12-18-2010, 09:30 AM   #5
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QuoteOriginally posted by bjan Quote
Just AF on the eyes of person with wide diafragma . You will find your Focus on the tip of the nose !! with or without flash .
One thing that's a bit odd about the Pentax AF sensors is that the cross sensors are a *lot* bigger than the little dots on the screen unlike e.g., a Nikon or Canon system.

Do this exercise...draw a cross on piece of white paper and put it on the wall. Set the AF point to each of the points and repeat: hit the cross from the left, right, top and bottom w/ the shutter half pressed. This will give you the actual size of the focus sensor at that point. Repeat the exercise w/ another DSLR that you own (sounds like you're used to another brand). Report back the results...
12-18-2010, 09:38 AM   #6
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I'm also very intersted in this..and I always have the feeling that the faster the shutter speed I use (so higher the iso for the given f number) the better the chance I get in-focus portraits of my son-now taking a portrait of somebody who is not 5 years old gives me even better chance for in-focus under low light-artificial lighting.

my 80 year's old father with the K-5 FA50 1.4 at f2.2 iso4000 1/50. The walls in my parent's flat are quite yelloish so the AWB just got it right. Focus on his left eye-seems good for me. Out of the four pictures I took three are in good focuslike that:



Andras
12-18-2010, 09:42 AM   #7
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QuoteOriginally posted by pxpaulx Quote
OP, you sure are good at finding camera faults judging by your post history!
In the OP's defence, I yesterday had the opportunity to try a K-5 in a local shop. I brought a number of my lenses along. The salesman was kind enough to take me back to a storage room dimly lit with tungsten light. Lenses that focused properly on the bright showroom floor missed AF focus terribly under low tungsten light on this K-5.

Yes, it certainly could be operator error of some kind. I am not an expert photogapher. I have no experience with the K-7, but my K20D will sometimes miss focus slightly under this type of condition, but this K-5 was not even close.

Just figured I would share that experience.
12-18-2010, 10:21 AM   #8
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Very nice shot planedriver !
It looks that your camera/ lens combo had the AF spot on here.
Did you microadjust the lens for this circumstance or is it the same setting that would give you a spot on focus in daylight ?
My experience is that 0 out of 100 would be in focus like yours. 2 bodys tried extensively and no way to get what you have there withe tamron 17-50 2.8 in 50 . 2.8 settting. I do believe that with primes the problem might be les pronounced than with zoom lenses though.
I have tried a D700 with 24-70. 2.8 combo (wich is in an other ballgame of course) that did not present the artificial light AF issue . Problem is that I don`t want to get so "BIG" with my equipment and would pay anything in case PENTAX got it right . So believe me I am not trying to bash the K5 but I cannot work with the shortcoming of bad AF in Tungsten light and short DOF

12-18-2010, 10:30 AM   #9
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I've got the same problem and we are not alone, there are rumors about a new firmware but if it's true, who knows? Something has to be done, the "+" sign in the AF name suggests that the camera should compensate for tungsten light but it's not very successful.
12-18-2010, 10:43 AM   #10
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Well I did make some nice pictures, so it's not all misery.

12-18-2010, 11:32 AM   #11
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Hey Ron Hendriks,
That portrait seems to be made with a wider than 50 mm to me . You will have a dof of several inchess and not facing the issue here even wide open. Sharp it is though.
12-18-2010, 11:59 AM   #12
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Sorry, but I disagree with your assessment. I have had very little difficulty focussing in tungsten or even very poor light with my K5.
All cameras of all makes are going have a little difficulty in finding focus in adverse conditions but, honestly, I would suggest that the K5, in particular, is up there with the best of them.

Imcidentally, which do you own, the K-r of the K5, or, come to that, both?? (edit: I notice you have the K5. sorry)

It is early morning here, no daylight, I just went and turned the tungsten light on in one room, went into the next room, door open, and my K5 focussed on several subject almost instantaneously.
Tried in almost dark, enough light that I could just see, and with AF assist (green light) again almost instant focus.
K5/DA35mm 2.8.

Where the problem exists is very vague to me??

Last edited by Bramela; 12-18-2010 at 12:13 PM.
12-18-2010, 12:13 PM   #13
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The K-7 is not particularly accurate in low light conditions, but I was hoping the K-5 would be much improved. I still use my 5D for tough light, and while it is slower than the K-7, the 5D is pretty consistent in low/difficult light. Hopefully Pentax can improve the AF accuracy. I really like the compact size of the K-7/K-5 and the quiet shutter compared to my 5D.
12-18-2010, 12:14 PM   #14
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QuoteOriginally posted by bjan Quote
Very nice shot planedriver !
It looks that your camera/ lens combo had the AF spot on here.
Did you microadjust the lens for this circumstance or is it the same setting that would give you a spot on focus in daylight ?
Thanks..no I haven't touched the "adjust" at all-I know that my FA50 front focuses on my K-x at f2..but at this time I just tried..and seems to work fine..on the other hand I still believe that a moving "object" like a child is a very very difficult target..as even they sit on a chair they constantly keep moving..so for a good focus we need fast shutter..that's my impression (which can be unscientific of course).

Andras
12-18-2010, 12:15 PM   #15
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I think it is hard to argue or discuss about the issue without physically being together and being able to show picturewise ad hoc the findings and meaning of our words. However I am jealeaous to those who don`t experience any serious AF issue whereas I am completed frustrated by wanting to like the K5 very much but had to return it because of the large aperture tungsten AF issue that I don`t want to work around.
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