[HockeyDad]

I've had my K-r since March/April 2011 and have a shutter count of 22,577. Here's my take:

• The 5-point and 11-point settings have been useless in my hands. I used center-point for a long time and then switched to Select-point back in April of this year.
• Since the AF fine-tune is a global setting for the camera and not a per-lens setting like it is in K-5, K-30 and others, I have found it to be more inconvenient than it's worth.
• Some lenses are better than others.
• The AF system in the K-r is not nearly as decisive under low tungsten lighting conditions as it is in other lighting conditions.
• When the AF misses under low light, it is always front focused. However, I might shoot 3 shots of the same scene, refocusing in between and maybe only 1 has missed focus. So it is not consistent. I have many shots by the light of only 1 low wattage tungsten bulb that are dead on.
• If you have the time, using Live View and clicking the info button a few times to zoom into your subject makes for an awesome way to nail focus manually in near darkness every time.

All that said, I don't tend to rely on my K-r as a "snapshot" camera at indoor family events. That's what our point-n-shoot excels at and my wife knows to always have my back grabbing those snapshot moments while I grab candid portraits and more "artsy" photos.


There are a lot of things to love about the K-r but I believe auto-focus performance is not one of them. I've said this before in other threads... Like anything, you have to weigh the pros and cons and decide for yourself if it fits your needs. It's a real struggle to fit 3 hockey bags, myself and 2 boys into my Mustang but I live with that shortcoming because it is crazy fun to drive and it was a great value.

[Mr Spocko]

I use a K-r and it does FF in tungsten light. The focus adjustment is not per lens as in the K-5 and newer bodies.

I may be wrong but I think the general consensus was that the AF module (SAFOX IX) design was flawed to begin with. I think this is caused by CA on the AF sensor when under tungsten light. The K-5 uses the same AF module but it has an additional light source sensor to compensate for this. The the K-30 went even further by adding (or improving) a lens in front of the AF sensor.

I'm not a camera technical expert, just basing on information I read from the internet. So anyone please correct me if I'm wrong.

I've done some AF comparison with my old DS in case you are interested. First test I did here.

That was my understanding too. K-r = FF in low kelvin lighting (it does not have to be low light just the light temperature) it is quite substantial to the point where phase detect AF is basically not usable. But varies depending on focal length/aperture. The K-5 also suffered from this though not as much (note how everyone is now saying it has a problem since the K5II turned up)

I have not used a K-30 but would hope it does address this serious flaw. I did not notice any specific issues with the K-x in this respect or lighting conditions. Or on older bodies DL2 etc etc
These issues should have been resolved by the manufacturer whilst the models were still in production, and a fix offered for customers, sadly this was not the case.

[lister6520]

......

These issues should have been resolved by the manufacturer whilst the models were still in production, and a fix offered for customers, sadly this was not the case.

I've seen mention that setting the WB manually to tungsten gets it to focus properly. At first sight it doesn't make sense as the focus sensor is not affected by the WB setting. However it struck me as a possible stopgap solution that could be provided via a firmware upgrade as all it would need is to automatically change the focus fine adjust when that WB setting is selected. Not a real solution to the problem but would make life easier than manually setting the fine adjust when shooting in tungsten light.

I have not been able to check whether this fix is actually in the firmware as oddly enough I don't have any tungsten lights around to try it with.

[GrinMode]

I've seen mention that setting the WB manually to tungsten gets it to focus properly. At first sight it doesn't make sense as the focus sensor is not affected by the WB setting. However it struck me as a possible stopgap solution that could be provided via a firmware upgrade as all it would need is to automatically change the focus fine adjust when that WB setting is selected. Not a real solution to the problem but would make life easier than manually setting the fine adjust when shooting in tungsten light.

I have not been able to check whether this fix is actually in the firmware as oddly enough I don't have any tungsten lights around to try it with.

See my tests. Setting to tungsten does help a bit. I guess the software can offset because it then knows it's shooting under tungsten light. The light sensor in the K-5 allows this to be set automatically.

FWIW, except for the FF issue in tungsten light, I have no problems with my K-r whatsoever.

[Mr Spocko]

Setting to tungten did not in my case make any significant difference..if there is one it's only very minor. In normal lighting I had no issues with AF at all. Just if you shoot a lot in this type of artificial light you'll get quite frustrated. In Europe this lighting is very very common indoors. I suspect the AF module was flawed and not field tested properly. I'm still a bit shocked that they did not address this with a new AF sensor.

[GrinMode]

Setting to tungten did not in my case make any significant difference..if there is one it's only very minor. In normal lighting I had no issues with AF at all. Just if you shoot a lot in this type of artificial light you'll get quite frustrated. In Europe this lighting is very very common indoors. I suspect the AF module was flawed and not field tested properly. I'm still a bit shocked that they did not address this with a new AF sensor.

I guess results in setting to tungsten WB depends on what you are shooting and settings. My not-so-scientific tests show improvement. But I have not really pixel peeped in real world situations. In cases I'm under tungsten light, I usually use live view. And that's because in most cases, it's just casual shooting :-).

If I remember correctly, the tungsten light causes or is seen as CA (or enhances it) by the sensor, hence they added the correction(?) lens in the K-30 AF module. I think this was suggested by someone who really knew what he was talking about. Not sure if it was Falk or someone else. (These discusssions are a year old, I cannot remember exactly).

So maybe did not need a new sensor, just fix the current one.

[photoshoper]

Received My K-r today ,,, a friend of mine got it used from UAE ,,, unfortunately after test ,, i found it has "Global" FF in different lighting ,,, but fortunately :-) after setting fine AF adjustment for( -10 ) ,,, all lenses works spot on ...

[GrinMode]

Received My K-r today ,,, a friend of mine got it used from UAE ,,, unfortunately after test ,, i found it has "Global" FF in different lighting ,,, but fortunately :-) after setting fine AF adjustment for( -10 ) ,,, all lenses works spot on ...

That's good to know

[geru2000]

Received My K-r today ,,, a friend of mine got it used from UAE ,,, unfortunately after test ,, i found it has "Global" FF in different lighting ,,, but fortunately :-) after setting fine AF adjustment for( -10 ) ,,, all lenses works spot on ...

If all your lenses are at - or + 10 why not download pktether and set the cameras global adjustment to that then you'd have them set to 0?

[jlaubza]

Many people have reported a FF on the KR in yellow light i.e. a low Kelvin temperature.

I have an idea which I wonder if anyone has tried out - use a light blue filter on the lens - this will shift the wavelength back up the Kelvin scale and possibly correct the problem?

WB can be custom set with the filter in place so wont be a problem.

It seems that the AF module is confused by the longer wavelength of low Kelvin temperatures.

Adjusting the WB to a tungsten setting should not make any difference as it is simply a blue filter applied after light reaches the sensor - the same light reaches the focus module and therefore is still light at a low Kelvin temp. The light has to be 'blued up' before it reaches the sensor.

Please let us know if this works - I dont have a blue filter to try out this theory and have in any case thus far not had problems in indoor lighting.

[Tim A]

Many people have reported a FF on the KR in yellow light i.e. a low Kelvin temperature.

I have an idea which I wonder if anyone has tried out - use a light blue filter on the lens - this will shift the wavelength back up the Kelvin scale and possibly correct the problem?

WB can be custom set with the filter in place so wont be a problem.

It seems that the AF module is confused by the longer wavelength of low Kelvin temperatures.

Adjusting the WB to a tungsten setting should not make any difference as it is simply a blue filter applied after light reaches the sensor - the same light reaches the focus module and therefore is still light at a low Kelvin temp. The light has to be 'blued up' before it reaches the sensor.

Please let us know if this works - I dont have a blue filter to try out this theory and have in any case thus far not had problems in indoor lighting.

This was answered a couple of years ago, or so. I will give that answer, but don't know how accurate it is. The Kr tungsten light issue is only in both low light and tungsten light. In sufficient tungsten light there is no FF problem. The thinking was that the blue filter would actually compound the problem in low light.

[Mr Spocko]

The problem is with the AF module itself the design was flawed and the optics are subject to colour light shifts which causes problems even "if" the light levels are not that low. But it's usually seen in low light as many energy saver bulbs have a low kelvin rating. Also present on halogen bulbs but not flourescent lighting.
The only solution would have been for Pentax to fit new AF modules, but the decided not to change this during production or offer it as a service fix.
There are no real work arounds bar using live view/manual focus, filters don't help I tried all that

Alternatively they could have made the AF assist light come on frequently (which it does not) that might have been an acceptable (to some) solution.

[ThomasSimon]

Did all K-r users have FF or BF AF problems ? did the k-r have af fine adjustment option ?

Hi, never had a problem with AF on my K-r I have since almost one year and a half. Even though it's weakness (the most common on basics reflexes) is making an accurate focus in low light while you're shooting a moving subject as in night street photography. I used it first with the 18-55 kit which is very poor to me and was slow on AF but later on with a DA 35mm AL or the 50-135mm SMD I never stated a really issue coming from the body AF system. I agree with people saying it's a great camera. For an entry point camera it's the best I could ever choose. No regrets at all, I'll keep it until the end!

[jlaubza]

I had to send mine in. I had to adjust some lenses all the way to -10. I first noticed it with a fast lens, the FA50/1.4. My K100D didn't have any focus issues and the K-r did. I found that the adjustment was too extreme, and gave me no leeway, so I sent it to CRIS. If you are talking about the FF in tungsten lighting, if you set your white balance to tungsten then it will fix that particular issue.

This so called Tungsten light setting solution does not fix the problem, as many readers have attested. What can fix it is a replacement of the relevant circuitry in the camera, or, simply, a blue filter over the lens, leaving WB set to white light e.g. daylight. The Tungsten setting in WB menu simply adds a blue filter to the image to cancel the yellow colouring. You can do the same in PP with a raw image. The FF problem is caused by the wavelength of Tungsten light. Balancing the incoming light with blue filtering enables correct focus.

[Mr Spocko]

What should have happened is Pentax should have fixed the problem during production and offered a free fix to buyers. That was the only acceptable way to deal with this.
They could have made the AF assist light work properly that might have helped or eased the pain.