[GeneV]

FWIW, I haven't found that the K5 is less accurate than any other Pentax when it locks, but I have found it more picky about whether it will lock at all. In low, tungsten light conditions, I've had the K5 fail to lock focus with a zoom (f4 max aperture) where the K20d had fewer issues in the same location. I've also had it refuse to lock in very bright sun until I replaced a fast prime with a slower zoom. Go figure.

[hml]

Picked up the K5 last week. Now I had tried the K5 during the summer in parallel with my K20. Shots were sharp as a tack and really enjoyed its speed and quietness for pictures taken in the forest. I do alot of nature photography. Figured I would wait until the price dropped which it did and picked it up. Been taking shots in testing out the K5 and noticed the same thing about the AF accuracy. Shots were not tack sharp and actually appeared a little soft. JPG was worse then RAW. With RAW was able to manipulate the processing but felt that this was not acceptable where sharpness was concerned. Used the same lenses as I did during the summer. After reading this thread decided to return the K5 for another one. On quick review the shots are definitely sharper both JPG and RAW. Will do a proper test over the weekend.

Here is a question for the group that have experienced the AF issue: What firmware number are you running?

When I had the AF issues I had updated the firmware to 1.11. With the replaced K5 it is sitting at 1.01. The test I will do is same shot same lenses but will then upgrade firmware and repeat to see if that was the cause or if the previous K5 was just a lemon. Is it possible to downgrade the firmware upgrade if that issue comes up again?

[westmill]

I had problems with inacurate focusing using the tamron 17 - 50 F2.8. Finally sorted it with - 5 in fine adjustment.
I took a pic of the wife in bed in almost total darkness using metz 50 flash. Focussed no problem and good pic to boot.
because of the initial problems i have not yet got the same confidence as I have with my nikon d300 etc... but its getting there.
Micro focus motors in lenses wear out and sumtimes prematurley. Try your lens on a different K5 !!!!
That would at least tell you if its the camera or the lens !

[ogl]

So I played around with K-5 and the FA43 Limited (okay it's low light, given off by a single energy saver bulb) and I noticed the AF is just not very consistent. Sometimes it will get the focus right, but more often than not it's slightly front focusing.

In comparison, focusing using Live View nails the focus each and every time.

I have a Katz eye focusing screen, and I noticed that whenever using AF, often the resultant focus lock is slightly "off". If I manually correct it, I get better results.

I tried to correct the front focus using the AF fine adjustment, but the problem is because the AF focus is inconsistent, there is no single adjustment setting that will improve focusing.

Should I send the K-5 for repair? Will that improve AF consistency?

The same sad history with my combo K-5 + FA43. Different apertures + different light conditions need different correction...It's a problem.
For example, I made some photos with -6 correction = some photos wide-opened (f1.9-f2.5) are almost in spot, but f2.8-3.5 are out of focus...
Put ZERO - some photos wide-opened front-focused, f2.8-4 are close to good...Insane...

I've made a lot of photos today with FA43 - with VARIOUS (+) and (-) correction - it drives me to despair....With tripod and remote cord.
No results. No any sharp photo. AT ALL.
I can download PEF files.



FA77 (+7 correction), FA135 and FA*24 work fine.

I have K200D and can put FA43 into K200D. My K200D is superb with all may lenses. But...K-5 is more expensive and modern camera...For what I've paid money?

---

Last edited by ogl; 01-07-2012 at 10:40 AM.

[GeneV]

I'm using the latest firmware, and still have issues with focus lock in low, tungsten light.

[Ray Pulley]

I'm using the latest firmware, and still have issues with focus lock in low, tungsten light.

Gene,

My K5 has been very good since 1.03 was installed. Definitely better than my K20 or any earlier Pentax I have owned.

Can you post an example with EXIF or at least the details (lens, fstop, ISO shutter speed and so on)?

I am interested mainly in what the real light level was.

Thanks,

Ray

[jazzcat]

Is AF accuracy an issue with the pentax brand lenses as well? I bought the 18-135 WR but have only taken a few shots because of move since I bought the camera a few weeks ago.

[felixkh]

Is AF accuracy an issue with the pentax brand lenses as well? I bought the 18-135 WR but have only taken a few shots because of move since I bought the camera a few weeks ago.

I have used the DA18-135WR in both the K7 and my new K5 snd it is sharp.

[felixkh]

Will need to look for my last low light photos to share here

[ogl]

I've uploaded 1.11 firmware from Japanese site into K-5 now. I will test FA43 tomorrow again.

It's silly - but with in-camera flash all photos with FA43 are good. But I don't like flash. Outside - at the streets - no any results...

I will retest and inform here...

[westmill]

Ive just downloaded 1.11 ... but it seems 1.2 is almost ready. With luck... maybe pentax has solved
a lot of the problems
mmmmm I was on pentax site the other day and they had 1.12 in there downloads but it wasnt yet ready as it wouldnt download.
Ive just been on there again and its dissapeared and 1.11 is back.... Strange !!!!

[Anvh]

Ive just downloaded 1.11 ... but it seems 1.2 is almost ready. With luck... maybe pentax has solved
a lot of the problems
mmmmm I was on pentax site the other day and they had 1.12 in there downloads but it wasnt yet ready as it wouldnt download.
Ive just been on there again and its dissapeared and 1.11 is back.... Strange !!!!

Ricehigh did some tests.
Looks like the AF sensor is quite sensitive for infra-red light, when he used a filter to stop the infra-red light also his focus improved.

I wonder if you can cut a piece of such a filter and place it infront of the opening of the AF module...

Anyway, looks like it's a hardware problem so it would be hard to fix with software.

[philbaum]

Ricehigh did some tests.
Looks like the AF sensor is quite sensitive for infra-red light, when he used a filter to stop the infra-red light also his focus improved.

I wonder if you can cut a piece of such a filter and place it infront of the opening of the AF module...

Anyway, looks like it's a hardware problem so it would be hard to fix with software.

I just downloaded the NEW 1.11 ver and i'm still getting sharp focusing in my somewhat dim basement room.

Haven't tested it, but still remember one report where a poster said they were having better low light results by manually selecting the tungsten light white balance in those situations rather than relying on AWB.

[goubejp]

I've uploaded 1.11 firmware from Japanese site into K-5 now. I will test FA43 tomorrow again.

It's silly - but with in-camera flash all photos with FA43 are good. But I don't like flash. Outside - at the streets - no any results...

I will retest and inform here...

OGL, it is rather common on fast lenses to see residual "spherical aberrations" that makes the focus point move when stopping down; see for example photozone tests of the DA 40 Pentax SMC DA 40mm f/2.8 Limited - Review / Lab Test - Analysis
I experienced the same thing on the FA43, the FA 85 and... FA*600f4
It can be a design option to under correct spherical aberrations to achieve better out of focus (bokeh) rendering.
I myself calibrate my lenses, not wide open, but stopped down 1 to 1.5 stop
Cheers

[goubejp]

It is also the case for high end portrait lenses from Nikon, aka 85mm f1.4
Nikkor AF-S 85mm f/1.4 G (FX) - Review / Test Report - Analysis