K-5 AF issues

Started Nov 25, 2010 | Discussions
moertl Junior Member • Posts: 43
K-5 AF issues

Hi,

I received my K-5 on Saturday and basically I'm very impressed by the overall performance, especially in comparison to my old GX-10.

Nevertheless I experience some strange AF issues with it, no matter which lens I use.
I tried the following lenses and get similar issues with either one:
Pentax DA 35mm/2.8 ltd.
Pentax DA 40mm/2.8 ltd.
18-55mm Kit lens
Tamron 18-250mm
All the lenses work well on my old GX-10.

On my K-5 AF works fine and is spot on in short and long ranges.

When I try to focus objects in a distance roughly about 3m (lets say between 1,5 to 4 meters) I get all blurry (out of focus) images. With the zoom-lenses its especially noticeable at short focal lengths (e.g. 18mm).

If I use LiveView (LV) instead and with it the second focusing method images are as sharp as it gets. The difference in focusing results between the two AF methods can also be seen repeatedly on the focus distance indicator ring at each lens.
When not using LV focus distance is always too short (e.g. 1,5m instead of 2m).

Results are the same in bright daylight an in artificial light.

Does anyone experience the same issues and can give advice how I can get rid of them?

Thanks,
martin

 moertl's gear list:moertl's gear list
Samsung GX-10 Pentax K-5 Sony a7R III Pentax smc DA 18-55mm F3.5-5.6 AL WR Sony FE 35mm F1.4 +7 more
nigbat Senior Member • Posts: 1,939
Re: K-5 AF issues

With the zoom-lenses its especially noticeable at short focal lengths

I think I may be seeing something like this as well.

But - I've only had the camera a couple of days; I've been shooting mostly at long focal lengths (and in very low light); I haven't yet downloaded the firmware update. Mostly, the AF has been a big improvement on the K20D.

Have you updated your firmware ?
As soon as I get some time, I plan to get this done and run some tests.

awaldram
awaldram Forum Pro • Posts: 13,271
Re: K-5 AF issues

Sounds like your camera is faulty, Can you get to a shop to try another body with your lens.?

If not I think you'll need a DOA replacement from your supplier.

Here is some examples in the raneg 18mm-2 Meters.

 awaldram's gear list:awaldram's gear list
Pentax K-x Pentax Q Olympus PEN E-PM2 Pentax Q7 Pentax K-3 +17 more
OP moertl Junior Member • Posts: 43
Re: K-5 AF issues

I updated mine to firmware version 1.01 but discovered the strange behavior after the update, so I can't say how it is with 1.00.

 moertl's gear list:moertl's gear list
Samsung GX-10 Pentax K-5 Sony a7R III Pentax smc DA 18-55mm F3.5-5.6 AL WR Sony FE 35mm F1.4 +7 more
Russell Evans Forum Pro • Posts: 12,617
Re: K-5 AF issues

I would try the reset options in the menus to get the camera back to its defaults, and then apply the firmware update again. There were a couple of reset options in the older cameras and I have no experience with the new, so I can't tell you the specific resets. I would just do them all.

I know it sounds odd to redo the firmware upgrade, but I have supported machines that kernel developers used and have seen a lot of things that I wouldn't think possible, and wouldn't expect to be able to affect at the hardware level. I am therefore more open to the possibility and will try to do what I can to avoid the hassle of returns or repairs if I can, so it is just something I would try. This puts the camera into a known good configuration and is the base line for testing again.

If you still have the issue, then probably is that the camera has an issue and you will have to make the decision to repair or return. I have two cameras, and now always will, so I probably would send mine in for repair instead of replacement. The reason for this is that I figure I would have on return, a hand calibrated camera by a certified tech, as opposed to one that might or might not have passed QC on an assembly line. Some people would just want a working camera from the box that they know doesn't have an issue, and that makes sense too. I always had a pretty good experience with Pentax repairs so this also plays into my decision. I just think I'll get more from the repair.

Thank you
Russell

-- hide signature --
OP moertl Junior Member • Posts: 43
Re: K-5 AF issues

Hi Russel,

thanks for your advice!
I'll give it a try tonight and will report if it helped.

martin

 moertl's gear list:moertl's gear list
Samsung GX-10 Pentax K-5 Sony a7R III Pentax smc DA 18-55mm F3.5-5.6 AL WR Sony FE 35mm F1.4 +7 more
OP moertl Junior Member • Posts: 43
Re: K-5 AF issues

Hi,

ok I did a reset of every configuration I could find. Then applied again a newly downloaded firmware update from 1.01 to 1.01 and resetted everything to factory defaults again.

Sadly nothing improved.

After all I experimented again with AF calibration. An overall setting of -10 at least improved things, but still contrast AF in LV produces by far better results.

So I guess I'll have to get it repaired and/or properly calibrated.

Thanks for the try!
martin

 moertl's gear list:moertl's gear list
Samsung GX-10 Pentax K-5 Sony a7R III Pentax smc DA 18-55mm F3.5-5.6 AL WR Sony FE 35mm F1.4 +7 more
Ronald E. Chambers
Ronald E. Chambers Senior Member • Posts: 1,249
Re: K-5 AF issues

Try cleaning the contacts on each lens and then try.

RON C

 Ronald E. Chambers's gear list:Ronald E. Chambers's gear list
Pentax smc FA 50mm F1.4 Tamron SP AF 10-24mm F/3.5-4.5 Di II LD Aspherical (IF) Pentax K-1 II Pentax smc DA* 50-135mm F2.8 ED (IF) SDM Tamron AF 28-300mm F/3.5-6.3 XR Di LD Aspherical (IF) Macro +4 more
Britney Elvis Veteran Member • Posts: 5,373
Not sure the contacts are it

Ronald E. Chambers wrote:

Try cleaning the contacts on each lens and then try.

RON C

Not sure that is an issue since in 'Live View' the Op says it is focusing spot on.

But I love how the clean the contacts is still one of first fall backs. I have had three Pentax dslrs and have never cleaned the contacts on the cameras or the lenses...

-- hide signature --

'Nothing is worse than active ignorance'

Johann Wolfgang von Goethe

OP moertl Junior Member • Posts: 43
Re: K-5 AF issues

Hi!

I tried it, but didn't help. Contacts were still nice and clean.

I suspect its not correctly calibrated, because some improvement can be seen if I use in camera AF adjustment settings.

Thanks,
martin

 moertl's gear list:moertl's gear list
Samsung GX-10 Pentax K-5 Sony a7R III Pentax smc DA 18-55mm F3.5-5.6 AL WR Sony FE 35mm F1.4 +7 more
spawns New Member • Posts: 5
Re: K-5 AF issues

Your K-5 AF sensor is Front Focusing you can send it in and let it adjust under warranty or wait for the K-5 Debug Menu hack and adjust it yourself further of -10

Model Mike Veteran Member • Posts: 3,892
Re: K-5 AF issues

spawns wrote:

..or wait for the K-5 Debug Menu hack

Debug hack? The K-5 already has per-lens AF micro-adjustment, or am I missing something...

-- hide signature --
Mr_Cynical Regular Member • Posts: 294
Re: K-5 AF issues

Model Mike wrote:

Debug hack? The K-5 already has per-lens AF micro-adjustment, or am I missing something...

Yep

Most Pentax DSLRs (even the recent ones with the 'official' lens microadjustment) have a debug menu which allows adjustment beyond the normal +10/-10 limits of the microadjust.

limbonaut Regular Member • Posts: 152
Re: K-5 AF issues

I recently returned my first K-5 body due to a delayed reaction on the rear e-wheel. I also noticed the same phenomenon raised by the OP and have now confirmed that my second body is also significantly out of focus on objects approximately between 8 and 30 feet away. I've tested with the kit 18-55, tamron 28-75 and pentax 55-300 da lenses and they all begin to miss focus in that range. That does not mean that all shots are OOF but at least half or more are. However, I do notice that it occurs more in low light than in good.

This might mean that Pentax's phase detect is just poorer than its contrast in low light, but I am coming from a Nikon D90 that did not have this issue. If this is my second body with the same issue I think its not a problem limited to a "few bodies." Live view focus does not have this problem. Anyone else?

RPulley Senior Member • Posts: 1,175
Re: K-5 AF issues

limbonaut wrote:

I recently returned my first K-5 body due to a delayed reaction on the rear e-wheel. I also noticed the same phenomenon raised by the OP and have now confirmed that my second body is also significantly out of focus on objects approximately between 8 and 30 feet away. I've tested with the kit 18-55, tamron 28-75 and pentax 55-300 da lenses and they all begin to miss focus in that range. That does not mean that all shots are OOF but at least half or more are. However, I do notice that it occurs more in low light than in good.

This might mean that Pentax's phase detect is just poorer than its contrast in low light, but I am coming from a Nikon D90 that did not have this issue. If this is my second body with the same issue I think its not a problem limited to a "few bodies." Live view focus does not have this problem. Anyone else?

My K5 behaves this way as well, and no mater what AF mode I use, the output is rather soft. It sharpens up ok, but it does seem that something is amiss.

Ray

limbonaut Regular Member • Posts: 152
Re: K-5 AF issues

I've dialed in -10 on af adjust which has minimized but not cured the problem. Perhaps we need to figure out what serial number range does not have this problem.

Model Mike Veteran Member • Posts: 3,892
Re: K-5 AF issues

limbonaut wrote:

This might mean that Pentax's phase detect is just poorer than its contrast in low light

Phase detect is less accurate than Live View/contrast detect, period. But PD focus should still be acceptable at all distances, especially after calibration. Perhaps you have a faulty combo.
--
Mike
http://flickr.com/rc-soar

awaldram
awaldram Forum Pro • Posts: 13,271
Re: K-5 AF issues

Model Mike wrote:

limbonaut wrote:

This might mean that Pentax's phase detect is just poorer than its contrast in low light

Phase detect is less accurate than Live View/contrast detect, period. But PD focus should still be acceptable at all distances, especially after calibration. Perhaps you have a faulty combo.

I've found the opposite not accuracy but in low light I can continue to achieve AF lock with PD long after Contrast detect has failed.

Admittedly this is with 200mm+ lens but I don't think that should make any difference.

-- hide signature --
 awaldram's gear list:awaldram's gear list
Pentax K-x Pentax Q Olympus PEN E-PM2 Pentax Q7 Pentax K-3 +17 more
Elderly Regular Member • Posts: 369
Re: K-5 AF issues

For me considering a K5 this is rather worrying.
As I said in my K5 or D7k post, accuracy of focus is vital to me.

I had a similar problem of innacurate focus at certain (mid-range) distances with my Fuji S5Pro but when I sent it back they just said that at their test criterion (short range) it had no problem.

I then took it back to Fuji UK myself, they just swapped it for another body
and that one was fine.

nigbat Senior Member • Posts: 1,939
Re: low light

I've been using a (rented) 60-250 in very low light, and have no problem getting focus lock at 200mm and up, in light my K20D would have given up on. Focus was spot on, as well.

At the other end (60-80mm), focus locked just as quickly, but many off the shots were way out of focus.

Keyboard shortcuts:
FForum MMy threads