K-1mkII missing focus only in LV

MadBill · 06-01-2021, 11:37 PM - **1 Like**

Live View CDAF is not always as accurate as I would hope, sometimes significantly worse than PDAF or manual focus (using magnification.) Assuming the camera is set to spot focus with the spot on a well lighted subject of reasonable contrast, are there any menu items that can affect CDAF accuracy?

Clavius · 06-02-2021, 12:51 AM

Ok, this morning I did some more testing... Some suggested to use the select focus instead of spot focus and I wanted to quickly try that. At first I thought that that resolved the issues. Which is great of course! But when I returned to spot focus again I could no longer reproduce the error?! I cannot just let that go and forget about it without knowing what caused it.

Only after some more extensive testing, trying to reproduce the error, it came back. In both spot AF and select AF. I also noticed that the colors in photos taken with LV seem desaturated in comparison to photos taken through the OVF. It can also be seen in the test photos that I posted earlier in this thread.

This maybe a stupid theory of mine, but could it be caused by the sensor heating up? Or because it's used longer in live view mode? In live view the sensor is used to feed information to the screen constantly. But when using the OVF it is "resting" until the actual picture is taken.

I find this so strange, because in my K-5 I am so used to AF in live view being much more precise. There it would seem the other way round.

Bertrand3000 · 06-02-2021, 03:42 AM

Overheating sensor would, I think, results in more noise. Your problem is very odd.

dlhawes · 06-02-2021, 04:14 AM

My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus.

Clavius · 06-02-2021, 04:22 AM

Originally posted by Medex

Did you try central spot focus only in Live View? How about "Select" focus mode and using another area to auto focus? Same missed focus?

Originally posted by dlhawes

My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus.

No, I have no microadjustments active. Menu for microadjustments is set to 1 / defaults.

Unregistered User · 06-02-2021, 08:56 AM - **1 Like**

I have found that Tamron 70-200 are unable to nail focus in Live View on K-5. Why? I never understood. Always back or front focus. But OVF no problem.

Then there is the problem that when you focus the lens it is fully open and if stopped down when shooting there may be a shift in focus, called focus shift. I have had that on a couple of lenses. The OVF focus knows this and compensates while LV focus seeks maximum contrast.

---------- Post added 06-02-21 at 05:58 PM ----------

Originally posted by Clavius

Ok, this morning I did some more testing... Some suggested to use the select focus instead of spot focus and I wanted to quickly try that. At first I thought that that resolved the issues. Which is great of course! But when I returned to spot focus again I could no longer reproduce the error?! I cannot just let that go and forget about it without knowing what caused it.

Only after some more extensive testing, trying to reproduce the error, it came back. In both spot AF and select AF. I also noticed that the colors in photos taken with LV seem desaturated in comparison to photos taken through the OVF. It can also be seen in the test photos that I posted earlier in this thread.

This maybe a stupid theory of mine, but could it be caused by the sensor heating up? Or because it's used longer in live view mode? In live view the sensor is used to feed information to the screen constantly. But when using the OVF it is "resting" until the actual picture is taken.

I find this so strange, because in my K-5 I am so used to AF in live view being much more precise. There it would seem the other way round.

Are you shooting in strong light and using LV you may get light leaks through the viewfinder. Make sure to always cover the OVF.

Bertrand3000 · 06-03-2021, 04:49 AM

Originally posted by Tjompen1968

Then there is the problem that when you focus the lens it is fully open and if stopped down when shooting there may be a shift in focus, called focus shift. I have had that on a couple of lenses. The OVF focus knows this and compensates while LV focus seeks maximum contrast.

I'm not sure. OVF focus is wide open, but live view is done at F4, perhaps even lower if there is a lot of light. That said field of view is wider when stopped down. At which apertures the actual pictures are taken?

Clavius · 06-03-2021, 07:33 AM - **2 Likes**

Originally posted by Tjompen1968

Are you shooting in strong light and using LV you may get light leaks through the viewfinder. Make sure to always cover the OVF.

Covering the OVF resolves all issues! I hadn't thought of that, because that wasn't necessary with my K-5. The viewfinder of the K-1 is much larger and brighter of course, and lets in much more light through the other direction too.

I'm so happy that my camera isn't broken. Embarrassed, but happy.

**BarryE** · 06-03-2021, 08:52 AM - **2 Likes**

Originally posted by Clavius

Covering the OVF resolves all issues! I hadn't thought of that, because that wasn't necessary with my K-5. The viewfinder of the K-1 is much larger and brighter of course, and lets in much more light through the other direction too.

I'm so happy that my camera isn't broken. Embarrassed, but happy.

Covering the viewfinder is key for exposure too, at times. Just get in the habit of doing it. Wearing black/dark colours can also be useful as I found out when I had some odd results after wearing a white t-shirt on a sunny day. I just cover the viewfinder automatically when I'm MUP/remote etc. on sunny days.

dlhawes · 06-03-2021, 09:00 AM - **1 Like**

Originally posted by Clavius

No, I have no microadjustments active. Menu for microadjustments is set to 1 / defaults.

That being the case, I strongly suspect the camera is "broken". My suggestion that the camera itself is not properly adjusted was based on my own experience and learning curve with respect to a K-1 I eventually had to send back to be repaired.

**mikesbike** · 06-05-2021, 11:43 AM

Originally posted by Clavius

I'm so happy that my camera isn't broken. Embarrassed, but happy.

No need to be embarrassed- I have learned through your experience! Perhaps others have as well. I do usually cover the VF when shooting on tripod, but not always if in a well-shaded spot. However, that has always been to address proper exposure. I would never have guessed AF would be affected! I shall now always do so when using LV!!

**Mikesul** · 06-05-2021, 01:00 PM

Pentax includes a viewfinder cover in the box just for this kind of problem.

**mikesbike** · 06-05-2021, 05:03 PM

And, LV is not always done on a tripod, so the covering of the OVF is always important both for AF and for exposure!

**Bonner04** · 06-05-2021, 08:45 PM

Originally posted by Mikesul

Pentax includes a viewfinder cover in the box just for this kind of problem.

I think one of my MZ-S camera straps has one on it and a remote shutter release on the other side.

pschlute · 06-06-2021, 04:44 AM

Originally posted by BarryE

Wearing black/dark colours can also be useful as I found out when I had some odd results after wearing a white t-shirt on a sunny day.

Although for different reasons (flash meter), the portrait photographer's standard garb is black t shirt.

---------- Post added 06-06-21 at 12:46 PM ----------

Originally posted by dlhawes

My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus.

But in LV focussing is done "on the sensor".....there can be no misalignment.

06-02-2021, 12:51 AM	#17
Clavius Veteran Member Join Date: Feb 2011 Location: De Klundert Photos: Gallery Posts: 4,150 Original Poster	Ok, this morning I did some more testing... Some suggested to use the select focus instead of spot focus and I wanted to quickly try that. At first I thought that that resolved the issues. Which is great of course! But when I returned to spot focus again I could no longer reproduce the error?! I cannot just let that go and forget about it without knowing what caused it. Only after some more extensive testing, trying to reproduce the error, it came back. In both spot AF and select AF. I also noticed that the colors in photos taken with LV seem desaturated in comparison to photos taken through the OVF. It can also be seen in the test photos that I posted earlier in this thread. This maybe a stupid theory of mine, but could it be caused by the sensor heating up? Or because it's used longer in live view mode? In live view the sensor is used to feed information to the screen constantly. But when using the OVF it is "resting" until the actual picture is taken. I find this so strange, because in my K-5 I am so used to AF in live view being much more precise. There it would seem the other way round. Last edited by Clavius; 06-02-2021 at 02:53 AM.

06-05-2021, 08:45 PM	#29
Bonner04 Loyal Site Supporter Join Date: Jan 2016 Location: Ventura, CA Photos: Gallery Posts: 685	Cover Originally posted by Mikesul Pentax includes a viewfinder cover in the box just for this kind of problem. I think one of my MZ-S camera straps has one on it and a remote shutter release on the other side.

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06-01-2021, 11:37 PM - 1 Like	#16
MadBill Forum Member Join Date: Dec 2018 Posts: 76	Live View CDAF is not always as accurate as I would hope, sometimes significantly worse than PDAF or manual focus (using magnification.) Assuming the camera is set to spot focus with the spot on a well lighted subject of reasonable contrast, are there any menu items that can affect CDAF accuracy?

06-02-2021, 03:42 AM	#18
Bertrand3000 Veteran Member Join Date: Feb 2019 Posts: 2,009	Overheating sensor would, I think, results in more noise. Your problem is very odd.

06-02-2021, 04:14 AM	#19
dlhawes Guest	My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus.

06-02-2021, 04:22 AM	#20
Clavius Veteran Member Join Date: Feb 2011 Location: De Klundert Photos: Gallery Posts: 4,150 Original Poster	Originally posted by Medex Did you try central spot focus only in Live View? How about "Select" focus mode and using another area to auto focus? Same missed focus? Originally posted by dlhawes My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus. No, I have no microadjustments active. Menu for microadjustments is set to 1 / defaults.

06-02-2021, 08:56 AM - 1 Like	#21
Unregistered User Guest	I have found that Tamron 70-200 are unable to nail focus in Live View on K-5. Why? I never understood. Always back or front focus. But OVF no problem. Then there is the problem that when you focus the lens it is fully open and if stopped down when shooting there may be a shift in focus, called focus shift. I have had that on a couple of lenses. The OVF focus knows this and compensates while LV focus seeks maximum contrast. ---------- Post added 06-02-21 at 05:58 PM ---------- Originally posted by Clavius Ok, this morning I did some more testing... Some suggested to use the select focus instead of spot focus and I wanted to quickly try that. At first I thought that that resolved the issues. Which is great of course! But when I returned to spot focus again I could no longer reproduce the error?! I cannot just let that go and forget about it without knowing what caused it. Only after some more extensive testing, trying to reproduce the error, it came back. In both spot AF and select AF. I also noticed that the colors in photos taken with LV seem desaturated in comparison to photos taken through the OVF. It can also be seen in the test photos that I posted earlier in this thread. This maybe a stupid theory of mine, but could it be caused by the sensor heating up? Or because it's used longer in live view mode? In live view the sensor is used to feed information to the screen constantly. But when using the OVF it is "resting" until the actual picture is taken. I find this so strange, because in my K-5 I am so used to AF in live view being much more precise. There it would seem the other way round. Are you shooting in strong light and using LV you may get light leaks through the viewfinder. Make sure to always cover the OVF.

06-03-2021, 04:49 AM	#22
Bertrand3000 Veteran Member Join Date: Feb 2019 Posts: 2,009	Originally posted by Tjompen1968 Then there is the problem that when you focus the lens it is fully open and if stopped down when shooting there may be a shift in focus, called focus shift. I have had that on a couple of lenses. The OVF focus knows this and compensates while LV focus seeks maximum contrast. I'm not sure. OVF focus is wide open, but live view is done at F4, perhaps even lower if there is a lot of light. That said field of view is wider when stopped down. At which apertures the actual pictures are taken?

06-03-2021, 07:33 AM - 2 Likes	#23
Clavius Veteran Member Join Date: Feb 2011 Location: De Klundert Photos: Gallery Posts: 4,150 Original Poster	Originally posted by Tjompen1968 Are you shooting in strong light and using LV you may get light leaks through the viewfinder. Make sure to always cover the OVF. Covering the OVF resolves all issues! I hadn't thought of that, because that wasn't necessary with my K-5. The viewfinder of the K-1 is much larger and brighter of course, and lets in much more light through the other direction too. I'm so happy that my camera isn't broken. Embarrassed, but happy.

06-03-2021, 08:52 AM - 2 Likes	#24
BarryE Site Supporter Join Date: Jan 2013 Location: Hampshire, UK Posts: 1,654	Originally posted by Clavius Covering the OVF resolves all issues! I hadn't thought of that, because that wasn't necessary with my K-5. The viewfinder of the K-1 is much larger and brighter of course, and lets in much more light through the other direction too. I'm so happy that my camera isn't broken. Embarrassed, but happy. Covering the viewfinder is key for exposure too, at times. Just get in the habit of doing it. Wearing black/dark colours can also be useful as I found out when I had some odd results after wearing a white t-shirt on a sunny day. I just cover the viewfinder automatically when I'm MUP/remote etc. on sunny days.

06-03-2021, 09:00 AM - 1 Like	#25
dlhawes Guest	Originally posted by Clavius No, I have no microadjustments active. Menu for microadjustments is set to 1 / defaults. That being the case, I strongly suspect the camera is "broken". My suggestion that the camera itself is not properly adjusted was based on my own experience and learning curve with respect to a K-1 I eventually had to send back to be repaired.

06-05-2021, 11:43 AM	#26
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,558	Originally posted by Clavius I'm so happy that my camera isn't broken. Embarrassed, but happy. No need to be embarrassed- I have learned through your experience! Perhaps others have as well. I do usually cover the VF when shooting on tripod, but not always if in a well-shaded spot. However, that has always been to address proper exposure. I would never have guessed AF would be affected! I shall now always do so when using LV!!

06-05-2021, 01:00 PM	#27
Mikesul Loyal Site Supporter Join Date: Sep 2009 Location: Phoenix, AZ Posts: 7,594	Pentax includes a viewfinder cover in the box just for this kind of problem.

06-05-2021, 05:03 PM	#28
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,558	And, LV is not always done on a tripod, so the covering of the OVF is always important both for AF and for exposure!

06-06-2021, 04:44 AM	#30
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,215	Originally posted by BarryE Wearing black/dark colours can also be useful as I found out when I had some odd results after wearing a white t-shirt on a sunny day. Although for different reasons (flash meter), the portrait photographer's standard garb is black t shirt. ---------- Post added 06-06-21 at 12:46 PM ---------- Originally posted by dlhawes My guess is that the camera's internals are slightly maladjusted such that the distance from the lens to the sensor isn't the same as the distance from the lens to the focusing sensor. You may have compensated for that using the AF microadjustment function for viewfinder focus, so that's coming out right, but that compensation doesn't apply to live-view focus. But in LV focussing is done "on the sensor".....there can be no misalignment.