K-01 AutoFocus Issues

*eoschneeman* · 09-21-2020, 04:55 PM

Hello,

I feel silly about this question but I'm really struggling with the K-01 Auto Focus: Yesterday, I was taking a picture of a friend with the K-01 body and the D FA 85mm F1.4 Lens. I had the focus set to face detection. When I hit the shutter, it would go out of focus and I ended up with a blurry abstract collage of color. There's been other times when I had the subject's face focused, tried locking it in, but it changed to his/her leg or something. Thoughts?

~Eric

**clackers** · 09-21-2020, 06:14 PM

Originally posted by eoschneeman

I had the focus set to face detection. When I hit the shutter, it would go out of focus and I ended up with a blurry abstract collage of color

Hi Eoschneeman,

Hope we can help. You left out a lot between your first and second sentences. Please describe the process!

Cheers,
Ian

Suzhouren · 09-21-2020, 06:21 PM - **1 Like**

The DFA 85 1.4 is a new lens. I suspect the K-01 being a much older body won't be fully compatible. Even if you can get the lens to focus manually, presumably it won't stop down as I believe the K-01 does not support electronic aperture control (KAF4).

**ramseybuckeye** · 09-21-2020, 07:08 PM - **1 Like**

Originally posted by Suzhouren

The DFA 85 1.4 is a new lens. I suspect the K-01 being a much older body won't be fully compatible. Even if you can get the lens to focus manually, presumably it won't stop down as I believe the K-01 does not support electronic aperture control (KAF4).

That's correct, the K-50 is the oldest camera that can use this lens properly, and shooting at F1.4 you've got a very thin plane that is in focus.

**luftfluss** · 09-21-2020, 07:45 PM

As noted above... Pentax K-01 and HD Pentax-D FA* 85mm F1.4 SDM AW - Compatibility | PentaxForums.com

Breakfastographer · 09-22-2020, 04:46 AM

I don't agree with the apparent consensus here that aperture being wide open explains why face AF is not working. That's just kicking the ball into the long grass.

Eric, you should probably try back button focus. That way, your focus should not slip off the next time you press the shutter button.

**UncleVanya** · 09-22-2020, 06:12 AM

Originally posted by Breakfastographer

I don't agree with the apparent consensus here that aperture being wide open explains why face AF is not working. That's just kicking the ball into the long grass.

Eric, you should probably try back button focus. That way, your focus should not slip off the next time you press the shutter button.

I'm not sure if it is relevant but using live view I've found most lenses partially stop down (on my k3), but I'm unclear if they remain so during focusing. It isn't clear if this is due to brightness of the scene or some other factor.

If the lens normally stops down some during focusing, it might be more difficult to focus without aperture control given the very shallow depth of field of that lens wide open.

*eoschneeman* · 09-23-2020, 10:15 AM

Thanks for the responses. I did have the aperture wide open when it stop down. Maybe I'll try some test shots with a narrower aperture.

**clackers** · 09-23-2020, 03:45 PM

Originally posted by eoschneeman

Thanks for the responses. I did have the aperture wide open when it stop down. Maybe I'll try some test shots with a narrower aperture.

You can't stop it down, Esoschneeman, the K-01 cannot control the DFA*50's aperture, it's too old.

**photogem** · 09-27-2020, 11:25 AM

It is as others say:

The HD DFA85/1,4 is a KAF4 lens!

The K-01 cannot drive KAF4 lenses except wide open.

The K30 with special firmware and then the K50 are the only earlier DSLR which can drive it.

The DFA85 anyway would be kind if misusing an amazing lens if used this way.

09-21-2020, 04:55 PM	#1
eoschneeman Marketplace Reseller Join Date: Aug 2020 Posts: 22	K-01 AutoFocus Issues Hello, I feel silly about this question but I'm really struggling with the K-01 Auto Focus: Yesterday, I was taking a picture of a friend with the K-01 body and the D FA 85mm F1.4 Lens. I had the focus set to face detection. When I hit the shutter, it would go out of focus and I ended up with a blurry abstract collage of color. There's been other times when I had the subject's face focused, tried locking it in, but it changed to his/her leg or something. Thoughts? ~Eric

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09-21-2020, 06:14 PM	#2
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by eoschneeman I had the focus set to face detection. When I hit the shutter, it would go out of focus and I ended up with a blurry abstract collage of color Hi Eoschneeman, Hope we can help. You left out a lot between your first and second sentences. Please describe the process! Cheers, Ian

09-21-2020, 06:21 PM - 1 Like	#3
Suzhouren Forum Member Join Date: Jul 2012 Posts: 53	The DFA 85 1.4 is a new lens. I suspect the K-01 being a much older body won't be fully compatible. Even if you can get the lens to focus manually, presumably it won't stop down as I believe the K-01 does not support electronic aperture control (KAF4).

09-21-2020, 07:08 PM - 1 Like	#4
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,291	Originally posted by Suzhouren The DFA 85 1.4 is a new lens. I suspect the K-01 being a much older body won't be fully compatible. Even if you can get the lens to focus manually, presumably it won't stop down as I believe the K-01 does not support electronic aperture control (KAF4). That's correct, the K-50 is the oldest camera that can use this lens properly, and shooting at F1.4 you've got a very thin plane that is in focus.

09-21-2020, 07:45 PM	#5
luftfluss Site Supporter Join Date: Jun 2011 Location: NJ Photos: Gallery \| Albums Posts: 11,619	As noted above... Pentax K-01 and HD Pentax-D FA* 85mm F1.4 SDM AW - Compatibility \| PentaxForums.com

09-22-2020, 04:46 AM	#6
Breakfastographer Pentaxian Join Date: Nov 2018 Posts: 673	I don't agree with the apparent consensus here that aperture being wide open explains why face AF is not working. That's just kicking the ball into the long grass. Eric, you should probably try back button focus. That way, your focus should not slip off the next time you press the shutter button.

09-22-2020, 06:12 AM	#7
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,398	Originally posted by Breakfastographer I don't agree with the apparent consensus here that aperture being wide open explains why face AF is not working. That's just kicking the ball into the long grass. Eric, you should probably try back button focus. That way, your focus should not slip off the next time you press the shutter button. I'm not sure if it is relevant but using live view I've found most lenses partially stop down (on my k3), but I'm unclear if they remain so during focusing. It isn't clear if this is due to brightness of the scene or some other factor. If the lens normally stops down some during focusing, it might be more difficult to focus without aperture control given the very shallow depth of field of that lens wide open.

09-23-2020, 10:15 AM	#8
eoschneeman Marketplace Reseller Join Date: Aug 2020 Posts: 22 Original Poster	Thanks for the responses. I did have the aperture wide open when it stop down. Maybe I'll try some test shots with a narrower aperture.

09-23-2020, 03:45 PM	#9
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by eoschneeman Thanks for the responses. I did have the aperture wide open when it stop down. Maybe I'll try some test shots with a narrower aperture. You can't stop it down, Esoschneeman, the K-01 cannot control the DFA*50's aperture, it's too old.

09-27-2020, 11:25 AM	#10
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	It is as others say: The HD DFA85/1,4 is a KAF4 lens! The K-01 cannot drive KAF4 lenses except wide open. The K30 with special firmware and then the K50 are the only earlier DSLR which can drive it. The DFA85 anyway would be kind if misusing an amazing lens if used this way.

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