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Logman · 01-17-2021, 11:59 AM

Hi, need some help. I have a k50, trying to use my older 50mm 1.4 on it. I set it to manual mode, set the selector to m/f and I can't get the aperture to come up, just reads f___. Whaat am I doing wrong?

**sergysergy** · 01-17-2021, 12:02 PM

Hello Logman, this should help:
How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos | PentaxForums.com

Logman · 01-17-2021, 03:54 PM

Originally posted by sergysergy

Hello Logman, this should help:
How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos | PentaxForums.com

No help, I almost give up

**jatrax** · 01-17-2021, 04:08 PM

What lens are you using? Unless it is Pentax-A or newer the camera has no way to read the aperture and will just show "F__". You have to follow the instructions in the tutorial for stop down metering.

Logman · 01-17-2021, 04:43 PM - **1 Like**

Have it now on my kx, let me try my 1.7 that's auto. 1.4 k mount isn't.

Sidney Porter · 01-17-2021, 06:19 PM

There are setting in the menu. You have to set it to allow aperture ring. I think you also need to setup the green button. Did you watch the videos?

jimboombapete · 01-17-2021, 09:54 PM

If it is showing "F----------" at least it's not just taking black photos due to ABF

**MSL** · 01-18-2021, 07:41 AM

In manual mode when using a m42, M or A type lens where you are using the aperture ring, the camera cannot detect the aperture. So it will always flash F---. However, by changing the setting in the menu to allow for the aperture ring, and putting the camera in M mode, you can use green button metering to get correct exposures. @jatrax and @sergysergy have also given similar advice.

**photogem** · 01-18-2021, 01:57 PM

Maybe I am not getting something here but isn't it simply that he has to go into the menu
C-4
22: Using Aperture Ring
Reset Custom Functions

and set it on 2 (Enable)
???

It looks like his lens is simply a manual lens, i.e. aperture ring without A-Position.

**jatrax** · 01-18-2021, 02:01 PM

Originally posted by photogem

Maybe I am not getting something here but isn't it simply that he has to go into the menu

Yes, but I suspect the OP is looking for the aperture info to show on the camera. Which is not going to happen on a non-A position lens. It will just show "F___" because the camera has no way to determine what the aperture ring is set to.

**photogem** · 01-19-2021, 03:38 AM

Well, with his collection of about 50 x M42 lenses made by Pentax he's going to have to learn green button metering.

**jatrax** · 01-19-2021, 11:05 AM

Originally posted by photogem

Well, with his collection of about 50 x M42 lenses made by Pentax he's going to have to learn green button metering.

Yes, and perhaps he does but that is not clear. Apparently his M42 are from his film years but again that is not clear. Hopefully he will report back as we still do not know what lenses he is using, M42 or K-mount. Hard to help when not all information is provided.

**photogem** · 01-19-2021, 11:19 AM

The option of reading his previous posts is giving all information needed I find.

01-17-2021, 11:59 AM	#1
Logman New Member Join Date: Jan 2021 Location: Iron Mountain, MI Posts: 12	Aperture problem Hi, need some help. I have a k50, trying to use my older 50mm 1.4 on it. I set it to manual mode, set the selector to m/f and I can't get the aperture to come up, just reads f___. Whaat am I doing wrong?

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01-17-2021, 12:02 PM	#2
sergysergy Site Supporter Join Date: Jan 2011 Photos: Gallery Posts: 5,175	Hello Logman, this should help: How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos \| PentaxForums.com

01-17-2021, 03:54 PM	#3
Logman New Member Join Date: Jan 2021 Location: Iron Mountain, MI Posts: 12 Original Poster	Originally posted by sergysergy Hello Logman, this should help: How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos \| PentaxForums.com No help, I almost give up

01-17-2021, 04:08 PM	#4
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	What lens are you using? Unless it is Pentax-A or newer the camera has no way to read the aperture and will just show "F__". You have to follow the instructions in the tutorial for stop down metering.

01-17-2021, 04:43 PM - 1 Like	#5
Logman New Member Join Date: Jan 2021 Location: Iron Mountain, MI Posts: 12 Original Poster	Have it now on my kx, let me try my 1.7 that's auto. 1.4 k mount isn't.

01-17-2021, 06:19 PM	#6
Sidney Porter Veteran Member Join Date: Feb 2012 Location: Columbus Ohio USA Posts: 353	There are setting in the menu. You have to set it to allow aperture ring. I think you also need to setup the green button. Did you watch the videos?

01-17-2021, 09:54 PM	#7
jimboombapete New Member Join Date: Aug 2013 Location: Jimboomba QLD Posts: 24	If it is showing "F----------" at least it's not just taking black photos due to ABF

01-18-2021, 07:41 AM	#8
MSL Site Supporter Join Date: Feb 2012 Location: Greater Toronto Area Photos: Gallery \| Albums Posts: 4,756	In manual mode when using a m42, M or A type lens where you are using the aperture ring, the camera cannot detect the aperture. So it will always flash F---. However, by changing the setting in the menu to allow for the aperture ring, and putting the camera in M mode, you can use green button metering to get correct exposures. @jatrax and @sergysergy have also given similar advice.

01-18-2021, 01:57 PM	#9
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	Maybe I am not getting something here but isn't it simply that he has to go into the menu C-4 22: Using Aperture Ring Reset Custom Functions and set it on 2 (Enable) ??? It looks like his lens is simply a manual lens, i.e. aperture ring without A-Position.

01-18-2021, 02:01 PM	#10
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by photogem Maybe I am not getting something here but isn't it simply that he has to go into the menu Yes, but I suspect the OP is looking for the aperture info to show on the camera. Which is not going to happen on a non-A position lens. It will just show "F___" because the camera has no way to determine what the aperture ring is set to.

01-19-2021, 03:38 AM	#11
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	Well, with his collection of about 50 x M42 lenses made by Pentax he's going to have to learn green button metering.

01-19-2021, 11:05 AM	#12
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by photogem Well, with his collection of about 50 x M42 lenses made by Pentax he's going to have to learn green button metering. Yes, and perhaps he does but that is not clear. Apparently his M42 are from his film years but again that is not clear. Hopefully he will report back as we still do not know what lenses he is using, M42 or K-mount. Hard to help when not all information is provided.

01-19-2021, 11:19 AM	#13
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	The option of reading his previous posts is giving all information needed I find.

Aperture problem

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