Aperture not changing with K-30 and SMC Pentax-M 1:1.7 50 mm SLR lens

kenbobblehead · 10-27-2013, 09:37 AM

Hey Guys- I'm somewhat new to photography. I bought this SLR lens for my K-30 which I realize I should only be able to change the aperture manually with the ring. (Yes, I have enabled Aperature Ring in the Custom menu). The lens takes beautiful photos but when I change the aperture from F 1.7 to F 22 I do NOT hear the shutter speed change nor do I notice any depth of field change or exposure change in the photos? If I look at the lens while I take photos and change the F stop I can see the blades stopping up and and down though. Weird right? Any help would be great. Maybe I am missing something? Or don't understand some concept?

Thanks!
Ken

**paulh** · 10-27-2013, 09:56 AM

When using an M or K-type lens, you need to be in M mode, and use the green button for stop-down metering.
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

Welcome to the forums

kenbobblehead · 10-27-2013, 10:52 AM

Originally posted by paulh

When using an M or K-type lens, you need to be in M mode, and use the green button for stop-down metering.
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

Welcome to the forums

Thank you, Paul. I have the Green button in Edial programming set to TV Shift but my aperture still stays wide open even when pressing the green button and changing aperture value to f22 with the ring? Nothing happens when I press the green button. Is there another setting that might be "blocking" this action?
I really appreciate your help as I am racking my brain trying to figure this out!

**paulh** · 10-27-2013, 11:00 AM

Are you in M mode? In Av mode the camera/lens will only shoot wide-open.

kenbobblehead · 10-27-2013, 11:01 AM

I figured it out Paul! Check this out- I had ISO-Auto turned on and set to 100-400! So once I changed it to a manual setting of 200 the Green button worked and I am now shooting in full manual with the M lens!
It sure feels good to figure it out! thanks for your assistance!

ken

**paulh** · 10-27-2013, 11:06 AM

Good to hear

Enjoy your M50/1.7 - it's an amazing lens. I suggest a lens hood if you don't already have one.

kenbobblehead · 10-27-2013, 11:10 AM

Originally posted by paulh

Good to hear

Enjoy your M50/1.7 - it's an amazing lens. I suggest a lens hood if you don't already have one.

Thanks, Paul! It is pretty great, considering it cost me $50! I am also surprised that there was no mention of making sure to take ISO out of Auto in any of the videos I saw regarding using M lenses with a K-30. I suppose its sort of a "no-brainer" though. Anyway, thanks again!

stevebrot · 10-28-2013, 07:48 PM

Originally posted by kenbobblehead

Thanks, Paul! It is pretty great, considering it cost me $50! I am also surprised that there was no mention of making sure to take ISO out of Auto in any of the videos I saw regarding using M lenses with a K-30. I suppose its sort of a "no-brainer" though. Anyway, thanks again!

Yep, the Pentax-M 50/1.7 is the value queen of K-mount lenses.

As for the auto-ISO confusion...you are not the first.

Steve

10-27-2013, 09:37 AM	#1
kenbobblehead New Member Join Date: Oct 2013 Posts: 4	Aperture not changing with K-30 and SMC Pentax-M 1:1.7 50 mm SLR lens Hey Guys- I'm somewhat new to photography. I bought this SLR lens for my K-30 which I realize I should only be able to change the aperture manually with the ring. (Yes, I have enabled Aperature Ring in the Custom menu). The lens takes beautiful photos but when I change the aperture from F 1.7 to F 22 I do NOT hear the shutter speed change nor do I notice any depth of field change or exposure change in the photos? If I look at the lens while I take photos and change the F stop I can see the blades stopping up and and down though. Weird right? Any help would be great. Maybe I am missing something? Or don't understand some concept? Thanks! Ken

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10-27-2013, 09:56 AM	#2
paulh Site Supporter Join Date: Sep 2010 Location: DFW Texas/Ventura County, CA Photos: Gallery \| Albums Posts: 33,301	When using an M or K-type lens, you need to be in M mode, and use the green button for stop-down metering. https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html Welcome to the forums

10-27-2013, 10:52 AM	#3
kenbobblehead New Member Join Date: Oct 2013 Posts: 4 Original Poster	Originally posted by paulh When using an M or K-type lens, you need to be in M mode, and use the green button for stop-down metering. https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html Welcome to the forums Thank you, Paul. I have the Green button in Edial programming set to TV Shift but my aperture still stays wide open even when pressing the green button and changing aperture value to f22 with the ring? Nothing happens when I press the green button. Is there another setting that might be "blocking" this action? I really appreciate your help as I am racking my brain trying to figure this out!

10-27-2013, 11:00 AM	#4
paulh Site Supporter Join Date: Sep 2010 Location: DFW Texas/Ventura County, CA Photos: Gallery \| Albums Posts: 33,301	Are you in M mode? In Av mode the camera/lens will only shoot wide-open.

10-27-2013, 11:01 AM	#5
kenbobblehead New Member Join Date: Oct 2013 Posts: 4 Original Poster	I figured it out Paul! Check this out- I had ISO-Auto turned on and set to 100-400! So once I changed it to a manual setting of 200 the Green button worked and I am now shooting in full manual with the M lens! It sure feels good to figure it out! thanks for your assistance! ken

10-27-2013, 11:06 AM	#6
paulh Site Supporter Join Date: Sep 2010 Location: DFW Texas/Ventura County, CA Photos: Gallery \| Albums Posts: 33,301	Good to hear Enjoy your M50/1.7 - it's an amazing lens. I suggest a lens hood if you don't already have one.

10-27-2013, 11:10 AM	#7
kenbobblehead New Member Join Date: Oct 2013 Posts: 4 Original Poster	Originally posted by paulh Good to hear Enjoy your M50/1.7 - it's an amazing lens. I suggest a lens hood if you don't already have one. Thanks, Paul! It is pretty great, considering it cost me $50! I am also surprised that there was no mention of making sure to take ISO out of Auto in any of the videos I saw regarding using M lenses with a K-30. I suppose its sort of a "no-brainer" though. Anyway, thanks again!

10-28-2013, 07:48 PM	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by kenbobblehead Thanks, Paul! It is pretty great, considering it cost me $50! I am also surprised that there was no mention of making sure to take ISO out of Auto in any of the videos I saw regarding using M lenses with a K-30. I suppose its sort of a "no-brainer" though. Anyway, thanks again! Yep, the Pentax-M 50/1.7 is the value queen of K-mount lenses. As for the auto-ISO confusion...you are not the first. Steve