I cant seem to get the aperture working as it should

MADDSNIPER · 03-23-2013, 10:49 AM

check out 2 attachments: they look just the same to me.

Last edited by MADDSNIPER; 06-26-2013 at 01:59 PM.

Parallax · 03-23-2013, 10:56 AM

They should look the same. According to the EXIF they were both shot at 1/125th second at ISO 3200. If they were both shot at the same shutter speed and ISO, and show identical exposure, then they had to have been shot at the same aperture.

Put the camera in manual, set the aperture to 1.7, select the appropriate shutter speed and take a picture. Change the aperture to something smaller, say f8 or 16, (don't change shutter speed or ISO) and take another picture. If the second one is grossly underexposed your aperture is changing as it should.

MADDSNIPER · 03-23-2013, 11:08 AM

ok guys i have it working now, i put the camera in manual ISO as it wasnt really in M mode othewise as boriscleto pointed out.

when in this mode pressing the green button is basically giving me a heads up of what shutter speed it thinks i should use yes? with the aperture at 22 it was a really slow shutter speed as you would expect so i put shake reduction on to help and i got a nice long depth of field. then with the aperture at 1.7 it did exactly as i wanted, made the depth of field shallow and the background blurry.

why wasnt it working before though? im manually turning the aperture ring with my hand...surely that should adjust the aperture in any mode just like turning the focus ring does. I didnt think the camera would have the ability to edit the aperture itself anymore than it can edit the focus on a manual focus lens, but in the 2 photos i posted they both had the same aperture setting when i clicked to take the shot?

**Just1MoreDave** · 03-23-2013, 01:02 PM

Originally posted by MADDSNIPER

why wasnt it working before though? im manually turning the aperture ring with my hand...surely that should adjust the aperture in any mode just like turning the focus ring does. I didnt think the camera would have the ability to edit the aperture itself anymore than it can edit the focus on a manual focus lens, but in the 2 photos i posted they both had the same aperture setting when i clicked to take the shot?

The basic K-mount design used on your M series lens has two ways to move the aperture blades. When the lens is off the camera you can see them both; turning the aperture ring or moving the lever both move the blades. The other feature of the K-mount holds the blades wide open for focusing and metering, only closing the blades when the shutter opens. The camera can tell if you have set the aperture ring to f8 and uses that information for metering. The original K-mount cameras used the aperture lever as an on-off switch: blades either fully open, or closed to whatever position the aperture ring indicated. The lever was never in-between. The lenses were designed with this on-off system in mind.

All the Pentax DSLRs use a mount that leaves out a part that would tell the camera where the aperture ring is. The part is not necessary if you are using an A series or later lens, because the camera doesn't need the ring and you can set the aperture on the camera. Lenses with an A position on the aperture ring are designed to move the blades to fit this system, using only the lever. On these cameras, the lens is fully open for focusing. The camera knows the minimum and maximum apertures of the lens you're using, and sends that to the (more complicated) light meter and controls. When you shoot, the camera moves an actuator arm that pushes the aperture lever exactly enough to get f6.3 or f19 or whatever. (DA and FA-J series lenses don't have aperture rings because the ring and second mechanism to move the blades was almost redundant.)

When a basic M or K series lens is mounted, the camera has no aperture information at all, and no ability to move the blades as precisely as it wants to. Without that information, a lot of the clever tricks that the camera could normally do are impossible: multisegment metering, P-TTL flash, program modes, etc. are all out. Pentax does allow the camera to function in a limited way, but only in M mode. When you have enabled the aperture ring, set M mode and the camera can't detect lens information, the actuator arm works like an on-off switch. The metering switches to an old-style mode and can be set with the green button.

It sort of works, but the camera and lens are 35 years apart and sometimes not really communicating that well.

MADDSNIPER · 03-23-2013, 01:48 PM

thats a super detailed reply but easy to read, thanks alot Just1MoreDave

**ramseybuckeye** · 03-23-2013, 03:50 PM

Originally posted by MADDSNIPER

thats a super detailed reply but easy to read, thanks alot Just1MoreDave

Something else that can help you is to go the Pentax Web Site and download the manual since you were "shorted" one. It's a searchable pdf so it should be helpful. Once you figure out how to use the manual lenses the K-30 does an excellent job with them.

You mentioned turning on shake reduction, leave it on unless you're using a tripod, it will help nearly every shot you take.

**Kerrowdown** · 03-23-2013, 09:55 PM

Originally posted by MADDSNIPER

super detailed reply but easy to read

I think that's you sorted now by the sounds of it, now go and enjoy your photography.

Not a Number · 03-24-2013, 04:03 AM

In order to check DOF through the viewfinder with AF and "A" type lenses you have to assign the RAW/Fx button to "Optical Preview". Once this is set when you press the RAW/Fx button the lens will stop down to the aperture shown in the viewfinder. Depending on the mode the aperture is either set using the e-dial or by the camera.

With non-"A" type k-mount lenses or "A"-type lenses not set to "A" mode pressing the RAW/Fx button will stop the lens down to the setting on the aperture ring provided aperture ring usage is enabled in the camera settings.

Non-K-mount lenses will always be stopped down to the setting on the aperture ring or their fixed aperture. Use stop-down metering with these. You can use Av mode but the exposure may be off except when the lens is set wide-open.

In manual mode pressing the green button will set the shutter speed. Non-"A"-type lenses will stop-down meter and the shutter speed will be set.

Here are the recommended settings for using older lenses on your K-30
Using Older Lenses on PENTAX K-30 | Pentax Support

Happy Photographing!

03-23-2013, 11:08 AM	#18
MADDSNIPER Senior Member Join Date: Feb 2013 Photos: Albums Posts: 108 Original Poster	ok guys i have it working now, i put the camera in manual ISO as it wasnt really in M mode othewise as boriscleto pointed out. when in this mode pressing the green button is basically giving me a heads up of what shutter speed it thinks i should use yes? with the aperture at 22 it was a really slow shutter speed as you would expect so i put shake reduction on to help and i got a nice long depth of field. then with the aperture at 1.7 it did exactly as i wanted, made the depth of field shallow and the background blurry. why wasnt it working before though? im manually turning the aperture ring with my hand...surely that should adjust the aperture in any mode just like turning the focus ring does. I didnt think the camera would have the ability to edit the aperture itself anymore than it can edit the focus on a manual focus lens, but in the 2 photos i posted they both had the same aperture setting when i clicked to take the shot? Last edited by MADDSNIPER; 03-23-2013 at 11:34 AM.

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03-23-2013, 10:49 AM	#16
MADDSNIPER Senior Member Join Date: Feb 2013 Photos: Albums Posts: 108 Original Poster	check out 2 attachments: they look just the same to me. Last edited by MADDSNIPER; 06-26-2013 at 01:59 PM.

03-23-2013, 10:56 AM	#17
Parallax Senior Moderator Loyal Site Supporter Join Date: Apr 2008 Location: South Dakota Photos: Gallery Posts: 19,332	They should look the same. According to the EXIF they were both shot at 1/125th second at ISO 3200. If they were both shot at the same shutter speed and ISO, and show identical exposure, then they had to have been shot at the same aperture. Put the camera in manual, set the aperture to 1.7, select the appropriate shutter speed and take a picture. Change the aperture to something smaller, say f8 or 16, (don't change shutter speed or ISO) and take another picture. If the second one is grossly underexposed your aperture is changing as it should.

03-23-2013, 01:02 PM	#19
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Originally posted by MADDSNIPER why wasnt it working before though? im manually turning the aperture ring with my hand...surely that should adjust the aperture in any mode just like turning the focus ring does. I didnt think the camera would have the ability to edit the aperture itself anymore than it can edit the focus on a manual focus lens, but in the 2 photos i posted they both had the same aperture setting when i clicked to take the shot? The basic K-mount design used on your M series lens has two ways to move the aperture blades. When the lens is off the camera you can see them both; turning the aperture ring or moving the lever both move the blades. The other feature of the K-mount holds the blades wide open for focusing and metering, only closing the blades when the shutter opens. The camera can tell if you have set the aperture ring to f8 and uses that information for metering. The original K-mount cameras used the aperture lever as an on-off switch: blades either fully open, or closed to whatever position the aperture ring indicated. The lever was never in-between. The lenses were designed with this on-off system in mind. All the Pentax DSLRs use a mount that leaves out a part that would tell the camera where the aperture ring is. The part is not necessary if you are using an A series or later lens, because the camera doesn't need the ring and you can set the aperture on the camera. Lenses with an A position on the aperture ring are designed to move the blades to fit this system, using only the lever. On these cameras, the lens is fully open for focusing. The camera knows the minimum and maximum apertures of the lens you're using, and sends that to the (more complicated) light meter and controls. When you shoot, the camera moves an actuator arm that pushes the aperture lever exactly enough to get f6.3 or f19 or whatever. (DA and FA-J series lenses don't have aperture rings because the ring and second mechanism to move the blades was almost redundant.) When a basic M or K series lens is mounted, the camera has no aperture information at all, and no ability to move the blades as precisely as it wants to. Without that information, a lot of the clever tricks that the camera could normally do are impossible: multisegment metering, P-TTL flash, program modes, etc. are all out. Pentax does allow the camera to function in a limited way, but only in M mode. When you have enabled the aperture ring, set M mode and the camera can't detect lens information, the actuator arm works like an on-off switch. The metering switches to an old-style mode and can be set with the green button. It sort of works, but the camera and lens are 35 years apart and sometimes not really communicating that well.

03-23-2013, 01:48 PM	#20
MADDSNIPER Senior Member Join Date: Feb 2013 Photos: Albums Posts: 108 Original Poster	thats a super detailed reply but easy to read, thanks alot Just1MoreDave

03-23-2013, 03:50 PM	#21
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,292	Originally posted by MADDSNIPER thats a super detailed reply but easy to read, thanks alot Just1MoreDave Something else that can help you is to go the Pentax Web Site and download the manual since you were "shorted" one. It's a searchable pdf so it should be helpful. Once you figure out how to use the manual lenses the K-30 does an excellent job with them. You mentioned turning on shake reduction, leave it on unless you're using a tripod, it will help nearly every shot you take.

03-23-2013, 09:55 PM	#22
Kerrowdown PEG Moderator Join Date: Aug 2008 Location: Highlands of Scotland... "Hold Infinity in the palm of your hand" - William Blake Photos: Gallery Posts: 57,818	Originally posted by MADDSNIPER super detailed reply but easy to read I think that's you sorted now by the sounds of it, now go and enjoy your photography.

03-24-2013, 04:03 AM	#23
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	In order to check DOF through the viewfinder with AF and "A" type lenses you have to assign the RAW/Fx button to "Optical Preview". Once this is set when you press the RAW/Fx button the lens will stop down to the aperture shown in the viewfinder. Depending on the mode the aperture is either set using the e-dial or by the camera. With non-"A" type k-mount lenses or "A"-type lenses not set to "A" mode pressing the RAW/Fx button will stop the lens down to the setting on the aperture ring provided aperture ring usage is enabled in the camera settings. Non-K-mount lenses will always be stopped down to the setting on the aperture ring or their fixed aperture. Use stop-down metering with these. You can use Av mode but the exposure may be off except when the lens is set wide-open. In manual mode pressing the green button will set the shutter speed. Non-"A"-type lenses will stop-down meter and the shutter speed will be set. Here are the recommended settings for using older lenses on your K-30 Using Older Lenses on PENTAX K-30 \| Pentax Support Happy Photographing!