Aperture stuck wide open!

Hi all, my only lenses at the moment are a manual 50mm 1.7 and a 28mm 3.5.
I have just noticed when looking at the photo info when using the 50 that the pics are all at 1.7! When used manually setting the aperture. When I looked at the lens and adjusted the aperture manually the lens remained wide open.

The lens has an A so I can control the aperture automatically.

Is it an easy task to try a DIY repair of the lens? Or is it best left alone seeing as the A still works?

P.s. I now know why I was struggling to get the speed down on the P30N. I was adjusting the aperture manually, but of course the aperture was stuck at 1.7, and that's why I must have been struggling to get the speed down as indicated by the flashing speed numbers in the eyepiece. I need the aperture to be working so I can use it on the P30n so a DIY would be a good idea. Or else I'll just have the 28 to play with.

Deryn

If you set the aperture manually you'd have to treat it as if it was an M lens and meter using the Green Button. To have it meter automatically and set it with the camera dial leave it on the A setting. It doesn't sound like there is anything wrong with the lens at all; what you've found is normal.

John K

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John K

Hi John, yes, it seems you are right. When I have the lens off and change the aperture manually the elements open and close! But when I looked at the info from the pics,in Elements, the aperture is always stated as 1.7 And that's what initially made me think the aperture was stuck open. SO, it isn't! I'll do some shots in the morning wide open and closed and look at the results.

many thanks.

Deryn

If you want to experiment, there is a custom menu setting "Using aperture Ring". Turn that on and you can then use what Pentax call it "M (Hyper-manual) Mode". You can leave that turned on, it doesn't affect normal auto lenses.

To take a photo you'd have to set the camera dial to Manual (M), set the aperture, press the green button and the camera will set the shutter speed. Pressing the green button closes the lens down and take a meter reading.

This is exactly what you'd have to do with a fully manual lens unless it is being used on an older film body before Pentax crippled the lens mount.

Leaving the camera mode on Av does what you've found, takes the photo at full aperture.

John K

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John K

That's interesting John.

I have set the camera to M, set the aperture manually, pressed the green button, and yes the camera sets the shutter speed.

And then, if I set f11 in A mode on the lens, the lens resets to 1.7 when I press the green button.

So for me. It is best to set the aperture manually in camera M mode, and let the camera set the shutter speed.

Well 5 years and I never ever questioned what that green button was for!?

Thanks,

Deryn

On the old film cameras,eg ME etc. you could just set the aperture and the shutter speed would be calculated as you pressed the shutter release to take the photo. So much for progress!

John K

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John K

Yes John, that's just what I do with the P30n. Set the aperture manually then half press the shutter for auto shutter speed. I also think about just how much progress has actually been made with cameras considering the changes in specifications and the consequent increases in prices!!!

thanks again for the help.

Deryn

According to the Inflation Calculator, the Spotmatic 1000 I bought, my first SLR, would cost around £707 today. I don't think that is an increase in price - I can buy a much more sophisticated DSLR for less.

You can use Aperture Priority on the DSLR just as easily as you could on an ME Super. The only difference is that the aperture is selected on the camera body rather than the lens.

However, we digress, and if you want to then older lenses can be used, with limitations. The A series onwards are fully functional.

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Best regards, John

I actually would prefer to set the aperture on the lens. One can be setting up the camera while getting into position to take the shot. Yes, I know there is an aperture readout on the LCD screen, but setting an aperture on an M lens is much more instinctive, it can be done by feel without having to look at it so one is ready to press the shutter that much sooner.

I never changed to a more modern film body (ie stayed with a K2, ME & MX) for that very reason. The newer ones appeared so much more fiddly beside looking more plasticy; I'd be more than happy now with a digital equivalent to an ME that worked well with M lenses. The only other features it would need are a preview button for depth of field, an ISO button coupled with an exposure override. Not worried about shake reduction, fancy filters (but a digital red/yellow/green wouldn't go amiss) and a colour/mono setting. Also the ability to take RAW / JPEG / TIFFS. That's about it. A super version might also include an LCD screen!

John K

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John K

I was surprised the K-5 has a crippled mount, even my MZ-M not only open-aperture meters with the lens off 'A', but with an FA (and I suspect F) lens attached, even reports the aperture in the finder when it's not on A (of course the MX & LX etc. do this too ).

The green button is a convenient work-around which works well, but I feel is it a backwards step, especially for the 'top end' bodies.

John H.

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PPG Flickr

It's actually been that way for a very long time John H, from the early MZ models onwards, with a few exceptions. Modern cameras are designed to work with apertures being selected by the camera body rather than on the lens. I too thought I'd rather use the aperture ring on the lens, at first anyway, but after a while decided it actually didn't make any difference whatsoever.

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Best regards, John