Is there life after aperture block failure?

Futax wrote:

Massao wrote:

Futax wrote:

peterpainter wrote:

TacticDesigns wrote:

Massao wrote:

peterpainter wrote:

Futax wrote:

You could also try using Av mode. On my K-50, the camera still stops down the aperture as defined by the ring. Since the camera doesn't actually know that aperture, you need to get it to provide the correct exposure, and you can do that by using exposure compensation. If you're shooting wide open, then exposure is correct without compensation. Otherwise use the appropriate compensation.

Seems to be a much more accurate method for getting the correct exposure than using the green button in M mode. Also, can make shooting off several frames a lot quicker.

The camera is pretty-much always et on AV mode and was when I was getting odd exposures using just the shutter button rather than the green button. As I mentioned in another comment, I'll experiment further but from limited testing today the green button seems to work better - and frankly, I can't understand why it should!

Ok, then I wonder whether you have done these changes in settings as recommended by PF. See here .

If your Aperture Block failed, will stopped down metering work with Pentax-M or Pentax-A lenses?

I was just thinking about that.

I pulled out my Pentax K100d and tossed a Pentax-M lens on it.

To do stopped down metering, since I don't have a "Green" button, I push the AE-L button instead.

But . . . I can hear the lens being stopped down.

If the Aperture Block motor has failed, how can the camera stop down a Pentax-A or Pentax-M lens?

Take care & Happy Shooting!

I think the only way would be to do stop-down metering on A and M lenses (but I don't have any that I can test with) - can't see how the camera could set the aperture. I'm using it (stop-down metering) with my screw mount (Carl Zeiss Jena) lenses and it's a pain, really, but I suppose people got used to it in the old days.

If you're using M42 lenses, they'll almost certainly have black anodised rears. This means you have to use stop-down metering (and you can't use Catch-in-Focus). With the K-50, it seems that you can use Av mode (as well as Catch-in-Focus) - with most K-mount lenses. That's because they mostly have bare metal rears. The camera will detect the conductive rear, and act accordingly.

Not sure if black anodised vs conductive rear theory is correct, but anynow I have not noticed any difference in metering based on this difference.

Aperture block failure just means the camera can't stop down an "A" type lens (i.e those without an aperture ring, or one which has been set to "A") to the correct aperture

Correct :-)..

And since the camera doesn't know what aperture you set - it'll assume wide-open - you have to compensate using EV compensation.

Not correct. The camera does not know what "wide-open" is either. With fully manual old lenses (like M42), the camera has no idea of knowing what the smallest F value/widest aperture lens offers.

The camera doesn't know what aperture it's shooting at, but it assumes the lens is set to the same aperture as when it does the metering - i.e. wide-open in Av mode. It will expose accordingly unless instructed differently.

You are mixing everything here. If you set the aperture (on the aperture ring) on ANY non-PK mount lens like M42 or Adaptall 2 lens and set M on lens (which implies: any change in aperture is evident immediatly) then there is no way a camera can EVER know anything about wide-open. The only thing camera sees is through the stopped-down lens. Seriously, what is so complicated about this?

The cameras metering system sees only what you show to it, i.e., by stopping down the aperture ON the lens, i.e., rotating the aperture ring and selecting manual mode ON the lens.

The metering in Av mode is done before the shot is taken, so the lens is wide open. The camera has no knowledge of how much the lens will be stopped down when it takes the shot.

Are you trying to convince me that your pentax camera can literally change aperture on all non-PK mount lenses with adapters? The wholegame about wide open and then camera stopping it down implies it.

So, when you set the aperture on your m42 lens or other lenses with adapters (M mode on lens) and then take a picture with it in Av mode (on camera), the camera first magically changes the aperture on your manual non-PK mount lens to wide-open then notes the exposure, and then applies that exposure again while magicallystopping down your non-PK lens? I need your camera. We all do

There is absolutely no need to use EV compensation when using any manual lens on Pentax DLR's--unless you are trying to under or over- expose an image intentionally.

You can't even use exposure compensation in M mode - which is what you would normally use for aperture-ring lenses (You modify the shutter speed using the thumbwheel if you want to intentionally over/under expose).

But I'm talking about use of Av mode.

You don't have to use Av mode - you can use M mode, but it does have its shortcomings.

So, to wrap up: 1) M mode (on camera) despite pressing the green button does not exposes properly, and; 2) in Av mode, it still does not expose properly which is why you use exposure compensation? There is something seriously wrong with your camera!