Is there life after aperture block failure?

TacticDesigns 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.

Yes. It was how it was done in the old days.

But even the Pentax M42 screw mount eventually got the Auto Pin that allowed automatic stop down of the aperture.

I had that on my Pentax Spotmatic.

I was just wondering about a failed Aperture Block motor. If it fails and cannot stop down the lens, then you can't do the stop down metering with it.

Another option would be to not mount the lens all the way so that when you stopped down the lens with the aperture ring, the lens would actually stop down.

Someone told me to drill an extra hole on my Pentax-M lenses so that when you stopped down the lens, it would stop down . . . and then I could do an aperture-priority mode on my Pentax ist DS and Pentax K100d.

So basically, the extra hold would act as a the locking pin on the K-mount. Except that it locked the lens before it had a chance to completely mount.

Take care & Happy Shooting!

Hi again.

My old M42 screw lenses are Praktica EDC (Electronic Diaphragm Control) mount and have a switch between manual an automatic on them.  The way I use them is to leave them in automatic mode (aperture blades / diaphragm fully open), focus, then go into manual mode which stops the lens down to the correct aperture to meter, check DOF and take photo.  With the lens wide open (the ones I use most are F1.8 and F2.4) focusing by eye is actually reasonably easy.

I don't know how it would work with old Pentax lenses.   Hopefully somebody else can advise.

regards,
Pete