[ossi]

Hi All,

I have noticed that when using manual diaphram lenses, if you use Manual mode on the camera and the AE-L button to meter then take the photo it works as it should (exposes correctly). However when you switch to Av mode, exactly the same scene is underexposed by a number of stops.

This happens with both a mirror lens i have and also my 500 f4.5, has anyone else experienced this?

Does Av Mode work differently than i assume (ie are the electronics in the lens required for this to work and hence it will not work with Manual lenses).

Also as a note to give as much info as possible, yes i have enabled the use of aperture ring in the custom menu.

Any help would be appreciated.

Thanks to all.

[NaClH2O]

Hi Ossie
I noticed the same thing on my DS. But since Av mode doesn't do anything with a manual lens, (there's no aperture to change) I stick with M mode. I don't know why that is, but the other works so well, I don't really care. My DS manual says "use M mode" so I use M mode and my shots come out properly exposed.

NaCl(everything else can be bad but at least I've got a properly exposed poorly framed, oof, and blurred image)H2O

[egordon99]

With Av, the lens will ALWAYS be wide open, so it you se exposure for something other then wide open, it will be over exposed. You MUST use manual mode (unless you want to shoot wide open).
This is in the manual.

[blende8]

But he says the shots are underexposed. That's strange.

[ossi]

Thanks to all for there replies.

Just to clarify, as i mentioned above i am using a manual diaphram lens, ie stopped down manually, if you close down the aperture then it happens strait away and the viewfinder gets dimmer.

With this in mind i am aware that in Av mode the camera will always shoot wide open on auto aperture lenses (not lenses with 'A' on the aperture ring or manual diaphram), however given that with manual diaphram lenses the aperture is manually closed down this should not be a problem, i would have thought.

I would have thought that in Av mode the camera would meter 'on the fly' when the lens is manually stopped down.

Thanks again to those who replied.

ossi

[Alvin]

Someone correct me if I'm wrong but as to what I was told, the only mode you can use Manual lenses is in Manual Mode (with the exception of the lenses that have the A mode on the aperture ring).

The lens mount on all the Pentax D-SLR's does not have the capability of reading the aperture ring setting, defeating the Av mode. In the top LCD you will see -- beside the Av reading.

The lenses with the A mode, when set, will allow the user to to adjust the aperture on the camera in Av mode thus allowing the camera to know what shutter speed to use.

Hope that made sense.

[-=JoN=-]

just tried this on the k10, Av mode, on a reverse mounted lens (essentially the same as what he's using, all manual)

basically it did what he wanted to do, it was adjusting Tv on the fly as i adjusted Av settings

[ossi]

Thanks for the replies again.

I can also confirm as Jon did that this works as it should with the K10D i tried this a few weeks ago, it is only the DL that i have the problem.

The way i interpreted the manual was that you can use the camera in Av mode with manual diaphram lenses and and they will work fine, auto diaphram lenses will only work wide open as others have said. My local camera shop assumed the same as i did and were surprised that it didnt work.

The other thing to note is that i have not go the latest firmware i have the first update that supports high density SD cards, maybe the issue was introduced in the first update?

Thanks again to all who replied!