Yep.(Confess I'm not familiar with the K1000 but ...) most SLRs meter with the lens wide open and only close down to the set aperture during exposure. You probably need to do "stopped-down metering" with the art lens if your camera has a way to do that.
No meter coupling is one thing. However, it should only indicate 2 stops under as the lens I believe is rated at f/2.9. Whatever, it's the lens that is wrong and not the camera.
I only just got this lens on the 25th and where I'm shooting him I haven't yet had a chance to see what the actual final results will accomplish. I plan to take a few photos of a sheet of paper labelled "pentax control lens" "daguerreotype using pentax settings" "daguerreotype using inbuilt light meter settings" and she which ones actually work.Not sure, but just to bring a hypothesis on the table...
The lens could possibly change the polarization of the light? some meters are sensitive to that.
Have you tried to take 2 identical shots using the same exposure settings, preferably given by an independent/external meter, using both lenses?
My first question is: does the K1000 meter on-axis, or by picking off from the edges of the light cone going through the viewfinder prism? The daguerrotype lens may be vignetting in a way the meter doesn't expect.
The pentax k1000 uses a full scene averaging light meter.
My second question: how do you know the aperture plates are correct? Depending on the prescription of the lens, the physical diameter of the opening isn't necessarily f.l. divided by f/# (think magnification of the entrance pupil).
The aperture plates are labelled at the factory with their F stop number
-Jason
(Confess I'm not familiar with the K1000 but ...) most SLRs meter with the lens wide open and only close down to the set aperture during exposure. You probably need to do "stopped-down metering" with the art lens if your camera has a way to do that.
I wish I read your reply before answering everyone's replies! Thanks for your help! I'm likely going to assume that I will need to always use an external light meter and that the issue is likely how the lens interacts with the light meter. I have a roll of colour film in there right now, but once I'm done with it I'll shoot some black and white and process that at home. I should have the results back before the lab can process my film.IIRC the K-1000 is full aperture, full screen metering with no stop-down metering possibility. I'd try a test roll with the art lens; BW is cheap and should certainly indicate a 4 stop problem.
Pentax has one lever for stop down, coupled to the iris diafragm and another signaling the selected f-Stop to the camera (by angle).... so i guess theese are both missing and in the end the camera estimates the working aperture (f4 in your example) as its open aperture and f22 or something as working aperture.
Strange that Lomo missed this point in the lens/mount design, but it makes sense, since all digital SLRs with K-mount do stop-down metering (they don't have a blesator... thats what the guys here in the german digital pentax forums call it... shorthand for blendensimulator, meaning the lenscoupling lever). So actually there is no workaround but metering manually.
Although the lens has a "native" aperture of f/2.9, the adapter may be communicating false information to the metering lever in the camera.
You may not be able to use the meter in your camera with this lens.
The manual for the K-1000 does refer to the use of stop-down metering when using accessories or lenses that don't couple to the open-aperture metering system. As per my previous post, I'm guessing that the adapter you are using is actually communicating false information - rather than no information - to the camera.
If lomography offers a way to ask questions, yours would be an excellent one.
Sorry, I missed the fact that it was available in K mount, and assumed you were using it with a lens mount adapter.The lens is native k mount.
I'm not familiar with how far the compatibility of current, digital K mount cameras to legacy K mount lenses extends (does it include open aperture metering?) but it may be that your lens was designed for a later metering system.
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