[Xavierm]

Hi All!

I just bought a Pentax k1000 kit very clean like as new and tried everything yesterday.

I use to have a Minolta x-570 witch have very different features like cross-image focusing system and light meter seem to operate differently.

Tell me if am wrong but the Pentax light meter seem to act more like center-weighted than spot metering.

I've tried all the lenses:

sigma 24 mm
the original 50mm
image 135mm
image 80-200mm

All operate as expected except for the 80-200mm

As soon as i attach this lens everything appear darker and grainy in the viewfinder, I decided to give it a shot and take few pictures with both the 50mm and the 80-200 with the same setting same light condition to compare the result. The pictures shot with the 80-200mm as expected are darker and also seem faded. Strange fact, I get the aprox the same result on light meter for both lens, but the one shot with the 80-200 seem to be underexposed by at least one stop.

Is somebody already get this issue? Do you think my lens is broken or something?

Thanks for your help guys!

Xavier

[ProfessorBuzz]

I've never heard of "Image" brand lenses. How fast is it ? e.g. f/4 ? f/5.6 ?

There is a lot less light will make it through that lens, and it is normal for images to appear darker in the viewfinder.
You might check to see if the aperature blades are fully open and moving properly.
The K1000 is a very simple, reliable camera, so don't expect a lot from it - you need to do the work - so if your images are appearing underexposed with that lens, correct for it.
You might try looking for a better quality zoom lens.

[Adam]

Could it be due to vignetting?

[Xavierm]

I've never heard of "Image" brand lenses. How fast is it ? e.g. f/4 ? f/5.6 ?

There is a lot less light will make it through that lens, and it is normal for images to appear darker in the viewfinder.
You might check to see if the aperature blades are fully open and moving properly.
The K1000 is a very simple, reliable camera, so don't expect a lot from it - you need to do the work - so if your images are appearing underexposed with that lens, correct for it.
You might try looking for a better quality zoom lens.

Is a f5.6 ... Not very exciting i admit...

Which better quality lens would you suggest in replacement?

[Xavierm]

Could it be due to vignetting?

haven't noticed any visible vignetting on the neg.

[Not a Number]

Slower lens tend to be darker in the viewfinder. Does the X-570 have a DOF preview button on it? If it does, push it in and open and stop down the aperture while looking through the viewfinder.

Minolta used a modified center-weighted metering pattern - imagine holding your thumb with the tip pointing upward over the viewfinder and the tip a fraction below the top of the frame. The part covered by thumb gives a very rough approximation of the metering emphasis.

Minolta used to tout their very bright screens (I can't recall what they called the surface) relative to competitors. As I recall comparing between the Canon AE-1 and Olympus OM-1 in the camera store this claim was more or less true. I'd say my X-700 viewfinder is brighter than that of my Pentax Program Plus, both with 50mm f/1.4 lenses.

[stevebrot]

Welcome to the Pentax Forums!

Your K1000 features averaging metering using CdS cells, with very little weighting to center. The Minolta X-570 , on the other hand, has a center-weighted meter (not spot) using SPD cells* such as is common on current cameras. Both systems work well, though one would expect differences depending on conditions. As for the viewfinders, that on the K1000 traces its heritage to the Pentax Spotmatic II of the early 1970s and was typical for the time the camera was first released. The Minolta's viewfinder was regarded as excellent at the time and is easily as good or better than the best available today, regardless of brand. It is an advanced camera with many nice features; a step up from its Pentax Super Program competition, IMHO. I seriously considered purchase of an X-570 back in the day. The K1000's finder is not as bright, but should be quite usable.

So there you have it. Your K1000 is basic and the X-570 quite a bit less so. With either, one can take quite amazing photos. One (the Pentax) will make you learn and the other (the Minolta) will allow you to do so, should you so choose. Both are backed by impressive selections of excellent lenses.

Moving on to the lenses. The Sigma 24mm and Pentax 50mm are name brand, the Image 135mm and 80-200mm are "off-brand" meaning a generic product sold under various names, often those associated with the store where they were sold. The Image brand has come up on this site before** and while generic, there is no reason to assume that either lens is inferior. Am I correct in assuming that the 135mm is f/2.8 maximum aperture? That is wide enough to provide a reasonably bright viewfinder image. It is probably safe to assume that the zoom, however, is f/4.5 (1-1/2 stops less light to the viewfinder) at best. This will not affect metering, but may make the lens harder to focus, particularly in low light. The "grainy" appearance of the focus screen is what we see when it gets less light.

There is the outside chance that the aperture on the zoom is not opening all the way or has some other functional problem. You can check this with the lens off the camera as outlined below:

• Inspect the aperture actuator lever on the lens rear. It should appear similar to that on your other lenses.
• Looking through the front of the lens, turn the aperture ring to fully open the iris diaphragm (smallest "f" number). The ring should turn easily with little resistance other than the click-stops.
• Turn the aperture ring to put the iris at its smallest opening (largest "f" number) and note that the movement is predictable between clicks and that the blades close down without hesitation. A non-symmetrical opening at smaller diameters is not a cause for concern.
• With the iris at its smallest opening, turn the lens around so you can see the aperture blades from the rear. This is most easily done with the focus at infinity and the zoom at its shortest focal length (80mm). You should be able to open the aperture to its widest by flicking the actuator lever with your finger. The action should be snappy and complete, without sticking or hesitation.
• Repeat the previous step at each click-stop position until at the fully open position. When fully open, flicking the lever should do nothing.

Since you are getting reasonable exposure results from the zoom, it is likely that it is working properly, but there is no harm in checking.


Steve

* Silicon photodiode (SPD) meters are both more sensitive and faster responding than cadmium sulphide (CdS) meters. Both are accurate and may be used with confidence.

** I found a thread where your lens is actually mentioned Old "Image" Brand Lens question - PentaxForums.com and also this other... https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/30396-lens...lp-please.html

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Last edited by stevebrot; 06-23-2019 at 09:58 AM.

[Not a Number]

Minolta call the surface on their screens Acute-Matte™.