D lenses with non ADI bodies?

[FilmFrenzy]

Anybody know why I see a dithering effect through the viewfinder on the 7000i when I attach both a Minolta 28-80 3.5-5.6 and Sigma 28-200 DG Macro lens both with ADI? My older 5 contact lenses look normal. Both lenses look clear through viewfinders on the Dynax 5 and Dynax 40.

I guess it's something to do with the way the ADI cameras gather metering information for flash?
I haven't tested it but once the shutters open, it presumably makes no differnece which camera the lenses are mounted on (other than for exposure settings with flash).

Am I right in thinking the 7000i viewfinder coating filters light differently?

[El_Sid]

Anybody know why I see a dithering effect...

Que?

Do you mean a darkening effect of the screen or the AF not settling or what?

If it's a darkening effect it's probably down to the finder - especially if the 7000i is a low end model. Budget cameras often have less efficient prisms and poorer screens than the better models and in some cases the prism is replaced by a pentamirror system which is less efficient in terms of light transmission. Assming this is the case it should have no effect on the actual exposure - though it does make manual focussing a bit more tricky...

[FilmFrenzy]

Quite the opposite. The 7000i is just an older camera. It has a pentaprism whereas my other two bodies are pentamirror.

As I say it is just with these two lenses which are D specified. On both my 50mm f1.7 and 35-70 f4 the image in the viewfinder is normal and very clear.

The image looks uniformly speckled or pixelated, so yes light,dark,light,dark etc.
It wouldn't be unusable just a bit distracting almost like using an electronic viewfinder on some digital bridge cameras.

[Malcolm_Stewart]

Quite the opposite. The 7000i is just an older camera. It has a pentaprism ...

The image looks uniformly speckled or pixelated, so yes light,dark,light,dark etc.
It wouldn't be unusable just a bit distracting almost like using an electronic viewfinder on some digital bridge cameras.

I have a 7000i, somewhere(!), and a 28-80 f3.5, 5.6 D zoom, and and also a Dynax 7, so I'll see if I can reproduce what you're describing, and report back.

[Malcolm_Stewart]

I've now found my 7000i, fitted my Minolta AF 28-80 f3.5, f5.6 D lens to it, turned it on, and can't see any hint of what you've described. That's checking it indoors, and also outdoors on a sunlit scene. Apart from the extra clutter in the Dynax 7 viewfinder, the two views appear similar.

[El_Sid]

Sorry... I missed your reply somehow.

The image looks uniformly speckled or pixelated, so yes light,dark,light,dark etc.

Hmm... the effect almost sounds as though the aperture diaphragm is being partially stopped down. Does the the Minolta sytem stopdown mechanically or electronically? If it's electronic then cleaning the lens contacts may help. If mechanical it may worth looking at the coupling levers for misalingment, wear or deformation.

[FilmFrenzy]

I don't think I'm explaining too well.

It almost looks like an old newspaper photograph. I can see the image clearly but there are uniform darker spots across the image, very small but noticeable.

The lenses look normal on my Dynax 40 and 5. And I can only detect the effect on the 7000i when attaching these two lenses. With my 50mm 1.7 and 35-70 f4 it looks fine.

[El_Sid]

Got me stumped then.

The only other culprit I can think of is the viewfinder screen itself. Possibly the patterning on the screen on your camera is a little more intolerant of some lenses than others and is showing a little more contrast on occasion. What may be happening is the matt surface of the screen is creating an exaggerated, slightly artificial, difference between the dark and light patterning that actually creates the image you see.

Unless it's adversely affecting the exposure of your pictures I suspect it's something you may have to learn to live with...

[Malcolm_Stewart]

Following on from El Sid's suggestion, have you tried stopping down the 50 f1.7 on your 7000i, and noting whether you get the same problem? Assuming you have the necessary expansion card, of course.

[FilmFrenzy]

Thanks I'm going to try those suggestions.

Just bought another 7000i to get a 35-105 3.5-4.5 lens. Included 3200i flash, Minolta leather case, numerous filters, books etc, etc. All looks in very nice condition.

Will try the lenses with this 7000i and also try swapping the viewfinder screens which I'm starting to think could be the issue.

No need for an expansion card on the 7000i as it has full PASM modes but if the viewfinder swap doesn't work I will try stopping down some of the other lenses.

I can't believe how unwanted 35mm film cameras are! E-bay is a risk compared to camera shops but the cameras themselves go for peanuts.