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MINOLTA 200mm F4 MD TELE ROKKOR problem
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PostPosted: Tue Dec 04, 2018 5:47 pm    Post subject: MINOLTA 200mm F4 MD TELE ROKKOR problem Reply with quote

Hello guys,

I just received my first manual lens for my A7ii. After stepped down, this is showing, making the image very soft in the center (even stepped up, but the "cross" transforms into big white spot.

No problems with other younger lenses. Visually almost clean, the rear lens has litle spots and generally minumum dust inside.
Im using novoflex adapter. It is visible indoors and outdoors, almost at any angle with most backgrounds.

Is the item faulty?

Thanx for any advices,

Vyky


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PostPosted: Tue Dec 04, 2018 7:32 pm    Post subject: Re: MINOLTA 200mm F4 MD TELE ROKKOR problem Reply with quote

vyky wrote:
Hello guys,

I just received my first manual lens for my A7ii. After stepped down, this is showing, making the image very soft in the center (even stepped up, but the "cross" transforms into big white spot.

No problems with other younger lenses. Visually almost clean, the rear lens has litle spots and generally minumum dust inside.
Im using novoflex adapter. It is visible indoors and outdoors, almost at any angle with most backgrounds.

Is the item faulty?

Thanx for any advices,

Vyky


[/img][/img]


Welcome vyky

Some lenses have sensor reflections looking similar, due to flat rear element or lack of coatings on an element. Sorry I don’t know about your lens. Somebody here will know...


PostPosted: Tue Dec 04, 2018 8:18 pm    Post subject: Reply with quote

I get similar artifacts on certain lenses with a helicoid adapter nex to m42. (most notably the asahi pentax 50mm macro) Mine is caused by inferior interior blackening or grease. The light bounces off the shiny stuff and onto the sensor. It only does it with certain lenses though. Can you try a different adapter? They are quite inexpnsive.


PostPosted: Tue Dec 04, 2018 8:54 pm    Post subject: Reply with quote

I dont have another yet. I have only Novoflex (which should be the best against reflections).

Ill probably return the lens and buy other type (noticed, that there is difference between the MD types (didnt know that) and that my type is missing some polstering around the back lens)).

But thanx for answer.

Vyky


PostPosted: Tue Dec 04, 2018 9:04 pm    Post subject: Reply with quote

Never seen such effect with Minolta 200 mm f4!... Bizarre...is it the 400grams version or the 520 grams version?


PostPosted: Wed Dec 05, 2018 6:35 am    Post subject: Reply with quote

Yeah, bizzare. Its the 400g version.


PostPosted: Wed Dec 05, 2018 7:01 am    Post subject: Reply with quote

vyky wrote:
Yeah, bizzare. Its the 400g version.


Does not show with my MD I 520 grams version on an MC-11 adapter. Mount converted to EF.


PostPosted: Wed Dec 05, 2018 7:47 am    Post subject: Reply with quote

Looks like a reflection from the back element on the sensor to me.


PostPosted: Wed Dec 05, 2018 8:36 am    Post subject: Reply with quote

Just made a quick and dirty test shot with my Minolta MD 200/4 (same 400 gr. version) on my Sony A7R II in order to look for incompatibilty issues.
Lens was mounted on a cheap MD to Leica-M adapter and a Novoflex Leica-M to Sony NEX one.
Even against the light I wasn't able to reproduce any reflections as you can see yourself.
Fully open at F4:



Either your lens is faulty or there is an adapter issue.

Edit: A second test on a cheap MD to NEX adapter delivered exactly the same result without any reflections whatsoever.


PostPosted: Wed Dec 05, 2018 9:20 am    Post subject: Reply with quote

Reflections appear with lens stopped, however


PostPosted: Wed Dec 05, 2018 9:48 am    Post subject: Reply with quote

visualopsins wrote:
Reflections appear with lens stopped, however


Stopped down to F8 with cheap Chinese MD/NEX adapter:



Doesn't change anything.


PostPosted: Wed Dec 05, 2018 9:56 am    Post subject: Reply with quote

visualopsins wrote:
Reflections appear with lens stopped, however


Then check the aperture blades on deformation or oil that may reflect light from/to the sensor.
The different MD 200mm 4.0 versions are quite close in optical design so I doubt a reflection of a lens element is causing this.


PostPosted: Wed Dec 05, 2018 11:16 am    Post subject: Reply with quote



This is how the rear element looks like. In comparison with other images os MD 200mm from ebay, there is maybe the black polstering missing? dunno.

Vyky


PostPosted: Wed Dec 05, 2018 11:45 am    Post subject: Reply with quote

vyky wrote:
This is how the rear element looks like. In comparison with other images os MD 200mm from ebay, there is maybe the black polstering missing? dunno.


Obviously there is one part missing to prevent reflections.

That's my lens for comparison:



PostPosted: Wed Dec 05, 2018 2:03 pm    Post subject: Reply with quote

#1


For comparison MD I version but with EF mount conversion.

However unlikely that the absence of the baffle does create that special reflection, you would expect rings etc.


PostPosted: Wed Dec 05, 2018 3:09 pm    Post subject: Reply with quote

Thanx anyway guys, obviously faulty lens or faulty combination with the adapter.

Vyky


PostPosted: Wed Dec 05, 2018 5:38 pm    Post subject: Reply with quote

Obviously, no, sorry, I'm not seeing any difference between the three lenses shown here in regards to the baffling. Although too large an image circle, i.e. unbaffled, does sometimes cause reflections.

The reflections do occur with smaller apertures, when there's more darkness behind the diaphragm, in combination with strong front lighting.

You could try a temporary black cardboard baffle to look for a fix.


PostPosted: Wed Dec 05, 2018 6:27 pm    Post subject: Reply with quote

visualopsins wrote:
Obviously, no, sorry, I'm not seeing any difference between the three lenses shown here in regards to the baffling.


I've checked once again and I think you are right. Just the surface of this part looks a little bit different on the first lens. Maybe somebody polished it?


PostPosted: Fri Dec 07, 2018 9:22 am    Post subject: Reply with quote

Some years ago, in the german "Minolta-Forum", similar problems were reported using the Novoflex adapters. Obviously there was light leaking into the adapter. I suspect you may have an adapter of the first generation.

Stephan


PostPosted: Mon Dec 10, 2018 6:20 pm    Post subject: Reply with quote

Hey guys, ordered new piece, returned the last.

And guess what: same adapter, but this time the images are flawless.

Niiiice 😀


PostPosted: Mon Dec 10, 2018 10:05 pm    Post subject: Reply with quote

vyky wrote:
Hey guys, ordered new piece, returned the last.

And guess what: same adapter, but this time the images are flawless.

Niiiice 😀



I like a result Like 1 .


PostPosted: Tue Dec 11, 2018 8:05 am    Post subject: Reply with quote

Sciolist wrote:
vyky wrote:
Hey guys, ordered new piece, returned the last.

And guess what: same adapter, but this time the images are flawless.

Niiiice 😀



I like a result Like 1 .


Well, for the time being one from another source;
https://www.dpreview.com/forums/post/59944050