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Minolta 50 f1.7 exposure problems

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XeKayeM View Drop Down
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Post Options Post Options   Quote XeKayeM Quote  Post ReplyReply Direct Link To This Post Topic: Minolta 50 f1.7 exposure problems
    Posted: 14 January 2019 at 11:04
G'day guys,

I own a few minolta lenses which pair with my LA-EA4 and my A7III. All lenses work great except my 50 1.7.
It isnt so much a fault with the lens as its sharp and works perfectly, however the EVF on the camera shows a very different exposure. I generally have to shoot about 3 or 4 stops under (according to the EVF) in order to get a correctly exposed image. No issues with my 20mm 2.8 or 200mm 2.8 though as they both perform flawlessly in this regard.
Just wondering if this is a common thing and or something which is easily fixed.

Cheers.
 



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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 11:29
It might be a stuck aperture.

Try shooting the lens wide open @ f1.7. If that one is correctly exposed you've got sticky or stuck aperture blades at smaller apertures, hence the need to underexpose to correct for the aperture that's still too large vs. what you have set on the camera.
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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zbozic View Drop Down
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Post Options Post Options   Quote zbozic Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 12:01
I've got problem like this.
You need to degrease aperture blades.
Soft cotton and 100% alcohol solved problem. If you able to completly dismantle lens.

How to do it, I wrote long time ago.


http://www.e-fotografija.com/cro/publish/article_278.shtml

Edited by zbozic - 14 January 2019 at 12:22
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 13:17
... or preview the image stopped down before you press the shutter (assuming the iris blades move at all

*All* my old 50mm Miranda lenses now suffer this problem .
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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neilt3 View Drop Down
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Post Options Post Options   Quote neilt3 Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 21:20
Originally posted by Miranda F Miranda F wrote:

... or preview the image stopped down before you press the shutter (assuming the iris blades move at all

*All* my old 50mm Miranda lenses now suffer this problem .


How do you enable a D.O.F preview on an LA-EA4 to stop the lens down prior to an exposure ?
I'm not aware you can do that , I have an LA-EA4 that I use on a NEX 7 , and don't think I can do that , maybe the a7 models are different ?
see my photostream on flickr;
http://www.flickr.com/photos/neilt3/
C & C welcome.
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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 21:43
Originally posted by neilt3 neilt3 wrote:

Originally posted by Miranda F Miranda F wrote:

... or preview the image stopped down before you press the shutter (assuming the iris blades move at all

*All* my old 50mm Miranda lenses now suffer this problem .


How do you enable a D.O.F preview on an LA-EA4 to stop the lens down prior to an exposure ?
I'm not aware you can do that , I have an LA-EA4 that I use on a NEX 7 , and don't think I can do that , maybe the a7 models are different ?

"Aperture Preview" and "Shot. Result Preview" fuctions can be assigned to a custom key. These work with the LA-EA1 and LA-EA3 for me.
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
A6000 LA-EA1 6.5 16 20 30 50 60 16-50 18-55 55-210
600si: 20 24 28 50 100M 135 24-85 24-105 28-105 35-70 35-105 70-210 75-300 100-200
 



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neilt3 View Drop Down
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Post Options Post Options   Quote neilt3 Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 22:10
Originally posted by QuietOC QuietOC wrote:

Originally posted by neilt3 neilt3 wrote:

Originally posted by Miranda F Miranda F wrote:

... or preview the image stopped down before you press the shutter (assuming the iris blades move at all

*All* my old 50mm Miranda lenses now suffer this problem .


How do you enable a D.O.F preview on an LA-EA4 to stop the lens down prior to an exposure ?
I'm not aware you can do that , I have an LA-EA4 that I use on a NEX 7 , and don't think I can do that , maybe the a7 models are different ?

"Aperture Preview" and "Shot. Result Preview" fuctions can be assigned to a custom key. These work with the LA-EA1 and LA-EA3 for me.


Thank's , I'll have to look into that .
see my photostream on flickr;
http://www.flickr.com/photos/neilt3/
C & C welcome.
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Phil Wood View Drop Down
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Post Options Post Options   Quote Phil Wood Quote  Post ReplyReply Direct Link To This Post Posted: 14 January 2019 at 23:09
I have an old Min 28mm f2.8 that had oily aperture blades - it was easy enough to clean and works a treat now.
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XeKayeM View Drop Down
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Post Options Post Options   Quote XeKayeM Quote  Post ReplyReply Direct Link To This Post Posted: 15 January 2019 at 05:51
Originally posted by zbozic zbozic wrote:

I've got problem like this.
You need to degrease aperture blades.
Soft cotton and 100% alcohol solved problem. If you able to completly dismantle lens.

How to do it, I wrote long time ago.


http://www.e-fotografija.com/cro/publish/article_278.shtml


Absolute legend! I pulled it apart, cleaned the blades with some alcohol and boom! working flawlessly.

Thanks mate.
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