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Topcor 3,5cm 1:2.8 flowers etc
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PostPosted: Wed Mar 13, 2019 5:58 am    Post subject: Topcor 3,5cm 1:2.8 flowers etc Reply with quote

The short MFD is really a plus. Close shots performance is really good.

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PostPosted: Wed Mar 13, 2019 6:07 am    Post subject: Reply with quote

But at regular distance, my particular copy shows some weird things.

The flowers in the left pot are very fuzzy.
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The right headlight is also fuzzy.
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What could be the reasons? I don't think they are just oof or because of out of dof area.


PostPosted: Wed Mar 13, 2019 8:15 am    Post subject: Reply with quote

vivaldibow wrote:
But at regular distance, my particular copy shows some weird things.

What could be the reasons? I don't think they are just oof or because of out of dof area.
Since it's always the left side I would say it's a case of severe decentering.

You can perform a test - you take a pic in a regular way and then rotate your camera upside down and take the same picture again. Then you rotate the second shot and compare both fotos. If the "glow/weirdness/blurriness" migrates from one corner to another it's a case of decentering.

Is the adapter OK? Does it work fine with other Exa/Topcor lenses?

Is the lens OK? Does it "tick" when you shake it? Is a glass element visibly loose? Does the lens look like it was dropped (dents, bents, etc.)?


PostPosted: Wed Mar 13, 2019 8:57 am    Post subject: Reply with quote

Interestingly, my copy seems to perform best at close range and more poorly at distance.
Nicely made and a pleasure to use, but with limitations for me.
Tom


PostPosted: Thu Mar 14, 2019 4:45 am    Post subject: Reply with quote

y wrote:
vivaldibow wrote:
But at regular distance, my particular copy shows some weird things.

What could be the reasons? I don't think they are just oof or because of out of dof area.
Since it's always the left side I would say it's a case of severe decentering.

You can perform a test - you take a pic in a regular way and then rotate your camera upside down and take the same picture again. Then you rotate the second shot and compare both fotos. If the "glow/weirdness/blurriness" migrates from one corner to another it's a case of decentering.

Is the adapter OK? Does it work fine with other Exa/Topcor lenses?

Is the lens OK? Does it "tick" when you shake it? Is a glass element visibly loose? Does the lens look like it was dropped (dents, bents, etc.)?


Thank you very much for the detailed information. I ran the test. Windows 10 automatically rotates the picture for me. It seems I saw what you described: the glow area migrates to the upper right corner. In addition, there is a very small dent at the lens rear, at the silver part adjacent to the aperture ring, between f11 and f16. So most likely the lens is decentered. When I hold the little tab at the bottom (otherwise it would make noise) and shake the lens, I feel there is only some rattle, probably sounding like from bearing. If you ever own a Kiron lens, it sounds similar. I had a Soligor having a loosen front element and that sounds different. I searched on the internet and found an optical bench is needed. That seems not an easy fix. Do you have any other recommendation on how this might be fixed?

Additionally, I found the aperture ring doesn't have distinct click at each f number; rather, it behaves much like a preset lens. Is this normal?

Many thanks!


PostPosted: Thu Mar 14, 2019 5:13 am    Post subject: Reply with quote

Which camera is it again please?


PostPosted: Thu Mar 14, 2019 5:28 am    Post subject: Reply with quote

[quote="vivaldibow"][quote="y"]
vivaldibow wrote:


Additionally, I found the aperture ring doesn't have distinct click at each f number; rather, it behaves much like a preset lens. Is this normal?

Many thanks!


My copy has definite click stops and click half stops between.
So maybe your lens has had some work done at some stage.
Tom


PostPosted: Thu Mar 14, 2019 6:19 am    Post subject: Reply with quote

vivaldibow wrote:
y wrote:
vivaldibow wrote:
But at regular distance, my particular copy shows some weird things.

What could be the reasons? I don't think they are just oof or because of out of dof area.
Since it's always the left side I would say it's a case of severe decentering.

You can perform a test - you take a pic in a regular way and then rotate your camera upside down and take the same picture again. Then you rotate the second shot and compare both fotos. If the "glow/weirdness/blurriness" migrates from one corner to another it's a case of decentering.

Is the adapter OK? Does it work fine with other Exa/Topcor lenses?

Is the lens OK? Does it "tick" when you shake it? Is a glass element visibly loose? Does the lens look like it was dropped (dents, bents, etc.)?


Thank you very much for the detailed information. I ran the test. Windows 10 automatically rotates the picture for me. It seems I saw what you described: the glow area migrates to the upper right corner. In addition, there is a very small dent at the lens rear, at the silver part adjacent to the aperture ring, between f11 and f16. So most likely the lens is decentered. When I hold the little tab at the bottom (otherwise it would make noise) and shake the lens, I feel there is only some rattle, probably sounding like from bearing.

It's probably the ball bearings for the aperture, you can hear them click as you slowly rotate the lens on it's axis.
He was referring to shaking the lens forwards and back along it's axis, you will hear clicking from a loose element, I experienced this with an OM 35/2 that had a loose front element that was giving me incontinent results, I thought it was me till I heard the clicking as I stopped and started the lens movement along it's axis. Not hearing it click doesn't mean the elements are seated correctly, it's possible there is some contaminant between the element and it's mounting surface, just thick enough to soften one side.
Most lenses I've worked on the elements fit like a glove into their resting place, a machined fit.

Quote:
If you ever own a Kiron lens, it sounds similar. I had a Soligor having a loosen front element and that sounds different. I searched on the internet and found an optical bench is needed. That seems not an easy fix. Do you have any other recommendation on how this might be fixed?

If an element isn't sitting properly, a disassembly and reassembly might cure the softness.

Quote:
Additionally, I found the aperture ring doesn't have distinct click at each f number; rather, it behaves much like a preset lens. Is this normal?

Nope, someone has been in there, there should definitely be detents every half stop.
Quote:
Many thanks!


Last edited by Lightshow on Thu Mar 14, 2019 6:31 am; edited 1 time in total


PostPosted: Thu Mar 14, 2019 6:25 am    Post subject: Reply with quote

vivaldibow wrote:
Thank you very much for the detailed information. I ran the test. Windows 10 automatically rotates the picture for me. It seems I saw what you described: the glow area migrates to the upper right corner. In addition, there is a very small dent at the lens rear, at the silver part adjacent to the aperture ring, between f11 and f16. So most likely the lens is decentered. When I hold the little tab at the bottom (otherwise it would make noise) and shake the lens, I feel there is only some rattle, probably sounding like from bearing. If you ever own a Kiron lens, it sounds similar. I had a Soligor having a loosen front element and that sounds different. I searched on the internet and found an optical bench is needed. That seems not an easy fix. Do you have any other recommendation on how this might be fixed?

Additionally, I found the aperture ring doesn't have distinct click at each f number; rather, it behaves much like a preset lens. Is this normal?

Many thanks!
Sad to hear it is decentered. Loosen glass elements give a specific "clicky/ticky" sound. But it might be stuck in a wrong position as well.

Topcor RE lenses can be easily delicked (no click when chaning f number) - right under the bottom plate there is a spring-like stripe of metal which pushes a ball bearing against small pits. However, there is also a chance somebody opened the lens in order to fix it and lost the ball unintentionally...


PostPosted: Thu Mar 14, 2019 7:58 am    Post subject: Reply with quote

This looks quit good for near infinity.
St Pauls in afternoon by White_Dragon_09, on Flickr


Even does decent soap bubbles:
Gold rules the world (even in winter) by rik janssen, on Flickr


PostPosted: Fri Mar 15, 2019 5:07 am    Post subject: Reply with quote

Thanks a lot. I double-check the lens and all the screws. It looks like it's not been opened before. I "suspect" it was bumped/dropped from the little dent, which caused the decenter.

I removed the front sustaining ring and the front element is in a group and can't be simply removed from the top like some other Japanese made lenses. I also removed the rear sustaining ring and was able to remove the rear element(s). I've yet tested it.

Lightshow wrote:
vivaldibow wrote:
y wrote:
vivaldibow wrote:
But at regular distance, my particular copy shows some weird things.

What could be the reasons? I don't think they are just oof or because of out of dof area.
Since it's always the left side I would say it's a case of severe decentering.

You can perform a test - you take a pic in a regular way and then rotate your camera upside down and take the same picture again. Then you rotate the second shot and compare both fotos. If the "glow/weirdness/blurriness" migrates from one corner to another it's a case of decentering.

Is the adapter OK? Does it work fine with other Exa/Topcor lenses?

Is the lens OK? Does it "tick" when you shake it? Is a glass element visibly loose? Does the lens look like it was dropped (dents, bents, etc.)?


Thank you very much for the detailed information. I ran the test. Windows 10 automatically rotates the picture for me. It seems I saw what you described: the glow area migrates to the upper right corner. In addition, there is a very small dent at the lens rear, at the silver part adjacent to the aperture ring, between f11 and f16. So most likely the lens is decentered. When I hold the little tab at the bottom (otherwise it would make noise) and shake the lens, I feel there is only some rattle, probably sounding like from bearing.

It's probably the ball bearings for the aperture, you can hear them click as you slowly rotate the lens on it's axis.
He was referring to shaking the lens forwards and back along it's axis, you will hear clicking from a loose element, I experienced this with an OM 35/2 that had a loose front element that was giving me incontinent results, I thought it was me till I heard the clicking as I stopped and started the lens movement along it's axis. Not hearing it click doesn't mean the elements are seated correctly, it's possible there is some contaminant between the element and it's mounting surface, just thick enough to soften one side.
Most lenses I've worked on the elements fit like a glove into their resting place, a machined fit.

Quote:
If you ever own a Kiron lens, it sounds similar. I had a Soligor having a loosen front element and that sounds different. I searched on the internet and found an optical bench is needed. That seems not an easy fix. Do you have any other recommendation on how this might be fixed?

If an element isn't sitting properly, a disassembly and reassembly might cure the softness.

Quote:
Additionally, I found the aperture ring doesn't have distinct click at each f number; rather, it behaves much like a preset lens. Is this normal?

Nope, someone has been in there, there should definitely be detents every half stop.
Quote:
Many thanks!


PostPosted: Fri Mar 15, 2019 5:12 am    Post subject: Reply with quote

What I don't quite understand is the blurry area doesn't always appear. Some photos are fine and some are not.



[/quote]Sad to hear it is decentered. Loosen glass elements give a specific "clicky/ticky" sound. But it might be stuck in a wrong position as well.

Topcor RE lenses can be easily delicked (no click when chaning f number) - right under the bottom plate there is a spring-like stripe of metal which pushes a ball bearing against small pits. However, there is also a chance somebody opened the lens in order to fix it and lost the ball unintentionally...[/quote]


PostPosted: Fri Mar 15, 2019 8:05 am    Post subject: Reply with quote

vivaldibow wrote:
What I don't quite understand is the blurry area doesn't always appear. Some photos are fine and some are not.



Are you using larger f stop numbers when the blurriness disappears?


PostPosted: Fri Mar 15, 2019 9:51 pm    Post subject: Reply with quote

Sciolist wrote:
vivaldibow wrote:
What I don't quite understand is the blurry area doesn't always appear. Some photos are fine and some are not.



Are you using larger f stop numbers when the blurriness disappears?


+1

The flower images show consistent OOF areas, so I don't think it's a physical problem with the glass. Focus issue maybe? Try adjusting the diopter on the viewfinder. Or the chip on your adapter may need to be calibrated for focus distance.


PostPosted: Wed May 01, 2019 4:52 pm    Post subject: Reply with quote

vivaldibow wrote:
Thanks a lot. I double-check the lens and all the screws. It looks like it's not been opened before. I "suspect" it was bumped/dropped from the little dent, which caused the decenter.


Load a Siemen's Chart on your screen, and go through the focus from maybe 3-5 feet away. You will easily be able to tell if there is a decenter or power bias issue in a corner. The source image looks like a wagon wheel.

If this is the Re-Auto 35mm 2.5 in silver, then I have two copies. One with haze in a doublet causing glow and contrast loss. Another copy is optically perfect. I've taken them apart many times and I don't really see how it could easily decenter, but maybe.

De-center lenses show all kinds of anomalies; astimatigm being the most likely. Each corner will look different, and the effect will not appear to be radiating from the center.

For example with LightShow's soap bubble example as you reach the corner the bokeh balls "cat eye" align with that corner. If this is not happening then you have a de-center.

There is also the chance of reversing a lens element. The following link contains the optical diagrams. Depending if you have the standard or the Re-auto; each has an element that appears very similar on both sides.

http://www.topgabacho.jp/Topconclub/lenscut.htm