The Off-Brand Club!!

pimpim · 09-07-2010, 12:30 AM

Originally posted by Matthew

Thanks for the review, however it would be nice to include colour images rather than monochrome. Is the colour performance of the lens one of it's weak points?
Also listing the lens weight and minimum focus distance in it's description would be nice.

I think the "auto" probably refers to the fact that it can leave the aperture open for focusing and the camera will stop it down to what you have set for taking the photo or when you press the green button.

Thanks for the explanation! I thought all lenses left aperture open for focusing, but I'm probably just used to new lenses.

Colors seem ok! Just didn't make too many color photos that day. I put one of them up there by the way. As for weight and minimum focus distance, I don't have a scale

and I don't really know how to figure out minimum focus distance.

Is it usual to put exotic lenses in the database or doesn't it make much sense?

**Matthew** · 09-07-2010, 05:32 AM

Originally posted by pimpim

As for weight and minimum focus distance, I don't have a scale

and I don't really know how to figure out minimum focus distance.

Minimum focus is a bit of a problem for zooms I guess, but I'd focus at the closest distance on a flat object, then measure to the camera focal plane. Not sure where the focal plane actually is but on K20D I think it was pretty close to the back of the flash housing.
Failing this just read it from the lens distance scale as a ball park figure.

Originally posted by pimpim

Is it usual to put exotic lenses in the database or doesn't it make much sense?

If it will fit a Pentax then it should go in the database, particularly K mount or the old Pentax screw mount. Within this, the more exotic the better.
I've resisted adding old Nikkor lenses which can be fitted with the same functionality as screw mount lenses.

elle.e · 09-07-2010, 07:03 AM

Received my two Vivitars yesterday.
1. Vivitar series 1 70-210mm f/3.5 (version 1 so Kiron made)
2. Vivitar 70-150mm f/3.8

Had to remove the flange of the 70-210 first.

Here some test shots from the 70-150mm
Both @ 3.5

stevebrot · 09-07-2010, 12:55 PM

Originally posted by civiletti

Anyone familiar with the Carl Zeiss Jena II 28mm f2.8 in P/KA mount? There was one on ebay a few days ago.

Originally posted by sherwood

I didn't know there were CZJs in P/KA mount, but why not ? There's always something to learn...

The CZ Jena II lenses are not really CZ Jena. They were made in Asia and marketed under the CZ name. Quality is reputed to be about the same as off-brand lenses of similar construction.

Steve

civiletti · 09-07-2010, 10:22 PM

Originally posted by stevebrot

The CZ Jena II lenses are not really CZ Jena. They were made in Asia and marketed under the CZ name. Quality is reputed to be about the same as off-brand lenses of similar construction.

Steve

Thanks, Steve

fb_penpho · 09-10-2010, 11:37 PM

Having never repaired a lens before, I came across a Cosina, 28mm f2.8 (not macro version), with a stiff focal movement. Seeing it is about 25 years old, I thought nothing to lose, so why not a strip down. Before I started I took some test photo’s. I was really taken by the sharpness and resolution, so that made me decide to go ahead. The construction of the lens is a permanent lens assembly which is moved all together by the focussing ring. So the rear object lens is not fixed, but moves forwards and backwards with the lens assembly relative to the camera.

I took off the rear plates, which exposes the lens sub assembly. Two brass guides, 180 deg apart, have to be unscrewed, then the lens assembly can be removed by unscrewed it from the outer carcass using the focus thread. The removal of a grub screw from the top cover allows this to be unscrewed from the assembly. The top part, containing the front lens, can now be unscrewed from the lens assembly. The front lens is in reality yet another lens sub assembly, unscrew this and the lens sub assembly can be removed. The iris and both sides of the rear lens can now be accessed, this was as far as I went with the strip down. Clean and reassemble, lube where necessary.

What I found out: -- working with small screws is not easy. -- file off the point of the crosspoint screwdriver they seat better and less likely to strip. -- keep a note of the orientation of parts so they do back in the right place.

stevebrot · 09-10-2010, 11:42 PM

Originally posted by fb_penpho

Having never repaired a lens before, I came across a Cosina, 28mm f2.8 (not macro version), with a stiff focal movement. Seeing it is about 25 years old, I thought nothing to lose, so why not a strip down. Before I started I took some test photo’s. I was really taken by the sharpness and resolution, so that made me decide to go ahead. The construction of the lens is a permanent lens assembly which is moved all together by the focussing ring. So the rear object lens is not fixed, but moves forwards and backwards with the lens assembly relative to the camera.

I took off the rear plates, which exposes the lens sub assembly. Two brass guides, 180 deg apart, have to be unscrewed, then the lens assembly can be removed by unscrewed it from the outer carcass using the focus thread. The removal of a grub screw from the top cover allows this to be unscrewed from the assembly. The top part, containing the front lens, can now be unscrewed from the lens assembly. The front lens is in reality yet another lens sub assembly, unscrew this and the lens sub assembly can be removed. The iris and both sides of the rear lens can now be accessed, this was as far as I went with the strip down. Clean and reassemble, lube where necessary.

What I found out: -- working with small screws is not easy. -- file off the point of the crosspoint screwdriver they seat better and less likely to strip. -- keep a note of the orientation of parts so they do back in the right place.

Looks like the patient is doing well! Congratulations on a successful surgery.

Steve

sherwood · 09-10-2010, 11:46 PM

Originally posted by fb_penpho

Having never repaired a lens before, I came across a Cosina, 28mm f2.8 (not macro version), with a stiff focal movement. Seeing it is about 25 years old, I thought nothing to lose, so why not a strip down. Before I started I took some test photo’s. I was really taken by the sharpness and resolution, so that made me decide to go ahead. The construction of the lens is a permanent lens assembly which is moved all together by the focussing ring. So the rear object lens is not fixed, but moves forwards and backwards with the lens assembly relative to the camera.

I took off the rear plates, which exposes the lens sub assembly. Two brass guides, 180 deg apart, have to be unscrewed, then the lens assembly can be removed by unscrewed it from the outer carcass using the focus thread. The removal of a grub screw from the top cover allows this to be unscrewed from the assembly. The top part, containing the front lens, can now be unscrewed from the lens assembly. The front lens is in reality yet another lens sub assembly, unscrew this and the lens sub assembly can be removed. The iris and both sides of the rear lens can now be accessed, this was as far as I went with the strip down. Clean and reassemble, lube where necessary.

What I found out: -- working with small screws is not easy. -- file off the point of the crosspoint screwdriver they seat better and less likely to strip. -- keep a note of the orientation of parts so they do back in the right place.

Thank you very much for sharing your experience !

BillM · 09-11-2010, 10:38 PM

Im 60 acres short of a section in corn and bean, took a walk today after some rain
yesterday to have a look, thought I grabbed m50/1.4, turns out I snatched
an old Tamron 28/2.8 PK, had my 1.7xAF with me, this is what happens when
you put them together. app. 2 cent - 10 inches

fb_penpho · 09-21-2010, 03:54 AM

Here's another refurb, after showing some early shots on the 135mm club, ' Pentaxor' spotted significant flare. I was sure the flare was caused by lens contamination. So after fixing the sticky iris and sloppy focus knob, there was a good cleanup. The first pic at f16 shows the tool and cleaners. The flash off some of the tool bits show some flare, but seems low ( I am no expert when it comes the flare). The next at f5.6 at 5ft shows the narrow DOF, with the centre flower just out of focus. The last is at f8, shows no sign of significant flare as my original shot on the 135mm club.

Jewelltrail · 09-22-2010, 10:55 AM

Quote:

fb penpho: OSAWA 70-150mm f3.8

Nice pics--I have an Osawa 70-210mm which I like too. It is small, light and has the built in hood. I find it easier to manual focus than most of my other lenses.

Mike Cash · 09-25-2010, 08:09 PM

Just a couple days past full moon, typhoon just passed leaving behind clear skies, and it was a Saturday so I didn't have to get up the next morning. Just as I finished work at 7:30 Saturday evening I noticed the coming together of the conditions I had been waiting for since January and called my wife to tell her not to bother with my supper, as I was going straight to Mount Akagi, a defunct volcano, to do some night photography.

Pentax K20D
Cosina MF 20/3.8
10 min. @ f11

Mike Cash · 09-26-2010, 08:55 AM

Another midnight shot from the mountain:

Pentax K20D
Cosina MF 20/3.8

georgweb · 09-26-2010, 01:29 PM

Great effort Mike and I really like the red shrine (if it is a shrine) and the swirly stars in the sky. The tree shadow from the moon is special.

Enna/Revuenon 240/4.5 on K100D

sherwood · 09-27-2010, 10:50 AM

The first one is very special. If you didn't wrote it's a night shot, I'd have asked "what are the white marks in the sky ?"

Am I so stupid ?

09-07-2010, 05:32 AM	#692
Matthew Site Supporter Join Date: Feb 2008 Location: Hawkesbury Photos: Gallery Posts: 1,896	If it will fit a Pentax... Originally posted by pimpim As for weight and minimum focus distance, I don't have a scale and I don't really know how to figure out minimum focus distance. Minimum focus is a bit of a problem for zooms I guess, but I'd focus at the closest distance on a flat object, then measure to the camera focal plane. Not sure where the focal plane actually is but on K20D I think it was pretty close to the back of the flash housing. Failing this just read it from the lens distance scale as a ball park figure. Originally posted by pimpim Is it usual to put exotic lenses in the database or doesn't it make much sense? If it will fit a Pentax then it should go in the database, particularly K mount or the old Pentax screw mount. Within this, the more exotic the better. I've resisted adding old Nikkor lenses which can be fitted with the same functionality as screw mount lenses.

09-11-2010, 10:38 PM	#699
BillM Veteran Member Join Date: Jan 2010 Location: Ferguson, Mo. Photos: Gallery Posts: 1,348	Im 60 acres short of a section in corn and bean, took a walk today after some rain yesterday to have a look, thought I grabbed m50/1.4, turns out I snatched an old Tamron 28/2.8 PK, had my 1.7xAF with me, this is what happens when you put them together. app. 2 cent - 10 inches Attached Images

09-21-2010, 03:54 AM	#700
fb_penpho Senior Member Join Date: Jul 2009 Location: London Photos: Gallery Posts: 212	Cosina Cosinon 135mm f3.5 Here's another refurb, after showing some early shots on the 135mm club, ' Pentaxor' spotted significant flare. I was sure the flare was caused by lens contamination. So after fixing the sticky iris and sloppy focus knob, there was a good cleanup. The first pic at f16 shows the tool and cleaners. The flash off some of the tool bits show some flare, but seems low ( I am no expert when it comes the flare). The next at f5.6 at 5ft shows the narrow DOF, with the centre flower just out of focus. The last is at f8, shows no sign of significant flare as my original shot on the 135mm club. Last edited by fb_penpho; 12-17-2016 at 05:02 AM.

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09-07-2010, 12:30 AM	#691
pimpim Senior Member Join Date: Sep 2010 Location: Mainz Photos: Albums Posts: 253	Originally posted by Matthew Thanks for the review, however it would be nice to include colour images rather than monochrome. Is the colour performance of the lens one of it's weak points? Also listing the lens weight and minimum focus distance in it's description would be nice. I think the "auto" probably refers to the fact that it can leave the aperture open for focusing and the camera will stop it down to what you have set for taking the photo or when you press the green button. Thanks for the explanation! I thought all lenses left aperture open for focusing, but I'm probably just used to new lenses. Colors seem ok! Just didn't make too many color photos that day. I put one of them up there by the way. As for weight and minimum focus distance, I don't have a scale and I don't really know how to figure out minimum focus distance. Is it usual to put exotic lenses in the database or doesn't it make much sense?

09-07-2010, 07:03 AM	#693
elle.e Senior Member Join Date: Aug 2008 Location: Netherlands Photos: Gallery Posts: 106	Received my two Vivitars yesterday. 1. Vivitar series 1 70-210mm f/3.5 (version 1 so Kiron made) 2. Vivitar 70-150mm f/3.8 Had to remove the flange of the 70-210 first. Here some test shots from the 70-150mm Both @ 3.5

09-07-2010, 12:55 PM	#694
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007 Original Poster	Originally posted by civiletti Anyone familiar with the Carl Zeiss Jena II 28mm f2.8 in P/KA mount? There was one on ebay a few days ago. Originally posted by sherwood I didn't know there were CZJs in P/KA mount, but why not ? There's always something to learn... The CZ Jena II lenses are not really CZ Jena. They were made in Asia and marketed under the CZ name. Quality is reputed to be about the same as off-brand lenses of similar construction. Steve

09-07-2010, 10:22 PM	#695
civiletti Pentaxian Join Date: Jul 2010 Location: Oregon Photos: Albums Posts: 1,435	Originally posted by stevebrot The CZ Jena II lenses are not really CZ Jena. They were made in Asia and marketed under the CZ name. Quality is reputed to be about the same as off-brand lenses of similar construction. Steve Thanks, Steve

09-10-2010, 11:42 PM	#697
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007 Original Poster	Originally posted by fb_penpho Having never repaired a lens before, I came across a Cosina, 28mm f2.8 (not macro version), with a stiff focal movement. Seeing it is about 25 years old, I thought nothing to lose, so why not a strip down. Before I started I took some test photo’s. I was really taken by the sharpness and resolution, so that made me decide to go ahead. The construction of the lens is a permanent lens assembly which is moved all together by the focussing ring. So the rear object lens is not fixed, but moves forwards and backwards with the lens assembly relative to the camera. I took off the rear plates, which exposes the lens sub assembly. Two brass guides, 180 deg apart, have to be unscrewed, then the lens assembly can be removed by unscrewed it from the outer carcass using the focus thread. The removal of a grub screw from the top cover allows this to be unscrewed from the assembly. The top part, containing the front lens, can now be unscrewed from the lens assembly. The front lens is in reality yet another lens sub assembly, unscrew this and the lens sub assembly can be removed. The iris and both sides of the rear lens can now be accessed, this was as far as I went with the strip down. Clean and reassemble, lube where necessary. What I found out: -- working with small screws is not easy. -- file off the point of the crosspoint screwdriver they seat better and less likely to strip. -- keep a note of the orientation of parts so they do back in the right place. Looks like the patient is doing well! Congratulations on a successful surgery. Steve

09-10-2010, 11:46 PM	#698
sherwood Forum Member Join Date: Aug 2010 Location: Belgium Photos: Albums Posts: 60	Originally posted by fb_penpho Having never repaired a lens before, I came across a Cosina, 28mm f2.8 (not macro version), with a stiff focal movement. Seeing it is about 25 years old, I thought nothing to lose, so why not a strip down. Before I started I took some test photo’s. I was really taken by the sharpness and resolution, so that made me decide to go ahead. The construction of the lens is a permanent lens assembly which is moved all together by the focussing ring. So the rear object lens is not fixed, but moves forwards and backwards with the lens assembly relative to the camera. I took off the rear plates, which exposes the lens sub assembly. Two brass guides, 180 deg apart, have to be unscrewed, then the lens assembly can be removed by unscrewed it from the outer carcass using the focus thread. The removal of a grub screw from the top cover allows this to be unscrewed from the assembly. The top part, containing the front lens, can now be unscrewed from the lens assembly. The front lens is in reality yet another lens sub assembly, unscrew this and the lens sub assembly can be removed. The iris and both sides of the rear lens can now be accessed, this was as far as I went with the strip down. Clean and reassemble, lube where necessary. What I found out: -- working with small screws is not easy. -- file off the point of the crosspoint screwdriver they seat better and less likely to strip. -- keep a note of the orientation of parts so they do back in the right place. Thank you very much for sharing your experience !

09-22-2010, 10:55 AM	#701
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: fb penpho: OSAWA 70-150mm f3.8 Nice pics--I have an Osawa 70-210mm which I like too. It is small, light and has the built in hood. I find it easier to manual focus than most of my other lenses.

09-25-2010, 08:09 PM	#702
Mike Cash Veteran Member Join Date: Jan 2007 Location: Japan Photos: Gallery Posts: 6,950	Just a couple days past full moon, typhoon just passed leaving behind clear skies, and it was a Saturday so I didn't have to get up the next morning. Just as I finished work at 7:30 Saturday evening I noticed the coming together of the conditions I had been waiting for since January and called my wife to tell her not to bother with my supper, as I was going straight to Mount Akagi, a defunct volcano, to do some night photography. Pentax K20D Cosina MF 20/3.8 10 min. @ f11

09-26-2010, 08:55 AM	#703
Mike Cash Veteran Member Join Date: Jan 2007 Location: Japan Photos: Gallery Posts: 6,950	Another midnight shot from the mountain: Pentax K20D Cosina MF 20/3.8

09-26-2010, 01:29 PM	#704
georgweb Veteran Member Join Date: Apr 2008 Location: Berlin, Germany Photos: Gallery Posts: 1,386	Great effort Mike and I really like the red shrine (if it is a shrine) and the swirly stars in the sky. The tree shadow from the moon is special. Enna/Revuenon 240/4.5 on K100D

09-27-2010, 10:50 AM	#705
sherwood Forum Member Join Date: Aug 2010 Location: Belgium Photos: Albums Posts: 60	The first one is very special. If you didn't wrote it's a night shot, I'd have asked "what are the white marks in the sky ?" Am I so stupid ?