Help me identify this mount! Vivitar 135 2.8

RioRico · 11-19-2011, 02:33 AM

Originally posted by wolfiegirl

Ok I need to ask... NIF adapter? What's that short for? Not In Focus?

Non-infinity focus. The wide-flange M42-PK adapters are NIF. They push the lens 1mm further away from the sensor. Bye-bye infinity. Hi there, intimacy. The effect can be minor for lenses 180mm and longer, or striking for glass shorter than 60mm. An NIF adapter is great for portraiture because we don't care about infinity.

Quote:

Hrmm.. more 50s... I was hoping to get out of the fast fifites.. I've got like 6 or so of those now, all with different aperture speeds as well as a few doubles with different coatings. Still, if it lets me in super close perhaps it can push out the manuals.

Let's talk about close-focus distance (CFD). My SuperTak 50/1.4 and 55/1.8 each have a nominal CFD= 45cm. The cheap safe NIF adapter pushes that down to about 27cm. Many 28mm lenses have a nominal CFD= 30cm. On a NIF adapter, that drops to 15cm. Far focus on a 28 drops from infinity down to maybe 1m.

Quote:

Just as important, did any of the three you just recommended require modding?

The Meyer|Pentacon and Porst are straight M42. The Porst has an A/M switch. The Meyer Orestron | Pentacon Color copies seen lack that switch; the aperture pin must be jammed down in order to work the iris. The CZJ Tessar is Exakta mount -- mod the adapter, not the lens. For close work, don't even bother modding the adapter. NOTE: the 12-iris-blade 1-ring-preset Tessar is one of my absolute favorite lenses, literally always in my bag, tiny and superb. And mine was cheap!

I know -- you'll ask, MOD THE ADAPTER? Like this: Take an Exakta mount lens. Glue an ultra-cheap M39-M42 ring around the bayonet. Grind down (on sandpaper) a cheap M42-PK adapter till the lens reaches infinity focus, if that is important to you. No cutting, no lens damage.

Originally posted by vonBaloney

The 18-250 can be focused at a foot or so over its entire zoom range (which only gets to about 180mm when focused on close subjects). Very versatile.

Yes, it does go close. Its nominal CFD= 45cm but I measure it closer to 25cm. The DA18-55 also focuses closer than its nominal CFD of 25cm -- I measure it as under 15cm. Why are the specs so far off?

Last edited by RioRico; 11-19-2011 at 05:10 AM.

wolfiegirl · 11-19-2011, 04:39 AM

You're a walking lens encyclopedia Rico!!

RioRico · 11-19-2011, 05:11 AM

Originally posted by wolfiegirl

You're a walking lens encyclopedia Rico!!

Sometimes my pages drag in the muck.

drougge · 11-21-2011, 02:21 AM

Originally posted by RioRico

Yes, it does go close. Its nominal CFD= 45cm but I measure it closer to 25cm. The DA18-55 also focuses closer than its nominal CFD of 25cm -- I measure it as under 15cm. Why are the specs so far off?

I don't have my kit lens handy, but as I recall it's at least 10cm long. That would put your <15cm inside the lens. I'm pretty sure it doesn't focus that close. So I would guess you're not measuring from the film plane.

So the answer to your question is: They're not off, they're just not measuring the same thing as you. (Well, they probably are off, but not as much as you think.)

RioRico · 11-21-2011, 03:25 AM

Originally posted by drougge

I don't have my kit lens handy, but as I recall it's at least 10cm long. That would put your <15cm inside the lens. I'm pretty sure it doesn't focus that close. So I would guess you're not measuring from the film plane.

So the answer to your question is: They're not off, they're just not measuring the same thing as you. (Well, they probably are off, but not as much as you think.)

My DA18-55 measures 7cm long.

Measuring from the film plane adds ~4.5cm, not 10 or 20. But it's a good question: where do the distance marks on a lens measure from? The film plane? The optical center? We mere mortal end-users usually put a ruler between the subject and the lens front to measure distances. I see that some macro lenses show magnification, not distance, for close work. Is there a standard for basing focus measurements?

jolepp · 11-21-2011, 03:30 AM

My understanding has been that the 'official' lens spec (and scale) distances are always from the image (film/sensor) plane (?).

wolfiegirl · 11-21-2011, 03:30 AM

Originally posted by RioRico

My DA18-55 measures 7cm long.

Quote of the Day?

Sorry, I'll umm go back to PP...

drougge · 11-21-2011, 03:47 AM

Originally posted by RioRico

My DA18-55 measures 7cm long.

I have been known to be wrong.

Originally posted by RioRico

Measuring from the film plane adds ~4.5cm, not 10 or 20. But it's a good question: where do the distance marks on a lens measure from? The film plane? The optical center? We mere mortal end-users usually put a ruler between the subject and the lens front to measure distances. I see that some macro lenses show magnification, not distance, for close work. Is there a standard for basing focus measurements?

Obviously, as seen by adding my numbers, I assumed you were measuring from the front element. Which would make your measurement 11.5cm short in this case, which fits well with your >10cm error.

Originally posted by jolepp

My understanding has been that the 'official' lens spec (and scale) distances are always from the image (film/sensor) plane (?).

Mine as well. Which fits both with measurements, what they say, and reason (or what passes for it in my case at any rate).

RioRico · 11-21-2011, 03:57 AM

Originally posted by wolfiegirl

Quote of the Day?

Not a brag, obviously.

Originally posted by drougge

Obviously, as seen by adding my numbers, I assumed you were measuring from the front element. Which would make your measurement 11.5cm short in this case, which fits well with your >10cm error.

Oh bother. Now I must re-do a number of measurements.

wolfiegirl · 11-21-2011, 04:20 AM

Originally posted by RioRico

Not a brag, obviously.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Need help to identify lens, which kind of mount?	cofra	Pentax SLR Lens Discussion	2	08-10-2010 03:27 PM
Can Vivitar fans help to identify this 28mm F2?	badbrother	Pentax SLR Lens Discussion	4	04-25-2010 04:52 PM
Please help me identify this mount	ducdao	Canon, Nikon, Sony, and Other Camera Brands	8	02-12-2010 03:13 AM
Can someone identify this Vivitar 135 f2.8?	ducdao	Pentax SLR Lens Discussion	10	01-09-2010 01:02 PM

11-19-2011, 02:33 AM	#31
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by wolfiegirl Ok I need to ask... NIF adapter? What's that short for? Not In Focus? Non-infinity focus. The wide-flange M42-PK adapters are NIF. They push the lens 1mm further away from the sensor. Bye-bye infinity. Hi there, intimacy. The effect can be minor for lenses 180mm and longer, or striking for glass shorter than 60mm. An NIF adapter is great for portraiture because we don't care about infinity. Quote: Hrmm.. more 50s... I was hoping to get out of the fast fifites.. I've got like 6 or so of those now, all with different aperture speeds as well as a few doubles with different coatings. Still, if it lets me in super close perhaps it can push out the manuals. Let's talk about close-focus distance (CFD). My SuperTak 50/1.4 and 55/1.8 each have a nominal CFD= 45cm. The cheap safe NIF adapter pushes that down to about 27cm. Many 28mm lenses have a nominal CFD= 30cm. On a NIF adapter, that drops to 15cm. Far focus on a 28 drops from infinity down to maybe 1m. Quote: Just as important, did any of the three you just recommended require modding? The Meyer\|Pentacon and Porst are straight M42. The Porst has an A/M switch. The Meyer Orestron \| Pentacon Color copies seen lack that switch; the aperture pin must be jammed down in order to work the iris. The CZJ Tessar is Exakta mount -- mod the adapter, not the lens. For close work, don't even bother modding the adapter. NOTE: the 12-iris-blade 1-ring-preset Tessar is one of my absolute favorite lenses, literally always in my bag, tiny and superb. And mine was cheap! I know -- you'll ask, MOD THE ADAPTER? Like this: Take an Exakta mount lens. Glue an ultra-cheap M39-M42 ring around the bayonet. Grind down (on sandpaper) a cheap M42-PK adapter till the lens reaches infinity focus, if that is important to you. No cutting, no lens damage. Originally posted by vonBaloney The 18-250 can be focused at a foot or so over its entire zoom range (which only gets to about 180mm when focused on close subjects). Very versatile. Yes, it does go close. Its nominal CFD= 45cm but I measure it closer to 25cm. The DA18-55 also focuses closer than its nominal CFD of 25cm -- I measure it as under 15cm. Why are the specs so far off? Last edited by RioRico; 11-19-2011 at 05:10 AM.

11-19-2011, 04:39 AM	#32
wolfiegirl Veteran Member Join Date: Oct 2011 Location: Mystery Bay, NSW Photos: Gallery Posts: 4,111 Original Poster	You're a walking lens encyclopedia Rico!!

11-19-2011, 05:11 AM	#33
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by wolfiegirl You're a walking lens encyclopedia Rico!! Sometimes my pages drag in the muck.

11-21-2011, 02:21 AM	#34
drougge Veteran Member Join Date: Jan 2010 Location: Malmö Photos: Gallery Posts: 787	Originally posted by RioRico Yes, it does go close. Its nominal CFD= 45cm but I measure it closer to 25cm. The DA18-55 also focuses closer than its nominal CFD of 25cm -- I measure it as under 15cm. Why are the specs so far off? I don't have my kit lens handy, but as I recall it's at least 10cm long. That would put your <15cm inside the lens. I'm pretty sure it doesn't focus that close. So I would guess you're not measuring from the film plane. So the answer to your question is: They're not off, they're just not measuring the same thing as you. (Well, they probably are off, but not as much as you think.)

11-21-2011, 03:25 AM	#35
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by drougge I don't have my kit lens handy, but as I recall it's at least 10cm long. That would put your <15cm inside the lens. I'm pretty sure it doesn't focus that close. So I would guess you're not measuring from the film plane. So the answer to your question is: They're not off, they're just not measuring the same thing as you. (Well, they probably are off, but not as much as you think.) My DA18-55 measures 7cm long. Measuring from the film plane adds ~4.5cm, not 10 or 20. But it's a good question: where do the distance marks on a lens measure from? The film plane? The optical center? We mere mortal end-users usually put a ruler between the subject and the lens front to measure distances. I see that some macro lenses show magnification, not distance, for close work. Is there a standard for basing focus measurements?

11-21-2011, 03:30 AM	#36
jolepp Veteran Member Join Date: Oct 2010 Location: Finland Photos: Albums Posts: 3,196	My understanding has been that the 'official' lens spec (and scale) distances are always from the image (film/sensor) plane (?).

11-21-2011, 03:30 AM	#37
wolfiegirl Veteran Member Join Date: Oct 2011 Location: Mystery Bay, NSW Photos: Gallery Posts: 4,111 Original Poster	Originally posted by RioRico My DA18-55 measures 7cm long. Quote of the Day? Sorry, I'll umm go back to PP...

11-21-2011, 03:47 AM	#38
drougge Veteran Member Join Date: Jan 2010 Location: Malmö Photos: Gallery Posts: 787	Originally posted by RioRico My DA18-55 measures 7cm long. I have been known to be wrong. Originally posted by RioRico Measuring from the film plane adds ~4.5cm, not 10 or 20. But it's a good question: where do the distance marks on a lens measure from? The film plane? The optical center? We mere mortal end-users usually put a ruler between the subject and the lens front to measure distances. I see that some macro lenses show magnification, not distance, for close work. Is there a standard for basing focus measurements? Obviously, as seen by adding my numbers, I assumed you were measuring from the front element. Which would make your measurement 11.5cm short in this case, which fits well with your >10cm error. Originally posted by jolepp My understanding has been that the 'official' lens spec (and scale) distances are always from the image (film/sensor) plane (?). Mine as well. Which fits both with measurements, what they say, and reason (or what passes for it in my case at any rate).

11-21-2011, 03:57 AM	#39
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by wolfiegirl Quote of the Day? Not a brag, obviously. Originally posted by drougge Obviously, as seen by adding my numbers, I assumed you were measuring from the front element. Which would make your measurement 11.5cm short in this case, which fits well with your >10cm error. Oh bother. Now I must re-do a number of measurements.

11-21-2011, 04:20 AM	#40
wolfiegirl Veteran Member Join Date: Oct 2011 Location: Mystery Bay, NSW Photos: Gallery Posts: 4,111 Original Poster	Originally posted by RioRico Not a brag, obviously.