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aoeu · 07-01-2016, 01:37 PM

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SMC Pentax FA 50mm F 1 7 PK Autofocus Mount Caps Japan Unique Sought After | eBay

Quote:

SMC PENTAX-FA 50mm f=1.7 PK autofocus mount caps JAPAN UNIQUE! SOUGHT AFTER

famous and sought after manual focus standard lens for PENTAX K-AF bayonet SLR, DSLR and other digital cameras (by adapter) in almost NEW condition. It's unique specimen of PENTAX FA 50mm 1.7 lens - it has metal focusing ring with locking knob similar to some PENTAX "MACRO" lenses. I think that it could be some prototype or pre-production sample because there is no serial number and nothing found in the internet about such construction.

**jatrax** · 07-01-2016, 01:43 PM

This was shown on ebay some time ago. The consensus, if I remember right, was that this was a frankenlens that someone had added the "lock/off" ring thing to. So nothing more than an FA 50mm that may or may not even work correctly. Certainly there is no official listing for this anywhere.

Na Horuk · 07-01-2016, 01:46 PM

There is a difference between a focus limiter and a focus clamp/lock. The limiter would be complex to add, while a clamp would be a relatively easy modification. But there might be a danger of the lock putting pressure onto the AF system.
I would avoid that lens, you can just get a regular F or FA 50mm. There are few cases where a non-macro 50mm lens would require a focus lock

aoeu · 07-01-2016, 01:48 PM

Originally posted by jatrax

This was shown on ebay some time ago. The consensus, if I remember right, was that this was a frankenlens that someone had added the "lock/off" ring thing to. So nothing more than an FA 50mm that may or may not even work correctly. Certainly there is no official listing for this anywhere.

What would be the point?
Other than fraud.

stevebrot · 07-01-2016, 01:49 PM

The lens is real and has been listed on eBay before. The so-called focus limiter is sort of strange and I have my doubts that it is a factory one-off. I do know that I would have no desire to mount it one of my cameras without knowing exactly how it works.

Edit: As noted above, this appears to be a focus clamp to lock the focus in a particular position. This type of device is commonly used for time-lapse and similar cases.

Steve

**jatrax** · 07-01-2016, 01:58 PM

Originally posted by aoeu

What would be the point? Other than fraud.

More likely the seller has no idea what he has but knows it is unique, thus he is asking a premium 'collector' price for it. The clamp or limiter seems to just be an and on. But without having it in hand who knows? it has been offered for sale before with no takers.

aoeu · 07-01-2016, 02:03 PM

Originally posted by stevebrot

The lens is real and has been listed on eBay before. The so-called focus limiter is sort of strange and I have my doubts that it is a factory one-off. I do know that I would have no desire to mount it one of my cameras without knowing exactly how it works.

Edit: As noted above, this appears to be a focus clamp to lock the focus in a particular position. This type of device is commonly used for time-lapse and similar cases.

Steve

aoeuaoeu

stevebrot · 07-01-2016, 02:09 PM

Originally posted by aoeu

aoeuaoeu

The lock is for manual focus. At the body, one can leave AF on and simply disengage AF on half-press for the shutter. Gaffer's tape is another common solution.

Steve

stevebrot · 07-01-2016, 02:19 PM

Originally posted by jatrax

More likely the seller has no idea what he has but knows it is unique, thus he is asking a premium 'collector' price for it. The clamp or limiter seems to just be an and on. But without having it in hand who knows? it has been offered for sale before with no takers.

I noticed that the serial number has gone missing and that the lens body is matte finish rather than the more typical FA semi-gloss. It may be that the lens was used in an industrial application. Zeiss makes a series for that purpose and all feature focus locks.

Steve

Not a Number · 07-01-2016, 09:45 PM

Locked off focus is(was) commonly used in automated and industrial systems. There may be hundreds of these lenses and the only rarity is finding one for sale.

**Digitalis** · 07-01-2016, 11:53 PM

Originally posted by Not a Number

Locked off focus is(was) commonly used in automated and industrial systems. There may be hundreds of these lenses and the only rarity is finding one for sale.

I agree - this may well be a lens built for industrial purposes, these lenses are often environmentally sealed as well against dust and water that may be encountered in industrial settings. I suspect there isn't any significant advantage in using this lens over the standard FA50mm f/1.7...unless you have a specific need for a focus lock feature.

**LeChefRouge** · 12-10-2016, 06:58 PM - **1 Like**

So I own one of these lenses and the previous owner had no explanation as to why the lock was there. He never used it. There is some damage caused by the lock, but it has no effect on the lens at all including the AF. It's still fast and accurate. The serial number is also intacted as well. I purchased this lens along with an F 35-70 for $150 so I don't have any complaints.

Picture of my dog taken with the lens

bxf · 12-11-2016, 02:08 PM - **2 Likes**

Originally posted by LeChefRouge

Picture of my dog taken with the lens

I can see the problem with these lenses. It appears they have the effect of rotating the image 88 degrees clockwise.

angerdan · 03-04-2018, 08:00 AM

There's no 50mm from Pentax with focus limiter.
Lenses for Pentax with focus limiter - PentaxForums.com

07-01-2016, 01:37 PM	#1
aoeu Veteran Member Join Date: Sep 2010 Location: Oregon Posts: 496	Real? SMC PENTAX-FA 50mm f=1.7 with a focus limiter? Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. SMC Pentax FA 50mm F 1 7 PK Autofocus Mount Caps Japan Unique Sought After \| eBay Quote: SMC PENTAX-FA 50mm f=1.7 PK autofocus mount caps JAPAN UNIQUE! SOUGHT AFTER famous and sought after manual focus standard lens for PENTAX K-AF bayonet SLR, DSLR and other digital cameras (by adapter) in almost NEW condition. It's unique specimen of PENTAX FA 50mm 1.7 lens - it has metal focusing ring with locking knob similar to some PENTAX "MACRO" lenses. I think that it could be some prototype or pre-production sample because there is no serial number and nothing found in the internet about such construction.

07-01-2016, 02:03 PM	#7
aoeu Veteran Member Join Date: Sep 2010 Location: Oregon Posts: 496 Original Poster	Wouldn't it be easier to turn the AF off in the body? Originally posted by stevebrot The lens is real and has been listed on eBay before. The so-called focus limiter is sort of strange and I have my doubts that it is a factory one-off. I do know that I would have no desire to mount it one of my cameras without knowing exactly how it works. Edit: As noted above, this appears to be a focus clamp to lock the focus in a particular position. This type of device is commonly used for time-lapse and similar cases. Steve aoeuaoeu

07-01-2016, 02:09 PM	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by aoeu aoeuaoeu The lock is for manual focus. At the body, one can leave AF on and simply disengage AF on half-press for the shutter. Gaffer's tape is another common solution. Steve Last edited by stevebrot; 07-01-2016 at 02:23 PM.

12-10-2016, 06:58 PM - 1 Like	#12
LeChefRouge Site Supporter Join Date: Dec 2016 Location: Huntsville, AL Photos: Gallery Posts: 92	So I own one of these lenses and the previous owner had no explanation as to why the lock was there. He never used it. There is some damage caused by the lock, but it has no effect on the lens at all including the AF. It's still fast and accurate. The serial number is also intacted as well. I purchased this lens along with an F 35-70 for $150 so I don't have any complaints. Picture of my dog taken with the lens Last edited by LeChefRouge; 04-10-2017 at 08:39 PM.

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07-01-2016, 01:43 PM	#2
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	This was shown on ebay some time ago. The consensus, if I remember right, was that this was a frankenlens that someone had added the "lock/off" ring thing to. So nothing more than an FA 50mm that may or may not even work correctly. Certainly there is no official listing for this anywhere.

07-01-2016, 01:46 PM	#3
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	There is a difference between a focus limiter and a focus clamp/lock. The limiter would be complex to add, while a clamp would be a relatively easy modification. But there might be a danger of the lock putting pressure onto the AF system. I would avoid that lens, you can just get a regular F or FA 50mm. There are few cases where a non-macro 50mm lens would require a focus lock

07-01-2016, 01:48 PM	#4
aoeu Veteran Member Join Date: Sep 2010 Location: Oregon Posts: 496 Original Poster	Originally posted by jatrax This was shown on ebay some time ago. The consensus, if I remember right, was that this was a frankenlens that someone had added the "lock/off" ring thing to. So nothing more than an FA 50mm that may or may not even work correctly. Certainly there is no official listing for this anywhere. What would be the point? Other than fraud.

07-01-2016, 01:49 PM	#5
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	The lens is real and has been listed on eBay before. The so-called focus limiter is sort of strange and I have my doubts that it is a factory one-off. I do know that I would have no desire to mount it one of my cameras without knowing exactly how it works. Edit: As noted above, this appears to be a focus clamp to lock the focus in a particular position. This type of device is commonly used for time-lapse and similar cases. Steve

07-01-2016, 01:58 PM	#6
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by aoeu What would be the point? Other than fraud. More likely the seller has no idea what he has but knows it is unique, thus he is asking a premium 'collector' price for it. The clamp or limiter seems to just be an and on. But without having it in hand who knows? it has been offered for sale before with no takers.

07-01-2016, 02:19 PM	#9
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by jatrax More likely the seller has no idea what he has but knows it is unique, thus he is asking a premium 'collector' price for it. The clamp or limiter seems to just be an and on. But without having it in hand who knows? it has been offered for sale before with no takers. I noticed that the serial number has gone missing and that the lens body is matte finish rather than the more typical FA semi-gloss. It may be that the lens was used in an industrial application. Zeiss makes a series for that purpose and all feature focus locks. Steve

07-01-2016, 09:45 PM	#10
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Locked off focus is(was) commonly used in automated and industrial systems. There may be hundreds of these lenses and the only rarity is finding one for sale.

07-01-2016, 11:53 PM	#11
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by Not a Number Locked off focus is(was) commonly used in automated and industrial systems. There may be hundreds of these lenses and the only rarity is finding one for sale. I agree - this may well be a lens built for industrial purposes, these lenses are often environmentally sealed as well against dust and water that may be encountered in industrial settings. I suspect there isn't any significant advantage in using this lens over the standard FA50mm f/1.7...unless you have a specific need for a focus lock feature.

12-11-2016, 02:08 PM - 2 Likes	#13
bxf Veteran Member Join Date: Jul 2010 Location: Lisbon area Posts: 1,660	Originally posted by LeChefRouge Picture of my dog taken with the lens I can see the problem with these lenses. It appears they have the effect of rotating the image 88 degrees clockwise.

03-04-2018, 08:00 AM	#14
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,643	There's no 50mm from Pentax with focus limiter. Lenses for Pentax with focus limiter - PentaxForums.com

Real? SMC PENTAX-FA 50mm f=1.7 with a focus limiter?

Win a Pentax Limited Lens: Raffle Now Live!