Pentax Auto-focus

**Baard-Einar** · 01-27-2019, 05:09 AM - **1 Like**

Dear forum

I came across this about an early Autofocus system called Visitronics. The system was invented by Honeywell mid-1970 (according to Wikipedia), and it made it into a Konica compact camera, the C35AF. And it seems that Pentax did some experimenting with it, as the attached photo indicates. This ended up later in a different wrapping as the standard lens for the Pentax ME-F. According to Wikipedia, many Japanese manufactureres stole their patent, resulting in more than $120 million in back royalties to Honeywell.

The photo is from a publication called History of Automatic Focusing Reflected by Patents.

Anyone with some more info about this?

Attached Images

**TwoUptons** · 01-27-2019, 06:17 AM

That photo makes it look a lot like the Chinon infrared autofocus system, with the extra windows below the lens...

-Eric

**ramseybuckeye** · 01-27-2019, 06:35 AM

These come up on ebay occasionally.

edit: A quick check reveals there are a few listed now, some cameras without lens, some with.

pschlute · 01-27-2019, 07:32 AM - **1 Like**

I don't know anything about that early model/prototype, but I have the ME-F with the AF 35-70 2.8 autofocus lens.

A lovely bit of nostalgic kit to play with it is.

**TwoUptons** · 01-27-2019, 08:02 AM

Originally posted by pschlute

I don't know anything about that early model/prototype, but I have the ME-F with the AF 35-70 2.8 autofocus lens.

A lovely bit of nostalgic kit to play with it is.

And the lens is better than I expected. They didn’t cheap out on the glass to get a fast aperture... which makes sense since it’s easier to focus a lens that isn’t fuzzy...

-Eric

pschlute · 01-27-2019, 08:14 AM - **5 Likes**

Originally posted by TwoUptons

And the lens is better than I expected

Agreed. I took these two with the ME-F + AF 35-70 last summer

**limestonecowboy** · 01-27-2019, 10:28 AM - **1 Like**

Originally posted by pschlute

Agreed. I took these two with the ME-F + AF 35-70 last summer

Superb shots

**gofour3** · 01-27-2019, 11:25 AM

Originally posted by Baard-Einar

Anyone with some more info about this?

The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom.

Pentax Prototype Zoom Lenses | The K-Mount Page

Phil.

pschlute · 01-27-2019, 12:12 PM

Originally posted by limestonecowboy

Superb shots

Many thanks for your kind comments

---------- Post added 01-27-19 at 07:13 PM ----------

Originally posted by gofour3

The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom.

Pentax Prototype Zoom Lenses | The K-Mount Page

Phil.

Interesting thing is that the Af 35-70 even when not paired with a ME-F can still give focus confirmation. Pretty advanced stuff for 1981 !

**Baard-Einar** · 01-27-2019, 02:08 PM - **1 Like**

Originally posted by ramseybuckeye

These come up on ebay occasionally.

edit: A quick check reveals there are a few listed now, some cameras without lens, some with.

Hello, I dont think you'll find that lens shown in my post on ebay. It is only a prototype.

---------- Post added 01-27-2019 at 10:09 PM ----------

Originally posted by gofour3

The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom.

Pentax Prototype Zoom Lenses | The K-Mount Page

Phil.

Thanks for the link.

---------- Post added 01-27-2019 at 10:09 PM ----------

Originally posted by pschlute

Agreed. I took these two with the ME-F + AF 35-70 last summer

Really nice pics.

**TwoUptons** · 01-27-2019, 02:26 PM - **1 Like**

Originally posted by pschlute

Interesting thing is that the Af 35-70 even when not paired with a ME-F can still give focus confirmation. Pretty advanced stuff for 1981 !

I think that’s the other way around...

The ME-F will focus confirm with other lenses, but I’ve never seen the lens do anything ‘smart’ on a camera other than the ME-F...

-Eric

pschlute · 01-27-2019, 02:47 PM

Originally posted by TwoUptons

I think that’s the other way around...

The ME-F will focus confirm with other lenses, but I’ve never seen the lens do anything ‘smart’ on a camera other than the ME-F...

-Eric

Oh gosh yes you are right. thanks for pointing that out. One too many cocktails tonight methinks !!!

**ramseybuckeye** · 01-27-2019, 03:11 PM

Originally posted by Baard-Einar

Hello, I dont think you'll find that lens shown in my post on ebay. It is only a prototype.[COLOR="Silver"]
.

right, only production copies

01-27-2019, 05:09 AM - 1 Like	#1
Baard-Einar Site Supporter Join Date: Jan 2010 Location: Oslo Photos: Gallery Posts: 964	Pentax Auto-focus Dear forum I came across this about an early Autofocus system called Visitronics. The system was invented by Honeywell mid-1970 (according to Wikipedia), and it made it into a Konica compact camera, the C35AF. And it seems that Pentax did some experimenting with it, as the attached photo indicates. This ended up later in a different wrapping as the standard lens for the Pentax ME-F. According to Wikipedia, many Japanese manufactureres stole their patent, resulting in more than $120 million in back royalties to Honeywell. The photo is from a publication called History of Automatic Focusing Reflected by Patents. Anyone with some more info about this? Attached Images

01-27-2019, 06:35 AM	#3
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,295	These come up on ebay occasionally. edit: A quick check reveals there are a few listed now, some cameras without lens, some with. Last edited by ramseybuckeye; 01-27-2019 at 06:41 AM.

01-27-2019, 02:47 PM	#12
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,216	Originally posted by TwoUptons I think that’s the other way around... The ME-F will focus confirm with other lenses, but I’ve never seen the lens do anything ‘smart’ on a camera other than the ME-F... -Eric Oh gosh yes you are right. thanks for pointing that out. One too many cocktails tonight methinks !!! Last edited by pschlute; 01-27-2019 at 04:11 PM.

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01-27-2019, 06:17 AM	#2
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,225	That photo makes it look a lot like the Chinon infrared autofocus system, with the extra windows below the lens... -Eric

01-27-2019, 07:32 AM - 1 Like	#4
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,216	I don't know anything about that early model/prototype, but I have the ME-F with the AF 35-70 2.8 autofocus lens. A lovely bit of nostalgic kit to play with it is.

01-27-2019, 08:02 AM	#5
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,225	Originally posted by pschlute I don't know anything about that early model/prototype, but I have the ME-F with the AF 35-70 2.8 autofocus lens. A lovely bit of nostalgic kit to play with it is. And the lens is better than I expected. They didn’t cheap out on the glass to get a fast aperture... which makes sense since it’s easier to focus a lens that isn’t fuzzy... -Eric

01-27-2019, 08:14 AM - 5 Likes	#6
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,216	Originally posted by TwoUptons And the lens is better than I expected Agreed. I took these two with the ME-F + AF 35-70 last summer

01-27-2019, 10:28 AM - 1 Like	#7
limestonecowboy Site Supporter Join Date: Aug 2016 Location: Newcastle upon Tyne Photos: Albums Posts: 151	Originally posted by pschlute Agreed. I took these two with the ME-F + AF 35-70 last summer Superb shots

01-27-2019, 11:25 AM	#8
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,092	Originally posted by Baard-Einar Anyone with some more info about this? The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom. Pentax Prototype Zoom Lenses \| The K-Mount Page Phil.

01-27-2019, 12:12 PM	#9
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,216	Originally posted by limestonecowboy Superb shots Many thanks for your kind comments ---------- Post added 01-27-19 at 07:13 PM ---------- Originally posted by gofour3 The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom. Pentax Prototype Zoom Lenses \| The K-Mount Page Phil. Interesting thing is that the Af 35-70 even when not paired with a ME-F can still give focus confirmation. Pretty advanced stuff for 1981 !

01-27-2019, 02:08 PM - 1 Like	#10
Baard-Einar Site Supporter Join Date: Jan 2010 Location: Oslo Photos: Gallery Posts: 964 Original Poster	Originally posted by ramseybuckeye These come up on ebay occasionally. edit: A quick check reveals there are a few listed now, some cameras without lens, some with. Hello, I dont think you'll find that lens shown in my post on ebay. It is only a prototype. ---------- Post added 01-27-2019 at 10:09 PM ---------- Originally posted by gofour3 The Pentax K-Mount site has a couple K35-70/2.8 zoom prototypes listed. Ones a manual focus lens and the second is the one you have pictured. Both are optically similar to the eventual production ME-F AF zoom. Pentax Prototype Zoom Lenses \| The K-Mount Page Phil. Thanks for the link. ---------- Post added 01-27-2019 at 10:09 PM ---------- Originally posted by pschlute Agreed. I took these two with the ME-F + AF 35-70 last summer Really nice pics.

01-27-2019, 02:26 PM - 1 Like	#11
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,225	Originally posted by pschlute Interesting thing is that the Af 35-70 even when not paired with a ME-F can still give focus confirmation. Pretty advanced stuff for 1981 ! I think that’s the other way around... The ME-F will focus confirm with other lenses, but I’ve never seen the lens do anything ‘smart’ on a camera other than the ME-F... -Eric

01-27-2019, 03:11 PM	#13
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,295	Originally posted by Baard-Einar Hello, I dont think you'll find that lens shown in my post on ebay. It is only a prototype.[COLOR="Silver"] . right, only production copies