Infinity adjustment on Pentax-F 50mm f/1.7

**Serkevan** · 11-06-2020, 12:38 PM

Hey there, lately I've noticed that my F-50's infinity stop is not quite at infinity but more like 10 meters away (oops) and I was checking to see if adjustment's an easy job (JIS screwdrivers needed I guess?). This thread FA50 disassembly and infinity focus adjustment - PentaxForums.com talks about the FA 50/1.7 and the construction should be the same, but... well, just wanting to double check before I make an unduly mess

. Anyone have confirmation that it is indeed the same work to be done?

Thanks a lot for the help!

WhatsMyNameAD67 · 11-06-2020, 12:49 PM

I can’t answer directly, but here is a link that can provide guidance in disassembling your lens for repair.

Fun with Fungus.!

**Serkevan** · 11-06-2020, 12:59 PM

Originally posted by WhatsMyNameAD67

I can’t answer directly, but here is a link that can provide guidance in disassembling your lens for repair.

Fun with Fungus.!

Thanks for the link, but unfortunately it's for the older M-series 50/1.7 (that one focuses perfectly to infinity, fortunately)... and the images don't load for me

.

Not a Number · 11-06-2020, 01:26 PM

Doesn't seem to be much difference between the F and FA. Taking the beauty/trim ring off shouldn't cause any sort of mess unless you need heroic measures to unscrew it. It should be obvious once you get the ring off if the adjustment is pretty much the same.

WhatsMyNameAD67 · 11-06-2020, 01:50 PM

Originally posted by Serkevan

Thanks for the link, but unfortunately it's for the older M-series 50/1.7 (that one focuses perfectly to infinity, fortunately)... and the images don't load for me

.

I’ll see what else I can find.🤞🏻

CarlJF · 11-06-2020, 04:53 PM

I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity.

**DWS1** · 11-06-2020, 06:14 PM

Originally posted by CarlJF

I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity.

This is my belief also.

**Serkevan** · 11-06-2020, 07:19 PM

Originally posted by CarlJF

I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity.

Beyond, yes. Not going further than 10 meters, that's slightly more complicated

**Just1MoreDave** · 11-07-2020, 06:48 PM

Yes, the F50/1.7 has the same 3 screws on the side of the barrel, pretty similar at the front. You'll want JIS screwdrivers even if only for cosmetic reasons, because jamming a Phillips driver in there will make the screw look ugly later. I should have pictures somewhere.

**Michail_P** · 11-08-2020, 01:39 AM

I wish I could get my hands on stuff like you. I haven’t even tried, but it seems impossible to me.

11-06-2020, 12:38 PM	#1
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976	Infinity adjustment on Pentax-F 50mm f/1.7 Hey there, lately I've noticed that my F-50's infinity stop is not quite at infinity but more like 10 meters away (oops) and I was checking to see if adjustment's an easy job (JIS screwdrivers needed I guess?). This thread FA50 disassembly and infinity focus adjustment - PentaxForums.com talks about the FA 50/1.7 and the construction should be the same, but... well, just wanting to double check before I make an unduly mess . Anyone have confirmation that it is indeed the same work to be done? Thanks a lot for the help!

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11-06-2020, 12:49 PM	#2
WhatsMyNameAD67 Veteran Member Join Date: Sep 2018 Posts: 307	I can’t answer directly, but here is a link that can provide guidance in disassembling your lens for repair. Fun with Fungus.!

11-06-2020, 12:59 PM	#3
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976 Original Poster	Originally posted by WhatsMyNameAD67 I can’t answer directly, but here is a link that can provide guidance in disassembling your lens for repair. Fun with Fungus.! Thanks for the link, but unfortunately it's for the older M-series 50/1.7 (that one focuses perfectly to infinity, fortunately)... and the images don't load for me .

11-06-2020, 01:26 PM	#4
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Doesn't seem to be much difference between the F and FA. Taking the beauty/trim ring off shouldn't cause any sort of mess unless you need heroic measures to unscrew it. It should be obvious once you get the ring off if the adjustment is pretty much the same.

11-06-2020, 01:50 PM	#5
WhatsMyNameAD67 Veteran Member Join Date: Sep 2018 Posts: 307	Originally posted by Serkevan Thanks for the link, but unfortunately it's for the older M-series 50/1.7 (that one focuses perfectly to infinity, fortunately)... and the images don't load for me . I’ll see what else I can find.🤞🏻

11-06-2020, 04:53 PM	#6
CarlJF Veteran Member Join Date: Sep 2014 Location: Quebec City Posts: 1,185	I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity.

11-06-2020, 06:14 PM	#7
DWS1 Site Supporter Join Date: Aug 2018 Location: Arkansas, USA Posts: 1,169	Originally posted by CarlJF I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity. This is my belief also.

11-06-2020, 07:19 PM	#8
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976 Original Poster	Originally posted by CarlJF I may be wrong, but I think it’s perfectly normal for autofocus lenses to go slightly beyond infinity. Beyond, yes. Not going further than 10 meters, that's slightly more complicated

11-07-2020, 06:48 PM	#9
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Yes, the F50/1.7 has the same 3 screws on the side of the barrel, pretty similar at the front. You'll want JIS screwdrivers even if only for cosmetic reasons, because jamming a Phillips driver in there will make the screw look ugly later. I should have pictures somewhere.

11-08-2020, 01:39 AM	#10
Michail_P Site Supporter Join Date: Nov 2019 Location: Kalymnos Photos: Gallery Posts: 3,006	I wish I could get my hands on stuff like you. I haven’t even tried, but it seems impossible to me.