Interesting fabled lens turned on PF


LennyBloke

Link Posted 07/01/2020 - 10:39
Over on PF there's a discussion about the Pentax M 20mm f1.4 (Yes f1.4 not f4) - a lens unseen by many until now. A Japanese member has one and has posted some images of (and with) it!

I won't post a link (not sure what the policy is) but it's in the Pentax SLR Lens Discussion section!
LennyBloke

HarisF1

Link Posted 07/01/2020 - 11:08
Oh wow, very nice. I want to see the 35/1.4, now that would be special.
Last Edited by HarisF1 on 07/01/2020 - 11:19

pschlute

Link Posted 07/01/2020 - 11:25
LennyBloke wrote:
Over on PF there's a discussion about the Pentax M 20mm f1.4 (Yes f1.4 not f4) - a lens unseen by many until now. A Japanese member has one and has posted some images of (and with) it!

I won't post a link (not sure what the policy is) but it's in the Pentax SLR Lens Discussion section!

I have been patiently watching the classifieds section on here for you to advertise your copy
Peter



My Flickr page

LennyBloke

Link Posted 07/01/2020 - 18:08
pschlute wrote:
LennyBloke wrote:
Over on PF there's a discussion about the Pentax M 20mm f1.4 (Yes f1.4 not f4) - a lens unseen by many until now. A Japanese member has one and has posted some images of (and with) it!

I won't post a link (not sure what the policy is) but it's in the Pentax SLR Lens Discussion section!

I have been patiently watching the classifieds section on here for you to advertise your copy

I wish

I find it amazing that Pentax had such a fast super-wide in the wings so long ago. There was also a 35mm f1.4 and a 300mm f2.0 around the same time I believe, but whether these 2 were just prototypes or not I don't know
LennyBloke

Jonathan-Mac

Link Posted 08/01/2020 - 09:46
It's clearly a "K" lens rather than an "M".

https://imgur.com/bIWCXrh
https://imgur.com/tJRQYuc

This seems to be a wide open test shot: https://imgur.com/a/M9UuAiw

I'd say it looks decent in the centre, poor outside of the centre but nothing surprising from such a lens that's over forty years old.
I wouldn't mind getting my hands on it
Pentax hybrid user - Digital K3 & K200D, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X digital
Fan of DA limited and old manual lenses

LennyBloke

Link Posted 08/01/2020 - 12:13
Jonathan-Mac wrote:
It's clearly a "K" lens rather than an "M".

https://imgur.com/bIWCXrh
https://imgur.com/tJRQYuc

This seems to be a wide open test shot: https://imgur.com/a/M9UuAiw

I'd say it looks decent in the centre, poor outside of the centre but nothing surprising from such a lens that's over forty years old.
I wouldn't mind getting my hands on it

Agreed it looks like a K rather than an M, although there are a few lenses that "crossed-over" as the different series changed - so the distinction between M and K can be a little blurred (although the designation "M" on the lens is probably the marker to go by) - production date is rumoured to be 1976, which is just before the start of many M series lenses (1977) and it appears that some K's were manufactured into the 1980's.
LennyBloke

bforbes

Link Posted 08/01/2020 - 14:06
Could you enlighten me as to the difference between "M" and "K" mount. I thought it became "K" with the introduction of the contacts ie "KA", was there a pure "K" mount?
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

JAK

Link Posted 08/01/2020 - 14:35
K mount was the original fully manual lens series after the M42 was discontinued. normally designated 'SMC Pentax'
The M series were updated versions of these and other new introductions designed to be smaller (miniature) to go along with Pentax's new range of smaller SLRs staring with the ME and MX.

These are photos of both versions of the manual 20mm f/4 lenses for comparison:

SMC Pentax (K version):



SMC Pentax-M (M version):



These were followed by the A series with an auto diaphragm and then the F and FA series' both with auto focussing too. These led on to the D-FAs we now know and love(?)!

That 20mm f/1.4 falls in the first 'SMC Pentax' era rather than the later M version era.

Anyone got a spare 20mm f/1.4 and didn't know what it was?!
John K
Last Edited by JAK on 08/01/2020 - 14:41

bforbes

Link Posted 08/01/2020 - 14:40
Thanks. It looks like the shape of the lens changed, but are original K and following M bayonets physically the same?
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

JAK

Link Posted 08/01/2020 - 14:42
bforbes wrote:
Thanks. It looks like the shape of the lens changed, but are original K and following M bayonets physically the same?

Yes they are, no electrical contacts until the A series.


Many folk believe the M of the M series stands for manual, which of course they are, but was really indicating the new 'miniature' range. This has led to some believing all K mount manual lenses are M series, which they are not. Many dealers and sellers don't understand this subtle difference, even if you point it out to them, hence many confusing adverts appear which are technically misdescribed..
John K
Last Edited by JAK on 08/01/2020 - 14:49

JAK

Link Posted 08/01/2020 - 15:03
If anyone's trying to complete a full set, this list includes to my knowledge, all known K & M variants.

Asahi Pentax (K) Series
8.4mm F2.8 Fish-eye
8.4mm F2.8 Bird's-eye (Prototype)
15mm F3.5 (AL) (SMC PENTAX 1:3.5/15) (distance-scale in feet is … 7 4 2 1.5) (1975)
15mm F3.5 (SMC PENTAX 1:3.5/15) (distance-scale in feet is … 7 3 2 1.5) (1975)
15mm F3.5 (smc PENTAX 1:3.5 15mm) (distance-scale in feet is … 7 3 2 1.5) (1977)
17mm F4 Fish-Eye
18mm F2 ED (Prototype)
18mm F3.5 SMC PENTAX 1:3.5/18 (early variant),
18mm F3.5 smc PENTAX 1:3.5 18mm (later variant)
20mm f1.4
20mm F2 ED (Prototype)
20mm F4
24mm F2.8
24mm F3.5
28mm F2
28mm F3.5
28mm F3.5 Shift (SMC PENTAX SHIFT 1:3.5/28 ) (1975)
28mm F3.5 Shift (smc PENTAX SHIFT 1:3.5 28mm) (1977)
30mm F2.8
35mm F2
35mm F3.5
50mm F1.2
50mm F1.2 Gold
50mm F1.2 VRL (Prototype)
50mm F1.4
50mm F4 Macro
55mm F1.8
55mm F2
85mm F1.8
85mm F2.2 Soft
100mm F4 Bellows
100mm F4 Macro
105mm F2.8
120mm F2.8
135mm F2.5 (1975 SMC PENTAX 1:2.5/135)
135mm F2.5 (1977 SMC PENTAX 1:2.5 135mm)
135mm F3.5 (1977)
150mm F4
200mm F2.5
200mm F4
300mm F4
300mm F2 (Prototype)
400mm F5.6
500mm F4.5
1000mm F8
1000mm F11 Reflex
2000mm F13.5 Reflex

ZOOM 28-50mm F3.5-4.5
ZOOM 45-125mm F4
ZOOM 80-200mm F4.5
ZOOM 85-210mm F3.5
ZOOM 85-210mm F4.5
ZOOM 135-600mm F6.7
ZOOM 400-600mm F8-12 Reflex


Asahi Pentax-M Series
M 20mm F1.4 AL (Prototype) - appears to have been previously miscategorised
M 20mm F4
M 28mm F2
M 28mm F2.8 ver I
M 28mm F2.8 ver 2 lacks silver ring
M 28mm F3.5
M 35mm F1.4
M 35mm F2
M 35mm F2.8
M 40mm F2.8
M 50mm F1.4
M 50mm F1.7
M 50mm F2
M 50mm F4 Macro
M 85mm F2
M 100mm F2.8
M 100mm F4 Macro
M 120mm F2.8
M 135mm F3.5
M 150mm F3.5
M 200mm F4
M* 300mm F4
M 400mm F5.6
M 2000mm F13.5 Reflex

M ZOOM 24-35mm F3.5
M ZOOM 24-50mm F4
M ZOOM 28-50mm F3.5-4.5
M ZOOM 35-70mm F2.8-3.5
M ZOOM 40-80mm F2.8-4
M ZOOM 75-150mm F4
M ZOOM 80-200mm F4.5

Own up if you've got a complete set!
John K
Last Edited by JAK on 08/01/2020 - 15:12

HarisF1

Link Posted 08/01/2020 - 17:38
It's worth noting that the K series lenses are usually sharper than their M counterparts, but quite a bit heavier. More elements/glass also means they're a bit more expensive.

JAK

Link Posted 08/01/2020 - 21:38
HarisF1 wrote:
It's worth noting that the K series lenses are usually sharper than their M counterparts, but quite a bit heavier. More elements/glass also means they're a bit more expensive.

Agreed, less compromises in their design.

It would be interesting to see some images from that 20 1.4 taken stopped down. That lens would appear to be second in the batch so presumably there is at least a #0 and a #1 somewhere. I wonder how many more and where they might be hiding.
Shame the known example is in the hands of someone who doesn't even use a Pentax and hasn't bothered to obtain one to use that jewel of a lens, instead sticking it on a cheap adapter.
Hope he hasn't taken out the click stops and aperture lever as some on this site might have done to lenses they own!
John K
Last Edited by JAK on 08/01/2020 - 21:44

HarisF1

Link Posted 08/01/2020 - 22:07
Imagine if that's how the story ended. Either that or fungus

I knew an eBay seller that inherited a Takumar 100/2 as part of a huge Pentax collection and he refused to sell it because it had fungus damage!

womble

Link Posted 09/01/2020 - 01:02
LennyBloke wrote:
Agreed it looks like a K rather than an M, although there are a few lenses that "crossed-over" as the different series changed - so the distinction between M and K can be a little blurred (although the designation "M" on the lens is probably the marker to go by) - production date is rumoured to be 1976, which is just before the start of many M series lenses (1977) and it appears that some K's were manufactured into the 1980's.

I have a Pentax lenses and accessories catalogue from 1987 that lists K, M and A series lenses. For example, for 135mm it lists the A* f/1.8, the "K" f/2.5, the A f/2.8 and the M f/3.5! There seems to be quite a bit of overlap in availability, at least, if not manufacturing.

Thanks for the heads-up. I tend to hang out in the film section of the US fora so had missed this.

K
Kris Lockyear
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.

My website
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