[aruk5]

I came across this lens on ebay called welmy 28mm mc f2.5 for pentax k mount. I ran a search on google and surprisingly didnt see any specific search results in regard to it. Usually when I run a search on any pentax lens I usually get a search result related to pentaxforums.com but funnily not for this lens. I was wondering if any of you have heard of this lens or tried it.

[eddie1960]

Welmy was made by Taisei Koki, they made rigid and folding medium format and disappeared around 1958. Never heard of them making a k mount lens (highly unlikely since kmount didn't exist until the 70's) maybe someone has made a Frankenstein lens? but a 28 2.5 wouldn't have existed on the welmy product since 4x4 was the smallest neg.
maybe someone making under a pile of names bought the name?? Does the auction show the mount?
If you can get it for $10 or less could be fun to find out.

[RioRico]

As Eddie says, if it's cheap, go for it! My rule of thumb for lens-buying is:

If it costs less than a sandwich or burger, grab it.
If it costs more than a big fancy pizza, think hard about it.
If it costs more than a good dinner out with your partner, ask the forums.

No, I've never heard of this lens. Might be a frankenlens. Might be real fun. Good luck!

[aruk5]

As Eddie says, if it's cheap, go for it! My rule of thumb for lens-buying is:

If it costs less than a sandwich or burger, grab it.
If it costs more than a big fancy pizza, think hard about it.
If it costs more than a good dinner out with your partner, ask the forums.

No, I've never heard of this lens. Might be a frankenlens. Might be real fun. Good luck!

Lol what you said is funny and this particular lens costs somewhere between the pizza and good dinner so I thought hard about it and came here to the forum to ask about it! Its quite possible this is a frankenstein where someone placed a pentax k mount bayonet onto the rear or it could be a fake!

Welmy was made by Taisei Koki, they made rigid and folding medium format and disappeared around 1958. Never heard of them making a k mount lens (highly unlikely since kmount didn't exist until the 70's) maybe someone has made a Frankenstein lens? but a 28 2.5 wouldn't have existed on the welmy product since 4x4 was the smallest neg.
maybe someone making under a pile of names bought the name?? Does the auction show the mount?
If you can get it for $10 or less could be fun to find out.

Thats interesting to know that welmy discontinued after 1958. This could very well be a frankenstein or a fake. Unfortunately the lens costs around 17 pounds + 3 pounds p&p and is above 10$ price.


*update someone bought the lens from ebay and is no longer for sale so I never got to try this out!

[eddie1960]

Lol what you said is funny and this particular lens costs somewhere between the pizza and good dinner so I thought hard about it and came here to the forum to ask about it! Its quite possible this is a frankenstein where someone placed a pentax k mount bayonet onto the rear or it could be a fake!



Thats interesting to know that welmy discontinued after 1958. This could very well be a frankenstein or a fake. Unfortunately the lens costs around 17 pounds + 3 pounds p&p and is above 10$ price.


*update someone bought the lens from ebay and is no longer for sale so I never got to try this out!

I did see a welmy in exacta mount, maybe the seller was in error the exacta mount is a flanged bayonet that someone could mistake for K mount if they had no idea (the Topcon mount is the same minus the big arm out the side so maybe welby made a Topcon as well)
exacta cannot be adapted to K mount (44.7 mm reg distance vs k mount 45.46mm)




A little more research and it turns out that they were bought in 1960(no longer making cameras) and morphed into Konicaan even shorter registration distance (40.5 for the Konica Auto reflex - ie K/ar mount) maybe they had a lens line under welmy for K/Ar ? though under Konica they were 28 in 1.8,2.8 and 3.5 variants - I could see how a junk deal could mistake K/AR for K mount

[RioRico]

(the Topcon mount is the same minus the big arm out the side so maybe welby made a Topcon as well)

Some Exakta-mount lenses have the big-arm stop-down button, some don't. There's a way to remove it, but it's messy.

exacta cannot be adapted to K mount (44.7 mm reg distance vs k mount 45.46mm)

Ah, but it can be finessed! I use a number of armless Exakta-mount lenses on my K20D. The procedure is very simple:

1) Get a cheap clone thin-flange M42-PK adapter, and a chunk of rubber or soft wood.
2) Remove the index screw on the lens base. Save the screw if you ever intend to use the lens on an Exakta again.
3) Use contact cement to glue a cheap M39-M42 adapter ring around the lens bayonets.
4) While the glue is drying, tape a piece of 100-grit sandpaper to a very flat hard surface like a kitchen tile. Put the M42-PK adapter flange-down on the sandpaper. Use the rubber or wood as a grip while you grind away about 0.7mm from the flange. Don't remove too much of the thin flange or the adapter won't seat on the camera's PK mount.
5) When the glue is thoroughly dry, thread the ground-down adapter onto the lens, then mount it on your camera. Check to see if you have infinity focus. If not, grind a little more, but not too much (as I warned above).

In the last few days I've used the following Exakta-mount lenses via this solution:

* CZJ Tessar 50/2.8 (12 iris blades)
* Meyer Primagon 35/3.5 (retrofocus)
* Meyer Helioplan 40/4.5 (pancake)
* Isco Westar 100/4.5 (long lens)

The Primagon doesn't quite reach infinity-focus wide-open, but infinity is in focus when stopped-down to f/8.

I also have a Kilfitt Makro Kilar-E 40/3.5 (not with me at the moment) whose index peg is not removable, so the procedure for adapting it is slightly different:

6) Grind-down an adapter as above, and cut a small notch in the thin part of the ring so it seats over the lens index peg.
7) Thread an M39-M42 ring inside the the ground-down adapter.
8) Glue the threaded adapters onto the lens' bayonets.

All these are fairly small light-weight lenses. I don't think I'd try this with a 200/3.5 weighing 500g or so.

[eddie1960]

Rico you are the master (and absolutely batsh*t crazy lol)

[zelda_n64]

Trying to research this particular lens, I came across this thread.

I purchased this lens for £5 from a carboot sale in the UK on Sunday 21st April 2013.

It is definitely a PK bayonet mount and it fits my Pentax K-x perfectly.

The attachment shows it attached to my camera and also a picture taken with this lens at wide open, ISO 200 and 1/400s shutter speed.

I really like the softness (weirdness) of this lens and the bokeh to me is awesome.


Attached to camera



Wide open, ISO 400, 1/400 sec


Wide open, ISO 400, 1/1250 sec, levels auto adjusted



The 2 images below is the lens being used with a Hoya multi-vision attachment,

Wide open, ISO 400, 1/50 sec, levels auto adjusted


Wide open, ISO 400, 1/50 sec. This was only taken in natural light, the light background is a garage wall, not a light.

[52mm]

You wouldn't have some pictures of the side and back of the lens? That may help IDing the actual manufacturer - it looks like another of these old designs "recycled" with multicoating at the time, pretty much a "no-name" cheapie. (The massive spherical overcorrection and resulting wacky bokeh tells an old construction from like the early '70s, as does the comparatively larger front element.) I have a similar Porst-branded 28/2.8, presumably made by Sun Optical. Big hunk o' glass (58mm filter thread), but nothing special performance wise - not an awful lot better than a little Korea special wide open and worse when stopped down.

[zelda_n64]

@ 52mm

I will take some pictures tonight of different angles of the lens.

It is made in Japan - it says on the bottom.

This is a very sharp lens and performs really well, but I do like the wide open effect as it is completely different to my other 28mm lenses. Although those are 2.8 and not 2.5 like this one.

The photo's below are straight off the camera, only resized.

Here is a picture that was taken on a dull and dreary day - F8, ISO 400, 1/200 sec


and another F8, ISO 400, 1/80 sec

[zelda_n64]

As requested, please find below (apologise for the mobile phone images), some different angled shots of the Welmy 28mm f2.5:













The next photograph is the Welmy 28mm next to my M42 Cosinon auto MC 28mm f2.8

[MattCarey]

Just bought a WELMY F4.5 300 mm lens .. strangely with two aperture rings ...
Amazing condition in a case
Fits nicely onto my asahi pentax Spotmatic k mount.