[aurele]

It means that when you change the aperture ring to a smaller aperture it immediately closes down the blades. You can change the aperture with the ring but the camera has no connection or control over the lens or its aperture including no stopping down from the camera.

That's what i plan to do. It just require to use a wire or a spring. it's the easiest part.

Your option is to remove parts and or grind down

that's what i should do, but i don't have the tools here to do that on metal mount

[aliasant]

I really need to check the forum more often. That's awesome aliasant! Great job. It's amazing how many great diy ideas pop up in here.

Im guessing prices for old S2 Bronicas might go up a notch ? At least for the 75mm's
I would like something a bit wider so I have been looking at the only option I found.. A Bronica 50mm f4 but the speed of that lens isnt really what I want.

One of these days I need to find some time to hack together simple k mount tilt and shift adapters for my 645 A 75mm f/2.8. It's small, light, and has about 25mm of space behind it to fit an adapter into, plus I shouldn't need to buy much in the way of parts.

Do you have a sketch of how to do that already?
I have been thinking about getting an extension tube or mount converter for 645, cut it in half and then try to link them back together with some kind of tilt option but havnt figured it out yet.
Would be nice to hear any ideas.

[Steinback]

For adapting the 645 lens I have a spare k mount and I was thinking of screwing enough of a base onto it that installation and removal from the body won't be a problem. For the lens side I was going to build up a mount using glued sheets of plastic to make a matching female 645 bayonet since I don't have a spare rear 645 cap or tubes. To connect the two, home made bellows attached to the 645 lens mount at one end and the K mount on the other. I want to lay out the adapter so that the rear element of a 645 lens can't come into contact with anything metal.

There will be plenty of range of motion, and if everything works acceptably I'll make some sort of adjustable rigid support connecting the lens/ lens mount to the camera body using the tripod socket.

[aliasant]

For adapting the 645 lens I have a spare k mount and I was thinking of screwing enough of a base onto it that installation and removal from the body won't be a problem. For the lens side I was going to build up a mount using glued sheets of plastic to make a matching female 645 bayonet since I don't have a spare rear 645 cap or tubes. To connect the two, home made bellows attached to the 645 lens mount at one end and the K mount on the other. I want to lay out the adapter so that the rear element of a 645 lens can't come into contact with anything metal.

There will be plenty of range of motion, and if everything works acceptably I'll make some sort of adjustable rigid support connecting the lens/ lens mount to the camera body using the tripod socket.

That sounds very interesting!
You have to document it here. Maybe we can help with ideas or at least steal the design.....
I have been thinking about all these medium formats like Pentacon Six, Kiev, Pentax 645 and others.
Must be many of these that would like to sit on my K5 with a tilt thing adapter in between?

[aurele]

Hum, Hum... english is not my mother tong and i don't use auto translation, so would you please excuse me if i don't use the exact word.

Hum, Hum...

Dear member of the impossible lense club, i'm here to submit a request to all of you.

Hereby, i'm requesting the honor and privilege to join the impossible lense club as a fellow member.

To prove my willingness, here is my first work in the conversion of all sort of lense to god "K mount": A venerable Vivitar S1 70-210/3.5 OM mount converted as a K mount







Like the Padawan who wants to become a Jedi, i need to improve my skill, but my main goal is to master the art of conversion.

Hope you will give a positive answer to my request.




...

Must be many of these that would like to sit on my K5 with a tilt thing adapter in between?

i think so !

All this sounds very interresting, i can't wait to see what you, fellow member of the impossible club, can do

[Damian]

To prove my willingness, here is my first work in the conversion of all sort of lense to god "K mount": A venerable Vivitar S1 70-210/3.5 OM mount converted as a K mount

Is that a piece of wire wrapped around the stop down lever holding the aperture in the "manual" position. Is that a permanent solution? Not the "prettiest" I must say. But hey, if it works that's all that really matters.

[aurele]

Is that a piece of wire wrapped around the stop down lever holding the aperture in the "manual" position.

yes

Is that a permanent solution?

nop

Not the "prettiest" I must say

i agree

But hey, if it works that's all that really matters.

indeed

In fact, i tried during half an hour to put a spring or something, but i was always failling. I started to be angry, so i did the simpliest thing i could to make this hold.
i planned to re-do it tomorrow morning

[hoanpham]

I have completed the mod for nikkor last month. Pretty cool. And now have several nikkors waiting in line: 180/2.8ED, 400/5.6ED, and 28/3.5 PC (shift). These will be compared with the pentax K200/2.5, K28/3.5shift. I dont have any 400 in pentax line, but the A*300 should be a good match.
Photos of the nikkor 50/1.4:
https://picasaweb.google.com/111102833818394930252/Nikkor50f14

[Damian]

Failure!

My Topcor 58mm f1.4 conversion solution won't work the way I hoped. Luckily I know a man with a lathe who is willing to work for beer and conversation. Of course, I may get bored and try the shim solution instead. We'll see.

[aliasant]

Failure!

My Topcor 58mm f1.4 conversion solution won't work the way I hoped. Luckily I know a man with a lathe who is willing to work for beer and conversation. Of course, I may get bored and try the shim solution instead. We'll see.

What went wrong?
Im planning to do one of those as soon as I can find one cheap enough....

[Damian]

I purchased a 62mm reverse pk adapter. The main adapter plate is 1.15mm thicker then necessary to get infinity focus. Everything else will work, I just need to mill down the plate. Otherwise I'll need to use a standard m42-pk adapter and add a flange to hold the aperture ring in place and provide a home for the spring.

[aliasant]

I purchased a 62mm reverse pk adapter. The main adapter plate is 1.15mm thicker then necessary to get infinity focus. Everything else will work, I just need to mill down the plate. Otherwise I'll need to use a standard m42-pk adapter and add a flange to hold the aperture ring in place and provide a home for the spring.

Wait.

On my 35/2.8 there were 2 thin shims/rings between the glass part and the focus part.
I just unscrew the whole glass part and removed those thin rings.
Another way to change without milling is to remove the stop screw, set the lens on a camera and dial in perfect infinity.
Then make a mark and drill a new 1,5mm hole and screw in a new screw.
I havnt seen the 58/1,4 so I cant tell you exactly how to do this but I have played with a 135, 58/1,7 and my 35/2,8 and they are all almost identical.

[ripit]

I purchased a 62mm reverse pk adapter. The main adapter plate is 1.15mm thicker then necessary to get infinity focus. Everything else will work, I just need to mill down the plate. Otherwise I'll need to use a standard m42-pk adapter and add a flange to hold the aperture ring in place and provide a home for the spring.

What was the total thickness of the flange on the 62mm-pk adapter?

[Damian]

What was the total thickness of the flange on the 62mm-pk adapter?

2mm roughly. It varies from side to side by up to .09mm. 2-2.02mm on one side to 2.09-2.11mm on the other. Basically, it's not entirely flat. Chinese quality control.

I havnt seen the 58/1,4 so I cant tell you exactly how to do this but I have played with a 135, 58/1,7 and my 35/2,8 and they are all almost identical.

I've only messed with the 58 1.8 other then the 58 1.4. I took the optics out of the 58 1.4 for cleaning, but did not mess with the focusing helical. It worked fine, so there was no need to fix it. I can't remember if there are any shims or rings that can be removed. I'll have to go back and look at the pictures from the cleaning to see if there is anything visible. That might be an option though. My goal for this project was to make no modifications to the lens, but simply swap mounts. Totally reversible modification in case I don't like the lens, I can revert it and sell it like it was. Typically they are worth more as collectors items then as "modified for pentax".

[aliasant]

2mm roughly. It varies from side to side by up to .09mm. 2-2.02mm on one side to 2.09-2.11mm on the other. Basically, it's not entirely flat. Chinese quality control.



I've only messed with the 58 1.8 other then the 58 1.4. I took the optics out of the 58 1.4 for cleaning, but did not mess with the focusing helical. It worked fine, so there was no need to fix it. I can't remember if there are any shims or rings that can be removed. I'll have to go back and look at the pictures from the cleaning to see if there is anything visible. That might be an option though. My goal for this project was to make no modifications to the lens, but simply swap mounts. Totally reversible modification in case I don't like the lens, I can revert it and sell it like it was. Typically they are worth more as collectors items then as "modified for pentax".

Ok.

The shims in my case were 2 very very thin rings that might not be anough.
I did however make a similar thing with a 58/1.8.
I made it non destructable but one part that made me earn some space was to remove the half circular plate that that sits between the mount and the aperture ring.
I have unfortunatly sold that lens but I found some images of it.

First image shows that half circular plate. Remove it and save about a mm.
I did remove the whole original mount and replaced it with a pentax mount from a scrap lens.
I didnt just place the new mount over the old one.
Its still fully reversable as long as you remember were you put the parts

Second image shows the focus stop screw.
Its easy to unscrew it and then find the real infinity, make a little mark and drill a small new hole for the screw.
When you reverse it just move the screw back to its original hole.
using this method you dont have to do anything to the mount. The 1.5 mm you need is just a cm or so that the focus stop screw needs to move.
You should have more then that to play with but if you do this just make sure the Aperture lever works zoomed fully in and out.

Last image shows the inside and at the bottom you can see a dark area. In the right side of that dark area is a "square" hole. Thats were the aperture lever goes down. On my 35/2.8 Topcor RE I replaced the mount with an old Vivitar mount and managed to get full aperture control just like any Pentax-M lens. Green button stop down works perfect. It did take some tinkering to get it right though so not as easy to do as it might sound.