Reversing makro-iris Componons

[JKT]

Half a year ago I was looking for a simple way to reverse makro-iris Componons. In the end I couldn't find a clever system, so the best I could think of was very basic: just a male and female T2 adapters. In addition to being my standard T2 has shorter thread length, which enables shorter parts and shorter extension rings. It also combines more readily to step-up and step-down rings. I think Robert has mentioned somewhere a plan for V38 to female M42x1 adapter, but that has not materialized, so I went with T2.

I've left a few dimension out of the drawing. Those are copied from Robert's V38 adapter.

These can be put very close to each other and in most - if not all - cases too close. It is easy to add up to 1.5 mm of spacers to increase the distance, but additions from that up to +5mm are not available as the shortest T2 extension I recall seeing is 5 mm. From then on any length is possible with appropriate spacers and extensions.

If there is any interest, I'll talk to RAF.

[RobertOToole]

Half a year ago I was looking for a simple way to reverse makro-iris Componons. In the end I couldn't find a clever system, so the best I could think of was very basic: just a male and female T2 adapters. In addition to being my standard T2 has shorter thread length, which enables shorter parts and shorter extension rings. It also combines more readily to step-up and step-down rings. I think Robert has mentioned somewhere a plan for V38 to female M42x1 adapter, but that has not materialized, so I went with T2.

V38 adapter pair v6 a.jpg
I've left a few dimension out of the drawing. Those are copied from Robert's V38 adapter.
Draft.jpg

These can be put very close to each other and in most - if not all - cases too close. It is easy to add up to 1.5 mm of spacers to increase the distance, but additions from that up to +5mm are not available as the shortest T2 extension I recall seeing is 5 mm. From then on any length is possible with appropriate spacers and extensions.

If there is any interest, I'll talk to RAF.

Hi JKT,

We were speaking about an adapter to stack two Makro-Iris lenses face-to-face right? Raf did make an v38 to M42 x 1 after all, but thats only half the parts needed for a complete unit. Your idea would be good since with a lock ring or a short tube you could vary the distance between the two. Some lenses work best close, almost touching, others work best with more space.

This is half of what you would need:

https://rafcamera.com/adapter-38mm-id-to-m42x1m

Best,

Robert

[JKT]

We were speaking about an adapter to stack two Makro-Iris lenses face-to-face right?

We did indeed. But it is not limited to that. Either side can be used alone with an appropriate step-up/step down ring in order to achieve minimum distance with other lenses with filter threads. The selection of rings from/to T2 is vastly superior to M42. That is the other reason I prefer T2.

Raf did make an v38 to M42 x 1 after all, but thats only half the parts needed for a complete unit.

That's what I used for measuring the missing dimensions. Note the different outer diameter. It seemed to me the front end diameter was different from rear.

I wonder how automated machines RAF has. It might be just as easy for him to make both T2 and M42 variants of the female.

[RobertOToole]

We did indeed. But it is not limited to that. Either side can be used alone with an appropriate step-up/step down ring in order to achieve minimum distance with other lenses with filter threads. The selection of rings from/to T2 is vastly superior to M42. That is the other reason I prefer T2.

There are tons of T-thread adapters out there thanks to the Astro market, and I see lots of T-thread gun parts on eBay? Maybe for scopes?

The main advantage of T-thread is price, I've seen some T-thread extension tubes at $4.99 with free shipping

I should mention the T-thread/T-mount/T-2 thread details for reference for others. Technically T-thread should be the proper term for M42 x 0.75. Lots of people use T-mount and T-2 interchangeable but technically T-2 is really a camera mount system. T-mount or T-thread was the standard interchangeable lens mount in the 70s and 80s, I think, I could be wrong but Soligor invented the T-2 mount name for the same T-mount but it had a 2-part mount with some mount screws holding the inner ring in place with a v-mount. This allowed the user to rotate the lens mount, I assume for proper aperture ring alignment.

I wonder how automated machines RAF has. It might be just as easy for him to make both T2 and M42 variants of the female.

Easy I think. Raf has always really quick and willing to make small changes to any of the off-the-shelf pieces he sells. He gets new drawings and parts changed in no time.

The difference between T-thread and M42 x 1 is 0.25 pitch, I wonder if he can make a cut of a thread to fit both? That might be too much of a difference?

I am interested in a set!

[Scarodactyl]

I used to get a lot of stuff from RAF and still would for specialty things, but getting a 3D printer has simplified a lot of things for me.

[chris_ma]

I used to get a lot of stuff from RAF and still would for specialty things, but getting a 3D printer has simplified a lot of things for me.

that's interesting, so you can print lens adapters including threads with a 3D printer?
and if so, how would you describe the accuracy and solidity compared to a machined adapter?

[Scarodactyl]

Yeah, I've succeasfully printed threads down to 0.5mm pitch. Using PETG the results are tough and accuracy seems quite good once I have the model dialled in. It may take a few tries sometimes since inner diameters in general tend to come out smaller than specced, but it doesn't take that long to iterate and filament is lile 20 dollars a kilo. I haven't tried it on a horizontal setup where stresses would potentially be more severe but the resultant parts are quite solid and tough so I suspect you could design them so that wasn't an issue.

[JKT]

The difference between T-thread and M42 x 1 is 0.25 pitch, I wonder if he can make a cut of a thread to fit both? That might be too much of a difference?

I have a set of allegedly M42 body caps, which screw pretty much all the way into T2. I'm pretty sure I wouldn't trust any weight on them.

I am interested in a set!

Thats two then.

Though they likely will be sold individually. And if my guess is right, the male will sell more.

[Pau]

... I haven't tried it on a horizontal setup where stresses would potentially be more severe but the resultant parts are quite solid and tough so I suspect you could design them so that wasn't an issue.

Do you remember the nice printed M42 adapter that came with my Nikon V-T tube?
it worked well when vertically placed (I even put a heavy RED cine camera on it) but when I switched it horizontally only with the Pentax bellows attached it neatly broke and my beloved Auto-Bellows did fall from almost 2m to the hard floor resulting severely damaged (fortunately I have an spare one)
Good for compression but not for shear or extension stress
So... if the adapter is thin don't use it horizontally

[JKT]

Straight tension might work, but bending in threads is really a no-go. The stress levels get surprisingly high.

[Scarodactyl]

... I haven't tried it on a horizontal setup where stresses would potentially be more severe but the resultant parts are quite solid and tough so I suspect you could design them so that wasn't an issue.

Do you remember the nice printed M42 adapter that came with my Nikon V-T tube?
it worked well when vertically placed (I even put a heavy RED cine camera on it) but when I switched it horizontally only with the Pentax bellows attached it neatly broke and my beloved Auto-Bellows did fall from almost 2m to the hard floor resulting severely damaged (fortunately I have an spare one)
Good for compression but not for shear or extension stress
So... if the adapter is thin don't use it horizontally

Oh man, I'm really sorry to hear that. I'll admit I had only anticipated vertical usage in a microscope on that one--wasn't it for your AZ100?

[Pau]

Oh man, I'm really sorry to hear that. I'll admit I had only anticipated vertical usage in a microscope on that one--wasn't it for your AZ100?

Don't worry, this was entirely my fault, not yours. You're right, the AZ100 was used only vertically, the stupid accident happened when I was dismounting it from the stand to mount another device. Now I have a solid aluminum replacement. Fortunately I was not dumb enough to do it with a camera mounted and the PLI photo eyepiece didn't drop