Home-made Olympus Pen F lens adapters

[xkaes]

I don't really need one, but I was advising someone interested in finding a Pen-F lens adapter, and I realized that there is an option for any DIY-er.

Instead of trying to find the Olympus Pen F adapter that you need (pretty hard) and at a price you can afford (even harder!), you should be able to make one yourself.

All you need are a Pen F body cap, and an extension tube for the lens(es) that you want to attach to the Pen F.

Cut the center out of the body cap, and find an extension tube of the correct length for infinity focusing. If it's not exact, find one that is slightly shorter and add some gasket material.

Glue them together, and you are all set.

Am I nuts???

 

[r_a_feldman]

I don't really need one, but I was advising someone interested in finding a Pen-F lens adapter, and I realized that there is an option for any DIY-er.

Instead of trying to find the Olympus Pen F adapter that you need (pretty hard) and at a price you can afford (even harder!), you should be able to make one yourself.

All you need are a Pen F body cap, and an extension tube for the lens(es) that you want to attach to the Pen F.

Cut the center out of the body cap, and find an extension tube of the correct length for infinity focusing. If it's not exact, find one that is slightly shorter and add some gasket material.

Glue them together, and you are all set.

Am I nuts???

I have made Pen F adapters for both OM-1 and Nikon F lenses. I started with TWO extension tubes, one Pen F (to get the correct male bayonet) and one OM-1/Nikon F (for the female bayonet). I made them a number of years ago, when Pen F extension tubes could be purchased for a reasonable price. At the time, there was an article online about how to make a Pen F adapter for Nikon F lenses — try googling for that — that served as my guide.

<edit> This is one example of making an adapter, but not the one I remember: https://kyp.hauslendale.com/classics/penadapter.html </edit>

I will try to post photos of my adapters here tomorrow.

As to your last question, I will avoid answering that .

 

[xkaes]

The first thing I did was check the prices on Minolta & Pen F extension tubes. The Minolta versions (old non-automatic) were about 10% of the price of the Pen F models. That's why I thought of using a Minolta extension tube -- with a Pen F body cap instead.

I'm not surprised that others have been down this road before me.

 

[r_a_feldman]

<snip>

All you need are a Pen F body cap, and an extension tube for the lens(es) that you want to attach to the Pen F.

Cut the center out of the body cap, and find an extension tube of the correct length for infinity focusing. If it's not exact, find one that is slightly shorter and add some gasket material.

Glue them together, and you are all set.

Am I nuts???

I see two main problems with this approach:

1. It will be difficult to get the optical axis of the lens mount aligned (parallel and concentric) with the Pen F body cap.

2. I would not trust a glued joint to support a heavy lens without breaking off.

By using two extension tubes (or a cheap teleconverter without the optics) and fitting one tube inside the other, you can align the optical axes and provide support for the lens. I drilled and tapped for set screws to keep the tubes joined at the correct distance.

 

[xkaes]

Thanks, I had not thought about using a "trashed out" Pen F tele-converter or T-mount, etc as an alternative to a body cap, but that makes sense. I'm sure I can find something pretty cheap.

 

[r_a_feldman]

Here are pictures of my adapters:

OM-1 to Pen F:

The OM adapter needed a tab (sheet brass) to hold the diaphragm stopped down.


Nikon F to Pen F Adapter:

The explanation of the process at https://kyp.hauslendale.com/classics/penadapter.html is very good.

I do not have a machine shop or a milling machine (which would have been useful), only a drill press, belt sander and Dremel grinder, along with an old micrometer of my father's. I also have small jeweler's files and 1-72 and 0-80 drills and taps from my model railroad scratch-building days. I would say that I am mechanically apt, but I do not think the job was that difficult.

As explained in the kyp.hausendale site, you probably will need to either reduce the outer diameter of the Pen F tube or enlarge the inner diameter of the lens adapter tube. I drilled and tapped three holes in the lens adapter at 120 degrees apart for 1-72 set screws. After sliding the Pen tube into the lens tube, I loosely tightened the set screws and measured the flange-to-flange distance (e.g., 17.55mm for Nikon F lenses), adjusting it as needed before tightening the set screws.

 

[xkaes]

I don't have the issue of using an auto-diaphragm lens. Even though almost all Minolta-type lenses have an auto-diaphragm, unless the auto-diaphragm pin is pressed, the lens simply stops down as the aperture ring is turned.. Some of the early Minolta lenses had stop-down levers on the lenses to over-ride the auto-diaphragm when the lens was on the camera, but this feature was moved into the camera body with the SRT cameras. But using the lenses without the auto-diaphragm is not a big deal to me, and it makes the adaptation simpler.

But my initial search hasn't uncover anything "on the cheap" with a rear Pen F lens mount. Fortunately, I'm not in a rush. I'm sure I'll run into an off-brand, trashed out lens or extension tube soon enough.

 

[xkaes]

Here's my solution, and it might be helpful to others looking for an inexpensive, DIY Pen F adapter.

The "trick" that makes it easier is by using two (or more) step up rings. The step-up rings can be used because the Pen F lens mount is going to be smaller than any lens mount that you want to add to it.

I'm dealing with Minolta lenses, but the approach will be the same with other lenses -- although the distances and diameters will vary for Nikon, Canon, Pentax, etc.

I started out by getting a Pen F lens mount and a Minolta camera mount. There are lots of options here, and many have been mentioned above, such as old or broken extension tubes, lens adapters, lenses or cameras.

The Minolta camera mount that I chose is from the Minolta Extension Tube II set. You can get these for under $10, and they don't have to be in mint condition. The mount from this set is the thinnest mount that I could find that retains the lens release button. It's only TWO millimeters thick!!!

The same is true for the Olympus lens mount -- it can be in pretty bad shape -- and it might not need the lens release button. The one I found lacks the lens release button but fits perfectly -- without any fear of slipping off.

The front of the Olympus lens mount that I have is a perfect match for the rear of a 49mm step-up ring, and the rear of the Minolta camera mount that I have is a perfect match for the front of a 58mm step-up ring,

So all I did was combine a 49-55mm step up ring and a 55-58mm step-up ring in between the Olympus lens mount and the Minolta camera mount. A 49-52mm step up ring and a 52-58mm step-up ring would have worked just as well -- as would a 49-52mm step up ring and a 52-55mm step-up ring and a 55-58mm step-up ring, if more space is needed.

It's critical to get the distance right, of course.

The genuine Olympus Minolta to Pen F adapter that I have is 14.5mm thick -- so that was my goal. The Olympus lens mount and the Minolta camera mount that I found have a 3.5mm total width, so I need step-up rings that add 11mm total distance in between.

Step-up rings vary slightly in thickness, but one advantage of using TWO (or more, if needed) step-up rings is that they can be adjusted slightly to produce the correct amount of depth. A little epoxy will cement the depth, once it is established.

I was able to find two step-up rings that created the correct depth that I needed using a caliper. I then attached a 200mm lens (equivalent to a 300mm in half-frame) -- focused at infinity, to verify that the depth was correct for infinity focusing.

The last step before epoxying it all together was to make sure the Minolta lens index mark was on the top of the adapter (when attached to the Pen F camera).

The only thing I'll add is that you should check the adapter for light leaks. A little bit of black silicone sealant should do the trick. I had to plug three screw-holes in the Pen F lens mount -- but since they were inside the camera that was really not necessary.

The total cost will vary depending on what you already have. Mine cost me about $20 -- about 1/10th of the real McCoy.

 

[Petrochemist]

I've made a number of impossible to find adapters using body caps. The first for a 1920's Kodak lens designed to fix to a lens board which I then used on a set of bellows as considerable extension was needed to focus. That was nearly 15 years ago now!
bellows IMGP2838 by Mike Kanssen, on Flickr

Several tiny lenses have been shimmed to the right distance then stuck in place, but none of those have proved of real interest in use.

Most of the time I use helicoids to give a variable extension, which can significantly boost the focusing range. Often this is combined with commercial adapters (camera to M42, helicoid, M42 to lens) but for this microscope objective I needed to get a bit more Heath-Robinson.
ultra macro lens set up by Mike Kanssen, on Flickr

By combining the zoom & helicoid the finished article above can focus from infinity down to 9cm where it reaches three times life size. Vignetting on an infinity focus test shows it's not perfectly centered (this only changes the framing slightly and is easily corrected in just the same way framing is usually done. There doesn't seem to be any issue with tilt at all =though for macro use this wouldn't matter, (just causing the camera to need to be tilted to bring the plain of focus back).

Combining lens rear cap & camera body cap is a potential way to create to make adapters that are not available, but I've not attempted this yet.

As for nuts, I've only found little ones to be any use, even when mounting a monster like my 150mm 1.3
A challenging lens by Mike Kanssen, on Flickr
I think 4 M4 nuts & bolts mounted the flange to the lens board, 6 would have been preferable but the side ones fouled on the standard.

 

[loccdor]

@xkaes Can we see some pictures of your adapted Pen?

 

[xkaes]

Here is a comparison of the Olympus-made Minolta adapter (right) and my DIY model (left). The front of the DIY model is wider, but that's of no consequence.

The DIY consists of four parts: Olympus lens mount, TWO step-up rings, Minolta camera mount: This shows how thin the Minolta camera mount is -- and the all-important lens release button.

This is the other side. The two step-up rings are not glued together. The other parts fit together fine -- with the help of a little epoxy.

 

[xkaes]

There appears to be a "fly in the ointment". I only tested my DIY adapter with Minolta MC lenses. A problem arises when using MD lenses.

The MD tab sticks out about 2mm more than the MC tab on the lens. And as mentioned in my previous post, my DIY adapter is slightly wider than the original Olympus-to-Minolta adapter.

While this is not a problem on the original Olympus-to-Minolta adapter, on my DIY adapter, the MD tab presses against the Minolta camera mount, and the f-stop ring cannot be adjusted.

This problem might not afflict all MD lenses, but it's something to watch out for. It's only a 0.X mm difference -- so the MD lenses will fit on the adapter fine, but the f-stop ring might not turn.

Many MD lenses might work correctly, but some -- like the one I tested -- might get stuck.

Solutions?

#1 -- use a Minolta camera mount that is slimmer (smaller diameter) -- if you can find one -- to avoid the problem. Minolta exactly addressed this problem when they came out with their MD AUTO Extension tube set -- replacing the MC AUTO Extension Tube set.

#2 file down the MD tab on your MD lenses by 0.5mm. Maybe you are like me and don't have any cameras that actually use the MD tab -- (XD-series, X-700) -- problem solved.