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02-08-2020, 01:09 PM - 1 Like   #1
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First pictures with f:2.8/24 mm & homebrew Pentax auto 110 to M4/3 adapter

I've reposted this from another thread where prices of Pentax auto 110 were discussed. I think it is better placed here...

Save the planet - recycle your vintage lens!

As you well know, the powers that be have mandated we all must cut down on everything, except for taxation, to save the planet.

Hail Greta, full of Grace!

So, I've come up with this (nearly) tax free recipe to counteract climate change:

✅Take one M4/3 camera body of your choice.
✅Take one Pentax auto 110 lens (In my case: f:2.8/24 mm).
✅Take one C to M4/3 adapter.
✅Take two C to CS adapters.

File down one C to CS adapter about 1-1.5 mm to achieve infinity focus. If you take off too much, it's easy to shim back up.

While testing for infinity focus, simply hold, or melt glue, the lens to the filed down adapter. Melt glue is easy to remove, should you want, or need, to.

This combo is less expensive than the cheap Chinese adapters from Pentax 110 to M4/3.
All in all, less than US$ 5:-!

This isn't counting camera and lens.

Also, it's not leaking light, which can be a problem with these adapters.

Last, but not least, the adapter ordered from China I won't get for a month, or so, and I wanted to try the lens NOW!

Couldn't let a sleeping lens lie...

☢️ Shot with Olympus E-PL1 through Pentax-110 f:2.8/24 mm wide open.
☣️ RAW development in camera.
☢️ Pictures of E-PL1/adapter/auto 110 lens shot with Samsung Note 10 plus.
☣️ Post processing of all pictures in Snapseed app on Samsung Note 10 plus.


[EDIT] I did file down enough to need a thin shim, made out of a postcard. So now the adapter looks like: C to M4/3 adapter - C to CS adapter - filed down C to CS adapter - thin shim - P110 f:2.8/24 mm. I did away with melt glue, only good for proof of concept, and now the shim is glued with office glue between the modified adapter and the lens.

So what I have now is a C mount Pentax 110 lens. The C mount thread is same as the filter thread of the lens, so an extra C to CS adapter can be used as a non vignetting lens hood, or as an extension tube for close up pics. Also made an aperture disc out of a piece of cardboard (same as used for the shim), which I punched a hole in with (you guessed it) a hole puncher. This gives me an aperture that looks like f:4.5 to f:5.6.

Final thought: This recipe should also work nicely with the Q C mount adapter. [\EDIT]

Last edited by Erich_H; 02-17-2020 at 06:27 PM. Reason: Attachment space running out.
02-09-2020, 08:04 PM   #2
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Not much action in this thread, but I'm not ready to kiss it goodbye just yet, so, here goes....

Weather is really shitty, the storm Chiara is approaching, but I took a couple of test pictures from my balcony.

Pictures straight out of camera, no post processing. EV is -1/3 on both shots.

Olympus E-PL1 with Yashica ML f:2.8/28 mm
@ 1/100 f:5.6 ISO 400

Pentax 110 lens thread | Page 5 | Mu-43

Olympus E-PL1 with Pentax-110 f:2.8/24 mm
with aperture disc @ 1/200 ~f:4.5 ISO 400

Pentax 110 lens thread | Page 5 | Mu-43

Here's crops from lower left corner of both shots:

Pentax 110 lens thread | Page 5 | Mu-43

Pentax 110 lens thread | Page 5 | Mu-43

When thinking about it, the aperture on the Pentax lens should be around f:4 according to the respective exposure times. Both pictures were taken within a minute.

My eye measurement/guesstimate says closer to f:5.6 on my disc, though.

Anyhow, there's no doubt. The Yashica ML glass is better. Also bigger. My thoughts are that the Pentax-110 lens is well worth the room in your pocket, as it don't take any.

Complete weight of the Pentax-110 f:2.8/24 mm including adapter, rear lens cap and an extra C to CS adapter as lens hood is only 45 grammes.

The Yashica ML f:2.8/28 mm weighs in at a comparatively hefty 345 grammes in similar configuration, with a UV filter added to it.

Better and bigger glass f:2.8/28 mm (with hood)

Pentax 110 lens thread | Page 5 | Mu-43

Pocket friendly lens f:2.8/24 mm (with hood)
The C-mount adapter hood also makes focusing easier, as the knurls stick out in front.

Pentax 110 lens thread | Page 5 | Mu-43

Here's a view of the aperture disc in place

Pentax 110 lens thread | Page 5 | Mu-43


Also, this Pentax 110 to C-mount conversion should work equally well with everything you can put a C-mount adapter on. Pentax Q, NEX, Samsung NX, and others...

Last edited by Erich_H; 02-10-2020 at 06:33 AM.
02-17-2020, 03:25 PM - 1 Like   #3
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Final installment:

Olympus E-PL1 with Pentax-110 f:2.8/24 mm and a triangular aperture disc made of thin plastic inserted.

All pictures (except the first) uncropped at ISO400.

First picture is with Samsung note 10 plus.

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Last edited by Erich_H; 12-11-2020 at 11:05 PM.

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