Showcase Pentax 70mm f/2.8 auto 110

[kmcsmart]

hmmm, a C-mount adapter on its own has some thickness and that will leave you with very little room to work with...
Is there a reason not to start with a M39 adapter (thread mount common of so many old lenses)?
In my case I had to do very little cutting/shaving to create the room for the diaphragm, and then some JB-Weld.

Unless, if I understand you correctly, you want an interchangeable adapter where you can swap and mount all the Pentax-110 lenses?
In that case you have indeed 7.75mm to play with

I had a good look at what you did with the m39 adapter and that makes sense. Did you use a c-M39 adapter to glue to each lens? Something that looks like this below?

If you have time can you let me know the outside diameter of the iris that you bought or the inside measurement for the m39-m4/3 adapter and then I can order everything at once.
Thanks
K

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[gnarlydog australia]

I had a good look at what you did with the m39 adapter and that makes sense. Did you use a c-M39 adapter to glue to each lens? Something that looks like this below?

If you have time can you let me know the outside diameter of the iris that you bought or the inside measurement for the m39-m4/3 adapter and then I can order everything at once.
Thanks
K
View attachment 869201

I don't currently have the lens as is on loan to my niece, and god knows when I will see it again

On the notion of having an adapter like you show to then thread each Pentax-110 lens onto the common MFT to M39 adapter.... I rather go a different route.
I like to swap lenses as the conditions/subjects dictate and out in the field futzing with threaded adapters... is slow and cumbersome.
To have the same experience as I have with a native lens all of my vintage glass has a dedicated adapter; they are just too cheap to be messing around with one shared with many lenses.
So, on evilBay I source a generic MFT to M39 adapter, glue the "silver" ring to the lens (a tiny bit of spacing needed between the two surfaces) and then screw the "silver" ring into position in the adapter.
To me having infinity on the lens marking is somehow important and that way I can assure decent registration on each lens.

Happy tinkering

 

[kmcsmart]

I don't currently have the lens as is on loan to my niece, and god knows when I will see it again

On the notion of having an adapter like you show to then thread each Pentax-110 lens onto the common MFT to M39 adapter.... I rather go a different route.
I like to swap lenses as the conditions/subjects dictate and out in the field futzing with threaded adapters... is slow and cumbersome.
To have the same experience as I have with a native lens all of my vintage glass has a dedicated adapter; they are just too cheap to be messing around with one shared with many lenses.
So, on evilBay I source a generic MFT to M39 adapter, glue the "silver" ring to the lens (a tiny bit of spacing needed between the two surfaces) and then screw the "silver" ring into position in the adapter.
To me having infinity on the lens marking is somehow important and that way I can assure decent registration on each lens.

Happy tinkering

Thanks. I will make an adapter for each lens. I will buy a bunch of m39 adapters and play with the lenses a bit using a standard adapter and then add irises to my preferred lenses. This is my first go at making an adapter so there is lots to learn for sure.
K

 

[gnarlydog australia]

Thanks. I will make an adapter for each lens. I will buy a bunch of m39 adapters and play with the lenses a bit using a standard adapter and then add irises to my preferred lenses. This is my first go at making an adapter so there is lots to learn for sure.
K

hmmm, the M39 adapter will work well for the 70mm and the 50mm but for the smaller ones I think a C-mount base and then some C-mount macro rings (or even PVC plumbing tube) might be a more elegant solution since the lenses are so tiny. Here shown is the 70mm and the 24mm

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Pentax-110 70mm and 24mm_c by gnarlydog, on Flickr

 

[Mike Wingate]

I am pleased with my inexpensive Roxsen mount. No evidence of light leakage, quick to change lenses. Love the 70mm and have taken a liking to the 18mm. Still tempted to buy a P20.

 

[Mike Wingate]

I have re-read this missive, then gone out to photograph some flowers ”from below”. I started with the Pentax 110 70mm lens, could not focus. Moved back and the blue focus peaking picked up the background. Looked at the lens. 5 foot closest focusing distance. Replaced it with the P42.5 f1.7, focussing from a foot away. Hmm. Camera has now run out of battery, lunch time, then shifting rocks in the afternoon. But nice and bright, will be interested to see the images. Cheaper than an O75mm, for the moment. At least.

 

[barry]

I started with the Pentax 110 70mm lens, could not focus. Moved back and the blue focus peaking picked up the background. Looked at the lens. 5 foot closest focusing distance.

Yep.
There were some close-focus add-on filters sold in some of the larger kits. However, most kits didn't include the 70mm, so I don't know how many filters are out there... I don't have any but a UV for it.

 

[richardp]

Yep.
There were some close-focus add-on filters sold in some of the larger kits. However, most kits didn't include the 70mm, so I don't know how many filters are out there... I don't have any but a UV for it.

The shorter 110 lenses have small diameters so most of the filters out there that fit were the ones Pentax made. The 70mm however is 49mm diameter and there are many filters that size. I use an Olympus, works great. £3.50 on eBay.

 

[Mike Wingate]

I could use my Raynox DCR 250 on it. I have a 77mm close up filter that might work.but the P42.5 was perfect.

 

[richardp]

Haven't had any images on this thread for a while so I thought I would post this:

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70mm plus Olympus close up filter (+2.5 dioptre)