The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

Pentax 110 lens on G1

V

Vivek

Guest
Finally, I got around to work on one of the beauties, the 18/2.8s.

Now, I have one mounted for the m4/3rds. Covers the frame completely.:thumbs: Sharp enough for me. Field flatness is good. Most importantly, the lens is capable of showing some separation, even at f/2.8 (for the typical range I would sue it for). Only handicap is the fixed aperture. Does not bother me, considering the size (has a 30.5mm filter thread) and the weight.

Couple of shots showing the lens with the Computar-TV 25/1.3 (40.5mm filter thread and already mounted on a m4/3rds to C adapter).





Both the shots taken with a 18/2.8 on G1 at close range. Will take it out tomorrow to give it a workout.:)
 
V

Vivek

Guest
A few "real" pics from the Pentax-110 18/2.8 (all at its fixed aperture of f/2.8 and no crops). I love it.:thumbs:

It remains to be seen if the Olympus 17/2.8 (in addition to the AF and adjustable diaphram) would do better!







 
L

Lupo

Guest
Thanks Vivek! :thumbs:

I had already forgotten my 18/2.8.
now I have myself built a high-tech-adapter ... ;)

and I'm thrilled by the small lens ...


really great fun!
 
V

Vivek

Guest
Thanks Lilli. You used the Farsi word to describe the head dress (Hijab in arabic is more common).

Pellicle, I used a C-mount flange from one of the 12.5mm Computars to permanently house a 18mm lens.

Lupo, Looks good! As long as it works, there is nothing "low tech" about it. Post some pics when you make some.

BTW, the lack of distortion and the lack of lateral chromatic aberrations from the 18/2.8 (even in difficult light) is quite amazing!
 

pentacon6

New member
I am curious about the iris control. Is it able to adjust the iris on the lens?
This should give a sharper image, I believe.
 
V

Vivek

Guest
As I already mentioned twice, the aperture is fixed at f/2.8.
 

pellicle

New member
Pellicle, I used a C-mount flange from one of the 12.5mm Computars to permanently house a 18mm lens.
ok ... so this suggests to me that you've altered the lens to work with the c-mount lens.

hmm ... sounds a bit out of my league at present ... although if its simple would you mind giving a brief enumeration of the process?

PS I've just bought one one ebay and haven't seen it yet. and I do realise its a fixed aperture lens (although I think that it has focus adjustment)
 
V

Vivek

Guest
Hold your horses. It isn't a state secret.

Once I make some pics, I will show you.:)
 

pellicle

New member
Hold your horses. It isn't a state secret.

Once I make some pics, I will show you.:)
Oh goodie ... I love a tech tutorial :)

I'll just go 'n get some chocolate and some ice cream for the reading (when its done) ...

thanks for that
 

woodmancy

Subscriber Member
Thanks for doing this Vivek - at some point I was going to get around to doing it myself. I figured the lenses must be good because of the small format.

I have a complete set of lenses, filters, close-ups, and the zoom. Plus a defunct body. I wonder if I could find anyone to take the flange out of the body and meld it to a c-mount adapter?

Any suggestions?

Keith
 

pellicle

New member
hello

someone in Japan is already making a =Pentax 110 to M43 adapter

-jKK
bewdy

hmmm ... me thinks that caling micro 4/3rds m43 is a little too close to the M42 standard but you know, now that I think about it I hope its as long lived!
 
V

Vivek

Guest
OK, here is what I did in the end to make the 18mm a permanent c-mount lens.


A 10mm c-mount extension, 18/2.8 Pentax-110, RJ adapter.

The 10mm extension tube is bruised a bit by rubbing it on a grinding stone (you can use a fine sand paper, etc).

Next, mount the c-mount extension on the adapter and line up the red dots so that when finished, the focus scale will be on the correct side.



after that, glue them up keeping the lens centered. I used a special metal-metal expoxy that takes >6 hours to set. This is stronger than metal.


(sorry about the pic, don't have anything better)

Out of the 4 Pentax-110 lenses I have, I find the 18mm, the most useful. I won't be using it ever on the Pentax-110. So, no point in keeping it as is.

Besides, I love screw mount lenses. When the close focus distance (in case of the 18/2.8, it is 25cm) is insufficient, I can always unscrew the c-mount 18mm lens to make it focus to ~5-6cm (or even use an extension ring)to get shots like this:



Bee in a lavender bed.
 

pellicle

New member
Vivek

thanks for posting your methods. Seems easy enough.

I'll keep you posted on my progress with my lens
 
V

Vivek

Guest
You are welcome.:)

That was the 3rd iteration and the simplest possibility.
 
Top