Showcase Pentax 70mm f/2.8 auto 110

smartiepants

Mu-43 Veteran
Joined
Aug 17, 2014
Messages
356
Location
UNITED KINGDOM
I may live to regret it but I purchased a cheap one off ebay for just over £10, if I don't get on with it then i'll get the Kipon at a later date, I can always leave the cheap one on the small lens
 
Joined
Jun 17, 2015
Messages
356
Location
UK
Real Name
Richard
Saw one of these on eBay at a low starting price. Couldn't resist bidding ....
Subscribe to see EXIF info for this image (if available)

Used a 10mm extension tube to get close.
 

pellicle

Mu-43 Hall of Famer
Joined
Feb 10, 2010
Messages
3,956
Location
Killarney, OzTrailEYa
Real Name
pellicle
tried it a music festival, I struggled with the focusing but I think I need more practice
My tip is this:
  1. pick the composure you want
  2. pick the point of focus (with your brain) and then move the focal enlargement tool to there, zoom in
  3. it will jitter, but try to look at the sharpness and when its "right" just take (because composure won't have changed)
if you use both eyes you can check the scene with the other eye as a quick double check

This is what works for me across all my Manual Focus lenses (including this one).

Focus looked OK on the Sara Oliver picture, but shutter speed was a bit low so that softness you're seeing in her face (which isn't in the bass guitar or her pants) is motion blur ... hers not yours (as you have IBIS). Its a mistake to believe IBIS can help when photographing things which move.

PS: Also (if you aren't already) try just pulling the green channel from the RAW file and working with that for black and white, it will have least noise.
 

smartiepants

Mu-43 Veteran
Joined
Aug 17, 2014
Messages
356
Location
UNITED KINGDOM
Hi Martin,
Nice shot. I seem to remember taking a trip on a paddle steamer called Waverley back in the 1960s when it was on the Clyde. You could go down to the engine room and watch the pistons. Could this be the same vessel?
I would imagine its the same steamer, we were in the right place at the right time when we saw it sailing into the isle of Wight
 
Joined
Jun 17, 2015
Messages
356
Location
UK
Real Name
Richard
Still having fun with this lens.
Since it has a diameter of 49mm I am able to use a variable nd filter I already had to avoid overexposure.
Subscribe to see EXIF info for this image (if available)
Subscribe to see EXIF info for this image (if available)
Subscribe to see EXIF info for this image (if available)
 
Joined
Dec 10, 2020
Messages
18
Location
Ottawa, Ontario, Canada
Real Name
Karen McBride
Square bokeh balls were OK for some subjects but really became a bit much in most cases for me: I wanted round speckled highlight, not hexagonal, round!
The commercially available adapter for Pentax-110 lenses with aperture has been reported as a bit rickety and finicky to operate.
I wanted simple but good
So, I sourced a diaphragm with the potentially right dimension to be inserted between lens and DIY adapter.
Luck was on my side and the whole retrofit of my existing mounted 70mm f2.8 lens went smooth and fast: a couple of hours and I had this:
@gnarlydog australia
This is a great build. What size lens did you get the diaphragm from? I would like to give it a try.
BTW your photos are fabulous.
Thanks
Karen
 
Last edited:

gnarlydog australia

Mu-43 Hall of Famer
Joined
Feb 23, 2015
Messages
3,590
Location
Brisbane, Australia
Real Name
Damiano Visocnik
@gnarlydog australia
This is a great build. What size lens did you get the diaphragm from? I would like to give it a try.
BTW your photos are fabulous.
Thanks
Karen
the diaphragm is an inexpensive Chinese offering on evilBay. It required minimum adaptation and I love the high-count blades aperture gives round bokeh balls even stopped down a bit
Here are some current offerings with the search for "diaphragm iris aperture" https://tinyurl.com/yxwo4cnp
 

Mike Wingate

Mu-43 Hall of Famer
Joined
Feb 21, 2017
Messages
3,487
Location
Altrincham
Real Name
Mike Wingate
Still waiting for my eBay purchase adapter. Shocked to think that the Pentax 110 70mm lens is a little heavy for the mount. I wonder if my other adapter for the O150-400mm will make that too lens heavy for the Pentax 110 body, yes, may need to adapt a grip for the body.
 

Mike Wingate

Mu-43 Hall of Famer
Joined
Feb 21, 2017
Messages
3,487
Location
Altrincham
Real Name
Mike Wingate
It has arrived. I have even taken photos with it. I am really pleased with the performance of the P70mm, so far the only lens I have tested.
Subscribe to see EXIF info for this image (if available)
 

Mike Wingate

Mu-43 Hall of Famer
Joined
Feb 21, 2017
Messages
3,487
Location
Altrincham
Real Name
Mike Wingate
Nothing shots, just to see if it works. Interior shots without light. Outdoor shots with a dull grey sky. All 70mm.
Subscribe to see EXIF info for this image (if available)
Subscribe to see EXIF info for this image (if available)
Subscribe to see EXIF info for this image (if available)
 
Joined
Dec 10, 2020
Messages
18
Location
Ottawa, Ontario, Canada
Real Name
Karen McBride
the diaphragm is an inexpensive Chinese offering on evilBay. It required minimum adaptation and I love the high-count blades aperture gives round bokeh balls even stopped down a bit
Here are some current offerings with the search for "diaphragm iris aperture" https://tinyurl.com/yxwo4cnp
@gnarlydog australia
I have decided to make an adapter with a diaphragm. I am going to machine some aluminum to make a piece that I can attach the Pentax 110 lens mount to. I will put a diaphragm in the aluminum bit and then glue the aluminum bit to a c-mount adapter. They I can use it on all my 100 lenses.

I want to be sure I understand the math correctly. The flange distance for my GX85 is 19.25mm and the flange distance for the Pentax 100 is 27mm so I need to make the total depth of my adapter 7.75mm from the back flange of the c-mount adapter (that sits against my camera body) to the back of the glass on the lens. Is that right?

I was planning to make the inside of my aluminum adapter 16mm and I am buying a 16mm diaphragm.
Karen
 

gnarlydog australia

Mu-43 Hall of Famer
Joined
Feb 23, 2015
Messages
3,590
Location
Brisbane, Australia
Real Name
Damiano Visocnik
@gnarlydog australia
I have decided to make an adapter with a diaphragm. I am going to machine some aluminum to make a piece that I can attach the Pentax 110 lens mount to. I will put a diaphragm in the aluminum bit and then glue the aluminum bit to a c-mount adapter. They I can use it on all my 100 lenses.

I want to be sure I understand the math correctly. The flange distance for my GX85 is 19.25mm and the flange distance for the Pentax 100 is 27mm so I need to make the total depth of my adapter 7.75mm from the back flange of the c-mount adapter (that sits against my camera body) to the back of the glass on the lens. Is that right?

I was planning to make the inside of my aluminum adapter 16mm and I am buying a 16mm diaphragm.
Karen
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
 
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Mu-43 is a fan site and not associated with Olympus, Panasonic, or other manufacturers mentioned on this site.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Copyright © 2009-2019 Amin Forums, LLC
Top Bottom