Re: Takumar Pentax 6x7 tests RE: [ap-gto] [ap-ug] A colorful Southern Sky Beauty

Richard Crisp

I completely get it!

They are useless for color 

However they do work fine with mono sensors and emission line filters stopped down

I had an experiment I wanted to try but never did: I wanted to put an IR-cut and a UV-cut filter in series and try some color imaging and see if it improved any

The blue end was terrible with star bloat

This is an example

The ED type gave better results

But I still would like to cut both ends of the visible

With mono sensors and narrowband filters they make a dandy method to find PNe.

They stand out like a sore thumb

But with Ha I think they do pretty well if you have a mono sensor and can focus it well.

The thing I liked about them was the long back focus and the fairly large “sweet spot” for illumination of sensors a lot smaller than a 6x7 negative 

The back focus allowed an inline focuser to be used vs a belt drive etc like is usually used when 35mm type lenses are used 

“Corrected” by my iPhone

On Apr 30, 2021, at 2:48 PM, Roland Christen via <chris1011@...> wrote:

Try shooting stars wide open with a color digital chip. You will see the limitations. I wish I had kept the result of my 90mm F2.8 Pentax lens - you would not believe how bad it is wide open.


-----Original Message-----
From: Richard Crisp <rdcrisp@...>
To:; robert-wynne@...
Sent: Fri, Apr 30, 2021 3:28 pm
Subject: Takumar Pentax 6x7 tests RE: [ap-gto] [ap-ug] A colorful Southern Sky Beauty

Some years back I did some tests of a handful of Pentax6x7 lenses I had picked up on the cheap
Even though they aren’t very well corrected over an electronic imager’s broad spectral responsivity, it seemed if you stopped them down, used a single wavelength filter with a mono sensor, you could get pretty decent results
You might find the slide deck useful that I made
I was using an FLI ML4022 camera (KAI series sensor w/7.4 micron interline pixels).
From: <> On Behalf Of Roland Christen via
Sent: Friday, April 30, 2021 12:44 PM
To: robert-wynne@...;; chris1011@...
Subject: Re: [ap-gto] [ap-ug] A colorful Southern Sky Beauty
I did get an adapter for my 90mm focal length lens from the Pentax 6x7 medium format film camera. It's a very fast lens wide open F2.8, so I thought it would make an ideal wide field imaging system with either my Sony NEX7 digital camera or my astronomical CCD camera. Well, my first shot wide open produced 100 micron bloated stars in the center with quite severe chromatic aberration. Stopping it down to F8 helped some, but didn't really clean up until F11. At that point it had an aperture of only 8mm, not much more than a dark adapted human eyeball. So, pretty much none of the older film camera lenses, no matter how good they were back then, will hold a candle to a modern lens designed for a digital camera. Even a cheap and cheerful Rokinon will blow these old dinosaurs away.
-----Original Message-----
From: ROBERT WYNNE <robert-wynne@...>
To:; Roland Christen via <chris1011@...>
Sent: Fri, Apr 30, 2021 12:36 pm
Subject: Re: [ap-gto] [ap-ug] A colorful Southern Sky Beauty
It's really a shame that all these high end lenses are relegated to museum shelves. Someone ought to figure out some sort of adapter. I must have over 20k in lenses I can't seem to let go of. I was a Canon F1 fan. -Best, Robert
On 04/30/2021 10:13 AM Roland Christen via <chris1011@...> wrote:
I have a collection of Nikon and Pentax film cameras that sit unused on my "museum" shelves. It's a pity really. Couple of years back i bought some rolls of 120 color film and shot some pictures of our prairie. Even with the medium format film I could see the graininess that limited the resolution. It's like a factor of 10 in resolution gain of CCD/digital over film.
-----Original Message-----
From: Ross Elkins <rossmon1@...>
Sent: Fri, Apr 30, 2021 11:57 am
Subject: Re: [ap-gto] [ap-ug] A colorful Southern Sky Beauty
I had to console many a sad photographer! I managed a photo shop, “Milbee Photo Stores” part of a chain of 20 or so small shops where the nicest camera was made by Kodak and film processing was the profit center.
I was doing wedding/bar mitzvah photography and many of my pals were the top fashion photographers of the day.
I bought n sold 35mm cameras that came in the front door! Nikons F’s, the Olympus OM1, the Fugi 120 with the 120 negative. Our pal Hideoki Hagiwara was Japans most famous photographer at the time. On a trip to Tokyo, he brought back an Olympus Pen F ½ frame for each one of us! Him and My pal Paul Hyman had a large studio at 100 Fifth Ave, what an address! Almost across the street from Max’s Kansas City where all the photo/music/artists elite hung. Paul has a photo project from the atlas mountain tribes that is part of the MET’s permanent collection!
I still have my Pen F with a couple of lenses! I gave that life up for almost famous music and a California life in 1974!

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