Ron Gentry

Ron Gentry

Port Townsend, Washington

I am a retired professor of chemistry, including 10 years as head of the Department of Chemistry at the University of Minnesota. My interest in photography goes back to the 1960's, but became more serious with the advent of high-quality digital sens...
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Articles

Composing a Composite – Cliff Diver

The city of Acapulco, on Mexico’s west coast, has long been a major destination for tourists.  Of all its attractions, perhaps the most famous are the cliff divers at La Quebrada (The Creek), adjacent to the Mirador Hotel.  All members of the...

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  • Ron Gentry
    Ron Gentry
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    Does pixel-shift increase resolution?
    on: March 3, 2020 at 1:39 pm

    So far I’ve only used it in the studio.  Imaging Edge worked well for me.  There is at least one other software choice for merging pixel-shift images:  https://www.fastrawviewer.com/PixelShift2DNG, but I haven’t yet tried it.

    Ron Gentry

    Ron Gentry
    Ron Gentry
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    Posts: 4
    Re: Does pixel-shift increase resolution?
    Reply #1 on: March 2, 2020 at 7:54 pm

    As a scientist, I find all this theoretical debate very interesting.  However, on September 24, 2019 I posted a real-world test on the PhotoPXL website (Reply #8245).  It was admittedly done under ideal conditions, but it showed a definite improvement in resolution for the 16-frame pixel-shift image over the 4-frame version.  I will gladly be taking advantage of this capability whenever conditions seem appropriate.

    Ron Gentry

    Ron Gentry
    Ron Gentry
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    Posts: 4
    Re: Sony a7riv – Let The Fun Begin
    Reply #2 on: September 24, 2019 at 5:41 pm

    I just did my first test of the 16-frame pixel-shift feature in the new Sony a7rIV. I am very impressed. I photographed one of my wife’s art quilts with a Zeiss 55mm lens at f/8 from a distance of about 25 ft. I did a single shot, then the 4-frame pixel shift, then the 16-frame pixel shift. Here are the results: 1, 4, 16 left-to-right. The improvement from one frame to 4 is modest, but there is a huge improvement in the 19008×12672 image from the 16-frame composite made in Imaging Edge. Wow!Mark4-SS
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    Ron Gentry

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    Ron Gentry
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    Re: PXL News
    Reply #3 on: July 31, 2019 at 8:01 pm

    I am a bit confused about how camera manufacturers arrive at a spec on Dynamic Range.  The new Hasselblad camera specifies a dynamic range of 14 stops and records 16 bits of information.  The Sony a7R IV claims a dynamic range of 15 stops, yet still only records 14 bits.  The Hasselblad spec seems too conservative, while the Sony spec seems unlikely.  Can anyone clarify the difference between dynamic range and bit-depth?

    Ron Gentry