Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: Guillermo Luijk on April 20, 2022, 04:12:05 am

Title: Solargraphy simulation with pinhole cameras
Post by: Guillermo Luijk on April 20, 2022, 04:12:05 am
DIY pinhole film cameras are used to obtain ultra long exposure solargraphs, drawing the Sun trajectories in the sky. The most common camera format is a cylinder (beer can), but I have made the calculations on how an alternative half cylinder (semi can) would perform, and I find a lot of advantages in the half cylinder:

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4b4-Qn7ynjorsbY8twZIvO8tP3mwXIU2HiL-Vb2OfqWZtl8ArWTv0NF9Yqq0IIzAWuzHMlTeBKzh7VrsbBLQiIh9C0oBAfduu7LnbuTlO1BA1MpnQc_H4ZwdBtDlBUhgau24dRATzBobmy6WtI7pBQRaTuz8OvhhGwEedh_RJ0Mur9x5pD2C3AAnAKA/s16000/solar0.jpg)
Solargraph by Gianluca Belgrado

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPXUOaoFPvkbXxSc79NAT_nvMCVs62LTxzetujWG41hwNAUS7x0IZBLlauebXSESVbkTTCgiD6i0dSLzmxPLkc9yTT-H-nHlzdv8Z-2EIU_JXmjd_QQu1FjweMO5Baym2Lp_tzWxIc2mE_I6Gzpb0v-7rBYXWidSZi4Pl-jpO3XsndX5zVVOQcaidKFw/s16000/ecuacionescamaraestenopeica.png)
Studied cameras

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3E7n7uVHNBax4qokgXQNcvcneuYo9yiU7qRKUfls3-8rvTvTnUqPS3jOg54AUdgPyLw9FCZ38AAQsJvK0oQ19HcG7VcLlhUXZF6p7-zTxj-9yeF8x4w4jzhlvmx0yrT1eB4S7XqUs4KMbo6GdNcLmIKdZa5ugum62NmAdGQL1yec8-PhVyx5yKkj2mw/s16000/pinholeanalemmaanim.gif)
Sun trajectory projections of each camera, including analemmas

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipFX6WfrVWT5MuqAYPgtNHXGgqiLChXnqDCJ4xg33I5B8gGutc8JjBNmDa369rfS2yJ8ZHNPZj9qBIeKitWqksQLZVYbqXbrVpO1-FORU5ZIWQhz2DhUW4JHHYDbyqSDwmVajmhUa0QB7-LwUb5gkvRwNvSTUb-xr7225T8wjRA62FiWAEfHfOcfApXQ/s16000/pinholecheck.gif)
Check of calculations vs real beer can (actually PVC tube) solargraph


The article here (Engllish translation available top right): https://www.overfitting.net/2022/04/simulacion-de-solarigrafias-con-r.html

Regards


Title: Re: Solargraphy simulation with pinhole cameras
Post by: kers on April 20, 2022, 05:07:55 am
good subject!
Indeed pinhole makes a perfect wide angle lens- up tu 180º undistorted!
It surprised me when i made one; but it is never sharp and i mostly don't like the way it is unsharp...
nevertheless it is as spectacular as simple.
Title: Re: Solargraphy simulation with pinhole cameras
Post by: gebseng on April 20, 2022, 05:39:04 am
Hi Guillermo,

Back in 2007, a student of mine, Andreas Zingerle, tried the "half-can" pinhole camera. You can see the results here:https://gebseng.com/media_archeology/student_works/2007/Andreas%20Zingerle%20-%20Solargrafica/neoanalog_pinhole%20andreas%20zingerle.pdf

best, geb
Title: Re: Solargraphy simulation with pinhole cameras
Post by: Guillermo Luijk on April 20, 2022, 07:24:24 am
Cool Geb. I took a look at the PDF and I think it only shows full cylindric cameras, is that correct?

I just found another photographer, Steve Riegel, who built a half can camera. I'm a bit surprised on how few people use it vs the beer can, when it has advantages. Here we can see non-distorted analemmas thanks to the half can camera:

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqYZz74mYv89TQt8iSTtYc3r25yYIRizBdWvUloO8bpPQRwK5niZQTt4MgcRgzewNxEBDDLHq8EY8em3AAgLaYRU4nijR2OTCtMsIs_HgQAgBXkOdfFqmQpD8nKPCZ7LqwpxBRFAFm-JZuRpklXO-5GpJNDP6wm8fHAi6GKuzenLgimQAnzVG20d9E3Q/s16000/analemamultiple.png)

And the camera he built:
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZGivJfPcn8sjLBJ2tdWiOmidLVdTcGLCCjKCHI6iHgKGtrCvtmSOFC4bpH_sEh8DmsvE8EkCm2xW5fvZx0f021mzu-YaJmkzPWdYx3fRhCHQpYM14uSgq_AucbnGcEu19agmRcy5QTYKu5wy5dRMzjhQayRScKO_58FT-xd7aSjUmSCHKCU90-3BAIQ/s16000/camarasemilata.jpg)

Regards
Title: Re: Solargraphy simulation with pinhole cameras
Post by: ced on April 27, 2022, 11:47:35 am
Where would/was the pinhole on this half tube?
Title: Re: Solargraphy simulation with pinhole cameras
Post by: Guillermo Luijk on April 28, 2022, 07:19:13 pm
Quote from: ced on April 27, 2022, 11:47:35 am
Where would/was the pinhole on this half tube?
I guess in the upper half of the tube, to get more field of view over the horizon where the analemmas get formed, and with the camera slightly pointed over the horizon (which then projects a bit curved).

I have come across with an idea to improve the effective FOV. The physical dimensions of the pinhole make impossible to achieve a FOV=180º. What if some polished melted plastic/adhesive material is located surrounding the pinhole to save ray paths thanks to diffraction that would otherwise get lost? the camera FOV would be increased:

http://guillermoluijk.com/misc/estenopoplus.png

Regards

Title: Re: Solargraphy simulation with pinhole cameras
Post by: Guillermo Luijk on May 01, 2022, 04:56:58 am
A nicer simulation of the concept:

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirQplGDsE3v6gMXgN8t-GvxQ6wYxL2_9VLt3CnlhL6AKVUSKtM2-FYou8viRZxLkvTtS0yBIcO3-xQHo0hft9UPsm830NnSj0K6_fCcKa1t76_HbKM5xPF8gEIVz-H5Jk98b7W5PJcwATY7PZlPw5FeGVFZeFZ9lEr3a4UIJmdTceDXD90sh_50nqchg/s16000/pinholealt.gif)

Regards
Title: Re: Solargraphy simulation with pinhole cameras
Post by: Guillermo Luijk on May 04, 2022, 06:55:58 pm
Closer to a real implementation with microscopy coverslips and Superglue (same refraction index as glass: ~1.5):

(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhP3wV0u_nYlMQzX4817U-3YVEOjG27zpyivJp70iXaL41O1IDHRaYikexRneVcmXblLm66WPxLnTRSCYPQcnOu4zNg3EHXROibc9O0YXNEWLvmgkz2DiAi9cfByFd6a_9XRkaLKj3kugFSYxr_1fuk8BWv_iNJQPrJAPjXFJ6yIg3a4hYX6OGAtEsbQw/s16000/pinholealtsuperglue.png)

The adhesive fills the pinhole at the same time that sticks the coverslips.

Regards