How To Build an Integrating Sphere, Anyway?

(This article is a supporting part of our ongoing testing of low-light camera metering reliability)


An integrating sphere is used for measuring emission or detection of light. It is a sphere coated on the inside with diffuse white paint, and this scatters light uniformly and thereby eliminates directionality effects. To state simply, an integrating sphere has very even internal illumination, and in the case of this project, it doesn’t matter how a camera is pointed inside of it.

A vacuum-rated integrating sphere useful in cryogenic temperatures (which I used extensively in grad school for characterizing infrared detectors) costs tens of thousands of dollars. If you are alright with ambient temperature and normal air pressures, an integrating sphere can be 3D printed for a few hundred dollars. I could have done that, but part of the fun of this project was to do everything as cheaply as possible. I decided to papier mâché one.

I bought a beach ball at Walmart for $2 and collected the Penny Saver newsprint coupons that came in the mail for a few weeks. I read that flour and water papier mâché molds, so I used wood glue.

I did the first layer with white paper to make it easier to paint. The rest used newsprint.

After three couple-hour papier mâché sessions, separated by a day or two of drying, I had a newfound respect for just 3D printing these. Oh well.

Finally, I cut it in half and removed the beach ball. I cut a hole at one end for the lens.

I painted the inside with flat ultrawhite house paint and then sanded it to improve the smoothness. This image was after the first sanding but before the second coat.

Most integrating spheres use many LEDs for even illumination, but I only used two in order to achieve the dim lighting conditions.

I put a 1-stop neutral density and ¾ color temperature orange (CTO) gel over each LED to make it dimmer and warmer in color.

The center ring bounces the LED light back, thereby forcing at least two reflections before entering the lens. I later put a sheet of paper over this in order to dim it further.

The initial fit test, before additional painting, and work to make it light-tight.

 

Integrating sphere in use.

Here’s the Arduino (lower) and my interface board (on top). The Arduino is the Duemilanove I originally bought for my timelapse motion project a decade ago. The knurled knob in the top center of the photo is a variable resistor which controls the voltage to the LEDs. This enabled me to adjust the max brightness level to 0 EV, and then I glued it to avoid further brightness changes. The dual-pin female plug at right is where the LED connects. The 2.5mm connector at bottom connects to the wire for triggering the camera, and the two integrated circuits alongside it are optocouplers for triggering focus and exposure (equivalent to a half-press and full-press of the shutter button). The pushbutton on the left enables me to interrupt the code if I want to go faster. The Arduino provides a USB interface to the user, and the code it runs can be viewed here.

Project price list:

Beach ball $2
3 bottles wood glue $12
Flat ultrawhite paint – sample size $3
Black spray paint $4
Opaque black fabric $4
Arduino Duemilanove $20 if bought new
Paper folder (thin plastic for baffles) $2
LEDs $5 for 30, used 2
Optocouplers $5 for 50, used 2
Variable resistor $4 for 3, used 1
Total $61

 


 

Integrating Sphere & Camera Metering Test Project

Main Project Page – Test Results

Project Overview – What Is An Integrating Sphere, and How We Used One to Measure Cameras’ Low-Light Metering Capability

Frequently Asked Questions / FAQ

What are EVs, and What do They Mean for Different Cameras? (Non-Technical Explanation)

The Technical Explanation of EVs, and Calibration of the Integrating Sphere

So, How Did You Build an Integrating Sphere, Anyway?
(YOU ARE HERE)

Timelapse Methods Compared: Aperture Priority VS Holy Grail Method


 

The New Champion Of Astro-Landscape Lenses | Sigma 14-24mm f/2.8 DN for Sony FE Mirrorless

Sigma 14-24mm f/2.8 DG DN FE Art, Sony A7III | Photo by Sean Goebel, sgphotos.com

Ladies and gentlemen, we have more witchcraft at 14mm. And also at 24mm. The Sigma 14-24mm f/2.8 DN Art (FE; this is NOT the same optic as the previous DSLR version) …is basically flawless.

OK, we’ll wait to call it “flawless” until we can put it on a ridiculously high-res sensor like the 61-megapixel Sony A7R IV, but for now, let’s just leave it at this: It disproves at least two “impossibilities” that have been assumed about zooms…

Not only does it defeat one of the existing 14mm prime lens champions, the Sigma 14mm f/1.8 Art, it also performs astonishingly well at both ends of its focal range. In fact, it actually matches the current 24mm champion, the Sony 24mm f/1.4 GM.

Achieving just one of these feats is extremely rare, but achieving both at once is quite unprecedented. The “conventional wisdom” is absolutely that primes are always sharper than zooms, and that zooms are always noticeably softer at one end of the range or the other, or in the middle.

Of course, this isn’t an in-depth, extensive review. We’ll wait for Roger Cicala at LensRentals.com to put 10 copies of this lens on OLAF, and see how that goes. And, of course, more actual nightscape adventures with 40-60 megapixel cameras would be great, too.

[UPDATE: Read my full review of the Sigma 14-24mm f/2.8 DN Art HERE on SLR Lounge! Verdict: Even at 42-61 megapixels, it stands as the sharpest 14-24mm lens ever made.]

TLDR: if you’re an astro-landscape or nightscape etc. photographer of any kind, this is the lens to buy! In fact, it’s even a reason to switch to Sony completely, which is a third rarity for any lens. (Although, there are already adapters to use Sony FE mount lenses on Nikon Z mirrorless.)

Either way, it’s a good time to be a nightscape photographer! But, enough talk. Here’s the proof: (NOTE: these test images were made on a 24-megapixel Sony A7 III)

24mm Test (Sigma 14-24mm f/2.8 DG DN FE Art | Sigma 14mm f/1.8 Art | Click the image to view it full size!

24mm Test (Sigma 14-24mm f/2.8 DG DN FE Art | Sony 24mm f/1.4 GM | Click the image to view it full size!

That is unprecedented, indeed. The only question left might be, “how does it compare against the DSLR version, the Sigma 14-24mm f/2.8 DG HSM Art?” Well, we weren’t able to perform a direct comparison, however, based on all the tests I have seen, (and I’m really good at guessing coma performance from other people’s truly terrible sample images!) …I think it is indeed safe to say that although the DSLR Sigma 14-24mm is really good, this new Sigma 14-24mm is better.

Just about the only way in which that massive chunk of glass offers a bit more is its vignetting; the mirrorless 14-24mm, as a much smaller optic, does have a faint bit more extreme corner darkening. Of course if, as a nightscape photographer, low vignetting is EXTREMELY important to you, the Sigma 14mm f/1.8 will have the brightest f/2.8 corners of any lens ever to reach 14mm, simply because it’s stopped down more than a stop at that point.

So, if you don’t care about weight, and you do care a ton about vignetting, (and less about coma) …you could stick with either of the older Sigma DSLR lenses that hit 14mm. However, as a wilderness backpacker, this new mirrorless 14-24mm is the new champion.


These test images and the beautiful sample nightscape photo were provided by Sean Goebel. To see more of Sean’s work, visit sgphotos.com or follow him on Flickr.

2020 Astro-Landscapes Photo Calendar Available Now!

The 2020 Astro-Landscapes calendar is finally here!

It took me two years, but I’ve finally captured enough photos to create the next calendar I had dreamed of making: A panoramic landscape adventure photography calendar.

This is no ordinary landscape photo calendar, though. I had another ambitious goal for my next photo calendar: I’ve annotated the calendar days themselves with a few of my favorite types of landscape photography opportunities, such as a moonrise at sunset or moonset at sunrise, or nights when photographing the Milky Way could be optimal during a new or low crescent moon.

Now, each month you’ll not only be able to enjoy another photo from somewhere in the beautiful American West, but you’ll also be able to quickly glance at a few great shooting opportunities every week!

The 2020 calendar will be 7×12″, and is NOW SHIPPING! There will only be 200 printed, and only the first 100 will be signed and numbered.

Local pick-up is available, however, calendars cannot be reserved without entering into the system, so please order your calendar using the second link below, and you will be contacted for a chance to meet up around Orange County, CA.

Thank you in advance for your support, and here’s to 2020 being full of beautiful adventures!


Order Now! (limited supply remaining, discounted price) $14.99 + shipping






My Passion For Panoramic Photography

I’ve loved panoramic photography ever since I first picked up a camera about 20 years ago. I’ve always enjoyed creating “extreme” panoramic images, however, when I decided that I wanted my next photo calendar to be a panoramic calendar, I realized that most of my existing panoramic images simply would not work well in the desired format.

So, I made some compromises on my goals for the perfect aspect ratio, (7×12″) and I set off on many wilderness adventures to capture more images. Many of my adventures were centered around a singular photographic goal, and yet the images which found their way into this calendar turned out to be almost entirely the unexpected moments of serendipity and breathtaking light which simply cannot be predicted a year in advance.

For this reason, I decided to add not just helpful information about photo opportunities, but also a brief story behind each photo to help set the scene and give a brief glimpse into the moment itself. I am currently writing a book containing many more of these adventure stories, which showcase such authentic moments in the wilderness, and hopefully encourage other photographers to seek out the beautiful opportunities that nature has to offer.

My Passion For Astro-Landscape photography

I first began calling my imagery “astro-landscapes” when I became interested in nightscape photography, and for a period of time, it was the only subject I pursued. After a few years of nightscape photography “dedicated” adventures, however, I realized something- On all of the trips I took, many of the truly memorable moments, and indeed most of the best photographs, were not nightscapes, but images depicting whichever moments were simply the most breathtaking in terms of unique weather, seasonal phenomena, or serendipitous alignments of the sun or moon with earthly subjects.

During this process of discovery, not only did I realize that Astro-Landscapes was about so much more than just nightscape photography, but also, my desire to simply be outdoors as often as possible grew. Inevitably, also, my desire to sit at a computer and post-produce the images dwindled. I came to the following conclusion: I’d rather be outdoors capturing real moments of nature, instead of “fabricating” them later on a computer.

This has been my driving force ever since, and each of the images in this set of 13 represents very basic photographic techniques: Many are single exposures with nothing more than color-correction and cropping to a 7×12 aspect ratio, and others are very simple panoramic stitches, or basic noise reduction layers. In other words, these moments unfolded with the exact timing, scale, and juxtaposition that you see in each image.


Order Now! (limited supply remaining, discounted price) $14.99 + shipping






Moonset at Sunrise in the Alabama Hills | Eastern Sierra, California, August 2018 Nikon D750, 70-200mm f/2.8, 200mm, f/8, ISO 100, 1/100 sec

I wish I could say this moment was perfectly planned months in advance, but the truth is, it snuck up on me completely un-planned. I was car-camping in the Alabama Hills during a solo road trip, and had only planned to do a little nightscape photography before getting back on the road.

As per the usual for most of my road trips, I was too exhausted from driving and hiking all day, so a 40-minute nap at 1 AM turned into a 4-hour nap. When I awoke, the moon was still well above the distant, jagged peaks of the eastern Sierra.

At first, I didn’t think anything of it; I was more concerned about getting on the road as soon as possible. Thankfully, the fading stars and pink-blue light of astronomical dawn lured me into telling myself, “just a couple quick shots, then I’ll get going.” Another 30 minutes later, as the last few stars were disappearing and the moon was getting awfully close to the horizon, it finally hit me- I was about to witness one of the holy grails of mountain landscape photography: a perfect moonset at sunrise.

Except, it wouldn’t be perfect; I was in the wrong spot. After snapping two “safety shots” at 200mm of the first kiss of purple alpenglow on Mt Whitney, I threw my gear in my car and raced “backwards” away from the scene to a slightly more distant vantage point. That few hundred yards was exactly what was needed to allow me to start a timelapse in which the moon nestled perfectly into the visual notch to the right of Mt Whitney, as the sun’s first rays washed over the majestic Eastern Sierra.

This image was processed in Capture One Pro 11. I found that Capture One did the best job of representing such bright, warm colors and tonality without appearing artificially saturated, nor excessively “preserved” as some bright highlight tones can appear in other raw conversion software.

Thank you again for your support!


Order Now! (limited supply remaining, discounted price) $14.99 + shipping






Crowds, Chaos, & The Death Of Solitude

I did not grow up with “Nature-Deficit Disorder”, as Richard Louv puts it. Thankfully, I grew up exploring the outdoors, climbing trees and rocks, going camping, and eventually going on more arduous adventures to extremely remote places. Continue reading

February 2015 Road Trip | Grand Canyon B&Ws

The sunset on February 27th was nice, but not as epic as it could have been considering how much dramatic weather was swirling around. And just after sunset, it started snowing moderately fiercely. The Forester (stock road tires) actually slid around a bit for the very first time! (Well, on paved roads. Getting to White Pocket a year ago was a whole different ballgame!)

The next morning, waking before sunrise, it was completely dark, grey, and still lightly snowing outside.

It was also nice and warm in bed.

Get up and go, the little voice said. (Also, my wife Joy said…) Bad weather is awesome. YUP, it sure is! Continue reading

Full Review Of The Nikon 20mm f/1.8 G – The Astro-Landscape Photographer’s Dream Lens! …Almost

Click HERE to read the full written review on SLR Lounge!!!!

In short, I’m a bit torn- in many ways, this is my dream lens.  It’s light, small, and doesn’t cost $2,000. (I’m looking at you, 14-24!!!!) Oh, and those sunstars!!!! Continue reading

Don’t miss Marc Muench on Creative Live Tomorrow!!!

After watching Frans Lanting and Tom Mangelsen on Creative Live in late 2014, I didn’t think it could get any better.  Frans Lanting’s closing presentation was mind-blowing and truly inspiring, and Tom Mangelsen’s personal dedication to conservation had me in tears once or  twice. Continue reading