Macro stereo photography: a beginner’s perspective

written for the stereosite by Sangeeta Dhawan, USA

Macro pho­tog­ra­phy pro­vides a win­dow into what the naked eyes can­not see, offer­ing incred­i­ble detail and insight into the things around us. When com­bined with stereo pho­tog­ra­phy, the pow­er­ful and immer­sive art of ren­der­ing images in three dimen­sions, the detail of macro pho­tographs becomes even more vivid and ampli­fied. In this arti­cle, I will describe a sim­pli­fied approach to macro stere­os, which should serve as a start­ing point for fur­ther exper­i­men­ta­tion with this medium.

My choice of sub­jects varies from bugs, flow­ers, water drops and reflec­tions, things with tex­tures (such as leaves, tree barks, moss), light – any­thing that is like­ly to reveal extra detail in close up. Even sim­ply look­ing at bokeh in stereo can be a mag­i­cal win­dow to A hid­den world. I am more of a “pho­tog­ra­ph­er on the go”, and most­ly rely upon a very sim­ple and portable (and rel­a­tive­ly inex­pen­sive) set­up that con­sists of my iPhone XS and a clip-on macro adapter. There are plen­ty of good choic­es avail­able for macro adapters such as Ollo­Clip, Moment, Apex­el, and Cri­acr. I cur­rent­ly use the Ollo­Clip and Cri­acr macro adapters inter­change­ably. This handy set­up allows me to cap­ture any­thing inter­est­ing that I may find on the go. The porta­bil­i­ty also makes it rel­a­tive­ly easy for me to exper­i­ment with dif­fer­ent angles and light, and get very close to the sub­ject with­out dis­turb­ing it. This is espe­cial­ly help­ful when pho­tograph­ing insects! The down­side is the some­what lim­it­ed res­o­lu­tion, com­pared to a good cam­era and a ded­i­cat­ed macro lens. While this may not be a con­cern for plat­forms such as Insta­gram that are typ­i­cal­ly designed for view­ing on a phone screen, use of phone images may present a chal­lenge for sce­nar­ios where high­er res­o­lu­tion is essen­tial (such as pro­jec­tion on a big screen). That said, recent phone mod­els offer very good res­o­lu­tion and can gen­er­ate qual­i­ty images. Anoth­er chal­lenge posed by the use of sequen­tial images to assem­ble a stere­opair is that it can intro­duce dis­crep­an­cies between the two images, which can lead to visu­al dism­fort when look­ing at the stereo-view (reti­nal rivalries). 

I do most of my pho­tog­ra­phy dur­ing my morn­ing walks, evening runs, and lunch breaks. Typ­i­cal­ly, I pay spe­cial atten­tion to small patch­es of grass, shrubs, flow­ers, tree trunks (those tex­tures!!). I keep my eyes open for sub­jects such as small flow­ers, water drops, and any­thing like­ly to have a tex­ture. If I notice any bugs, I typ­i­cal­ly tend to fol­low them for a lit­tle bit, observe them, and wait for them to set­tle. Drag­on­flies, blue­bot­tles, and hov­er­flies are very macro friend­ly, in that they tend to set­tle down rel­a­tive­ly eas­i­ly and stay put at one spot for some time. Drag­on­flies espe­cial­ly lend them­selves beau­ti­ful­ly to stereo pho­tog­ra­phy, as they are crea­tures of habit, and tend to keep return­ing to the same spot. Once I find a sub­ject of inter­est, I first like to a regular/non macro pilot stereo shot (or two) just to get a sense of the sub­ject, the back­ground, and the light­ing. This is very help­ful for sce­nar­ios when the light may not be opti­mal, or it may be too windy. It allows me to decide if it is worth tak­ing pho­tos, or sim­ply enjoy the scene. For sub­jects like bugs and rain­drops where get­ting close to the sub­ject can poten­tial­ly dis­turb the scene (both the sub­ject and the light­ing), this exer­cise also ensures that I get “some­thing”. Once I have done this, I like to zoom in and play with one or more of the fol­low­ing parameters. 

  • Base­line: I like to do mul­ti­ple takes by vary­ing the base­line. An inap­pro­pri­ate base­line can ruin an oth­er­wise beau­ti­ful con­cept, cre­at­ing a stere­opair that either doesn’t have much depth (Fig­ure 1 A, B) or is uncom­fort­able to view (Fig­ure 2 C, D). In macro stere­os, even a lit­tle vari­a­tion in back­ground or bokeh can often cause a lot of visu­al dis­tress (Fig­ure 2 A‑C). Most impor­tant­ly, the focus is also very sen­si­tive to move­ment in macros, espe­cial­ly while try­ing to acquire sequen­tial shots. Lock­ing the focus and expo­sure set­tings on the phone cam­era can some­times be help­ful in such cas­es. Exper­i­ment­ing with the base­line helps me get sharp stere­opairs with opti­mal depth, with­out too much vari­a­tion in the back­ground (thus avoid­ing rival­ries). While the stan­dard 1:30 rule for deter­min­ing opti­mal base­line is just as applic­a­ble to sequen­tial macro stere­os, tak­ing the time to cal­cu­late the right base­line may not be prac­ti­cal for many of the typ­i­cal macro stereo sub­jects such as bugs. I find it sim­pler to just use a guessti­mate to cap­ture what­ev­er I can with­in the 2–3 sec­onds before the bug takes off. That said, one can devel­op a good sense of appro­pri­ate base­line by prac­tic­ing with inan­i­mate macro sub­jects, and employ that in sit­u­a­tions like the above. 
Fig­ure 1. Chang­ing the base­line to get opti­mal depth. (A, B) Pan­el A has a small­er base­line com­pared to pan­el B, and less depth. Pan­el B is much more suit­able for view­ing on plat­forms such as Instagram/phone screen, while pan­el A appear flat there. (C, D) Pan­el C has a larg­er than opti­mal base­line mak­ing the stere­opair very uncom­fort­able to view, while pan­el D has a more appro­pri­ate base­line, and is much more com­fort­able to view.
Fig­ure 2. Base­line and back­ground. (A) Pan­el A larg­er base­line and a lot of move­ment in the back­ground bokeh, mak­ing this pair very uncom­fort­able to view. (B, C) A much more appro­pri­ate base­line, and an improved view­ing expe­ri­ence, with some minor rival­ries in the bokeh. 

  • Angle and com­po­si­tion: While this aspect is rel­e­vant to all stereo pho­tog­ra­phy, choos­ing appro­pri­ate angle is espe­cial­ly crit­i­cal while cap­tur­ing a macro stereo. In a macro set­ting, even a slight change in the angle can poten­tial­ly intro­duce (or elim­i­nate) rival­ries, and change the light quite sig­nif­i­cant­ly. One can lever­age this to play with light­ing (Fig­ure 3A, B). Look­ing at the pilot image often serves as a guide for me to try dif­fer­ent angles and com­po­si­tion. For exam­ple, one could focus on the reflec­tions in a droplet, or zoom in on a lit­tle bug nes­tled in a flower, and attempt to cap­ture unique details of the scene. By play­ing with dif­fer­ent base­lines and angles, I can get a good vari­ety of dis­tinct look­ing stere­opairs from the same subject.
Fig­ure 3. Angles and com­po­si­tion. (A, B) Vary­ing the angle slight­ly to cap­ture the sun flare in pan­el B. To achieve that, I had to use a small­er base­line in B, such that the flare would be of sim­i­lar inten­si­ty in the two sequen­tial shots. Con­se­quent­ly, the droplet in pan­el B is a bit less round than in pan­el A.
  • Assem­bling the stere­opair: I use “i3DSteroid to assem­ble and align my stere­opairs. I live by the “crop till you drop” (or some wild approx­i­ma­tion of that) mantra. Exper­i­ment­ing with crop­ping has often helped me com­pose a bet­ter stere­opair, res­cue many a dull/failed stereo exper­i­ments, and cre­ate some­thing fun. Appro­pri­ate crop­ping can help with win­dow­ing, and also be use­ful in elim­i­nat­ing rival­ries.  I often also use crop­ping to zoom in on spe­cif­ic details and cre­ate mul­ti­ple stere­opairs from the same two sequen­tial shots (Fig­ure 4 A, B, C). i3DSteroid has a built in crop­ping tool that makes this very easy. 
Fig­ure 4. Crop­ping and cre­at­ing vari­ety. (A, B, C) Pan­el A is the orig­i­nal stere­opair and pan­el B and C are two dif­fer­ent areas zoomed and cropped to cre­ate dif­fer­ent stereopairs.

What else? One exer­cise that I find extreme­ly help­ful is to step away from my images for a bit and review them lat­er. This can pro­vide a fresh per­spec­tive on what worked and what did not. While this is applic­a­ble to all pho­tog­ra­phy, it is espe­cial­ly help­ful for macros, as review­ing an image lat­er can help iden­ti­fy a bet­ter area to zoom on or a bet­ter way of crop­ping etc. Over­all, macro stereo pho­tog­ra­phy is a medi­um that offers the view­er a greater appre­ci­a­tion of the hid­den beau­ty that exists in nature, and inspires the pho­tog­ra­ph­er to pay atten­tion to even the small­est details. I hope you enjoy explor­ing this medi­um and have fun find­ing new detail in the things around you!

Sangeeta Dhawan (Los Angeles, California, USA)

I am a bio-sci­en­tist and a pho­tog­ra­phy enthu­si­ast. I took up pho­tog­ra­phy about ten years ago, and start­ed my jour­ney into the world of stereo-pho­tog­ra­phy last year. Stere­os have a way of trans­form­ing some­thing ordi­nary into extra­or­di­nary and mag­i­cal. As some­one who looks at things at the cel­lu­lar lev­el on a dai­ly basis, I was par­tic­u­lar­ly drawn to macro stereo pho­tog­ra­phy. That’s my kind of mag­ic. I look for­ward to con­tin­ue shar­ing my stereo adven­tures with you.

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