Re: Best cameras for my needs? #capturing

Josep Barbera

Hi Nima

These are my considerations choosing a twinned 3D rig.

A) For years all we have been dreaming of the appearance in the market of a 3D camera with a technological level similar to the last 2D cams that were appearing in the shops... but since spring 2018, all we know (after testing many Sony models in an electronic megashop) that ALL the new Sony cameras, can be used in stereo photography, because they have a perfect synchronization through their Multi Terminal port, using two cables (female + male, plug & play, the best and natural method).

The sync ONLY appears following the 2 steps ritual:

I.-Press the SHUTTER button halfway down to focus.
When the images are in focus, a beep sounds and the 2 focus indicators (z) lights.
II.-Press the SHUTTER button fully down to shoot the synchronized images.

The drawback is that female DSRLKIT cable, now (two years later), are very scarce and difficult to find because they are much appreciated in stereo photography

But it is easy to obtain a cable with 2 MultiTerminal plugs (male-male) by soldering, or simply connecting the three internal cables.

In addition, now it is possible to get a cable with 2 right-angled plugs, thanks to the effort of an efficient companion in this mailing list, Laurent DOLDI:

A right-angled plug (but ONLY IN THE MALE CABLE, and not the female) is available from China via Ebay (very cheap, only 3 euros):

B) A few months late, in October 12, 2018, luckely, all we know that Sony developed the perfect sync through the MultiTerminal port of its current cams using the Sony VMC-MM2 cable, not to make perfectly synchronized 3D photos, but to increase the productivity of professional event photographers using a RX0 cam paired with the different Sony Alpha models.
Both (cable and port) was not designed with the 3D world in mind, but for event photographers:

C) The Sony Multi Port sync is perfect and seems miraculous. In 2018 Dec 18, using the new and smart method developed by Barry Aldous (exposed in the Stereoscopy magazine number 115, Issue 3.2018, with good illustrations by David Kuntz), we obtained a wonderfull synchronization: less than half a millisecond:

These three findings (3 dozen of usefull Sony cams, the VMC-MM2 cable, and the measurement of the prefect sync using Aldous Method) imply that today the best alternative to pair two cameras to make stereo photography is using the current Sony models (in APS-C, FullFrame and RX series, via Plug & Play) because all the latest 2D cameras marketed by Sony (more than three dozen) can be perfectly synchronized to obtain stereo photography rigs.

But only the last commercialized Sony Alpha cams are fully compatible (for still images and also for video) because we only in them we can assign in the menu, the movie recording-button to the shutter button:

Certainly a problem may be the price, but the gradient is huge: from 250 euros (Sony A5100) to 4500 euros (Sony A9 II), so there are adequate cameras for each budget. In addition it is possible to find the models, already discontinued, NEX 3N and A5100 (quality equivalent to the Samsung NX1000), for less than 100 euros.

Another small problem may be “the theoretically excessive stereo base”, but that “problem” is easily solvable:

A)_My wife prefers to use a very light equipment: a Sony Alpha botton to botton rig, with a fixed stereo base (68mm), close to the human interpupillary distance:

The photos obtained in portrait (vertical) format (no problem using the HR1 phone as a portrait screen :) can be cropped using the wonderful StereoPhotoMaker program, in order to obtain a landscape (horizontal) format, because the original resolution, 4000x6000, can easily be passed to 1920x1080.

With the Sony A7 R series (I,II,III) that's more easier, since they have a sensor with even more resolution.

B)_ I prefer to use a side by side equipment (APS-C 6x00 series, 6 models in the market) with slide variable stereo base (20 cm to the right and 26 to the left: 60 cm is the maximum) because it is easy to quickly change the settings using external buttons.

These stereo base implies that the nearest object should not be closer to 2.5 meters accordin the shooting golden rule of Gerhard Herbig:

""Distance to closest subject must be greater than the result of multiplying focal length by the stereo base (all values in mm)""

I also believe that it is a magical myth that the optimal interaxial distance for twinned cameras, in s3D photo, must be between 60 and 70 mm. That is only based on what is normal telorism because hypotelorism and hypertelorism generally involve a pathology or a congenital malformation.

But those people obsessed in that range, 60-70 mm, accept without hesitation all focal distances other than 50 mm (normal in our eyes)...

A question:

Is it more "normal" to use a 200mm or even a 3000 mm zoom with continuously variable mode (as Nikon COOLPIX P1000) than a half-meter camera stereo base, or 5 meters or even more, also with continuously variable and slider mode?

In fact the perception as miniatures of the subjects in s3D hyper-stereo photos is just a psychological phenomenon (not physiological) caused because our brain does not accept that it is possible to perceive depth over great distances. Later, after training, the brain accepts that phenomenon of augmented reality (far 3D depth ) and it no longer sees miniatures where there are none.

Obviously, in everyday practice ... only in an elevator, or in a car, or in a confessional, or in a toilet it is not possible to use 10-14 cm stereobase rigs, because in all other real-life situations if the main subject is too close, it is very easy to go back a few steps before shooting.

There are 4 different ways to avoid inconveniences dues to “a theoretical excess of stereo base”:

a) By using a bottom to bottom s3D rig for decrease the stereo base until 70 mm or less
b) Walking only one step back, before shooting for increase the distance to nearest object.
c) Varying the focal length, following the 3D photo Gerhard Herbig golden rule
d) Reduce the size the image pair is shown (half the size = half the disparity, Antonio dixit :)
The excess of stereo base of my Sony A6300 rig can been compensated using these 4 mechanisms described before, and it is not possible to know, (afterwards, "a posteriori") what procedure has been used to obtain each normo stereo pic:

C) The Sony RX100 series (travel cams) can be very interesing solution due its zoom, but its quality (one inch sensor) and possibilities (fixed less) are inferior:

D) The Sony RX0 series (I, II) is also on the market, but these cameras are focused for sports (including running :) and as secondary camera for events. The setting possibilities are very limited: fixed focal length, fixed aperture , fixed lens etc. Its lens is very inferior to other current Sony Alpha cams but its portability is a lot greater.

It is possible also they multi inter-connection via WIFI using a smartphone:

E) In addition to the the Sony Cams, other solution (also very loved by my wife for its portability) is to use a beam spliter (image spliter :). At Cardiff's convention she carry a Kula Deeper and at Suthampton a Carl Zeiss Jena f=50mm beam splitter).

Caerphilly Castle and the Stereoscopic Society Convention:

You can hear some comments about the beam splitter can produce keystone distortion, but that problem was only true in the no digital era and now that is an urban myth because StereoPhotoMaker can automatically correct that distortion when it is making the alignments. No one can visually distinguish, afterwards, photos taken with a beam splitter (and corrected with SPM) from those made with twinned cameras.

In fact, now there is a huge variety of Sony Alpha models with perfect synchronization on the market and every 3d photographer can choose his most suitable 3D Sony rig:

-A7 (I, II, III), A7R (I, II, III,IV), A7S (I, II) A9 (I, II) = 11 models mirrorless and Full Frame
-NEX-3N, A5000, A5100, A6000, A6100, A6300, A6400, A6500, A6600 = 9 models of mirrorlesss APS-C
-A3000, A3500
-A58, A68, A77II, A99II
-RX0 (I, II)
-RX10 II , III, IV
-RX100 II , III, IV, V, VI, VII
-HX300, HX350, HX400
-HX50, HX60, HX80, HX50, HX90, WX500 (using external trigger, so not Plug&Play)

Several characteristics determines the price and therefore the cost: Sensor size/quality, range of lenses/focal lengths, apertures, flash, image stabilization, viewfinder, tilting screen, RAW support, color depth and dynamic range, pixel sensor size in microns, number of focus points, face detection focus, eyes detection focus, continuous shoting at hight resolution, maximum light sensitivity and ISO whitout noise, faster max shutter, AE bracketing range, resolution of the screen and viewfinder, environmental sealing, batery life, WIFI, GPS, Bluetooth, NFC connectivity etc

A very interesting feature of modern Sony cameras, including the RX100 series, is that you can install abundant, excellent, and cheap applications to increase creativity (but not in the latest professional models so as not to offend possibly susceptible people:-)

Here, in each application are specified the compatible cameras:

Some Sony cams apps offer amazing results:

For many people that is the game-changer, and certainly that is a new era in photo 3D.

That is a new world... :-)

Best regards

Josep Barbera

El 2020-02-27 22:06, Nima escribió:
Hey everyone!
I'm finally in the market to build my own dual-camera rig. I'd love
to get some recommendations from the experts on what I should get!
Here are my requirements for such a camera:
* Global Shutter
* Minimum camera baseline _must_ go as low as 63.5mm
* Must have the ability to record video(preferably 60fps, but 30fps
is fine. 24fps is not)
* Must have a simple single button synced shutter. I'm okay with
paying for a modification or hacking one, but a manufacturer method
for synced shutter is preferable
* Optional: Both cameras should be able to be charged using a cable
without removing it from the rig. This isn't a hard requirement,
however, I'm willing to remove and put them back every time if it
leads to superior quality
That's it! Besides that, I obviously want the camera that fits the
above needs and has the highest available quality. Cost is not a
factor. Do any of you wonderful people have a suggestion for me?

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