3D Butterflies

[Padfield]

I did an experiment today, to see if I could produce 3D pictures of butterflies by taking two pictures slightly apart. My most successful attempt was the common blue below. To view it in 3D, use the 'cross-eyed' method. That is, with your eyeline horizontal (not leaning your head), go slowly cros-eyed until the common blue on the right merges with that on the left. Hold steady and wait for everything to come into focus. When it does, magic!, you have a 3D common blue in a 3D meadow. It seems not everyone can do this, so don't give yourself a headache trying!



This Duke works but is not quite so pleasing - I think I took the two pictures slightly too far apart.



Does anyone have any other experience of taking 3D pictures of butterflies, by this method or something more sophisticated?

Guy

[Denise]

I can do it Magic!!! I've never been any good at those 3D pictures before.
Nice one Guy.

Denise

[Padfield]

Glad they work for you, Denise!

Just for fun, here's a couple more: a speckled wood and a meadow frit (Mellicta parthenoides), taken on the same walk this afternoon.





Guy

[Jack Harrison]

I am quite familiar with the "cross-eyed" trick and people should rest assured that it doesn't harm the eyes!

All the pictures were easy for me to see in 3D and the effect was impressive.

Now some info of the photo techniques you used please. How did you use the camera? What horizontal distance between shots, etc, etc. How much "post-precessing" to get the images covering the same field of view?

I am certainly going to give the technique a try but might make the first experiments on flowers in calm windless weather.

Jack

[Padfield]

I took these on a whim while out walking the dog and was quite surprised they worked as well as they did (which was impossible to tell in the field, of course). But it means I haven't really sat down and calculated what parameters would give the most effective results. Also, I did slightly different things with each picture, just feeling my way around really.

Essentially, I chose a butterfly that looked as if it might stay motionless for at least a few seconds, then photographed it from close up, noting its position with respect to the central focusing rectangle (I have my Canon Compact on central focusing for butterflies). I then moved the camera a couple of centimetres or less to the left (difficult to say how much, because I was looking at the LCD the whole time) and slightly angled it back in towards the butterfly, attempting to place the butterfly in the same position relative to the focusing rectangle - but I didn't always succeed in that, for various reasons. My camera has quite a long recovery time between pictures, so the butterfly had to be rather patient.

I reduced each picture to 400 pixels across (mainly so they would fit across the UK Butts page comfortably when doubled) and joined them together in Microsoft Paint so the second picture taken (from the left vantage point) was on the right. For viewing by other stereoscopic techniques they would be the other way round, of course. It seems I did this merging badly too, because the division isn't down the centre of the final picture!

I'm quite sure you can produce better results than these, Jack!

Do they still sell 'stereoscopes' - those things you put paired slides in and look through at the Eiffel Tower or nude ladies? It would be more comfortable to view the images through those.

Guy

[Jack Harrison]

I have used a couple of photos that I took on Saturday morning with no thoughts at all about 3D viewing. They were part of a series of "clicks" in the hope of getting at least some that were in focus. After a little tweaking and cropping, here is a fortunate result. The legs and wing veins stand out remarkably well. But do remember, these are just fluky shots and with 3D in mind, much better outcome would have been possible.

Thanks Guy for the idea. It works very well with flowers and next sunny day, I'll experiment with landscape shots.

Jack

[Padfield]

The texture of the fur around the head is wonderful too, Jack! And having a less cluttered background makes it easier on the eye.

Guy

[eccles]

The viewing technique is easiest if you sit back away from the screen, say three feet or so, then hold a finger in front of your eyes, about a foot away. Move your finger back and forth slowly while focussing on it, and you should eventually align the two screen images into one to get the 3D effect.

[Trev Sawyer]

I think I read somewhere that the 'average, distance between people's eyes is 64mm , so moving the camera around that distance between shots should work well for 3D photos. I've seen a 3D camera with 2 lenses spaced apart for instant shots set at around that value too. I've also seen a mirror used to view the 3D photo (one image is flipped vertically and the mirror is placed between the viewer's nose and the picture (at right angles to the face).
Never tried either method, but I will certainly give it a go now, having seen the effect shown on this thread.

Trev

[Padfield]

I had a look on several sites about stereo photography after my initial experiment and most of them recommend a lateral shift of 1/30 of the distance to the nearest object. With very close objects, a shift equal to eye separation, combined with the necessary inward rotation towards the object, would result in two totally different backgrounds that would not be able to be combined (when you look into the distance from a close object you unrotate your eyes so they view nearly parallel again, but you can't change the angle the two images of a stereogram are taken from).

The Wikipedia article on Stereoscopy states (copyright Wikipedia):

Imaging methods
If anything is in motion within the field of view, it is necessary to take both images at once, either through use of a specialized two-lens camera, or by using two identical cameras, operated as close as possible to the same moment.

A single digital camera can also be used if the subject remains perfectly still (such as an object in a museum display). Two exposures are required. The camera can be moved on a sliding bar for offset, or with practice, the photographer can simply shift the camera while holding it straight and level. In practice the hand-held method works very well. This method of taking stereo photos is sometimes referred to as the "Cha-Cha" method.

A good rule of thumb is to shift sideways 1/30th of the distance to the closest subject for 'side by side' display, or just 1/60th if the image is to be also used for color anaglyph or anachrome image display. For example, if you are taking a photo of a person in front of a house, and the person is 30 feet away, then you should move the camera 1 foot between shots.

The stereo effect is not significantly diminished by slight pan or rotation between images. In fact slight rotation inwards (also called 'toe in') can be beneficial. Bear in mind that both images should show the same objects in the scene (just from different angles) - if a tree is on the edge of one image but out of view in the other image, then it will appear in a ghostly, semi-transparent way to the viewer, which is distracting and uncomfortable. Therefore, you can either crop the images so they completely overlap, or you can 'toe-in' the cameras so that the images completely overlap without having to discard any of the images. However, be a little cautious - too much 'toe-in' can cause eye strain for reasons best described here.

Other sites also recommend the 1/30 rule, though that is a very slight shift indeed if you are taking a real close-up.

Guy

[Jack Harrison]

I did know about this 3D technique but it had been way in the back of my mind until Guy reminded me. So many thanks.

The opportunities are unlimited. I await some decent skies and hope to be able to make 3D pictures of cloud structures. On windy days, the movement of the clouds themselves might suffice to produce a 3D effect if the two photos are taken at the appropriate interval (much experimenting needed here).

I have no trouble combining images but some people, eg my 15 year old daughter, simply can't do it. I had even tried the "finger trick" as that was how I first learnt to do it many years ago (thanks Eccles for reminding people).

Stereoscopic viewers to the best of my knowledge are only made for slide viewing. Now there's a challenge for you technical types - how to design one for viewing two images on a screen.

One of the problems already mentioned is that the brain perceives the image as being at the distance where the eyes converge so seems quite small. This is especially noticeable on a smallish computer screen. Maybe I must borrow my wife's identical laptop and put one image on each (have to wait till she's back to work later this week!)

Incidentally, two hard prints can be viewed quite easily and have the advantage that they can be quite large (but expensive).

Jack

[Padfield]

For clouds approximately 2km above your head, the 1/30 rule would suggest moving about 70m between shots.

On a still day I reckon I could easily do that on my bike before the clouds changed significantly (and anyway, where I live the clouds are quite frequently below me!!).

Thanks, in return, for that idea, Jack!!

Guy

[Padfield]

Two people taking simultaneous pictures an appropriate distance apart would be even better.

Guy

[Jack Harrison]

Try this one. Width of double-image is 100 pixels. Make sure you adjust setting to view whole double-image. It will probably be enough simply to click on the picture(s)

Jack

[Annie]

amazing photos, brilliant concept - but I still can't do it. I think my eyes might rather too close-set (that makes me sound attractive, doesn't it ) Perhaps this is the reason I don't get on too well with binoculars either.

I shall persevere, I'd love to see these piccies in 3D!

[Martin]

amazing photos, brilliant concept - but I still can't do it. I think my eyes might rather too close-set (that makes me sound attractive, doesn't it ) Perhaps this is the reason I don't get on too well with binoculars either.

I shall persevere, I'd love to see these piccies in 3D!

Annie,
I, too, am beset with close-set eyes but I can do it, keep trying and I'm sure you'll get there in the end

Martin.

PS - I have to say, Jack's Speckled Wood is by far the best for giving the 3D look...beautiful!

[Padfield]

Annie, I used some of these in a maths presentation recently and only one of the students could see it. I was standing at the back of the class with a huge, glowing, 3D military orchid looming in front of me and they claimed to see nothing. It was worth it, though, for the sight of them all looking like my dog when a fly lands on her nose...

Just for fun, I tried preparing 3D images completely from scratch, in Microsoft Paint. If you line up the red dots in the following picture and hold for a few seconds you should be able to identify the species. And no, it's no rival at all to Jack's fantastic speckled woods!



FYI, it took me over half an hour to make this - every dot was placed by hand, with a little help from 'copy and paste'. Don't expect any more!!

Guy

[Jack Harrison]

Annie said:

I think my eyes might rather too close-set (that makes me sound attractive, doesn't it )

Tony Blair's eyes are close together - gives him a shifty look.

Jack

[Trev Sawyer]

Hey Guy...
That's great... I don't have to go to Norfolk to see one anymore!!!

Trev

[Padfield]

Spot on, Trev (excuse the pun!). I think that proves you can see them!!

Guy