Is it really 3-D?

[thuggins]

I have been looking thru my vacation pics taken with an Olympus Chrome Six, a mix of Provia and VS. As always when viewing a good chrome on a light table, the images have an unmistakable depth. You can see this in 35mm, but in medium format it jumps out at you. With full frame 6x9 it looks like you can step into the image.

I got to wondering if this was due to the separation of the dye layers, i.e. physical depth separating each color, or an illusion created by the tonality of the film. When film is viewed under a microscope the sublety of light across an object is really remarkable, giving a real sense of the shape.

 

[NJH]

Funny you say that, its what my wife said when I first showed her Provia 6x6 slides projected onto a 5 foot square screen, the stepping into the image thing. In that case its more a sort of glow created by the projection which matches very well with the capture of summer holidays and happy times in bright sunny weather. I don't know about the science in the film itself but whether its anything to do with dye layer separation or not its pretty clear that a certain amount of light scattering is going on through the film which we interpret as a form of the light bringing the image to life. Given our relationship at the most basic human animal level to the sun, light and life there is probably a fairly powerful psychological effect going on there.

 

[trendland]

Yes sometimes it is indeed a phenomenon with slides. The most effect is given from red lights.For example from cars or trafic lights.It seams to be so that this lights are real 3 D but it isn't real of cause.
with regards

 

[Sirius Glass]

That is part of the wonderfulness of slides. After staring at computer screens for hours day after day, slides seem to jump out of the screen.

 

[Prof_Pixel]

I was a young college student working in a camera store in the late 1950s and was invited to attend a flashy presentation in Detroit when Kodak introduced the Star line of 127 cameras. The slide show made use of slides with red and blue elements. Since the eye can't focus on red and blue at the same time, these slides had a real 3-D effect. I was impressed and still remember it.

 

[zilch0md]

If I had a magic wand, everyone would wake up tomorrow morning with one of these on their beside table: A backlit stereo viewer equipped with achromatic lenses, that allows one to view a matched stereographic pair of medium format chromes at 4.3x magnification, shot with two Mamiya 7ii bodies, using a pair of 43mm or 65mm lenses.

Dead Link Removed

They're not for sale any longer, so I'm not advertising anything. The viewer lenses are no longer available and a minimum run of 500 pair would cost about $40,000 - and that's from a Chinese manufacturer, before coatings are applied. I fear I could never sell 500 viewers, even after spending about 10-hours a piece plus parts and finishing supplies to craft them. So, it's been game over for about ten years, now, except for family and friends to enjoy, as well as a handful of clients who bought my viewers while they could still be had.

These days, I'm strictly an amateur, but for the record, was never able to give up my day job, even when I was still making and selling viewers. It's hard enough selling prints. Try selling stereo medium format chromes to people who don't have viewers.

I shoot mostly landscapes with Provia or Velvia (the latter only in soft light) sometimes using the Mamiya 7's multi-exposure feature to pre-expose the film to affect in-camera contrast control - raising the shadows just a bit when necessary.

See: Dead Link Removed.

Everything has to be accomplished in-camera, because for me, the chrome that comes back from E-6 processing is my final product. I don't make dupes. I don't make prints. And I don't scan the chromes. There's no point in doing so, when my goal is to stick the original, first-generation pair of mounted chromes into the stereo viewer. As you might imagine, I do a lot of bracketing, despite using a Sekonic L-608 spot/incident meter, placing detail-retaining highlights at Zone VII. (Sorry, once a Zoner always a Zoner.) I typically bracket at +/- 1/3 stop, shooting a minimum of two frames of 120 (for a stereo pair) at five different shutter speeds (ten frames total), every time I setup the tripod - more if the light is changing or I'm doing pre-exposures in harsh light.

I've gone through as much as 54 rolls of 120 in two days of dusk-to-dawn shooting (at Arches NP). It can get expensive, but I didn't break down and buy my first digital camera until a year ago - a Sony a6000 with 10-18mm f/4 zoom. It's a fun toy. ;-)

I use two laser rangefinders to measure the distances from my cameras to the nearest and farthest subjects in the scene, then use a programmable HP 48G+ scientific calculator to obtain the ideal focus distance and minimum required f-Number to secure the equivalent of 8 lp/mm for a 25cm viewing distance - which is basically right at the limit of acuity for healthy human vision. If nothing in the scene resides at the calculated focus distance (except air), I use the laser rangefinder to search for a target that's at that distance, even if it's behind me, swing the cameras onto it, focus, then bring the cameras back to restore the original composition.

I sometimes stop down below the calculated minimum f-Number required to secure my required on-film CoC diameters, but as a rule, the resolution requirement I impose is so restrictive, I often find myself backing away from the nearest subject and recalculating - sometimes going up, instead of back if that's possible - (almost) never compromising my resolution goal of securing 8 lp/mm worth of real subject detail in the virtual image.

The HP48G+ is also used to calculate the proper separation (stereo base) between my camera lenses to achieve what is known as constant deviation stereography (where the amount of depth experienced in each scene is held at about 70% of the maximum acceptable deviation - that which is just short of forcing the eyes to diverge - an uncomfortable feat for most people. So, I am effectively doing reverse planimetry, by taking measurements of the subject space and adjusting the lens separation of my cameras to create the desired geometry in the stereo viewer. Hint: Less is more, when it comes to stereography. In my opinion, your audience should be able to immediately forget that they are looking at a 3D image (instead of being assaulted by it, as is so often the case in 3D motion pictures - don't get me started.) We don't walk around in this world saying, "Wow! I can see in 3D! This is so cool!" I actually strive to prevent that from happening in my stereography, as well. I'm going for the most natural, realistic experience possible.

I've also got a Minolta Booster II, which increases the sensitivity of my Sekonic L-608 by 8 stops. I've used it in Carlsbad Caverns, to shoot exposures as long as 44 minutes, with Ilford Delta 100, pulled to an ISO rating of 12 (not pushed, but pulled), to reduce the contrast of the extremely dim but very harsh lighting inside the caves. Pulling Delta 100 reduces the grain size, too! ;-) I used empirical data for Delta 100 reciprocity failure that was gathered and published by Howard Bond, the view camera guy who has done some really beautiful low-light work in the Everglades and elsewhere. I plotted all of his data in an Excel spreadsheet, then applied a polynomial trendline to extract a trustworthy equation for Delta 100 reciprocity failure. (Note: I've never corresponded with Howard Bond. He doesn't know me.)

I programmed the Excel trendline equation into my HP48G+ so that I could accurately translate meter readings taken with my Minolta Booster II-equipped Sekonic L-608 into much, much longer exposures that accurately compensate reciprocity failure for Delta 100. (Bracketing is next to impossible with 44-minute exposures, but I did so with a couple of scenes, going 1/2 over and 1/2 under.) I sent the exposed Delta 100 rolls to dr-5 for reversal processing, as I need positives in my stereo viewer, not negatives. You can see cave ceilings 100 feet or more overhead that are completely obscured in darkness when standing there in person, yet the brightly lit foreground elements, each typically lit at ground level by a single, hooded, 40W bulb, are not in the least bit overexposed. It almost looks as if I hid soft boxes throughout the entire cave. And it's all in 3D, at a resolution that pushes the limits of human acuity! ;-)

The use of medium format chromes, in combination with a relatively low enlargement factor of 4x means that not only is film grain pretty much invisible in open skies, even when Provia is pushed to ISO 200, it also means that my desired resolution of 8 lp/mm for a 25cm virtual image distance is not compromised by diffraction, even when stopping down as far as my lenses will go: f/22.6. The result is corner-to-corner plasticity - no evidence of defocus or diffraction, with the entire scene being devoid of any evidence of the usual indicators that say, "I'm looking at a photograph." It helps that I am masking out a 50x50cm crop from the original 6x7cm chromes - so you don't even have an opportunity to see into the corners of the original frames. When you look into the viewer, you really do feel as if you are THERE. In fact, many people who quickly buy into the reality of it, later comment that the total absence of movement is the only tip-off that it's not real. Digital VR cannot compete.

That was practically an autobiography, but I couldn't resist, given the title of this thread and the discussion of how nothing beats a backlit chrome. I hope I haven't worn anybody out.

 

[keenmaster486]

@zilch0md :

 

[zilch0md]

^. Best laugh I've had all day. Thanks!

 

[markbarendt]

I got to wondering if this was due to the separation of the dye layers, i.e. physical depth separating each color, or an illusion created by the tonality of the film.

No, no, and no. Same thing happens on the ground glass of a large format camera.

Your brain is doing the work.

One trigger for me is when a subject in a photo starts getting close to full/normal size. Another trigger is depth of field that makes sense to my brain.

 

[Craig75]

If I had a magic wand, everyone would wake up tomorrow morning with one of these on their beside table: A backlit stereo viewer equipped with achromatic lenses, that allows one to view a matched stereographic pair of medium format chromes at 4.3x magnification, shot with two Mamiya 7ii bodies, using a pair of 43mm or 65mm lenses.

Dead Link Removed

They're not for sale any longer, so I'm not advertising anything. The viewer lenses are no longer available and a minimum run of 500 pair would cost about $40,000 - and that's from a Chinese manufacturer, before coatings are applied. I fear I could never sell 500 viewers, even after spending about 10-hours a piece plus parts and finishing supplies to craft them. So, it's been game over for about ten years, now, except for family and friends to enjoy, as well as a handful of clients who bought my viewers while they could still be had.

View attachment 190131

These days, I'm strictly an amateur, but for the record, was never able to give up my day job, even when I was still making and selling viewers. It's hard enough selling prints. Try selling stereo medium format chromes to people who don't have viewers.

I shoot mostly landscapes with Provia or Velvia (the latter only in soft light) sometimes using the Mamiya 7's multi-exposure feature to pre-expose the film to affect in-camera contrast control - raising the shadows just a bit when necessary.

See: Dead Link Removed.

Everything has to be accomplished in-camera, because for me, the chrome that comes back from E-6 processing is my final product. I don't make dupes. I don't make prints. And I don't scan the chromes. There's no point in doing so, when my goal is to stick the original, first-generation pair of mounted chromes into the stereo viewer. As you might imagine, I do a lot of bracketing, despite using a Sekonic L-608 spot/incident meter, placing detail-retaining highlights at Zone VII. (Sorry, once a Zoner always a Zoner.) I typically bracket at +/- 1/3 stop, shooting a minimum of two frames of 120 (for a stereo pair) at five different shutter speeds (ten frames total), every time I setup the tripod - more if the light is changing or I'm doing pre-exposures in harsh light.

I've gone through as much as 54 rolls of 120 in two days of dusk-to-dawn shooting (at Arches NP). It can get expensive, but I didn't break down and buy my first digital camera until a year ago - a Sony a6000 with 10-18mm f/4 zoom. It's a fun toy. ;-)

I use two laser rangefinders to measure the distances from my cameras to the nearest and farthest subjects in the scene, then use a programmable HP 48G+ scientific calculator to obtain the ideal focus distance and minimum required f-Number to secure the equivalent of 8 lp/mm for a 25cm viewing distance - which is basically right at the limit of acuity for healthy human vision. If nothing in the scene resides at the calculated focus distance (except air), I use the laser rangefinder to search for a target that's at that distance, even if it's behind me, swing the cameras onto it, focus, then bring the cameras back to restore the original composition.

I sometimes stop down below the calculated minimum f-Number required to secure my required on-film CoC diameters, but as a rule, the resolution requirement I impose is so restrictive, I often find myself backing away from the nearest subject and recalculating - sometimes going up, instead of back if that's possible - (almost) never compromising my resolution goal of securing 8 lp/mm worth of real subject detail in the virtual image.

The HP48G+ is also used to calculate the proper separation (stereo base) between my camera lenses to achieve what is known as constant deviation stereography (where the amount of depth experienced in each scene is held at about 70% of the maximum acceptable deviation - that which is just short of forcing the eyes to diverge - an uncomfortable feat for most people. So, I am effectively doing reverse planimetry, by taking measurements of the subject space and adjusting the lens separation of my cameras to create the desired geometry in the stereo viewer. Hint: Less is more, when it comes to stereography. In my opinion, your audience should be able to immediately forget that they are looking at a 3D image (instead of being assaulted by it, as is so often the case in 3D motion pictures - don't get me started.) We don't walk around in this world saying, "Wow! I can see in 3D! This is so cool!" I actually strive to prevent that from happening in my stereography, as well. I'm going for the most natural, realistic experience possible.

I've also got a Minolta Booster II, which increases the sensitivity of my Sekonic L-608 by 8 stops. I've used it in Carlsbad Caverns, to shoot exposures as long as 44 minutes, with Ilford Delta 100, pulled to an ISO rating of 12 (not pushed, but pulled), to reduce the contrast of the extremely dim but very harsh lighting inside the caves. Pulling Delta 100 reduces the grain size, too! ;-) I used empirical data for Delta 100 reciprocity failure that was gathered and published by Howard Bond, the view camera guy who has done some really beautiful low-light work in the Everglades and elsewhere. I plotted all of his data in an Excel spreadsheet, then applied a polynomial trendline to extract a trustworthy equation for Delta 100 reciprocity failure. (Note: I've never corresponded with Howard Bond. He doesn't know me.)

I programmed the Excel trendline equation into my HP48G+ so that I could accurately translate meter readings taken with my Minolta Booster II-equipped Sekonic L-608 into much, much longer exposures that accurately compensate reciprocity failure for Delta 100. (Bracketing is next to impossible with 44-minute exposures, but I did so with a couple of scenes, going 1/2 over and 1/2 under.) I sent the exposed Delta 100 rolls to dr-5 for reversal processing, as I need positives in my stereo viewer, not negatives. You can see cave ceilings 100 feet or more overhead that are completely obscured in darkness when standing there in person, yet the brightly lit foreground elements, each typically lit at ground level by a single, hooded, 40W bulb, are not in the least bit overexposed. It almost looks as if I hid soft boxes throughout the entire cave. And it's all in 3D, at a resolution that pushes the limits of human acuity! ;-)

The use of medium format chromes, in combination with a relatively low enlargement factor of 4x means that not only is film grain pretty much invisible in open skies, even when Provia is pushed to ISO 200, it also means that my desired resolution of 8 lp/mm for a 25cm virtual image distance is not compromised by diffraction, even when stopping down as far as my lenses will go: f/22.6. The result is corner-to-corner plasticity - no evidence of defocus or diffraction, with the entire scene being devoid of any evidence of the usual indicators that say, "I'm looking at a photograph." It helps that I am masking out a 50x50cm crop from the original 6x7cm chromes - so you don't even have an opportunity to see into the corners of the original frames. When you look into the viewer, you really do feel as if you are THERE. In fact, many people who quickly buy into the reality of it, later comment that the total absence of movement is the only tip-off that it's not real. Digital VR cannot compete.

That was practically an autobiography, but I couldn't resist, given the title of this thread and the discussion of how nothing beats a backlit chrome. I hope I haven't worn anybody out.

Impressive! I hope all of that has been published somewhere

 

[thuggins]

No, no, and no. Same thing happens on the ground glass of a large format camera.

Your brain is doing the work.

One trigger for me is when a subject in a photo starts getting close to full/normal size. Another trigger is depth of field that makes sense to my brain.

I have never seen a large format ground glass, but the ground glass projections I have seem always look very soft, due to the texture of the glass. One thing I have noticed is that 3-D look is much stronger for close objects (just like true stereo images).

I'm also not sure of the "full size" impact. I have TV's and monitors that display life size images, but these look nothing like a slide.

 

[markbarendt]

My first opportunity under the dark cloth of an 8x10 camera was focused so that the subjects face nearly filled the viewable area. Not only did my brain see the 2D image as 3D, it flipped the image upright because I also had no easily visible reference; we were indoors and pretty dark so it was tough to see the floor and tripod.

 

[Newt_on_Swings]

^. Best laugh I've had all day. Thanks!

I had the same expression reading it. Sigh, I thought my stereo realist 2.8 was pretty sharp and neat. My heart is woe that I will never see such a stereo pair in a viewer that you described.