The size matters, doesn't it ?

[Pekka Uotila]

Hi Bill,
I left in a such a hurry early in the morning that during the day I was very sure that my vision was put so poorly into words that nobody could understand it.
Words, specially in english, are so difficult when getting into new field like this.
I am happy that atleast you got the idea somehow.
I have never played with these view cameras in reality.
During the day I have been thinking the meaning of the nodal point in this case ( It is in the middle of the groundglass, right?) . When lense is moving (tilting and panning) the "center" of it should remain it's distance to nodal point ... The camera must stay in the same position to a groundglass ( I believe) but why it should be "free" to change it's angle to a nodal point ?
I see it, I feel it has to do it, but just now I do not get it's effect, why?

The GG should be in the center of the fluidheads tilt&pan axl, then all the effects could be hidden...
Yeah, this is sure: All the camerabody and lense movements should be locked to the nodal point, unless something else is really wanted.

I give it up !

I must get one view camera to understand this matter better, maybe next year.
And I still feel that there is also some other essentials (not only technically) missing before it could be used.
Finally, I believe that there is less than five companies in this whole world who could make it work as smoothly as it should, forexample with 100mm lense. Very likely the whole thing should be computer controlled too.
Anyway, size matters.
What is your guess of the price of a single unit for a customer ?

[Pekka Uotila]

More real facts about the nodal point is for example here:
http://www.ncc.sdccd.cc.ca.us/resour...lm2/lm2p3.html
If somebody knows better source, please let us know.

[Glen Hurd]

I'm not sure I understand your question on the nodal point, but the "point" is to have the camera free to pan and tilt without travelling up and down or travelling left and right.
Take a look at the most recent video from Wayne Kinney (I hope you don't mind, Wayne ;)
(http://csxinfo.net/kinney/testfootage3.mov) Around 31 seconds into the movie, when he tilts up past a green vase, it feels as if the camera is also lifting, because his tripod is mounted behind the ground glass. If it were mounted where his ground glass was, the "nodal point," the tilt would be without vertical (or horizontal) motion.

Another thing to think about, Pekka, is with a larger format lens, your field of view grows. Which means you need longer lenses to get the same FOV as with a smaller format.
So a 50 mm on 35mm film is now replaced with an 80 mm or longer, depending on how much image you shoot on the ground glass. Now you have a longer lens, your depth-of-field is even less.
So maybe f/2.8 would be OK.

The only down side I see is expense.

As to the Scheimpflug principle, you lens' nodal point is important because you must rotate the lens at its optical center to keep the image from moving while the focus plane shifts. But a view camera set up, as Bill suggests, would take care of that, as long as your lens is positioned properly.
If you knew all this, I didn't mean to insult. Only trying to help.
Glen

[Pekka Uotila]

Thank you Glen for giving your time and thoughts to this subject that actually is now atleast two subjects or then, no subject at all.
I know the nodal point effect by experience in normal use quite well and I use it sometimes for artistical reasons with purpose.
I am also a big fan of Wayne's videos. It was nice to see it again from the nodalpoint's point of view.
With the "view videocamera" matter I am just walking on too thin ice and propably I should have kept my mouth shut up until my thoughts would have been more clear. Bill's idea about using the scheinplug principles is just so interesting. I know that these swing and shift lenses exist with PL mount for the 35mm but can they move the filmplane? Maybe this possibility is not really needed ...
But actually, all this is out of my today's concrete interests.

The PERSPECTIVE issue is something that after making some practical tests today I realised, that it is better for me to concentrate on art of telling stories and wait, that The dof adapter that I like is forsale and then I just buy it.

Intuitively, I just thought that the beauty of the films that are shot with 65 mm cameras is based partially on the fact that they "had" to use longer focal lenghts and there is a different perspective, not just dof.

The results of my today's practicaltest that was based on what I saw from the viewfinder:
Let's forget the dof and sharpness totally for a minute.
If I have two objects with the same size in the same shot but the other one is further away. I do frame my picture so that the object closer is in filling the frame but I see the other one on the background aswell.
When I look at them through the 16mm camera with 12,5mm lense the object further away is just so much smaller.
When I frame the closer object equally with 150mm lense and look it through Mamiya 645 the object further away is much bigger.
The longer lense just gives more realistic perspective but I believe now that it has very little to do with framesize/format that has been used.
It is the FOV issue, because when I look through the Mamiya 645 with 45 mm lense the perspective seems to be very much the same as in 16mm camera with 12,5mm. In this case the FOV is about the same.
Right?
Ok, now I believe it is the FOV that matters.

The problem of the aperture 2.8 I've talked here is just economical. In all interior shots, I would need more lights, crew, and time to rise the light level high enough if the camera's sensitivity with "Giant 65" is somewhere around 50 ASA.

For me it has been very educating and fun to think these matters but
right now I feel, that it is really better for me to concentrate on reading instead of writing here at DVinfo.
On the other hand, there is no point to start a discussion if I already know everything.
Thanks

(Bill, thank you and greetings to your friend with whom you have discussed about it before. I will continue dreaming of the "view videocamera machine" in privacy. Maybe in the year 2010 at NAB we see that someone has made a version of it.)

[Bill Porter]

One of the purposes of shifting (up/down or side to side) and tilting the front plane of a view camera is to correct for distortion in perspective. This would be a neat effect to see in video. AFAIK it has never been done before.

Another purpose is to move the plane of focus. You could use a really shallow depth of field, and, depending on how you shifted the front plane, have lots of your subject in crisp focus, or only a little, for example, the eyes. This is food photography is done, where the nearest and furthest edges of the serving plate are very out of focus while the food is in sharp focus. Since most food is photographed from above with the camera pointing downard at an angle, a normal non-view-camera plane of focus would intersect the subject at an angle, and with a shallow DOF this would make part of the subject out of focus. By tiling the front plane to correct for this, we keep the same shot composition but move around the areas that are in and out of focus. Magic! And brilliant on Mr. Scheimpflug's part.

Another way to describe what Glen was talking about in the first part of his post was this: The further back the camcorder's tripod mounting hole is, the more of a jib effect you have, or to be more accurate, "see-saw" effect. Imagine if you bolted your camcorder to a see-saw (I have no idea what you call these where you come from, Pekka), two inches away from the pivot point. As you tilted the see-saw, you'd get the same camera motion that many fluid heads give. Now imagine bolting the camcorder to the far end of the see-saw. As you tilt it, the camera makes an ever larger sweep upward as it tilts.

To correct for this as much as physically possible, the camcorder mount would need to be directly under the taking lens (on an unmodified camcorder, underneath the lens, and with a 35mm type adapter, it would need to be under the add-on lens). But I think the amount of camera motion with normal tripods and normal mount locations on cameras are so small, and we are all so accustomed to it, that it would have a negligible effect.

[Pekka Uotila]

Hi Bill, Glen and others,
it seems that I still have something to say about this matter you´ve brought up.
First, few words about the reality where I live (because of the language question) .
I live in a country with plenty of forests, lakes and Nokia, five million people are... (here you can hear the music composed by Jean Sibelius) ... and now we skip the Intro.
In our everyday work cine/video we use normally our own language, finnish. We use a lot of slang that comes from english or germany but for example when we discuss about DOF we say "syväterävyys". Straight translation of this would be something like "deepsharpness".
On the other hand, "tilt&pan" and "zoom" are just normal expressions in our work. The equipment here (in all rentalhouses) are well maintained and they are used all around Europe, so even though our "cine/videoindustry" is relatively small we play with good tools.
English is coming more and more important (almost everyone knows at least the basics) since the true knowledge in this field is written in english and projects are getting more international. The tools that are available and we are using you can see here, it's all in english:
http://www.elokuvakonepaja.com/
If something more is needed, they have relations to other rentalhouse in Europe.
My place in this world in the last years has been making documentaries and fictions, so the foodplate as a subject is not my everyday stuff.

About the nodal point, I' ve been using two slidingplates to get the nodal point as far as possible forward from the tilt&pan point, so I can just say that everything you have described works in reality very nice.
The only solution to get totally rid of this tracking feeling here is to use Ronford's F-7 fluid head where you can adjust the pan&tilt center to same place where the nodal point exactly is. The place varies depending on the lense`s focal lenght.

My main issue today is the tilt and shift lense. Yesterday I went to see the ones we have here at that rentalhouse. (The quys at the rentalhouse were very kind again and built it to me in front of Arri435, so I could see it.)
Here is my review what I saw in general and through the viewfinder.
My subject that I was looking through the viewfinder was the test pattern.
The whole lense unit is built on 19 mm support rods and first thing I realised is that oh sh.. you have to focus the picture by moving the whole lense system on the rods, it has to be done by eye. It is almost impossible to do the focusing during the shot.
The lenses seem to have quite simple construct, since there is no focusing mechanism. The quality and the coatings are very good, I believe.
Propably the simplicity of the lense is a benefit, since they have to cover more than just the 35mm cineframe and I guess that the normal mediumformat lenses would not work as well for various reasons, just like you said earlier.
The lense itself can be moved up and down, and it does tilt&pan, everything is done manually from quite small knobs and it feels that it is almost impossible to do some of the movements during the shot in a professional way to today's standards. Simply, I think there is too much mechanism in a too small place.
All the lense movements caused also a change to the composition of my framing.
After getting several times totally lost with focus and what is really happening and why, I got some new thoughts and in general I felt: THIS IS VERY INTERESTING (and time taking) !
When I was thinking of it later I started to realise that the bigger format could be a benefit, just like you said Bill.
The best would be a varying format. That would be possible if we had a "huge" gg (it is unbeliavable what is happening here on this site and field and how openly people share their knowledge, I rise my hat/cap and have a silent moment of the respect.) and we could zoom in and out there with videocamera´s own lense, maybe even during the shot?
Also, maybe it would be easier to focus the picture by moving the GG+camera and to do the shift movements aswell to GG+camera?
I guess these are the benefits you have seen here.
Thanks

PS. I went there again today, my subject, that I was looking through the viewfinder was this time a cup on a plate, I got quite quickly results that were pleasing what comes to a DOF. But I needed to vary also the aperture freely without thinking the right exposure. This tool is already really good for studiowork. It just takes more time, and it has it's limitations. Those limitations can be very hard to solve even with all today's technology.