hard core lens, camera question

[Joe G.]

Here's the situation: Let's say you needed to film a "poodle that ate the house" type of shot, a giant animal at 1/12th scale. From formulae found on the web, it looks like 1/90th frame rate, implying a shutter speed of 180th second. F stop has to be maxed out, something like f32 or f36 or even f45. Otherwise half the animal will be out of focus, and the effect won't work.

I'm not worried about background, because it will be in front of a green screen.

This implies a massive amount of light, even more than broad daylight (correct?)

1. Would I be better off with a Scarlett, with a smaller sensor, for increased depth of field on this shot?

2. Would the smaller sensor at the same focal length be equivalent to the Red sensor at that same focal length? Would the perspectives match? Is there some formula for converting the perspective so that I can match it?

3. I read about a "P" value for lenses that affects magnifcation and depth of field. Is there a way to get the optimal type of p value in a lens for this shot? How do I find this?

4. Is this feasible with Red and/or Scarlett, or should I rent a special high speed camera of some other variety for these scaled shots?

5. Can it be done with not so much light that it injures the animal's eyes?

Thanks.

[Florian Stadler]

-Full frontal California sun is 64/90 split at 320 ASA
-most lenses cap their stop at 32
-Although Scarlett will give you greater depth of field for the same image size, it won't help because the lens will not be wide enough to match perspective.
-With the wide lens you'd want to use (let's say it would be a 10mm, the widest one available without significant spherical distortion) at f/22 set at 2 feet you would hold focus from 6" to infinity. You could add diopters if you need to get closer than that which you will not (in case of a Poodle).
-If you take a 14mm at f/22 you'd get 9" to infinity at 2 feet

[Jorge Díaz-Amador]

For miniatures you want a wide lens, for realistic perspective, and you will get a wider angle with the full RED ONE sensor. Shooting at f22 will reduce resolution significantly due to diffraction, so this will add to the depth of field, and probably limit you to a real resolution of less than 2k.

I'd shoot with a Zeiss Distagon 10mm, or the Zeiss 8R if you can get it, at the lowest f number that will give enough DoF as viewed on the RED LCD. Hopefully f8 will be enough.

I'd avoid diopters because they reduce depth of field. Plus you would need an achromatic diopter like the Master Diopters or you'd introduce significant chromatic aberration. Also, I doubt there is a diopter that can cover a 10mm lens for S35mm.

I'd down-res the 4k to 2k with sharpening.

As long as the light level is no more that strong sunlight, the dog will not be in any danger. Otherwise, all outside dogs here in Miami would be blind.

[Steven Parker]

Also consider that when shooting 'miniatures' as giant-sized, you often have to go to high frame rates in order to sell the mass of the creature... at 1/12th scale, you should be shooting somewhere on the order of 60-72fps so that the 'giant' poodle seems to be big and heavy, rather than just enlarged to match perspective.

[Michael Lindsay]

Great advice...

however I don't agree with bellow...





I'd avoid diopters because they reduce depth of field....


take a lens that can focus close enough to match the same lens with a diopter (and the lens set at Infinity) and depth of field is the same..

Surprised me when I did it a few years ago..

regards

Michael Lindsay

PS Master diopters are superb got a 2 and love it!

[Joe G.]

"Full frontal California sun is 64/90 split at 320 ASA"

What does that mean? What is split?

"-most lenses cap their stop at 32"

Is there a list on the net of lens parameters, so I can look up which lenses go that high?

"at 1/12th scale, you should be shooting somewhere on the order of 60-72fps so that the 'giant' poodle seems to be big and heavy"

Another board gave the formula that wnen scaling you use the following guidelines:

Scale the distance, and focus setting. For a 1/12 scale to appear 20 ft away, you set the camera 20" away from subject.

For aperture you multiply the scale by the f number you are matching to. If you shoot the normal sized background at f2.0, you multiply * 12 for f24 for the miniature shot.

Frame rate uses a square root. For 24fps normal, it equals sqrt 12 * 24 = 3.46*24 = 83fps.

Q: Does the Red One have the ability to choose a value like "83"?

Q: Is a shutter speed double that required to avoid a strange look to the footage?

If you're shooting at 90fps, can you use a shutter of 1/90th or 1/100 rather than somethiing like 1/180?

[Stephen Williams]

"Full frontal California sun is 64/90 split at 320 ASA"

What does that mean? What is split?



If you're shooting at 90fps, can you use a shutter of 1/90th or 1/100 rather than somethiing like 1/180?

Hi,

A split is halfway between 2 stops.

I would shoot at 1/180 assuming you want normal film motion.

Stephen

[Jorge Díaz-Amador]

Great advice...

however I don't agree with bellow...

take a lens that can focus close enough to match the same lens with a diopter (and the lens set at Infinity) and depth of field is the same..


Michael,

I think that when you add a diopter, you are effectively increasing the focal length, because infinity focus (on the lens) is now at 1m (for a #1 diopter). Perhaps the increase in focal length is too slight to notice.

This is the same effect that causes breathing on a zoom lens like the Zeiss Vario-Sonnar 1,8/10-100 mm. As the front element moves away from the zoom group, focal length increases.

It could also be that closer focus = less DoF. So simple you don't think of it at first.

At least that's the way I understand it.

[Florian Stadler]

If there's no Diopter for the lens available, you can simply pull the lens out of the mount until the subject is in focus.

[Michael Lindsay]

Hi Jorge

I have noticed that Diopters (achromatic ones at least) narrow the field of view a little.

I don't have your lens knowledge... but I felt (and my simple tests bore this out) that depth of field was less with a diopter only because people use them to shoot CU.

kind regards

Michael

[David Mullen ASC]

You can use swing-tilt lenses to increase the illusion of depth of field if the nearer object is on one side of the frame -- combined with stopping down as much as possible. Split-diopters don't work as well since they need fairly shallow-focus actually in order to not see where the glass split begins (it has to be fuzzy.)

The frame rate rule is not set in stone, and only really applies when scaling motion -- i.e. if the objects don't move or move slowly, you can get away with closer to normal frame rates. For spaceship models, for example, you often get away with extremely low frame rates combined with very slow movements of camera or model in order to increase exposure time and stop down the lens.

Ultimately if often comes down to what's practical to achieve, not the math -- i.e. you use a wide-angle lens stopped down as much as you can at a frame rate that seems to work OK. Worrying about 80 fps vs. 83 fps is silly, no one can spot the difference. Stopping down the lens and getting as much depth of field as possible is more important if you have to choose between the high frame rate and the deep stop; there are post tricks for slowing down motion. Unless it is something that looks more spectacular at super high frame rates, like an explosion.

[Deanan]

Hi,

A split is halfway between 2 stops.

I would shoot at 1/180 assuming you want normal film motion.

Stephen


Normal film motion relative to 180deg @ 24fps (1/48th or the size of the motion blur at 1/48th) or with respect to the gap in motion between frames?

There are differing opinions on which one qualifies as 'normal' so the intent is important.

[KenjiHIBI-photographerJPN]

Hi!
Do you know the wide still Nikon mounted lense made from SIGMA like 20mm,24mm?
That only I know the wide lense , can take close-up shot.
It can take from 4 inch length in front of lense.
Hope it would be help info to you

[Steven Parker]

Frame rate uses a square root. For 24fps normal, it equals sqrt 12 * 24 = 3.46*24 = 83fps.



You are precisely right, when I posted I just did some quick math in my head, but as David mentions above, the math isn't as important as what you're able to do practically.

Math had me needing 73fps @ f/22 and a bump for a 1/8 scale model on a recent miniatures shoot. I could only get to 60fps (because of the camera) @ f/16 with the greenscreen a stop under (because of my light package) but it worked. Well, the VFX boys aren't complaining that much, anyway....:wink:

[chuck colburn]

If there's no Diopter for the lens available, you can simply pull the lens out of the mount until the subject is in focus.

Hahaha!

[Joe G.]

"I'd shoot with a Zeiss Distagon 10mm,"

Isn't 10mm considered a fisheye lens, with 180 degree viewing angle?

Do some 10mms have less image distortion than others(Distagon?)?

I was going to use a Nikon lens mount on the camera.

Would a 14mm or 16mm be too much, and not allow the depth of field I would need?

What about when I shoot the background plate on the 10mm, wouldn't that look a bit weird and distorted with a landscape that is t-o-o w-i-d-e? Or lines that turn into curves?

Doesn't that blow the effect?

[Bob Gruen]

When working with animals they must be comfortable, so flooding a small dog with a lot of light simply will not work; the dog will close its eyes and/or run away and/or bite you.

One more thing to consider: Depending on when you need this shot you might be able to rent a birger mount equipped Red One and use a cheap wide zoom that will not have the capabilities of shallow DoF anyway. It would be easy to test, just run down to the local camera shop and try it out on an old fashioned film SLR camera...

Bob

[Hans von Sonntag]

In this case I would use a Kenworthy-Nettemann snorkel. It considerably increases DOF. Additionally it is mounted on a crane with maximum flexibilty. Visuallly macro shots will look like "normal" shots. The only downside is its softness. Mixing shots with UPs for instance will not match.

More info here: http://www.hubbertvonsonntag.com/HVS080627/Projekte/Entries/2007/12/5_Kenworthy-Nettemann_Snorkel.html

Hans

[Joe G.]

Another issue may be shooting in the 2K windowed mode (in order to get the high frame rate). Does it alter the effective lens focal length? This is another issue I don't really understand.

I figured I would need to shoot the scaled up shots in 2K mode, and yet could probably match those to the 4K shots of the background. Is that not going to work?

I could just shoot all those shots in 2K. But, that goes back to the lens choice -- is the 10mm still a 10mm when in 2k mode?

Or will I lose depth of field?

[David Mullen ASC]

A 10mm is always a 10mm... but in 2K cropped mode, it has a narrower (cropped) field of view, as it also would on a 16mm camera, let's say, instead of a 35mm camera -- same principle. So a 10mm lens is less wide-angle in view in 2K cropped mode than it is in 4K mode; the view is more like a 20mm lens used in 4K mode, but the depth of field for a 10mm lens in 2K cropped mode is greater (deeper) than a 20mm lens in 4K mode, even though the field of view is the same, if the distance focused / size of subject is the same.