PDA

View Full Version : Question about movements on 20x24



Fragomeni
18-Jan-2011, 11:22
I understand that the larger you go the more movement is necessary to have an effect. Can someone provide some numbers on how much movement is necessary to be effective on 20x24? I'm speaking specifically to use of front tilt. Thank you!

Dan Fromm
18-Jan-2011, 12:27
A degree is a degree. You may be thinking of displacements parallel to the film plane.

Fragomeni
18-Jan-2011, 12:49
I was under the assumption that the larger the camera/image area the greater the movement necessary to have the same effect as it would have on a smaller format i.e. if photographing the same scene from same physical position an 11x14 camera would require a greater degree of tilt to achieve the same result and a lesser degree of tilt would achieve on a 4x5 camera. Is this accurate or have I been misled? The help is appreciated!

Mark Stahlke
18-Jan-2011, 12:57
I'm hardly an expert on these matters but I won't let that stop me.

I thought the phenomenon you refer to has more to do with the lens focal length than the film size. A long focal length lens requires more tilt than a shorter focal length lens.

I hope I'm not "misunderestimating" the situation. If I am, I'm confident someone will correct me.

Fragomeni
18-Jan-2011, 13:02
I'm hardly an expert on these matters but I won't let that stop me.

I thought the phenomenon you refer to has more to do with the lens focal length than the film size. A long focal length lens requires more tilt than a shorter focal length lens.

I hope I'm not "misunderestimating" the situation. If I am, I'm confident someone will correct me.

That, i have no idea about. I've never had to think about any of this. I just use my cameras! Now that I'm working on the restoration and modification of this ULF camera (the biggest and most involved restore job I've done) I have to start thinking about these things.

Liam:
18-Jan-2011, 15:13
I'm hardly an expert on these matters but I won't let that stop me.

I thought the phenomenon you refer to has more to do with the lens focal length than the film size. A long focal length lens requires more tilt than a shorter focal length lens.

I hope I'm not "misunderestimating" the situation. If I am, I'm confident someone will correct me.

I agree, changing the film size is not going to have an effect on tilt/shift as it all depends on the lens.

Nathan Potter
18-Jan-2011, 15:36
As Dan says "a degree is a degree" at any format or focal length when you're talking about tilt and swing. For rise, fall and shift of the standards the larger the format then the larger the % of rise, fall and shift will be required. :)

Nate Potter, Austin TX

Fragomeni
18-Jan-2011, 15:51
I guess that all makes sense since in most cases the more significant a jump you make in camera size larger the focal length of lenses you're likely to use... unless you're lucky enough to have a 150mm Goerz/Zeiss Hypergon with a 135 degree coverage capable of covering 20x24 (crazy lens!).

Fragomeni
18-Jan-2011, 15:51
By the way, thanks for the help everyone! Much appreciated!

Cor
19-Jan-2011, 02:24
by no means an expert, but the shorter the lens, the smaller the movements like tilt, ie if you have a 6X9 Technikardan with a 35 mm lens you really need geared movements it seems..., because you need tiny displacements of the lens plane versus the film plane.

The longer the lens the bigger the displacements for the same effect, so your 710mm (or whatever) lens will need relatively large displacements for the same effect than a shorter lens..

Hope I am correct or I will be corrected..;-)..

Best,

Cor

jb7
19-Jan-2011, 03:57
I'd imagine that bigger angles would be necessary for the same scene as you move up the formats, in order to use the same hinge point-

However, practically speaking, wouldn't you need a lot of excess coverage to be contemplating front tilts on 20x24?

Liam:
19-Jan-2011, 06:45
I'd imagine that bigger angles would be necessary for the same scene as you move up the formats, in order to use the same hinge point-

However, practically speaking, wouldn't you need a lot of excess coverage to be contemplating front tilts on 20x24?


I am not completely sure but I want to disagree because if you have a 4x5 camera and a 20x24 each with an equivalent focal length they would both give the same view. So moving the lens up 25mm (an inch) on both systems would still give you the same image...

jb7
19-Jan-2011, 07:38
Are you talking about parallel movements?
Shift, rise, fall?
Then we'd still have to disagree-
The lens would need to be moved by a proportional distance to produce the same view on 20x24- so a one inch displacement on 4x5 might be 4 or 5 inches on the larger format.

However, the question was about tilts-
and the differences between photographing the same scene to produce the same view on different formats-

Providing you can scale the height of the camera from the ground by the same factor,
then I'd agree that the same angles would apply-
However, this would change the perspective, and provide a different view-
So I'll stick with my original contention-
larger formats need bigger angles.

Fragomeni
19-Jan-2011, 11:04
Is there anyone who can just measure this somehow? Or tell me how and I'll measure it on my 4x5, 8x10, and 20x24. Anyone?

Liam:
19-Jan-2011, 13:10
Are you talking about parallel movements?
Shift, rise, fall?
Then we'd still have to disagree-
The lens would need to be moved by a proportional distance to produce the same view on 20x24- so a one inch displacement on 4x5 might be 4 or 5 inches on the larger format.


But if the lenses are of equivalent focal length (both 50mm (35mm)) why would it need to be moved up 5 times as much?

But agree with on tilts as you will be using telephoto lenses for 20x24.

jb7
19-Jan-2011, 16:10
Is there anyone who can just measure this somehow? Or tell me how and I'll measure it on my 4x5, 8x10, and 20x24. Anyone?

Looks like you have the tools to do it yourself-
you'll just need to know how to use a protractor-

Liam, let's use an example of two lenses that I know about, two different formats, similar angles of view-
24mm on 35mm, 90mm on 4x5-

Maximum shift on the smaller format is about 10mm, and it'll produce a similar view to a 40mm shift on a Super Angulon-

A 10mm shift on a 90mm on 4x5 is barely off axis-

A telephoto for 20x24 would need to be really quite long to cover-
the biggest format my 36" telephoto covers is 12x16...

Vlad Soare
20-Jan-2011, 07:12
Are you talking about parallel movements?
Shift, rise, fall?
Then we'd still have to disagree-
The lens would need to be moved by a proportional distance to produce the same view on 20x24- so a one inch displacement on 4x5 might be 4 or 5 inches on the larger format.
But if the lenses are of equivalent focal length (both 50mm (35mm)) why would it need to be moved up 5 times as much?
Because what really matters is not how much the lens shifts, but how much the image on the ground glass shifts. ;)
Imagine that your subject is placed in the middle of the frame, and that you want to shift the image sideways, to move the subject right next to the edge of the frame. On a 4x5" camera, assuming portrait orientation, you'd have to shift a little under two inches. On an 8x10" camera you'd have to shift almost four inches.

Liam:
20-Jan-2011, 11:16
Sorry but I don't see it, if the lenses are of equivalent focal length then you would shift the same for both.

If you were take just the shot on 8x10 with the shift but then crop it to 4x5 after developing then it would have shifted just as much.

sanking
20-Jan-2011, 11:28
I'd imagine that bigger angles would be necessary for the same scene as you move up the formats, in order to use the same hinge point-

However, practically speaking, wouldn't you need a lot of excess coverage to be contemplating front tilts on 20x24?

Yes you would, and there are very few lenses out there that will give you a lot of excess coverage. The 550 Schneider XXL gives several inches of front rise or fall but it is a very expensive piece of glass. And any of the older Dagors or other vintage double anastigmat lenses in the 24" to 30" range, which would in theory allow for a lot of movements, will also cost an arm and a leg. The 30"-35" process type lenses cover 20X24 but don't allow for much in the way of movements. To get a lot of movement on 20X24 with an apo lens you will need to go up to the 40" range.

Basically any lens that allows for a lot of movement on 20X24 is going to be very expensive, so we might consider the practical side of this issue as well, i.e. how much money are you prepared to spend?

Sandy

Ben Syverson
20-Jan-2011, 11:29
Sorry but I don't see it, if the lenses are of equivalent focal length then you would shift the same for both.
Think about it like this. You have two equivalent setups: one on 4x5 and one on 20x24, both "50mm" equivalent, both set up horizontally.

On both setups, once centered on a landscape, you find there's a distracting mark on the ground near the bottom of the frame, so you want to shift up by 20%.

20% of 4 inches is 0.8 inches, which is exactly the distance you need to shift up on the 4x5. There is a 1:1 relationship between the distance you want to shift the image on the GG/negative and how much shift you apply to the front standard.

20% of 20 inches is 4 inches, which is how much you need to shift the 20x24 setup. Sure, you need "more" coverage than the 4x5 setup, but if you're shooting 20x24, you're hopefully using a lens that covers the format with a few inches to spare. It's better to think of coverage in terms of percent of the format rather than strictly in mm. For example, "my 4x5 covers 120% of 4x5, my 8x10 covers 130%," etc. A 20x24 user will likely be using a lens with proportionally similar coverage to a lens designed for a press camera.

Liam:
20-Jan-2011, 11:40
Ahhh my bad, I guess my theory would only be true if the lenses where the same focal length.

Vlad Soare
20-Jan-2011, 11:52
Sorry but I don't see it, if the lenses are of equivalent focal length then you would shift the same for both.
Liam, here's how the same subject would look on the ground glass with lenses of equivalent focal lengths:

http://img441.imageshack.us/img441/4963/shiftv.th.png (http://img441.imageshack.us/img441/4963/shiftv.png)
(click to enlarge)

If you want to move the subject from A to B, you have to shift the lens (or the rear standard) by two inches on 4x5", and by four inches on 8x10". :)
Regardless of whether you shift the front or the back, the amount by which the standard shifts is precisely the amount by which the image on the ground glass shifts.
Or, to put it another way, a 12 mm shift on 35mm film along the short edge moves the image by a half frame, while a 12mm shift on 8x10" may be barely noticeable.

Liam:
20-Jan-2011, 13:45
Cheers for the picture, I have had a long week :rolleyes:

Can't believe 8x10 is that much bigger, I need to see an 8x10 transparency :eek: