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Author Topic: Tilts with Digital back on Sinar P/X  (Read 2897 times)

RobertJ

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Tilts with Digital back on Sinar P/X
« on: January 07, 2015, 04:22:36 pm »

Maybe a stupid question, but since the Sinar P/X have geared asymmetrical tilts for 4x5 instead of center tilts, I was wondering what happens when you do geared front tilt (or swing?) with a digital back that is simply mounted to the center of the rear carrier frame (like on a Kapture Group live video adapter: http://kapturegroup.com/solution/five.html ).

Since the sensor is not anywhere near the size of 4x5, and mounted in the center of the frame, you don't really have asymmetrical tilts anymore, right? 

What happens when you tilt the front?  Does it change the composition?  Do you have to recompose?  Do you focus on the near, and tilt to the far, or focus on the far, and tilt to the near?  Does it become a base tilt?
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Chris_Brown

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Re: Tilts with Digital back on Sinar P/X
« Reply #1 on: January 07, 2015, 09:20:57 pm »

The asymmetrical tilt/swing on the Sinar is on the rear standard. The front tilt/swing on the front standard align at the optical center of the lens. The rear standards asymmetrical tilt/swing are designed for achieving the perfect focal plane and largest f-stop to maintain depth of field. The system is ingenious. The manual is here (page 16–18 in P3 manual).

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Since the sensor is not anywhere near the size of 4x5, and mounted in the center of the frame, you don't really have asymmetrical tilts anymore, right?

Yes. Tilts & swings on rear standard are asymmetrical.

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What happens when you tilt the front?  Does it change the composition?  Do you have to recompose?  Do you focus on the near, and tilt to the far, or focus on the far, and tilt to the near?  Does it become a base tilt?

Your questions can be answered by reading the manual in the link above, and reading the info here.
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RobertJ

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Re: Tilts with Digital back on Sinar P/X
« Reply #2 on: January 07, 2015, 10:45:09 pm »

I understand that on the rear, you focus on those imaginary horizontal or vertical lines, then tilt/swing until the second point is in focus, then transfer the setting to the front, then reset the rear back to zero, and refocus if necessary...but how do you know where the lines are with a digital back?

So the front IS a center tilt, and it can be used as usual? (focus on the near, tilt to the far, refocus, adjust tilt, refocus, adjust tilt, etc)?

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Chris_Brown

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Re: Tilts with Digital back on Sinar P/X
« Reply #3 on: January 08, 2015, 12:58:10 am »

I understand that on the rear, you focus on those imaginary horizontal or vertical lines, then tilt/swing until the second point is in focus, then transfer the setting to the front, then reset the rear back to zero, and refocus if necessary...but how do you know where the lines are with a digital back?

I used a sliding back with the dashed lines and tried it in live view mode. See page 17 of the P3 manual. Maybe that'll help?

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So the front IS a center tilt, and it can be used as usual? (focus on the near, tilt to the far, refocus, adjust tilt, refocus, adjust tilt, etc)?

The Sinar method uses the rear standard for all that, as you described above.
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Hank Keeton

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Re: Tilts with Digital back on Sinar P/X
« Reply #4 on: January 08, 2015, 01:17:11 am »

For what it's worth...I shoot with a P-2 using a Leaf Aptus-65.

Rear movements change geometry.

Front movements change plane-of-focus.

Any movements can affect depth-of-field.

I use primarily front-movements, unless I want to change the geometry. Focus-far, tilt/swing-near. Rise/fall as required.

Physical movement is extremely limited in extent (mm), as the ratio of 4x5 to digital sensor is large (relatively speaking).

Cheers,

Hank
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RobertJ

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Re: Tilts with Digital back on Sinar P/X
« Reply #5 on: January 09, 2015, 02:43:00 pm »

Thanks for the replies.

Hank, do you feel that a 6x9 view camera made for digital would be much better, or do you think that using a P2/X with a digital back would be pretty much the same in terms of focusing and small movements?  I always hear conflicting arguments.  Some say the best 4x5 cameras are just fine, and others say it's impossible, and not precise enough.

I'm talking about if the back was a CMOS with real live view, so you can really see what you're doing...
« Last Edit: January 09, 2015, 02:44:36 pm by RobertJ »
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Doug Peterson

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Re: Tilts with Digital back on Sinar P/X
« Reply #6 on: January 09, 2015, 02:54:11 pm »

Thanks for the replies.

Hank, do you feel that a 6x9 view camera made for digital would be much better, or do you think that using a P2/X with a digital back would be pretty much the same in terms of focusing and small movements?  I always hear conflicting arguments.  Some say the best 4x5 cameras are just fine, and others say it's impossible, and not precise enough.

I'm talking about if the back was a CMOS with real live view, so you can really see what you're doing...

Where are you hearing conflicting information from??

A modern digital-oriented view camera like the Arca Swiss Univeralis is a significant improvement. Everything (typical lens lengths, amount of extension, required precision) is relative to sensor size. For a digital back, using a 4x5 view camera is absolutely possible, but not nearly as elegant as a modern digital-oriented view camera.

Best to put your hands on one yourself and make up your own mind - we have a Univeralis in our demo inventory we'd be glad to have you gear around.

Hank Keeton

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Re: Tilts with Digital back on Sinar P/X
« Reply #7 on: January 09, 2015, 04:16:07 pm »

Hello Robert,

First let me commend Doug's use of the term "elegant." Its very apropos! The digital-line of modern view-cameras employs existing technology for movements, but adds micrometer-scale adjustment. That's nice...of course!

But...having said that, let me address plane-of-focus first. On my P2 I use an optical eyepiece that allows me to view each portion of the image just like a regular free-hand eyepiece....mm-by-mm. Of course my viewing area is 1:3.47 smaller than 4x5, so Robert your ability to live-view will assist where my tired eyes fail.

One thing I have learned is that my rear-movements can aid the depth-of-field, if I am very careful about the geometry...emphasis on "careful."

The overall depth-of-field (however achieved) greatly enhances the impact of the final image when recorded on the digital sensor. With film we had  the thickness of the emulsion (16-18 microns for negative film, 25-27 microns for transparencies, 7-10 microns for B&W) to expose for peak focus, whereas with a digital sensor we have 1-7 microns (photosite depth, not width). Width varies greatly by manufacturer. So, in my direct experience there's at least a 3x greater sensitivity in focusing for digital.

Using live-view leaps all of those limitations easily.

Now to address sliding-backs. With the P3 (and similar cameras) the sliding back is limited by the cross-sectional area of the bellows. With the P2 I get to move my sensor up-down-sideways within the lens- IC to create a composition that not only pleases me, but expands my possibilities for stitching, etc. So, there is a distinct advantage to the larger bellows cross-sectional area.

Now......I'm not sure if this adequately addresses all your questions, but I hope it continues to carry your exploration further toward your goals.

Cheers,

Hank



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Hank Keeton

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Re: Tilts with Digital back on Sinar P/X
« Reply #8 on: January 10, 2015, 10:22:13 am »

Robert...another thought.

The term "asymmetrical" is an English translation of a German expression which may be misleading to the typical English-speaking soul.

For some LF cameras, the movement-mechanisms are pivoted at the base. For others the movements are pivoted at the lens-centerline.

For the P2 (and other Sinars in this line) it is BOTH! At least with tilt. Hence the term "asymmetrical."

What makes Sinar ingenuous (and different)  is the geometry between the base-point of both standards, and their tilt-action. It applies to BOTH standards, and not just one.

The standards (and hence the lens- or film-) tilt around the center-line, BUT the movement is achieved from the base only. The movement does not involve a "pivot" at that center-line (except for "swing," which IS centered on its pivot-point).

Does this make any sense, the way I'm expressing it?

Of course, it's in-the-using that makes the difference. That's another German expression which usually gets translated into English as "present-to-hand."

And yes, the Sinar does make one feel a bit magical in use!

Cheers,

Hank
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