How to make LF composing card with proper focal length?

Pieter12

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At only $3.5K this is a gadget every film photographer should have in their pocket.
I'm not sure where you get that price from. Maybe a whole camera? The viewfinder is listed at 1820 euros, expensive as all new Linhof equipment is. But they come up on auction sites and used equipment dealers quite often. If you don't buy the newest one (and it is certainly not necessary), they can be more reasonably priced--in the $150-300 range.
 
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Kino

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Ian,
Thanks for you're comprehensive response!
At the moment, I have the 207mm f7.7 Kodak lens for my 5x7. 4x5 and Whole Plate are yet to be determined.
 
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Kino

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Very generous! Thank you and I will give this a try.
 
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Kino

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Thanks to everyone who chimed-in!

I didn't think it would generate this much interest!
 
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That's what I use. 3.3 or 1/3.3 for the long side which is the usual horizontal field of view for landscape pictures between 135 and 4x5. I ignore the diagonal because I don;t use that when composing a scene. For horizontal landscapes, the width is the view most people use. Many advisors give the diagonal factor between lenses, but who looks that way? You check the left and the right sides. The height pretty much falls where it falls. Of course, if you're doing a vertical shot, then another factor should be used.
 
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Here' my Zone VI viewing filter and instructions. I think it's for my 6x7 medium format but I haven't used it in years.
 

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Pieter12

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Dunno if something like this might be of interest:
 

Ian C

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Per post #28

5” x 7” film holders mask the film to about 119 mm x 170 mm.

For a 207 mm lens, the angle of angle across the minor dimension and the equivalent 35 mm format lens that sees the same angle across its minor dimension are 32.1º, 41.7 mm.

Across the major dimension they are 44.6º, 43.8 mm

A viewing card for that lens and format requires an opening whose dimensions are in the ratio of 170/119. The viewing distance is

d = w/(2*tan(θ/2))

where w = the opening dimension (major or minor) and θ is the angle associated with that dimension.

If we use the major dimension of the format and its associated angle of view, then

d = 170 mm/(2*tan(44.6º/2)) = 207 mm viewing distance. [Thank you Sharktooth. You caught and reported my error in post #35. I've corrected it. Of course, the calculation for the viewing distance is unnecessary, in this case, since it' simply the same as the focal length of the lens.]

These give a viewing card of opening 170 mm x 119 mm with a viewing distance of 207 mm.
 
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Sharktooth

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Your formulas are correct, but you input the wrong value for θ. It should have been 44.6º, not 43.8. The 44.6º angle was your own correct calculation, but I have no idea what the 43.8 mm value represents. When the correct 44.6º angle is input in the formula, the viewing distance is 207mm.

This example actually demonstrates that you don't have to do any calculations if your card opening size is the same as the film image size. When that's the case, the card viewing distance is always the focal length of the lens.

If you're uncomfortable with the math, then just make your card opening size the same size as your film size. For any lens you mount, the card viewing distance will be the focal length of that lens.
 

xkaes

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That's one of the reasons I made mine a 4x5" hole in an 8x10" gray card. My bellows only opens 360mm, but my arm reaches out to about 600mm -- which fortunately is my longest lens.
 
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Gentlemen, you don't new the tan

Let me summarise this: you take the image dimensions and the fl to calculate the aov to calculate the fl?
 

Ian C

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Thank you Sharktooth. You caught and reported my error in post #35. I've corrected it in post #34. Of course, the calculation for the viewing distance is unnecessary, in this case, since it's simply the same as the focal length of the lens.
 
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David Lindquist

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Typical price for US reseller, e.g. B&H wants $3575 with 2-4 week delivery. Compare with Linhof & Studio at £1650 and they have it in stock.
You don't want to know what B&H wants for a new Master Technika Classic

I really like Linhof & Studio...

David
 

KinoGrafx

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I use a little graflex finder that you would find on top of a speed or crown graphic. Fits in a pocket, you can get masks for most common focal lengths, and it’s easy to use and pretty accurate.
 
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