Distance scales (wista?) for 4x5

[reinier_de_vlaam]

Hi

for my wista 45 I'm looking for metric distance scales for 75, 150 en 210mm

(have a 135 to trade-in). Can I use the scales for Graflexes, would they have

the same distances? Who sells these (for wista and others) scales and what

would they cost.

 

Problem that I also have is that it seems that the wista can hold only one

scale but I use 2 (75+210) sometimes 3 lenses. How to deal with that?

 

regards

Reinier

[reinier_de_vlaam]

PS it is a Wista 45-SP, the metal one

[pete_andrews10]

The scale will be particular to the lens, rather than the camera. Once you've got your infinity point set for each lens, then you should be able to calculate the distance scale quite accurately enough from the following formula:

 

Delta v = (f*u/(u-f))-f

 

Where Delta v is the change in bellows extension from infinity focus; f is the focal length of the lens; and u is the subject distance. Remember that all measurements must be in the same units, so your subject distance will have to be converted from metres, or feet and yards, into millimetres.

 

For example; with a 75mm lens and subject distance of 5 metres; u is 5000mm, and f is 75mm, therefore Delta v = (75*5000/(5000-75))-75 = 1.14mm.

 

That means that your 5 metre mark on the scale should be 1.14mm from the infinity mark. Now it's doubtful whether you'll be able to mark or set the scale to such an accuracy, so marking to the nearest half millimetre will be good enough.

 

There's also no reason why you can't mark off several distance scales for different lenses on one slide.

[leonard_evens]

Any distance scale involves translating the displacement along the rail (or bed) from infinity to a subject distance. The exact formula is

 

subject_distance = f x (f + d)/d

 

where f is the focal length of the lens and d is the displacement from infinity. For distant points, f is much larger than d, so this can be approximated by

 

subject_distance = square of focal_length divided by displacement.

 

For example, suppose you used a 150 mm lens and you measured a displacement of 3 mm from infinity. the subject would be at 150 square divided by 3, which is 7,500 mm or about 24.6 feet.

 

In the close-up range, i.e. less than 10 times the focal length, you would have to use the exact formula.

 

It is much easier to use the formula than to try to create a separate scale for each lens. If you don't want to carry a calculator, you can create table giving figures for different focal lengths and selected displacements on the rail. Interpolation will give you the desired result closely enough.

 

But, in most circumstances, there is no real point in finding the subject distance this way. You are trying to use your camera as an optical rangefinder, and it is not a very accurate device for doing that. Fortunately, for typical uses of subject distance, you can use instead the displacement from infinity or other measurments along the rail directly. For example, the focus spread method for focusing and determining appropriate f-stop for desired DOF, as described at LFphoto.info, does this.

[michael_briggs2]

If your purpose is to determined depth-of-field, then I second Leonard's suggestion to use the focus spread method instead. It is better and easier. All that you will need to do is measure the change in position of the standard as you focus from the closest and farthest object that you want to be in focus. You can do this by adding a mm scale to your camera. It doesn' matter which focal length lens you are using. Here is the URL to the article that he referred to: http://www.largeformatphotography.info/fstop.html

[reinier_de_vlaam]

what I will do is buy a simple rangefinder, just to determine the distance to the subject. I would like to set the extension of the bellows to a scale on the camera so I don't have to verify the groundglass, which is less easy

[leonard_evens]

Reiner,

 

If I now understand correctly, you want to focus without using the ground glass as is possible using the rangefinder mechanism on a Graflex or Linhof Technika. I don't think this is going to work very well, and it seem counter to the spirit of using a view camera. But if that is what you want to do, just follow Pete's instructions. He has pretty much told you what to do. The important point is that you don't want to look at the total bellows extension but rather the displacement from the infinity position. If you still can't figure it out, let us know, and we will try to explain it in more detail.

[brian_ellis16]

Linhof sells distance scales for various focal length lenses. Exactly how they would work on your camera or what you'd have to do to make them work I don't know, I've never used distance scales or a Wista camera, but I know Linhof makes them.

[dirk-san1]

I have the same camera trying to do the same thing. What is the best way to determine the infinity setting? I know that for e.g. a 75mm lens the lens plane and film plane are 75mm apart for infinity, but how is that measured, from lens board to film?

[michael_briggs2]

<p><i>"I know that for e.g. a 75mm lens the lens plane and film plane are 75mm apart for infinity, but how is that measured, from lens board to film?"</i> The exact things that you measure between are the image and the rear principal point of the lens -- see http://www.photo.net/learn/optics/lensTutorial. Typically the principal points will be near the aperture, but this isn't always true. For LF lenses, the most extreme exception is telephoto lenses. Sometimes lenses manufacturers provide the location of the principal points on the data sheets. But an easier item to use that is provided on the data sheet is the Flange Focal Distance (or Length). This is the distance from the image to the back of the shutter (=the front of the lensboard) when the lens is focused on infinity.</p>

 

<p><i>"What is the best way to determine the infinity setting?"</i> But another problem is that individual lenses may have focal lengths, and thus FFDs, that vary slightly from the design values listed on the datasheet. So probably the best way to determine the infinity setting is to simply focus on a very distant object.</p>

[dirk-san1]

Thanks Michael. I did the latter and managed to get a simple paper scale stuck on the rail working fairly well already.

[reinier_de_vlaam]

thanks all

 

I will make a distance scale according pete's instructions for the 3 lenses I have and use different color per lens. That should do the trick. Probably I will make it in the computer and glue onto some strap of metal so I can screw it in place of the current scale.

 

Will ofcourse use 3 infinity points, one for 75mm, one for 150 and one for 210. Am I correct to asume that the distance of the infinity mark from the film plane is equal to the lens length (75mm)? In that case I have to check if the 210mm mark would fit on the wista without extension

 

I'm mainly planning to use the Wista from hand and shoot polaroids... I will use image transfers en cyano contact prints as postcards...

I have ordered a 75mm viewfinder for pointing. I will use front rise and tilt (estimating using scheimpflug(?) rules)

 

Another wista question. I found that the 2 stoppers cannot be moved aside (to use one for each different lens) like the can on a Graflex. Is that correct?

[leonard_evens]

Reiner,

 

The placement of the infinity marks and the scale is to some extent arbitrary. That is because you are using the displacement from infinity rather than the actual distance to the film plane. Just what you do depends on which standard you use to focus. I'll assume you are focusing by moving the front standard. Choose an easily identifiable fixed position on the standard, focus very carefully at infinity and make a mark on the rail or bed opposite where this standard reference position lies. Then place the scale on the rail or bed with the infinity position at that mark. When you focus by moving the standard, the standard reference position will move a certain distance and will be opposite some mark on your scale from which you will read the subject distance. If you end up just opposite one of your subject distance marks, you can read it directly. Otherwise you would interpolate.

 

In principal you could use different reference positions on the standard for different scales. But usually there isn't much choice and it could get confusing.

 

When you are focused at infinity, there is of course some point whose distance from the film plane is the focal length. That point is called the rear principal point. Its position depends on the lens. For most ordinary lenses, it is very close to the front of the lens board, but for many lenses it lies elsewhere. For telephoto lenses, it can lie well in front of the lens. For short focal length lenses, it is usually a small disance in back of the lens board. For example, for my 75 mm lens, I believe it is about 5 mm back.

 

Lens specifications usually include a figure called the rear flange focal length (or some such words). That is supposed to be the distance from the front of the standard to the film when the lens is focused at infinity. Subtracting that from the focal length yields the distance from the standard to the principal point. If the flange distance is shorter than the focal length, the principal point is in front of the standard. If the flange distance is longer than the focal length, the principal point is in back of the standard.

 

By the way, these scales aren't specific to the camera; they are specific just to the focal length of the lens. Whether or not a scale designed for one camera will work on another will depend on other considerations, e.g., which standard is used for focusing and how long the scale is, which will affect where it will fit.

[carole_fishback]

i'm skimming over the dialogue here and realizing how much info I'm really going to need to be up to speed in using my Sinar. I just picked up a 60's version in Carmel - few knobs, spirit levels missing but otherwise pretty solid. Have a newer "student" model now too by Sinar but realize I know nothing about these lenses. I have a commercial Ektar 8.5 inch lens on the older one, a linhof Symmar 1:5.6/150 mm lens on the F1 Sinar. Not sure how interchangeable these cameras are but I guess that will be one option. For primarily portrait, some landscape photography will these lenses suffice or will I need others yet? Despite my heavy digital use lately, I'm determined to continue my studies in film and recently opted for taking up 4x5 following my classes and a workshop in Aspen. Words of encouragement, recommendations? thanks, Carole

[carole_fishback]

just adding the photo from the workshop I tried to attach with the last one...for anyone else who does this sort of thing. This was with a twin lens Mamiya however, not a large format.<div></div>

[leonard_evens]

Carole,

 

I don't know anything specific abou the lenses you mention. But whether or not they would be appropriate for portraiture would depend on the kind of portraiture you have in mind. You have to ask yourself just how far you want to place the subject from the camera and what size image of the subject you want. For a full size figure at a plausible distance, either lens would work. Such photography is often called envronmental portraiture. But it you want a head and shoulders portrait filling the frame, you will have to get pretty close with either lens, and you might not like the perspective. For example, from the top of my head to my waist is about 450 mm. In portrait mode, if that filled the 120 mm height of the frame, the magnification would be 120/450 = 4/15. With a 150 mm lens, the subject would be have to be about a bit over 2 feet away. With a 215 mm lens (8.5 inches), the subject would have to be bit over 3 feet away. Most people would find that too close.

[dirk-san1]

<i>I'm mainly planning to use the Wista from hand and shoot polaroids... I will use image transfers en cyano contact prints as postcards... </i><p><p>

 

Reiner:

 

I am planning to do the same thing with my Wista. I am using a Polaroid 550 back and Fuji peel-apart films, esp. the ASA 3000 film which should allow good depth of field. I have not tried the image transfers though.<p><p>

 

<i>I have ordered a 75mm viewfinder for pointing.</i><p><p>

 

I am looking to build my own (my lens is a 120mm) or have one built for me to fit into the accessory shoe. In fact, my plan is to have a finder that can be see from above so that the camera position will be chest height, and not eye level.<p><p>

 

 

<i>Another wista question. I found that the 2 stoppers cannot be moved aside (to use one for each different lens) like the can on a Graflex. Is that correct?</i><p><p>

 

Exactly the same with mine. This surprised me as the stoppers have tightening srews, but no matter how hard I try, I cannot move either of them.<p><p>

 

Looks like we are on a similar track. If you are interested in exchanging more experiences off-forum, please request my email address from photo.net.