Fixed focus 4x5 camera

[Degroto]

Hi,

Recently I picked up a sinar camera with a bunch of lenses. Including a sinaron F5,6 65mm lens. Now I want to try a simple fixed focus camera with this lens. My reasoning that the DoF will be big enough to do without a focusing system. Is my thinking correct?

Peter

[Jac@stafford.net]

Recently I picked up a sinar camera with a bunch of lenses. Including a sinaron F5,6 65mm lens. Now I want to try a simple fixed focus camera with this lens. My reasoning that the DoF will be big enough to do without a focusing system. Is my thinking correct?

It depends upon how critical you are. The rest is physics you can get from a DOF table - how close, what aperture, degree of enlargement.

[Bob Salomon]

Of course you can. The quality will depend on the depth of field that is acceptable to you and the distance that you shoot from. The 45 Linhof Aero Technica EL used lenses from 90mm up and the 90 was in a fixed focus mount. Of course, being an aerial camera,meant that the minimum legal altitude is 500'.

[Dan Fromm]

Physically possible? Of course. Wise? Doubtful unless, as Bob suggested you focus the camera for a distance -- aerial cameras are focused on infinity -- and then use it only at that distance.

[Drew Bedo]

Be on the look out for a TravelWide. It was originally designed as a fixed focus 65mm camera.

[Jac@stafford.net]

If the OP is interested I can post one of my 6x10cm cameras (Plaubel Veriwide) which zone focuses, but with an attached compact laser rangefinder it can knock-on focus. There is no reason it would not work with 4x5". I've made no pictures of it yet.

Aside, I'm upgrading my 4x5" cameras which have earlier 47mm Super-Angulons to 47mm Super-Angulon XL. Not finished. Here are the 'before' pictures. First the f/8, (http://www.digoliardi.net/super-wide-4x5-1.jpg) and another (f/5/6) (http://www.digoliardi.net/veriwide-4x5/1-front-on-1.jpg). (Yes, that's 4x5). Both are in focusing mounts.

[Degroto]

Hi Jac that would be awesome. The idea of fixed focus for me comes from street photography where you use aperture f/16 for example and focus the camera that everything is sharp between 1,5 meters to infinty. I want to use that principle for my camera. Also I use an old Eho boxcamera that is more or less sharp from 3 meters onward. I should be able to achieve something like that with my fixed focus camera. Maybe not but I wil have become a wiser man after that (haha).

From where do I measure de focal lenght of the lens? From the plate where the lens is attached?

[Emmanuel BIGLER]

From where do I measure de focal lenght of the lens? From the plate where the lens is attached?

Hello from France!

This is a frequently asked question ;)

What you want is to set the proper distance between the lens mount and the film.
Hence, to do this, the knowledge of the focal length is not really useful, as strange as it may seem!
What you need is a distance given by lens manufacturers, named "flange focal distance" or sometimes "Flange Focal Length" (e.g. in Fuji lenses documentation).
This is the distance between the back side of the shutter and the focal point. The focal point is where an image of a far-distant object is projected sharp.
Now in order to properly set your lens mount in front of your film holder, you have to take into account the film holder's depth, which is for modern film holders compliant with the ANSI standard
- 2" x 3" and 4" x 5" : 5.0 mm +- 180 microns (0.197" +-0.007")
- 5" x 7" : 5.8 +- 250 microns (0.228" + - 0.010")
- 8" x 10" : 6.6 mm +- 400 microns (0.260" + - 0.016")

If you already have a springback with ground glass, simply focus the image of a distant object, no computation is required.

And if you wish to fix-focus at the hyperfocal distance, instead of infinity, starting from the flange focal distance, you'll need to slightly increase the length between the lens and film by a small amount, to be easily computed according to your working f/number, focal length and sharpness criterion.

You can have a look at this article (in French) by Gilles Barbier who built a fix-focus camera for the 5x7" format.
http://www.galerie-photo.com/barbier-hybis-90.html
In this case, focal length was 90 mm, the sharpness criterion was 150 microns, the working aperture f/16, hence the offset required to focus at the hyperfocal distance instead of infinity was 3.3 mm.

[Dan Fromm]

Emmanuel, published flange-focal distances are nominal. So are the focal lengths engraved on lenses. A lens' design focal length -- the focal length if the lens matches its prescription -- can differ from the nominal. Example, the 260/10 Process Nikkor. Its design focal length is 267 mm. And actual focal length can differ from design. Example, the 38/4.5 Biogon. Design focal length 38.5 mm, actual focal length of the twenty (20) I've had as measured by the original customer ranged from 38.3 to 38.8 mm.

The OP is going to have to get his lens, decide the distance at which his fixed focus camera should be focused, measure his lens' flange-focal distance when focused at that distance and then build his camera.

[Jac@stafford.net]

Hi Jac that would be awesome. [...]

I do not have the digital camera today to offer a snapshot so let me just briefly describe the set-up.

The key part is a Bosch GLR225 laser distance meter that I used in construction work. It is small & handy. (Shop carefully. Prices are all over the map).

The meter has a 1/4" tripod socket. I have mine in an L-bracket that places it on the side of the camera (a Plaubel Veriwide). It has four different measurement reference points - #1 from its front, #2 from the tripod socket location, #3 from the bottom and #4 from a point a couple inches rear of the bottom. Forget about #4. Just mount the meter so that any from 1-3 locate at the film plane. It is easy with a bracket. I use #2 and it's about perfect.

I can trigger the laser from my left hand and see the laser dot in my viewfinder. It does not work trying to see the dot on a ground glass for good reasons (light frequency mainly & brightness). I use viewfinders on most of my cameras.

Good news - it is good to about 225' and is accurate. Bad news - it does not work well in bright sunlight without a special target placed at the subject. It is also not good for pointing at a subject's eye. Don't do that. :)

So, surf for Bosch GLR225 laser distance meter and instructions to get the whole idea. Hope this helps. Will get a snapshot soon.

EDIT - Dan Fromm's advice is right-on and suggests a more cost effective approach. One thing I did with a 4x5" box camera with a sprung rear door was to drill a hole in the middle of the back, then took a spare 4x5 holder, removed the two slides and drilled a hole in its center, then used a lope to aerial focus on various distances and jot down the distance shown on helical focus mount. With a wide lens you can probably note a few significant distances and use DOF to take care of the rest.

[DrTang]

figure out what distance want to shoot from... build the camera to that.. then use a finder from a Polaroid 'Big Shot' to get you to that distance

[Degroto]

I only have one big shot. So not gonna mess that one up. :-)

[Pfsor]

The OP is going to have to get his lens, decide the distance at which his fixed focus camera should be focused, measure his lens' flange-focal distance when focused at that distance and then build his camera.

That is a highly theoretical approach which shows you have not built a camera using this sequence, I'm afraid. The practical difficulties you find in doing so are rather great - the difficulty to exactly measure the lens FFD, (using gg focusing, just try it and you'll see how difficult it is to find the plane where you put your callipers) the difficulty to build a camera with this exact space between the gg and the lens flange (with many parts in between) and the difficulty to do so while maintaining the lens plane parallel to the gg plane (very important for a lens of such a short FL).
A much better approach and much more practical is to built the lens into the camera in a way that it can be slightly moved forward and backward - even just 5mm is enough. In this way you can measure the lens FFD and built the camera with less precision and find the precise infinity focus while moving the lens to its right position. It is much easier this way.
There is a way you can fine focus the lens (using 4 rods) and fasten it in the precise position and be done with it regardless of the precision of your measuring and manufacturing of the rest.
Been there, done that. I have built fix focus cameras with lenses ranging from 90mm to the long telephoto of 800mm. Knowing what you want to use it for is necessary - my 800 mm camera is always used at objects in the realm of practical infinity. The 90, 135, 150, 180, 300mm lens cameras are also usable at shorter distances with no surprises at all.

[Jac@stafford.net]

That is a highly theoretical approach which shows you have not built a camera using this sequence, I'm afraid.

That is a risky assertion when it concerns Mr. Fromm's work.

Building a box camera is simple enough if one has the fundamental measurements that Dan posted, AND a focus helical. Build the body as very close to the required metrics, which can be done with striking accuracy, and the focus helix can make up for the micro-millimeter difference.

When I built my first, all I used were Mitutoyo gauges and decent, not outrageous wood machnes. Sure, actual focal lengths vary. I have years of experience with military lenses in which every single one was marked with absolute focal length, and then shimmed to accommodate the camera. (For land-based photography their metrics were overkill, overly expensive.)

This one (http://www.digoliardi.net/super-wide-4x5-1.jpg)had the board very carefully micro-planed, then using a compliant (variable compression) gasket the back was settled into accurate infinity focus. Eighteen years later it is no longer in spec, but adjustments to the helix and retorquing the gasket makes new, accurate alignment trivial. Next week I am converting it from an early 47m Super-Angulon to a later 47mm XL thanks to help from one of our LF members.

[Pfsor]

Jac, the OP doesn't want to use helical, see the 1st thread. And believe me, I know what difficulties you would fall in if you just tried to put Dan's theory in practice. To "have the fundamental measurements" is not at all a given fact, see my reasoning.
OTOH a helical focusing ring would be surely very helpful too, no contradiction in it.

[Emmanuel BIGLER]

a highly theoretical approach

As the saying goes:

"When Real World differs from Dan Fromm's theoretical approach, for sure, Real World is plain wrong." ;)

Not kidding (I stand corrected)
- the knowledge of the focal length is useless, except if you want to re-compute your distance engravings on an helical;
- the knowledge of the nominal flange focal distance of your lens is much more useful!
- if you have a complete springback handy with a ground glass, this will definitely help;
- adding 2 or 3 nominal numbers together to compute a measurement does not seem highly theoretical to me, but instead, as practical as can be in a mechanics workshop!
- the depth of focus focus @f/16 with a sharpness criterion of 150 microns, is plus or minus 16x0.15 = plus or minus 2.4 mm; no need of a submicron caliper to properly set a working device, to re-use a well-know expression by physicist Charles H. Townes, one of the inventor of the laser: "Nothing stops naysayers like a working device" (C. Townes, 1999)

Well, theoretical mechanics also exists :)

[Jac@stafford.net]

Jac, the OP doesn't want to use helical, see the 1st thread. And believe me, I know what difficulties you would fall in if you just tried to put Dan's theory in practice. To "have the fundamental measurements" is not at all a given fact, see my reasoning.
OTOH a helical focusing ring would be surely very helpful too, no contradiction in it.

Okay, thank you for that. Now I see that I drifted to my own preference. I am sure if the OP builds a camera with enough of a 'ball park' measurement without a focus helical he will be happy. I may be too fussy and have gone overboard. Again! :)

Perhaps he could search the Web for HOBO 8X10 CAMERA


Emmanuel: "When Real World differs from Dan Fromm's theoretical approach, for sure, Real World is plain wrong."

We have very good humor here. Thanks for grounding our dialog in good spirit.

[LabRat]

Without a focusing helical, a good idea is while building is to build up the lensboard so that it is a little short of the "proper" focusing distance, but has allowance for different spacers to be added to shim in final focusing distances...

You can also test a mild close-up lens if you want to find another mildly closer setting if you are somewhere where you would be closer to your subject...

You can also check out PVC/ABS plumbing fittings to find something threaded where when screwed in, it would be your hyperfocal distance, but slightly unscrewed for closer focusing (like an interior or garden path, etc)...

A wire sportsfinder is good, but I like these kind of cameras to have a GG so I can confirm the focus setting, compose when the edges are important, and have the option to use a rollfilm back...

Good luck!!!

Steve K

[Jac@stafford.net]

Steve, finding shims has always been a problem for me.
Wire sports finders work! Good of you to mention!

I have poor eyesight which can no longer be corrected so I use viewfinders, and yes, wire finders. I wish to promote the idea.

[Pfsor]

a highly theoretical approach

As the saying goes:

"When Real World differs from Dan Fromm's theoretical approach, for sure, Real World is plain wrong." ;)

Not kidding (I stand corrected)
- the knowledge of the focal length is useless, except if you want to re-compute your distance engravings on an helical;
- the knowledge of the nominal flange focal distance of your lens is much more useful!
- if you have a complete springback handy with a ground glass, this will definitely help;
- adding 2 or 3 nominal numbers together to compute a measurement does not seem highly theoretical to me, but instead, as practical as can be in a mechanics workshop!
- the depth of focus focus @f/16 with a sharpness criterion of 150 microns, is plus or minus 16x0.15 = plus or minus 2.4 mm; no need of a submicron caliper to properly set a working device, to re-use a well-know expression by physicist Charles H. Townes, one of the inventor of the laser: "Nothing stops naysayers like a working device" (C. Townes, 1999)

Well, theoretical mechanics also exists :)

No, adding 2 or 3 measurements is not difficult, indeed. To take the 2 or 3 measurements is much more difficult, because of the practical difficulties you encounter. Where do you take the measure of the distance between the gg and the lens flange? Where do you put the callipers when the gg is inside the camera box and you calliper is outside of it? While measuring on the outside frame of the gg do you take into account the manufacturing imprecision you find on it? Before you add the 2 or 3 measurements you must find how precise you are when fiddling with your callipers on different parts of your "complete springback". Because the complete springback is not built to 0.01mm tolerance all over, you will soon discover.
And then - if you think your gg plane can go off one side with 2.4mm and be happy then build such a camera for 65mm lens and be happy... When you focus your 65mm lens, moving the gg 2.4mm gives you the same focus, under your focusing loupe, doesn't it? It's just adding 2 or 3 measurements together, isn't it? After all, a camera is just a light tight box between a lens and gg, isn't it?
I think, Dan is intelligent enough to know the difference between saying a theory and following it in the practical way.

[Jac@stafford.net]

No, adding 2 or 3 measurements is not difficult, indeed. To take the 2 or 3 measurements is much more difficult, because of the practical difficulties you encounter. Where do you take the measure of the distance between the gg and the lens flange? Where do you put the calliper when the gg is inside the camera box and you calliper is outside of it? While measuring on the outside frame of the gg do you take into account the manufacturing imprecision you find on it? Before you add the 2 or 3 measurements you must find how precise you are when fiddling with you callipers on different parts of your "complete springback". Because the complete springback is not built to 0.01mm tolerance all over, you will soon discover.
And then - if you think your gg plane can go off one side with 2.4mm and be happy then build such a camera for 65mm lens and be happy... When you focus your 65mm lens, moving the gg 2.4mm gives you the same focus, under your focusing loupe, doesn't it? It's just adding 2 or 3 measurements together, isn't it? After all, a camera is just a light tight box between a lens and gg, isn't it?
I think, Dan is intelligent enough to know the difference between saying a theory and following it in the practical way.

:) Do not worry so much for precision. You are on track. Make it the best you can and be happy. The pictures matter a whole lot more than technical minutiae.

[Pfsor]

Jac, don't worry, I will still sleep well. :)

[LabRat]

Steve, finding shims has always been a problem for me.


OR, make a proper square lensboard (wood, metal etc) that will fit on the front of your shortened camera, and allow space for a foam or other soft gasket to make a limited range collapsible "bellows", and have screws on the four corners that you can tweak to find your favorite focusing distance... You might even be able to add some on-the-fly focusing arrangement for at least some different focusing zones...

You could also come up with some way to mount different length lens cones for different FL's that can be screwed down at will...

Steve K

[LabRat]

Hmm. And the foam or other soft gasket will get pressed more and more in the time passing or will just keep the same dimension? Seems like a great idea to make your FFD differ while seasons flow.

Nah, the heads of the screws holding it down in the corners are the register points, the foam or rubber just fills the gap and create outward pressure...

Steve K

[Dan Fromm]

Where do you put the callipers when the gg is inside the camera box and you calliper is outside of it?

Funny that you should ask. What I've done has been to mount the lens in question on a Speed Graphic board, put it on (surprise!) a Speed Graphic, focus to the desired distance, take the lens off, a drilled board with no lens on the camera and measure the flange-to-film distance with a depth gauge. The OP may have to borrow a camera to do this. Speed Graphic not necessary, it was what I had at the time.

Its better than guessing, which is what using published flange-focal distances amounts to. Published flange-focal distances are great for finding out what can probably be done but that's not what the OP needs.

About the need for focusing. The shortest lens I've had -- still have it -- for 35 mm is a 24 mm. It has to be focused for best results. My 35 Apo-Grandagon has to be focused for best results.

[Pfsor]

Funny that you should ask. What I've done has been to mount the lens in question on a Speed Graphic board, put it on (surprise!) a Speed Graphic, focus to the desired distance, take the lens off, a drilled board with no lens on the camera and measure the flange-to-film distance with a depth gauge. The OP may have to borrow a camera to do this. Speed Graphic not necessary, it was what I had at the time.


And the second lens board must have the exact same thickness (best to 0.01mm) and geometry as the first one and the depth gauge must not be inclined on it in any direction so that the measure is not false and the standard may not move at all (to the precision of 0.01mm) and all added you're in the situation that taking the measure 5x you get 5x different results... Been there, done that.
How much easier to build a camera where fine focusing of the lens plate takes care of the excellent result without asking the depth gauge its opinion.
Or you can can just say - I have 2.4mm of free space, what do I care about precision, ain't any naysayer, don't need any atomic clock and am happy...
To each his own.

[Pfsor]

Nah, the heads of the screws holding it down in the corners are the register points, the foam or rubber just fills the gap and create outward pressure...

Steve K

Ok Steve, got that even before I deleted my post. No need to fill the gap and create outward pressure. You first build the box and fasten down the screws in their correct position - if you know how to - and then cover the box from one standard to the other with whatever suitable light tight material. My preference was black leather - lighter than anything else and interesting photo look is assured.

[Dan Fromm]

And the second lens board must have the exact same thickness (best to 0.01mm) and geometry as the first one and the depth gauge must not be inclined on it in any direction so that the measure is not false and the standard may not move at all (to the precision of 0.01mm) and all added you're in the situation that taking the measure 5x you get 5x different results... Been there, done that.
How much easier to build a camera where fine focusing of the lens plate takes care of the excellent result without asking the depth gauge its opinion.
Or you can can just say - I have 2.4mm of free space, what do I care about precision, ain't any naysayer, don't need any atomic clock and am happy...
To each his own.

Interesting. The OP has three posts in this discussion. In none of them does he mention making a camera with a ground glass. Your approach will certainly work with a camera in which focus can be seen and adjusted.

Oh, and by the way, the OP says he has a Sinar. He didn't say that his lens is on a Sinar board. If it isn't, he can get a board drilled to suit the lens, put the lens on the board, mount on the Sinar, focus ...

[Pfsor]

Interesting. The OP has three posts in this discussion. In none of them does he mention making a camera with a ground glass. Your approach will certainly work with a camera in which focus can be seen and adjusted.
.

Interesting. How would you control the focus if not on a gg? Trying the focus on film each time you want to adjust the FFD and see what it does? Would be a highly original approach, it seems. The OP wants to try a simple fixed focus camera. Must be simple to do that, I suppose. Just add his lens on a fixed focus box and voilà...

[Dan Fromm]

Interesting. How would you control the focus if not on a gg? Trying the focus on film each time you want to adjust the FFD and see what it does? Would be a highly original approach, it seems. The OP wants to try a simple fixed focus camera. Must be simple to do that, I suppose. Just add his lens on a fixed focus box and voilà...

As you said in post #26 above,


How much easier to build a camera where fine focusing of the lens plate takes care of the excellent result without asking the depth gauge its opinion.

[Pfsor]

Hello from France!


Now in order to properly set your lens mount in front of your film holder, you have to take into account the film holder's depth, which is for modern film holders compliant with the ANSI standard
- 2" x 3" and 4" x 5" : 5.0 mm +- 180 microns (0.197" +-0.007")
- 5" x 7" : 5.8 +- 250 microns (0.228" + - 0.010")
- 8" x 10" : 6.6 mm +- 400 microns (0.260" + - 0.016")





- the depth of focus focus @f/16 with a sharpness criterion of 150 microns, is plus or minus 16x0.15 = plus or minus 2.4 mm; no need of a submicron caliper to properly set a working device, to re-use a well-know expression by physicist Charles H. Townes, one of the inventor of the laser: "Nothing stops naysayers like a working device" (C. Townes, 1999)

Well, theoretical mechanics also exists :)

Interesting. I wonder why the OP needs to know the +- 180 microns tolerance on his film holder when the depth of focus for the film is plus or minus 2.4mm...

[Emmanuel BIGLER]

I wonder why the OP needs to know the +- 180 microns tolerance on his film holder when the depth of focus for the film is plus or minus 2.4mm...

Good question for which I have no clue!

The +- 180 microns tolerance = +- 0.007" (for 2x3, 3x4 and 4x5 holders) is reported here in this well-known document
http://home.earthlink.net/~eahoo/page8/filmhold.html
and data are supposed to come from an ANSI standard PIMA IT3.108:1998 that I have never read, like all other DIN or ISO standards actually, taking into account the high price you have to pay to get a copy of them ;)

And since I never read the ANSI standard for film holders, consequently I have absolutely no idea about the rationale behind depth tolerances in this standard!
Those tolerances do not seem to be correlated with the classical theoretical depth of focus model = plus or minus N c, where "N" is the f-number and "c" the diameter of circle of confusion chosen as a sharpness criterion. Plus or minus 180 microns @f/16 would correspond to an improbable sharpness criterion c=11 microns, i.e. smaller than a diffraction spot @f/16 ...

BTW there is an old discussion here in the archives related to tolerances on sizes for film holders: our readers like to be 100% sure of what they are using! (at least this was the case as of year 2001)
http://www.largeformatphotography.info/forum/showthread.php?4383-Measuring-Film-Holder-Accuracy

[Degroto]

Wow what a nice discussion. I will read everything later on and I do enjoy the enthusiasm from everybody. My plans are rather simple and consisting of the lens and lensboard it is on attached to a wooden box. On the other side or opposite side the filmholder at roughly the focal distance of the lens. Hoping the DoF of the lens will make up for a slightly out of ideal focus of the whole system :-)
If the results suck I can always rebuild :-D

The lens is on a Sinar lensboard. I do not want to use a groundglas. I plan on focusing with a piece of see thru paper and then fix everything. I then can see if I want the focus fixed on hyperfocal or normal infinity at a certain aperture that I think I will use most or is most convenient in most situations. A small list of DoF on various apertures should give me some guidance in what situation my image will be sharp using a certain aperture. Now I have to start building I am afraid :-) :-D

[Drew Bedo]

Degroto: I say go for it!

Plerase report back as your project comes together and post pictures.

[Emmanuel BIGLER]

A small list of DoF on various apertures should give me some guidance in what situation my image will be sharp using a certain aperture.

Simply provide us with a list of
- preferred focal lengths,
- preferred working f/#,
- and preferred film formats,
and downloadable free (although theoretical) DoF charts will appear here "magically" ;)

[Jac@stafford.net]

[...] I have absolutely no idea about the rationale behind depth tolerances in this standard! Those tolerances do not seem to be correlated with the classical theoretical depth of focus model [...]

Might the standards be guided by manufacturing precision requisites rather than optical necessity?

[Emmanuel BIGLER]

Might the standards be guided by manufacturing precision requisites rather than optical necessity?

Certainly.
With tolerances for film depth taken as a certain proportion of actual depth value? Still difficult to understand the choice of the proper figures. I can understand, however, that bigger film holders need to be thicker in order to stay as rigid as possible when size increases.

BTW I have found that the ANSI standard for film holders, together with many standards related to photography, film and slide projection, has been withdrawn in 2003!
I do not know the exact meaning of "withdrawn" for a standard, but the text is still not freely accessible!

[Degroto]

I will of course. My very crude first attempt to figure out how to measure the actual distance the lensboard has to be from the film plane is encouraging. But it is to dark now to focus on infinity. I'll keep you posted.

[Jac@stafford.net]

The suggestions to make some sort of pliable/compliant gasket under the lens board or on the back was excellent IF your camera is already dimensioned very close to one specific focal point, which is rather constricting and in this case unrealistic.

An alternative is to use 1/16" (1.6mm) plywood in as many layers as necessary under the lens board as shims. That is what I am using to make my new 4x5 camera correct at infinity. You can, of course, make the focal point any distance you choose. If you use little wing nuts you can carry several shims of different thicknesses to choose different points of focus in the field. A pocket on the side of the camera to hold the shims would be cool. (Don't carry them a back pocket. They might bend) :)

Measuring the flange focal distance is as simple as Dan Fromm mentioned. Just first insert a film holder with the film side slide removed. A finely marked steel ruler can help. And recall my earlier suggestion - you are going to use film holders, I presume. To visually identify focus you can put a 4x5" holder in the camera, then remove both the dark slides, and drill a 1/16" hole through the center of the back and through the film holder in one drilling. Finally, remove the film holder. Drill another hole in the back to fit your loupe. If you use a proper, affordable hole saw, the 1/16" hole already drilled will guide the saw to be concentric.

No ground glass necessary. Then we should describe aerial focusing. Quite easy.

Best of luck!

[LabRat]

Funny that you should ask. What I've done has been to mount the lens in question on a Speed Graphic board, put it on (surprise!) a Speed Graphic, focus to the desired distance, take the lens off, a drilled board with no lens on the camera and measure the flange-to-film distance with a depth gauge. The OP may have to borrow a camera to do this. Speed Graphic not necessary, it was what I had at the time.

Its better than guessing, which is what using published flange-focal distances amounts to. Published flange-focal distances are great for finding out what can probably be done but that's not what the OP needs.

About the need for focusing. The shortest lens I've had -- still have it -- for 35 mm is a 24 mm. It has to be focused for best results. My 35 Apo-Grandagon has to be focused for best results.

I'll back up this suggestion from Dan, but I'll add something about the depth gauge...

If your lensboard mounting hole is more than 1" dia, a good, cheap tool to measure would be an adjustable square from a hardware store... With a another test camera, focus the lens to subject at your desired distance, then remove lens (but not lensboard)... Then the ruler part is inserted through the lens hole (if it fits), have a film holder with a piece of scrap film loaded (with the dark slide removed), touch the end of the rule to the film,and slide the square until it touches flush with the area where the lens sits... Lock the rule to the square, remove, and read the distance... When setting up your new camera, Build/use the same distance you measured... Leaving it a little short of this distance and by leaving some room to adjust this distance will allow you to fine tune your final adjustment...

Don't feel that you have to use the lensboard you have already, as you can easily make a new, smaller board that will match up to your design better, and might make it easier to build in some adjustments to fine tune your fixed focus,or maybe add some simple focusing device you can rig up...

I might have missed it, but what lens FL/make were you thinking of using???

Have Fun!!!

Steve K

[Degroto]

Bit by bit my camera comes together. It looks like crap (still). Sorry I don't have photo's yet. As good as I could I managed to get infinity in focus and subsequently have tried ever since to get a filmholder in the plane of focus :-) Just a bit more and then painting the insides black and go for a testride with the camera. Propably my second attempt will be one following all the advise I have gotten here :-). Will post some photo's soon though... to be continued...

[Degroto]

@Steve I use a 65mm super angulon wide angle lens. I decided to use the Sinar lens board because it is already on it and I don't have the proper tools to take it off.

[McGirton]

From where do I measure de focal lenght of the lens? From the plate where the lens is attached?

Hello from France!

This is a frequently asked question ;)

What you want is to set the proper distance between the lens mount and the film.
Hence, to do this, the knowledge of the focal length is not really useful, as strange as it may seem!
What you need is a distance given by lens manufacturers, named "flange focal distance" or sometimes "Flange Focal Length" (e.g. in Fuji lenses documentation).
This is the distance between the back side of the shutter and the focal point. The focal point is where an image of a far-distant object is projected sharp.
Now in order to properly set your lens mount in front of your film holder, you have to take into account the film holder's depth, which is for modern film holders compliant with the ANSI standard
- 2" x 3" and 4" x 5" : 5.0 mm +- 180 microns (0.197" +-0.007")
- 5" x 7" : 5.8 +- 250 microns (0.228" + - 0.010")
- 8" x 10" : 6.6 mm +- 400 microns (0.260" + - 0.016")

If you already have a springback with ground glass, simply focus the image of a distant object, no computation is required.

And if you wish to fix-focus at the hyperfocal distance, instead of infinity, starting from the flange focal distance, you'll need to slightly increase the length between the lens and film by a small amount, to be easily computed according to your working f/number, focal length and sharpness criterion.

You can have a look at this article (in French) by Gilles Barbier who built a fix-focus camera for the 5x7" format.
http://www.galerie-photo.com/barbier-hybis-90.html
In this case, focal length was 90 mm, the sharpness criterion was 150 microns, the working aperture f/16, hence the offset required to focus at the hyperfocal distance instead of infinity was 3.3 mm.

I've seen your replies a couple of times in different threads regarding this question, so OP excuse me if I highjack this one for a question. If I want to set up a fix-focus camera with a 90mm Super-Angulon, I have a Flange Focal Distance of 99mm and a Back Focal Distance of 67mm. Do those numbers change ragarding the F Stop? If I wanted to have the image sharp at f8, would the distance of the lens to the film change at f22? Or is f16 / f22 just a more "comfortable" area for the setup. The 67mm BFD should stay the same, no matter the how the lens is stopped down, correct?

[Dan Fromm]

FFD at infinity is FFD at infinity is FFD at infinity ...

BFD at infinity is BFD at infinity is BFD at infinity ...

Both are independent of aperture.

When you set your camera up, focus the lens, don't rely on published FFD. Lenses as made rarely have the focal length engraved on them or the FFD published in the brochures. For best results, focus the lens or measure its FFD at infinity.

[McGirton]

Yes, first I will confirm the distance with my full plate camera, then with the one I am building. It's a custom 6x12 so no ground glass, but I am making one to confirm the focus. Thanks!

[Degroto]

McGirton: No problem as long as I learn something from it :-). I have decided to go back to the drawingboard. My experiment that I was working at was a hopeless disaster :-D. My next attempt will be a pinhole first. If the camera is nice and sturdy that leaves me time to figure out the focus issue. I decided to take apart the lens so I can make a camera the "same" size as a 4x5 filmholder. A lens wrench tool is underway. I have to figure out what I can use as the focus plan of the lens. Is that where the aperture is or somewhere else? Is it at the back of the shutter? So back to reading this thread once more for information. A couple of photos. At the moment held together by ducktape. That will change. Also the small peices of wood on the inside will be replaced for larger ones the will go all the way along the inside of the camera so the filmholder will rest on it completely. This is more for distance measuring and stuf. A tiny spot of glue to hold it in and yet easy to take it of again. Of course the home made pinhole will be attached to the outside.
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[Jac@stafford.net]

I make simalars.

For point-n-shoot at ordinary subject distances focus is critical. Choose wisely according to your habit. A focusing mount is best and worth the investment.

Here is my 4x5" with 47mm ƒ5.6 Super Angulon in a focusing mount. (It also has a ground glass back.) My next version on the bench at the moment uses the 47mm XL for more even coverage. The depth of the body will have to be deeper via a spacer.

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Hope this helps.

[Degroto]

Thanks. For some reason I am worried if the whole steup wil cover the whole negative. It will but still. Where did you get the screwthingy so you can attach the camera on a tripod? One for a decent price?

[Jac@stafford.net]

For some reason I am worried if the whole steup wil cover the whole negative. Where did you get the screwthingy so you can attach the camera on a tripod? One for a decent price?

Is 50-cents a decent price? :)

There a couple good options for either 1/4" or 3/8" mounting. For the camera shown below, the bottom piece is oak. I used a three prong T-nut (http://www.fastenersuperstore.com/product_specs/nuts-tee-3-4-prong)inserted from the top, and recessed so that it is flush at the top. (I choose a T-nut with shallow teeth or grind them down a bit.)

Another approach that works when you have a blind hole (cannot work from the top-down) is to use a threaded insert like this one (https://www.albanycountyfasteners.com/mm5/graphics/00000001/Brass-Thread-Inserts-Product-1-(RESIZE)-min.jpg). I like this particular kind because of the long lead which fits snugly in the predrilled hole to guide installation properly. Use bar soap to lubricate the brass threads to ease the installation.

The back is often the finicky part. For this camera I used a *Jay Bender 4x5 back (https://d2ydh70d4b5xgv.cloudfront.net/images/9/f/bender-4x5-wooden-view-camera-assembled-large-format-lightweight-exc-nr-03e5ebf0a52d8ae40b153680357066b0.jpg). For all the others I find a used Graflex universal. It makes life so much easier.

*Jay has retired, but sometimes you can find them.

[Havoc]

Bit like my try to make a pinhole for 4x5:
http://users.skynet.be/sb262617/forum_foto/pinhole.jpg
Used alu because I have some around. The large hole is made so that a Fuji SWD 75 can pass through but so far I only tried with a pinhole taped in place. To have a tripod screw I'm going to recover the mounting plate from a broken camera. Easy to find and a source for other pieces as well.

I should continue so it is ready for pinhole day.

[Degroto]

Does the screws have european threads or english?

[Havoc]

Tripod screws are some kind of imperial thread. I have not yet found a source for a tap in europe and for single use I'm not going to risk customs.

[Jac@stafford.net]

Tripod screws are some kind of imperial thread. I have not yet found a source for a tap in europe and for single use I'm not going to risk customs.

They are most common in the EU and USA. (Yep, even on my British motorcycles.) You don't need a tap if you use the fasteners I suggested earlier. Where is my friend Randy Moe when I need backup?

Tripod thread sizes originated in Europe or Britain. They are universal everywhere!
1/4" X 20 and 3/8" x 16.

If you worry about choosing one of the two, then get 3/8" x 16 and the common thread reducers (https://i5.walmartimages.com/asr/bff755f7-4cf3-411a-b142-8d09b958bcb4_1.d9eb40d0e4a2beeebe59801da51a7e21.jpeg?odnWidth=undefined&odnHeight=undefined&odnBg=ffffff) to 1/4 x 20 and be happy.

[Jac@stafford.net]

To have a tripod screw I'm going to recover the mounting plate from a broken camera.

Not necessary. The 1/4" or 3/8" sockets are common fasteners. Since you have some aluminum to add thickness you could cut a piece to fit inside the camera, screw it down from the outside, then drill and tap for the tripod screw. Keep it simple.
.

[Degroto]

I have my pinhole version almost ready. In the mean time I have ordered a lens tool so I can put my 65mm lens on a home made lensboard. Then I can start contructing camera nr2 with the lens. And the saga continues....

[ic-racer]

Hi,

Recently I picked up a sinar camera with a bunch of lenses. Including a sinaron F5,6 65mm lens. Now I want to try a simple fixed focus camera with this lens. My reasoning that the DoF will be big enough to do without a focusing system. Is my thinking correct?

Peter

If you place you subject always at the focal distance, results will be the same as a focusing camera.
If the subject is not at the focal distance, the results will be the same as a focusing camera with improper focus.

[animaux]

Here’s my take on the idea. A cardboard tube between two coupling frames. I’m still trying to get a Norma aux standard for the back too. It is really light and a joy to handle.

174255 (https://www.flickr.com/photos/animaux/25179285518/)

[Havoc]

If you place you subject always at the focal distance, results will be the same as a focusing camera.
If the subject is not at the focal distance, the results will be the same as a focusing camera with improper focus.

Shouldn't the depth of field also play a role? Like hyperfocal distance? At the apertures typicaly used for pinhole and LF photography it seems to me you could get away with it. Provided the distance lens-film is correct for the hyperfocal distance of course.

[LabRat]

Shouldn't the depth of field also play a role? Like hyperfocal distance? At the apertures typicaly used for pinhole and LF photography it seems to me you could get away with it. Provided the distance lens-film is correct for the hyperfocal distance of course.

Even at the hyperfocal point, and you used a medium f-stop, the focus is barely acceptable (for smaller enlargments), but not optimum... Take a smaller format SLR camera (like a 60mm on a 35mm or 6X6 SLR) and put on a FL close to what you are mounting on the new camera (65mm???), and walk around focusing it critically on a # of scenes and see what you see/shoot with a roll of film...

I think a camera should have at least some focusing capability, as "hyperfocal" means to me (in practice) that that things in the near front and behind the focus point will be in good focus, with a variable gradual fall-off close and further away , or the camera will be kinda a "one trick pony", instead of having a range to handle a variety of shooting situations...

Another focusing option is fixed mounting on the front, but the back moves outward... Technical cameras have the rear tilt feature where the rear slides out on rods etc, but if that were on threaded rods, one could turn or slide the back adjustment so the camera would set default at infinity closed, but could be extended as needed, and maybe even some back tilt could be added... Some sliding/locking rods, threaded rods with knobs, or even flat slotted brackets with a hold down knob can be used easily, and common hardware store items... Does not have to be super precise, as this is basically a LF camera with some slop factor within... (Fear not...)

Look at back tilt options on many older cameras for ideas...

Good luck!!!

Steve K

[Havoc]

Look at back tilt options on many older cameras for ideas...

If you mean something like the Mamiya Press (don't remember which version) then I'm not very fond of it. Completely unusable without a tripod.

[Pere Casals]

Hi,

Recently I picked up a sinar camera with a bunch of lenses. Including a sinaron F5,6 65mm lens. Now I want to try a simple fixed focus camera with this lens. My reasoning that the DoF will be big enough to do without a focusing system. Is my thinking correct?

Peter
Just google DOF Calculator, select film type, f, L, D, and see hyperfocal distance

you can also download an app for the phone...

[LabRat]

If you mean something like the Mamiya Press (don't remember which version) then I'm not very fond of it. Completely unusable without a tripod.

Yes, but not necessarily, as my Linhof Tek III has them and I can "trim" the focus when the 65mm is in the body shell, and lock down for a "hyperfocal" setting, but the same idea with threaded knobs (with springs pushing outward)... The knobs can be all set with the same amount of rotation, or a cog belt around all of the knobs/nuts to move them evenly, but in practice giving them all the same rotation should suffice (like 4 volume control knobs all set the same)...

This does not have to be rocket science, but can be something that can be built on a kitchen table if necessary... A good design is the first part...

Steve K

[Havoc]

Just google DOF Calculator, select film type, f, L, D, and see hyperfocal distance

you can also download an app for the phone...

If you do that and select 4x5 film and a 65mm at f/16 then if you focus at 2.7 meters, everything from 1.3m to infinity is about just as sharp. Close enough to a point-and-shoot to me. Even at f/8 it would be usable.


This does not have to be rocket science, but can be something that can be built on a kitchen table if necessary... A good design is the first part...

Yep, better spend twice as long designing then 4 times as long debugging.

[LabRat]

Yep, better spend twice as long designing then 4 times as long debugging.

Fine, do what you want, but maybe it was just easier to buy a cheap helical... :-(

Just trying to help...

Steve K

[Jac@stafford.net]

Here’s my take on the idea. A cardboard tube between two coupling frames. I’m still trying to get a Norma aux standard for the back too. It is really light and a joy to handle.

174255 (https://www.flickr.com/photos/animaux/25179285518/)

Interesting. You could have various spacers for specific 'bellows' extensions. Is what is already close to the lens board?
... what are you using for a tripod mount?

BTW - Graflex made aluminum extensions for some of their cameras, the XL I think,

[Jac@stafford.net]

Fine, do what you want, but maybe it was just easier to buy a cheap helical... :-(

OMG! Something like a function with one parameter. :) Nah. Too simple. Too perfect.

[animaux]

I just built this one »spacer« specifically for the 75mm focussed at infinity. The writing on top states the hyperfocal distances for the snadard aperture numbers:

ƒ5,6 —> 6.1m
ƒ8 —> 4.9m
etc.

I have yet to attach a tripod mount. Still not sure where to attach it. I’ve only just used it lying down on some wall or what else I could find.

[Degroto]

I have my forst version ready and turned it into a pinhole. My woodworking skills reaqlly suck! :-) Now busy with the second version. I think I will use one old filmholder to create a sort of groundglass holder so I can determin the correct distance of the lens to the film plane.

[LabRat]

I have my forst version ready and turned it into a pinhole. My woodworking skills reaqlly suck! :-) Now busy with the second version. I think I will use one old filmholder to create a sort of groundglass holder so I can determin the correct distance of the lens to the film plane.

Your woodworking does not have to get in the way... Using paper products (matboard, cardboard, boxes, tins, etc) that can be cut easily anywhere with sharp knives etc, work too...

With a camera back (with GG), box, lightproof tape, etc you could build one in the jungle, or anywhere else, so don't make it too hard to find a solution...

You can do it!!!

Steve K

[Degroto]

I have decided on the focal distance. I think it is pretty good but I want to be sure. So a photo and a 100% crop. Is it good or can it be better?

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[Jac@stafford.net]

Looks pretty darned good to me! Excellent compromise, which is the very hardest part. Good for you.

I am working on a similar project (http://www.digoliardi.net/4X5-skl/1.JPG)with a camera with three preset focus distances. Prognosis - not so good yet. :(

[Eric Woodbury]

Here's my version of a 4x5 fixed focus snapper. Lens' back-working distance is set such that by f/16 everything from 21 inches to infinity is in focus. This works well for a 47mm, since coverage is close even at f/16 and lens performance probably not that great until a few stops down. I calculated the distance from information available at Schneider webstie and machined the box appropriately. No viewer on it yet. I am going to use a peep-hole viewer for a door. Accessory points top and bottom are 1/4-20 T-nuts. Film holder is held in place with rubber band and velco strip. Funky, but it works. I'd like to add a grip.

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[Jac@stafford.net]

I like it, Eric. My favorite lens. Good wood joinery, too! I gotta learn how to do that.

Viewfinder from peep-hole? That's what Peter Gowland used in a beautifully machined body for one of his cameras. You can see one version here (https://www.ebay.com/itm/Peter-Gowland-gowlandflex-Antena-Scenic-4x5-Camara-construido-a-medida-con-extras-Excelente-/292344508002?_ul=AR&nma=true&si=rXEQh4G948PCUk%252BCP4Dt695cgoo%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557). I have his later refined version with a machined front frame shaped to make 6x12cm. I can post a picture of mine if you wish.

[Degroto]

Thanks Jac. I am pretty happy as well. Although I do realise the photo's appaer rather small here. Now I have to finish it of with a screwmount for a tripod and some paint. I will post some photo's shortly. Although after seing Eric build I almost don't dare anymore haha. For a first I am pretty pleased. I need to get some iron brackets to get beside the lens so it is a bit more protected. But that is something for the wishlist.

[Jac@stafford.net]

Thanks Jac. I am pretty happy as well. Although I do realise the photo's appaer rather small here. Now I have to finish it of with a screwmount for a tripod and some paint. I will post some photo's shortly. Although after seing Eric build I almost don't dare anymore haha. For a first I am pretty pleased. I need to get some iron brackets to get beside the lens so it is a bit more protected. But that is something for the wishlist.

Don't be self-conscious. We all begin from nothing. Just enjoy!
Regarding the lens protectors, for example on this (http://www.digoliardi.net/super-wide-4x5-1.jpg), go to your
local home supply place's drawer pull accessories. Add a couple
brass washers to the base and be happy. :) (In my build they
serve as a place to hold the camera.)

We have already discussed tripod mount. Google 'T-nut'.

[Degroto]

I already got two tripod mounts. One for my pinhole and one for this camera. I'll look into the lens protectors. Thanks for the link.

[Pfsor]

I'll look into the lens protectors.

You can choose those you like when you look for drawer handles (for furniture). All sizes and types available, good for your purpose.

[Degroto]

So thought a couple of photo's from my camera would be nice. I stil have to finish it but it is in working order.
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