Using a supplementary (AKA auxiliary or close-up) lens (AKA filter)
on a large format camera

"Supplementary Close-up filters".  Talk about a misnomer -- or two or THREE!  First of all, they are NOT "filters".  They are lenses and have a focal length to prove it.  Secondly, they CAN be used in close-up photography, but they have other uses as well.  Thirdly, they CAN be used to supplement another lens, but they don't have to.  They can function quite well on their own.

But normally, you would never think of using an auxiliary close-up lens/filter on a large format camera. Why? Because you don't need it. You simply add more bellows extension if you want to focus closer. But there are a couple of ways that close-up lenses can benefit your large format photography.

Most close-up lenses are marked with their diopter number, such as #1, #2, #3, etc.  Some use the designations +1, +2, +3, etc.  A #1 diopter close-up lens has a focal length of 1000mm (or 1000mm divided by 1), so any lens when focused at infinity will focus at 1000mm  (40") when the close-up lens is attached. A #4 diopter close-up lens has a focal length of 250mm (or 1000mm divided by 4), so any lens when focused at infinity will focus at 250mm (10") when the close-up lens is attached.

But some close-up lenses are not marked with standard diopters. Minolta, for example, uses it's own system. Its No. 0 close-up lens has a diopter of 0.94, its No. 1 close-up lens has a diopter of 2.00, and its No. 2 close-up lens has a diopter of 3.80. Minolta also made a close-up lens specifically for it's 100-500mm zoom, but it is not marked with any sort of power designation, but it happens to be a 0.37 diopter lens. Other companies, such as Nikon and Leica, use odd systems as well -- the numeric designation on Leica's close-up lenses actually DECREASES as the diopter strength INCREASES.  Go figure!

Close-up lenses can be purchased individually, if you have a particular diopter in mind, or they can be bought in sets. The most common set is a #1, a #2 and a #3 - which gives you diopters from #1 to #6 when used singly or together in various combinations. Combining a #1 with a #3 gives you a #4, for example.  Another frequently seen set is a #1, a #2 and a #4 -- since the #1 and #2 can be used together to make a #3. Another set is a #1, a #2, a #4, and a #10. When using close-up lenses, it is best to use as few as possible, and if you are using more than one filter, always put the highest diopter lens on the camera first for the best results. If using other types of filters, such as a polarizer, put them on last.

But not all close-up lenses are created equal. Most are single-element, meniscus lenses that are not coated.  They are referred to as "chromatic" (having color) optics with color-fringing -- most noticeably away from the center of the scene and especially on the edges of objects or shadows.  Minolta, like some other manufacturers, made higher quality, double-element close-up lenses that are fully coated. These are referred to as Achromatic lenses -- "A" (away from) "chromatic" (having color).  Although more expensive, this helps deal with some of the chromatic aberration that occurs, and the coating helps reduce flare. And then there are a few Apochromatic -- "Apo" (not having) -- close-up lenses that have even better correction for chromatic aberration, but these are even MORE expensive.  But in any case, it is best to stop-down as much as possible to obtain the greatest edge-to-edge sharpness (assuming that is what you want!). Stopping down is more important the higher the diopter of the close-up lens. And using a lens shade will help as well.  Here is a simplified comparison of how the different types of close-up lenses operate:

If you would like to delve a bit more deeply into the nature of "simple" lenses and optics, I highly recommend reading this well thought-out and well-worded summary before proceeding on this page.

While most people think of close-up lenses strictly for use in close-up photography, they actually have other good uses -- especially if you are using a camera with a bellows. Since the close-up lens shortens the focal length of the lens to which it is attached, it can be used to shorten the focal length of lenses on cameras with flexible bellows. The image will need to be refocused to the distance desired, but with a flexible bellows, focusing to infinity is usually very easy -- even though you are using a close-up lens! The formula and chart below show some of the possibilities with various lenses and close-up lens additions.

COMPUTING ADJUSTED FOCAL LENGTHS
WHEN ADDING SUPPLEMENTARY CLOSE-UP FILTERS/LENSES

Gullstrand's Equation

X = 1000 / (1000 / Y) + Z))

Where:

Y = the original (or starting) focal length in mm (in green)

Z = the diopter (not the focal length) of the close-up lens to be used (in yellow)

X = the new (or adjusted) focal length in mm (in blue)

Some examples are:

These figures are only approximations because the actual focal length (X) will vary slightly depending on your situation, such as how much distance exists between the prime lens and the close-up lens(es).  Using close-up filters in this way gives you much more flexibility in your existing list of lenses.  For example, if you only have access to three lenses, adding a couple of close-up lenses will basically put a dozen lenses in your camera bag.  But pick the close-up lens or lenses to meet the focal lengths that you will need to use -- until you can afford more lenses.  Even if you only buy one close-up lens, it can give you a lot more flexibility for very little money. For example, say you currently have a 300mm (tele), a 150mm (normal), and a 90mm (wide).  By adding a single #2 close-up lens, you'll end up a 300mm, a 190mm, a 150mm, a 115mm, a 90mm, and a 75mm.  Not bad!  Try to get two element optics that are fully coated in order to get the best possible results.  This is usually hard to determine, unfortunately.  For example, Minolta's close-up lenses are all excellent two-element optics that are fully-coated, but these facts are never mentioned on the box or on the instruction sheet.  Here is a website that can sort out some of your options:

http://fuzzcraft.com/achromats.html

And in any event, always use a lens shade, but the lens shade that you normally use with the lens might cause some vignetting due to the shortening of the focal length.

Here is a 77mm #4 close-up lens attached to my Fujinon CM-W 105mm lens.  The combination results in a 75mm lens, approximately.  

There is no need to adjust the exposure with close-up lenses, but you still need to use them carefully.  Make sure the close-up lens is physically wide enough to adequately cover the front of the lens it is placed on.  This is especially important with wide-angle lenses.  And watch out for vignetting after the close-up lens is attached, especially if you are using more than one close-up lens, additional filters, shifts, tilts, swings, or rise/fall.  You may find that a step-up ring to a larger close-up lens size will solve the problem -- should it occur.  

However, there is no free lunch!  The image circle created by the lens will decrease when a close-up lens is added and the stronger the diopter, the smaller the image circle will become.  And if the image circle shrinks enough, you are likely to lose the corners of the image.  This is especially true if the lens -- without the close-up lens attached -- had a small image circle to begin with.  Using the above set-up as an example, my CM-W 105mm will just barely cover the 4x5 format at infinity on its own.  With the addition of a #4 close-up lens, the image circle is decreased enough to cut off the corners of the film.  It's no big deal because with a little bit of cropping in the darkroom everything works out and I get the image I was hoping for.  You can estimate the change in the image circle with this formula (yes, yet another formula to remember):

X = (Y / Z ) * W

Where:

W = the original (or starting) image circle in mm

Y = the new (or adjusted) focal length in mm

Z = the original (or starting) focal length in mm

X = the new (or adjusted) image circle in mm

Again, using the above set-up as an example, my CM-W 105mm which starts out with a 174mm image circle will have a 124mm image circle with a #4 close-up lens -- (75mm / 105mm) * 174mm = 124mm.  Here is a GRAPH that will tell you if your new image circle will cover your film format completely.

But there is another, unexpected way to use close-up lenses on large format cameras.  Since close-up lenses have a focal length of their own, they can be attached to many cameras -- all by themselves -- to create wonderful pictures with a romantic, pictorial, soft-focus effect. Since close-up lenses are usually either simple one- or two-element lenses (there are a very few three and four element versions!), the result is a very soft image, especially at the edges -- much like the three element Fujinon SF series of lenses (they made a 180mm, 250mm and 420mm) or the two element Rodenstock Imagon series of lenses (they made a 200mm, 250mm and 300mm). And just like the Fujinon SF and Imagon lenses, the soft effect from close-up lenses can be varied by adjusting the f-stop.  Single-element close-up lenses will give the greatest softness effect, especially with higher diopter numbers, when used wide-open and toward the edges of the image, while lenses with more elements will give less chromatic and spherical aberration.  The choice is up to you.  While you don't need to use a lens shade, using one will reduce flare and glare.  Again, that it up to you.  You might be completely surprised by the quality of the images that you can obtain -- especially with lower power, achromatic or apochromatic diopter lenses, when stopped down -- and/or with B&W film.  You just might decide that the more expensive achromatic and apochromatic close-up lenses, even at higher diopters and even wide open, produce images that are too sharp for your needs!  

As the diopter of the close-up lens(s) increases, the focal length and f-stop decrease.  Since the flange focal lengths of the close-up lenses will be the same as the optical focal length, you need to keep in mind the minimum and maximum bellows extension of your camera(s). Here is a summary of what can be achieved singly or with various combinations of close-up lenses and shutters.  Please note that these are the MAXIMUM f-stops based on the width of the shutters.  You can always stop down for exposure control or to achieve more depth of field -- or sharper images:


 

Shutter

Copal #0

Copal #1

Copal #3

Diopter

Optical and Flange
Focal Length

f-stop

f-stop

f-stop

1

1000mm

41.7

33.3

22.2

2

500mm

20.8

16.7

11.1

3

333mm

13.9

11.1

7.4

4

250mm

10.4

8.3

5.6

5

200mm

8.3

6.7

4.4

6

167mm

6.9

5.6

3.7

7

143mm

6.0

4.8

3.2

8

125mm

5.2

4.2

2.8

9

111mm

4.6

3.7

2.5

10

100mm

4.2

3.3

2.2

11

91mm

3.8

3.0

2.0

12

83mm

3.5

2.8

1.9

13

77mm

3.2

2.6

1.7

14

71mm

3.0

2.4

1.6

15

67mm

2.8

2.2

1.5

16

63mm

2.6

2.1

1.4

17

59mm

2.5

2.0

1.3

18

56mm

2.3

1.9

1.2

19

53mm

2.2

1.8

1.2

20

50mm

2.1

1.7

1.1

But you need to do two things in order to use these close-up lenses as soft-focus lenses. First, figure out how to attach the close-up lens to a shutter -- with the lens elements removed from it.  I'll let you figure that out since everyone's situation is different.  The first step is, normally, to get an adapter for your shutter to a standard thread or connection of some type, such as a Leica (39mm) screw thread. Companies such as Kyvyx, Computar, Novoflex, and probably others, have made these -- or a competent machine shop could make one for you.  There are two things to think about here.  First, you need to find the adapter for your shutter(s).  For this you might want to shoot for your largest, i.e., widest shutter.  This will give you the brightest image on the groundglass, which is nice, but it also decreases the chance of vignetting -- all at once.  But depending on your shutter, an adapter might be harder or impossible to find, and you might have to go with wider, i.e., costlier close-up lenses -- or a smaller shutter. The current crop of Copal shutters have front threads of:  #0 -- 29.5mm x 0.50, #1 -- 40.0mm x 0.75, and #3 = 58.0mm x 0.75.  That's quite a difference.

Another possible roadblock is the connection between your shutter-to-close-up lens adapter.  The "male" back end of the adapter has to be the same thread size as the front of your shutter.  It's best if the pitch size is the same as well.  The "female" front of the adapter has to be the same thread size as the back of your close-up lens -- or intermediate step-up ring(s), if needed.  Again, it's best if the pitch size is the same as well.  With my set-up, the rear of the adapter is exactly the same size and pitch as the Copal #1 shutter -- 40.0mm x 0.75.  The front of my adapter, however, has a Leica screw -- 39mm x 1.0 -- while the back of my step-up ring is 39mm x 0.75 -- just a tiny bit different.  I've never heard of an adapter or step-up ring that switches from one sized pitch to another, but perhaps they exist.  So although my adapter allows me to put most of my enlarging lenses (which are SUPERB for macro and micro work) on my cameras since they have the Leica screw thread (39mm x 1.0), I must be careful when putting my 39mm-to-55mm step-up ring onto my Copal to Leica adapter.  It fits, but not perfectly.  If put on too tightly it will bind and be difficult or impossible to separate.  So be careful!  

Second, you need to figure out what the aperture of the new "lens" is.  There are different ways to do this from trial and error to using a ground glass metering probe.  A good starting point is to compute the focal length based on the diopter(s) and then divide by the shutter iris diameter (Copal #0 = 24mm, Copal #1 = 30mm, Copal #3 = 45mm).  Don't be surprised if you end up with an f2.0 lens!  And, of course, the f-stop numbers on your shutter is now pretty irrelevant, but you can use the scale to stop-down incrementally.  

With these types of setups you need to watch out for vignetting due to the lens shade, the diopter of the close-up lens(es), the width and depth of your adapter(s), the depth of your shutter, as well as the width of your aperture.  In some situations you might need to use a wider shutter, a shorter adapter, a wider lens shade -- or a combination of these.

Here I placed TWO Minolta No. 2 close-up lenses on a Copal #1 shutter with the help of a Copal to Leica adapter and a step-up ring.  This combination (7.6 diopters) results in an approximately 130mm f4.5 soft-focus lens (1000mm / 7.6diopter / 30mm = f4.4).  This is what you would expect, given that the Fujinon SF 180mm using the same shutter is an f5.6 lens.  The soft-focus effect, which is actually quite minimal, can be decreased (and the depth-of-field increased) by just stopping down.  So it is very similar to having a Fujinon SF or Imagon lens -- at a greatly reduced price.  And given the existing equipment that you currently have, it might cost you very little -- and perhaps nothing at all!

Why do I have both 55mm close-up filters and 77mm close-up filters?  I could get by with just the 77mm filters, but they are all single-element lenses and have the least amount of correction for chromatic and spherical aberration.  The 55mm are achromatic lenses and bring the red and blue spectrums together while reducing the spherical aberration as well.  They are fine for my 35mm and 4x5 lenses (even my 37mm fisheye!) with filter threads of 55mm, but many of my lenses, both 35mm and 4x5, have wider filter threads.  Plus, sometimes I want a softer effect than the 55mm achromatic lenses produce.  I can always get the chromatic 77mm lenses on with a step-up ring, when needed.

Here are a few websites that have some photographs using some of the techniques mentioned on this page.  OK, not all of them are taken with large format cameras, but the methods are the same -- or similar.  Some of these shots were taken with very old, very simple lenses from very old, very broken cameras -- very cheaply, I might add.  Websites like these can be hard to find on the web because if you search for "close-up lenses" or "supplementary filters", you undoubtedly end up with tons of macro shots.

http://galactinus.net/vilva/retro/eos350d_meniscus.html

http://galactinus.net/vilva/retro/meniscus_bw.html

http://forum.mflenses.com/meniscus-lenses-t63197,start,30.html

http://forum.mflenses.com/meniscus-lenses-t63197.html

http://tonopahpictures.0catch.com/150Eidy/12inchDarlotLandscape.html

Why pay hundreds of dollars for a Fujinon or Rodenstock Soft-focus lens when you can get an adjustable alternative for about 1/10th the price?

OK, so now we have gotten far afield from what close-up lenses were intended to do.  You now know that you can get great soft-focus pictures from using close-up lenses instead of your regular lenses on your large format camera.  But why not go a little further afield?  

What if you want to get even SOFTER results in your pictures? Of course, there are all sorts of approaches that you can use to do this, such as the numerous soft-focus, diffuser, texture screens and fog filters, as well as using movement, rotation, zooming or changing focus (during the exposure), and vaseline on the lens (wherever and how much you want) -- either on the camera lens or on the enlarger lens (using a spare filter, I hope).

One favored approach that is often overlooked is the pin-hole camera or lens.  You can't really call it a camera because it isn't -- even though that is sometimes how it is advertised or sold.  But you can't call it a lens either, because no lens is involved and they are not made by any major manufacturers. They are merely tiny, "needle" or "pin" holes in paper, plastic or metal. They have great depth of field due to their tiny apertures, but the edges of the image are always fuzzy. The further away from the center of the image, the softer the image becomes.  Similarly, there will be light fall-off and that too will increase the further away from the center of the image.

Different people describe the results differently -- such as romantic, soft-focus, ethereal, classic, old-timey, dreamy, misty, funny, mesmerizing, fuzzy, foggy, psychedelic, historical, hysterical, other-worldly, pictorial, out-of-focus, dizzying, mind-boggling, etc.  Some people love them and can't get enough;  others hate them with a passion. I'll leave that part up to you.

Here are two websites where you can see some of the amazing results obtainable if you turn your large format camera into a pinhole camera:

http://econtent.unm.edu/cdm/landingpage/collection/pinhole

http://www.pinhole.org/

The best pinholes are laser-made pinholes in small, very thin metal sheets because these have very clean edges -- but these are also the most expensive. They come in a variety of "focal lengths", just like real lenses. And they normally don't come in easy-to-use, common mounts, attachments or adapters. They are just pinholes in some sort of material. I'll let you figure out how to attach them to your camera. And if you want to use filters -- and you can -- you will need to figure out how to attach them.  Here's how I did it.

My pinholes are:

Here is the f-stop breakdown starting at f16:

f16 - f22 - f32 - f45 - f64 - f90 - f125 - f180 - f250 - f360 - f500 - f720

So, on a sunny day, which normally calls for f16 (at the reciprocal of the film speed as the shutter speed), with a 300mm pinhole (about f500) you will need about 250 times as much light.  With ISO 125 speed film that's about an eight second exposure -- or about 30 seconds after reciprocity failure adjustment.  It, of course will be even longer with slower film, darker settings, filtration adjustment and/or compensation for close-up bellows extension.  So be prepared for long exposures -- a steady tripod, lots to eat and drink, a comfortable chair and a good, locking cable release.  And NEVER forget to adjust your exposure and development for reciprocity rule failure after extension and filtration is added!

As you can see, the apertures are tiny and they are not adjustable. Other companies make pinholes of other focal lengths -- or you can make them yourself, but you will have to figure out the f-stop and the focal length. Either way, you have to attach them to your camera -- somehow. I know of no photographic meter that reads to f455, so bring a calculator or piece of paper. With pinhole cameras the focusing is not fixed. These are just estimates to get the overall sharpest results. So, for example, with a 75mm pinhole, create 75mm of extension on your camera between the pinhole and the film. You will need a tape measure. This will, of course, give you the best possible picture at infinity, but with the incredible depth-of-field it should cover all distances well. You can focus closer, but you will need to adjust the time accordingly and focus on the ground glass carefully -- if you can! You can focus pinholes at any distance, but getting an usable image on the ground glass is not easy. In all cases you will need a very good ground glass cover. People will think you are a complete idiot, but you will get great results. My Toko's maximum bellows length is 360mm so I can't go any longer than that (without some modification) but I like the wider-angle pinhole shots anyway. It's just something to keep in mind when searching for pinholes. With most 4x5 cameras you will not have a problem -- other than attaching the pinholes to the shutter.

The focal lengths and f-stops listed above are for my particular pin-holes AT INFINITY.  They can be used at closer distances, of coarse, with or without changing the focus, but for the sharpest results when focusing closer, it is best to adjust for the change in the f-stop and an increase in the exposure time as a result.  The closer you want to focus, the more change will be needed, just as with a regular lens.  If you find yourself wanting to focus closer than infinity often, it would behoove you to made a graph for each pinhole indicating the subject distance and the f-stop.  From that you can calculate the exposure time given the ambient light.  Here is an example:

For five of my pinholes (118mm to 289mm), are supported by using a Leica (39mm) thread, metal lens cap. First, a hole (about 1/4") is drilled in the center of the lens cap and then the pinhole is taped to the rear of the lens cap so that the pinhole is in the middle of the 1/4" hole. Together with a Leica-to-Copal #1 adapter (hard to find), they screw into the front of the Copal #1 shutter (after the lens has been removed, of course). This makes using them pretty easy. Chances are, one of your large lens shutters is a Copal #1. With other shutters you will need a different adapter(s).

For my other two pinholes, I had to get creative to avoid vignetting due to the width and length of the shutter and the adapter. If placed on the front of the shutter with the adapter, the image on the film was cut off on the edges. I could crop the image in the darkroom of course, but that basically gives me a longer focal length lens. Not what I wanted. These two pinholes, the 73mm and the 88mm, are attached to 32.5mm metal lens caps that ALMOST screw into the REAR of the Copal #1 shutter. I guess the rear thread is 33mm or 34mm - not something I could buy. They are just a little too small for the Copal #1 so I use a little bit of black tape to keep the lens cap and pinhole in place on the rear of the shutter.

Here are two websites to help you calculate the f-stop of your pin-hole(s) and the focal length(s) that will produce the optimal (i.e., sharpest) results:

http://www.mrpinhole.com/index.php

http://pinhole.stanford.edu/pinholemath.htm

And here is a great place that sells pinholes, singly or in sets.  It's where I got my set -- for under $50!

https://www.pinholeresource.com/

Then there are variations on the simple pinhole that gives you even more flexibility in the soft-focus realm. Think of this as a variable area or zone that lies between the true soft-focus lenses (where you can vary the softness from high to low by both adjusting the f-stop and by inserting different disks into the lens) and simple, pin-hole lenses. It's too lengthy to explain it all here, so I'll give you two resources. The first is a website from SKINK, a German company which makes a wide variety of pin-hole and pin-hole derived "lenses".  Some of their products are designed for large format cameras, some are easily adaptered (see below), while others might require some home-made ingenuity.

http://skinkpinhole.com/wp/

Here is a very nice independent review of the Skink "system" with plenty of example shots.  To see more photos just do a GOOGLE seach for SKINK and select the IMAGES tab.

http://lensgarden.com/light/skink-is-a-cool-way-to-pinhole/

OK, we've come a long way, down several paths.  It can seem pretty confusing.  So here's a summary table that might provide some perspective on the different available approaches.  The SKINK options are not listed in this graph but it basically covers the entire area of the gragh from one end to the other:

Here is a great article from Petersen's Photography (1979) by David Brooks about the various ways to get soft-focus results.  It has examples for 35mm, medium format and large format:

www.subclub.org/fujinon/softfocuscompressed.pdf

But I'm not done yet. If you are a "do it yourself" type of guy or gal, you might be interested in some similar approaches that other shutterbugs have devised using with simple, cheap (lots of times FREE) stuff and gotten GREAT results!

Here's a page from the DO IT YOURSELF PHOTOGRAPHY WEBSITE on how to build your own lenses -- from broken cameras, cheap cameras, old cameras, trashed cameras, etc.  There are several approches that you can use, some of which are outlined on this page, but their approaches are even cheaper and they have several pictures showing the results.  They don't use any large format cameras, but the techniques are the same and with details from this page you can figure out how to get it to work on your camera(s).

And I can't say goodnight before telling you about a great machine shop that either has or can make just about any adapter that you can't make, or prefer not to make, to finish your project.

Contact they by clicking on the above image or just go to http://www.skgrimes.com/products/adapters

Here is what you need to know before you contact them:

1. The diameter and pitch of the lens or filter or whatever that you want to attach to the front of your adapter.  See the diagram below.

2. The diameter and pitch of the shutter or whatever that you want to attach to the back of the adapter.  See the diagram below.

There are several, common diameters and pitches.  Use this information as a starting point.  SK Grimes might have what you need in stock.  If not, they can probably make what you need.  For CUSTOM adapters, their fees are $65 for smaller-sized adapters, $85 for medium-sized adapters, and $65 for larger-sized adapters.

Here are some common male lens and filter threads to attach to the female side of the adapter:

Regular screw mount lenses:

Microscope lenses:

Enlarging lenses:

Smaller-sized filters and close-up lenses (usually under 45mm) -- ??mm X 0.50mm per thread

Medium-sized filters and close-up lenses (usually over 35mm to 86mm) -- ??mm X 0.75mm per thread

Larger-sized filters and close-up lenses (usually over 77mm) -- ??mm X 1.0mm per thread

Here are some common female shutter threads to attach to the male side of the adapter:

So you'll need to tell SK GRIMES what the front, female end of the adapter needs to be (probably from the male lens list above) and what the rear, male end of the adapter needs to be (probably from the female shutter list above).  If what you need is not listed above, you might find it on their website, or you can email them with details.  

Last, but not least, if you contact any of the websites on this page please tell them that you found out about them from the FUJINON LENSES PAGE.  Good luck!