Black and White Film Photography - a Beginner's Primerby Jim Hannah, aka Torus34

IntroductionFor some film camera users, the lure of processing and printing their B&W film can become irresistible. This series of articles is designed to ease their path to darkroom competence. This article, and the ones that will following it, are presented as a guide through the various steps - from initial film choice to the mounting and framing of finished enlargements.

The general style is "How to" or "Cookbook". In each article, a single path will be outlined in sufficient detail to assure success. For the technically-minded, there will be information on the math, optics and/or chemistry involved. Hints, tips and other bits of information will appear here and there. Every attempt will be made to keep confusion resulting from alternative methods to a minimum. Low cost will be considered in equipment suggestions wherever possible.

Once you've followed the procedures in an article and achieved the expected result, you'll have a solid foundation of working technique to use as a basis for further exploration.

It's not possible to provide full instructions for all of the different cameras and enlargers currently available, so several assumptions have been made to simplify matters.

* It is assumed that the camera used for B&W film can be operated in a manual mode. [We'll mention a way to get around this.]* It is assumed that a 35mm or roll   film  camera will be used. * It is assumed that the enlarger permits the use of variable contrast filters or has a color head. [We'll explain how to get around this, too.] 

With that information out of the way, let's cover the first topic . . .

Film Choice

Note. Correct film choice requires some knowledge of camera shutter   speeds , lens openings (f stops) and depth of focus (DOF). That information will be presented in the second article in this series. Many wishing to explore B&W photography already know this material. If you do, skip the second article. If you don't, or if you're rusty, it will help you to understand an important relationship. 

There are a bewildering number of B&W films available for 35mm and roll film cameras. Some require special exposure techniques. Others require special processing. For now, we'll confine this discussion to films which can be processed in standard developers and fixers. We'll also add the requirement that the films are readily available. You might wish to explore the more exotic films at a later date. By then, you'll be better able to appreciate their special characteristics.

Any simple B&W film consists of three layers. The first is the light-sensitive emulsion layer. The second layer is a plastic strip which supports the emulsion layer. The third is an anti-halation layer coated on the back of the plastic strip. The purpose of this last layer is to capture light which has come through the emulsion and plastic layers and keep it from bouncing back -- blurring the image or fogging the film. 

The emulsion layer contains tiny grains of a silver salt. These salt grains have the amazing ability to soak up bits of light [photons] and, once the light has been absorbed, to react with a developer chemical and break down into pure silver. Until the silver salt absorbs light, though, it will not react with the developer. Each little grain requires a certain minimum amount of light before it will react. Curiously, the entire grain will then react with the developer -- not just the tiny parts of it where the photons struck. For each individual grain, it's all or nothing. 

This is the key the manufacturers use to make films more or less sensitive to light. If the grains are larger, less light is needed to produce a given amount of silver in the developed image. The film will turn a darker gray than one with smaller grains. It will be a "faster" film, and will produce a useable image with less total light. And of course if the grains are smaller, the opposite happens. The film will require more light to produce the same amount of silver in the developed image. It's a "slower" film.

* Film   speed  is stated as an ISO number. In years past, the letters ASA were used. The actual number is the same.

* An ASA 400 film has the same speed as an ISO 400 film.

At this point, you may be wondering why it's important to know all this information. 

There are two reasons:* Faster films are generally "grainier" when enlarged as compared to slower films. * Speed and graininess are the basis on which you choose which film to use for a specific photographic situation. 

By the way -- as you read through these articles, you'll run into the concept of a trade-off or "give-to-get" more than once. Film speed and graininess is just one example.

Commonly available B&W films have speed ratings of ISO 50 to ISO 400. The numbers you will most often see are 50, 100 or 125 and 400. The higher the number, the "faster" the film. Films with higher ISO numbers need less light to form a useful image than films with lower ISO numbers. The difference between 100 and 125 is too small to affect a choice. 

* A doubling of the film speed number means that the faster film will require only half the light to form an image just as dark as the slower film. 

This doubling adds up quickly. An ISO 100 film needs half the light of an ISO 50 film. An ISO 200 film needs one quarter the light of the ISO 50 film, and an ISO 400 film only needs one eighth as much light as the ISO 50 film. Another way to say this is that an ISO 400 film is 8 times faster than an ISO 50 film. You can see that the readily available films give you a real difference in performance. 

The image on a developed negative is made up of silver grains. The larger the grains in the film, the bigger they will appear in an enlargement. If the film is very grainy, the grains will be easily visible as speckling in an 8 by 10 inch enlargement of a 35mm negative.

We're almost ready to choose a film now, but first, we should learn two simple "rules of thumb."

* Shutter Speed Rule: Don't take hand-held pictures at shutter speeds slower than 1 over the focal length of the lens. 

The reason for this rule is that we want as sharp a negative image as possible. The longer the focal length of the lens, the more it will magnify any shakiness in our hands as we hold the camera. If the camera lens says 50mm, don't set the shutter to slower than 1/50th second.

If you put the camera on a tripod, this rule doesn't apply. You can use much slower shutter speeds as long as your subject doesn't move. That's one of several reasons to use a tripod. 

Another is to permit you to more precisely examine and "frame" the composition of the picture.

* f16 Rule: The correct exposure for an average subject in bright sunlight is 1 over the ISO number of the film, with the camera's   lens opening set at f16. 

This rule allows you to estimate the exposures you'll need with a film based on its ISO rating. For an ISO 50 film, this is 1/50th second at f16. For an ISO 400 film, it's 1/400th second at f16. If your camera's shutter doesn't have exactly the speed given by the rule, just choose the next higher speed. For ISO 50, you can use 1/60 second. For ISO 400 film, use 1/500 second.

That's all you need to know at this point to make a film selection. [If f numbers and shutter speeds don't quite make sense yet, they will once you read through the next article. We'll include information on depth of focus in that article, too.]

The 50 ASA [slow] films are the correct choice when:* the finished enlargement must have minimum 'graininess', or* the finished enlargement must have maximum detail, or* the light will be strong enough to allow an acceptable combination of shutter speeds and lens openings.

The ISO 400 [fast] films are the correct choice when:* graininess is not very important or perhaps even desired, or* the amount of light available will be low, or* shutter speeds must be high in order to stop motion.

The ISO 100/125 films are a compromise choice when you don't need either extreme. 

So, which film? Two commonly available brand names are Ilford and Kodak. Both make 35mm and roll films. The films are of high quality. The ones we recommend are:

ISO Kodak Ilford 50: Pan F

100/125: Plus X FP4400: Tri X HP5

So there you have it. If you're interested in, say, 35mm landscape   photography , you'll probably find that Ilford Pan F gives you sharp, fine-grained negatives that you can easily enlarge to 8 X 10

inches. If, on the other hand, you want to take pictures in low light situations or pictures of moving objects where high shutter speeds are necessary, Tri-X or HP5 will be your choice. And if you don't

feel that you need either extreme, Plus-X or FP4 are ready to serve your needs. 

Whichever film you choose, we recommend you work with it long enough to really get to know it. It will become your first standard to judge other films against. 

The next topic in this series will be shutter speeds, lens openings and depth of focus.

Welcome to the second installment of Jim Hannah's Black & White Film Photography! 

As promised, we will first let Jim address the questions that have been put to him since Part One. 

 

Q.   Dear Jim,  Thanks for your informative article posted on TPF. I'm only new to B&W photography and as such immensely appreciate this series of Beginner's Primer.

I have seen some nice B&W work with very soft-tones and would like to have a try myself. My question is: how to make a soft-tone B&W photo look highly contrasty as well, assuming high contrast is almost always desired in B&W photography (on this point, please correct me if I´m wrong). Is it something to do with film choice or is it more about after-work in an editing program of graphics?

I look forward to reading your next article and thanks again for your help.

A.   Thank you for the kind words. Believe it or not, I’m getting a kick out of writing these articles.

I’m not quite sure what you mean by soft-tone. I suspect that film choice is not the primary factor. Iif you mean a smooth rather than a grainy image, a low ISO film is the way to go. Full normal development should produce an image of good contrast for normal subjects.

There are many ways of modifying the appearance of a print, regardless of the film used for the negative. One is by controlling the warmth or coldness of the image. This is done through paper selection [warm, neutral or cold tone] and/or by toning the image of the final print [sepia and selenium toners, for example.] The contrast of the image is controlled by the use of variable contrast filters or by the choice of grade with single contrast papers. Finally, the basic exposure of an enlargement shifts the entire range of grays up or down the scale. There are also styles known as ‘high key’ and ‘low key.’

A finished print can also be scanned into a computer and manipulated in many ways with a program such as The Gimp or PhotoShop. There are some exotic wet-chemistry processes which manipulate the contrast and gray range of a print. Lith printing is one of them.

I’ll cover the basics of print contrast and exposure in an up-coming article on enlarging.

I’m glad you enjoy b&w. It’s a marvelous challenge.

If you have a question for Jim after reading this month's installment, just follow the link below!   Your questions and his answers will be published in this space next month.    Enjoy the series!   

Black and White Film Photography - a Beginner's Primer Part II:

Shutter Speeds, Lens Openings, and Depth of Field (DOF)

by Jim Hannah, aka Torus34

This article will provide the information required to set a camera for the correct exposure in manual mode.

Let's start with the lens openings and shutter speeds. It may make it easier for you to understand what they are all about if you think of the shutter of a camera as an on/off switch and the lens openings as a volume control.

Take a look at your camera. There will be a series of shutter speed numbers marked on a dial. (A few cameras, such as the Yashica Electro series, don't have such a dial. We'll provide a suggestion for these cameras at the end of this article in Appendix A.)

If your camera is quite old, the shutter speeds will include numbers in the series 1, 1/2, 1/5, 1/10, 1/25, 1/50, 1/100, 1/200 and 1/400 second. If your camera is newer, the series will be 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500 and 1/1000 second. Your camera might show them as 25, 50, 100, 200, etc. Also, your particular camera may not have numbers at the slow (1, 1/2, 1/5) or fast (1/500, 1/1000) end of the series, but it will have a range of numbers.

These numbers are the speeds you can set for your camera's shutter. The shutter, remember, is an on/off switch. The speed setting tells it how long it should be 'on' or open when you press the exposure button.

* Each number in the shutter speed series reduces the 'open' time by 1/2 compared to the previous number.

If this half or double concept sounds like that in the ISO film speed series, congratulations! Halves and doubles are the very foundation, the bedrock, of the film exposure system.

Now let's look at the lens opening numbers. Again, there will be a series of them. The series numbers are 1.4, 2, 4, 5.6, 8, 11 and 16. Again, your camera might not have all of them. In addition, it may have a different number at the start of the series, such as 1.2, 1.7 or 1.8. It

may even have an additional number, 22, at the end of the series.

OK. Here we go. Each number in the lens opening (or 'f' or 'f stop') series is a setting which controls how much light comes through the lens when the shutter is open. But be careful here -- as the f numbers get bigger, the amount of light allowed through the lens becomes less. It's a volume control, all right, but it's a volume control in reverse.

* Each number in the lens opening series reduces the light flow through the lens by 1/2 compared to the previous number. 

Now let's put what we've learned so far to use.In the first article, we stated a rule of thumb called the f16 rule. * f16 Rule: The correct exposure for an average subject in bright sunlight is 1 over the ISO number of the film, with the camera's lens opening set at f16. 

(What about light meters? Please see Appendix B.)

What this rule means in practice is that our basic bright sunlight exposure for an ISO 50 film is 1/50 (1/60) second at f16. But it doesn't mean that we must use only 1/50 second and f16. We can use any other combination of our available shutter speed (On/Off switch) settings and f (volume control) settings that will let in the same amount of light.

What are these combinations? This is where the half/double idea makes things very simple. 

Every time we make the shutter speed one speed number faster, we must make the lens opening f number one number lower. Remember that the f numbers run 'backward' -- larger numbers let in less light. 

In other words, 1/60 second at f16 is the same as 1/125 second at f11. And 1/250 second at f8. And 1/500 second at f5.6. The only restriction is that we eventually reach the end of one of the number ranges on our camera.

At this point, you might wonder how to go about choosing one correct combination from those available. They can't all be equally right, can they? The answer is that for each picture you take, there is one combination which is usually "better" than the others.

Here's one rule to help in choosing the right combination:

* Shutter Speed Rule: Don't take hand-held pictures at shutter speeds slower than 1 over the focal length of the lens. 

If you're using a 50mm lens and hand-holding the camera, all combinations with shutter speeds slower than 1/50 (1/60) second will probably give you a blurry negative. Using a 135mm lens? Discard combinations with shutter speeds less than 1/125 second.

Next, if you're photographing a fast-moving object and you don't want a blurry image, you'll probably want the fastest shutter speed that still has an f number matching those on your camera.

There's just one more thing to consider. We mentioned it at the beginning of this article, and that's depth of focus (DOF), or depth of field. Now is the time to learn about it and put it to use.

We'll start by looking at what a camera lens does. When you point a camera at a subject and open the shutter, light from the outside world enters the camera. When this happens, the camera lens will be set to some focusing distance; let's say 6 feet. The lens will capture the light from the scene that you've pointed it at. It will focus it and guide it to the film. 

Everything in the scene exactly 6 feet away from the camera will be in sharp focus. Anything closer or further away will not be in sharp focus. In fact, the closer the object is or the further away it is, the blurrier it will appear on the film.

Happily, there's some "wiggle room" here. While in a strict sense only one precise distance will be in sharp focus, this is the real world. We can tolerate small amounts of out-of-focus blur and not even know that it's there. There's a depth of focus - a "closest distance" and a "furthest distance" which define this range of acceptable distances. We abbreviate it as DOF.

* The distance range of acceptably sharp focus is the depth of focus (DOF). 

There's just one more piece to this entire puzzle. It's related to the size of the hole in the lens opening mechanism in the camera lens. We adjust this opening with the f number setting. Whenever we reduce the size of the opening (using a larger f number, which means less light), the range of the DOF increases. Think of it as making the lens 'squint' and you've got the idea firmly nailed down. Incidentally, the acceptable range closer than the actual focus setting on the lens is half as large as the acceptable range further away from the actual setting.

* To increase DOF, go to a larger f stop number. (Smaller actual opening.)

* To decrease DOF, go to a smaller f stop number. (Larger actual opening.)

As promised, that's the last piece of the puzzle for determining a basic exposure. If you remember, we mentioned give-to-get situations when we discussed film speed and graininess. We've now added a couple of others.They are:

* Increasing the shutter speed to reduce motion blur must include increasing the lens opening to let in more light. The increase in the lens opening reduces the depth of focus range.

* Decreasing the lens opening to increase the depth of focus range must include slowing the shutter speed to let in more light. The decrease in the shutter speed increases motion blur.

You now have the basic knowledge needed to pick out a reasonably correct combination of shutter speed and f number for a specific exposure. It depends on what you feel is more important in the final picture: reducing motion blur or increasing the depth of focus.

Once you make this decision, you'll find that there is one combination of shutter speed and f number that is better than the others. There will be times when you want to blur a background or show motion with a blurry image. That will mean that you choose a different combination to get the effect you want. 

When you begin to use manual settings, the choice becomes yours -- not that of the designer of the camera. It adds to your control over the final print.

Appendix A. Yashica Electro-style camerasAs mentioned above, these cameras do not have a speed control dial. Rather, they have a dial on the lens which allows you to adjust the lens opening. The camera then sets the shutter speed based on its light meter reading. This is called "aperture priority". While this does not give you the absolute control over exposure settings that you have with fully manual cameras, you can still decide on a smaller or larger lens opening. The camera will set the matching slower or faster shutter speed. With time and experience, you can learn to control the final results.

Appendix B. Light meters.We've used the f16 rule above because it simplifies the discussion. If your camera has a built-in light meter or if you have a separate light meter, you'll use it to determine the correct range of shutter speed/f numbers for all sorts of lighting conditions. You will probably still want to make the final choice of one particular combination based on the motion control/DOF "give-to-get" and the shutter speed/focal length rule.

The next topic in this series will be B&W film development. 

Black and White Film Photography - A Beginner's Primer.

Part VII:  Filters

by Jim Hannah

Introduction.

The black and white photographer can exercise considerable control over the shades of grey which make up the final print image. We covered overall exposure and contrast control in the section on enlarging. The techniques of burning in and dodging during the enlarging process can provide further darkening or lightening of specific areas of the print.

There's another way to modify the grays in a print. That method is to change the way a particular color or range of colors will be recorded on the negative itself. It's done by placing a filter in front of the camera lens and making the exposure with the filtered light. The discussion below will cover the basic filters used in black and white photography. 

Discussion.

What is a filter?

A photographic filter is most often a piece of glass or plastic which will block out some of the light which tries to go through it. This article will assume that the round glass screw-in filter designed for modern 35mm and 120 film cameras will be used. See Appendix A for information on filters to use with older cameras.

Two types of filters will be covered: polarizing and colored glass. A few specific colored glass filters will be discussed, but the general discussion will be useful for an understanding of other colors as well. 

Polarizing filters.

Under certain conditions, light coming to the camera can be polarized. The two most common situations are light reflections from glass or water and the light from a blue sky. A polarizing filter can block some of this light from reaching the camera lens. The result is that reflections are reduced or the blue sky is darkened in the final print. B&W photographers can get the best results from the older, or linear type of polarizing filter. The newer circular polarizing filters can be used, but the results will be somewhat different. Happily, the older linear polarizing filters are usually less expensive.

The rotation alignment of a linear polarizing filter is important. If the filter is rotated, it will block out the polarized light most strongly in one specific position. If it is rotated 90 degrees from that position, it will not block the polarized light at all. This is easy to control with a through-the-lens camera. You simply look through the viewfinder and rotate the polarizer until you get the effect you want. With a rangefinder or simple viewfinder camera, you must look at the scene through the filter before putting it on the camera. Rotate the filter to get the desired effect and note the filter orientation. Then put it on the camera and rotate it to the same orientation before making the exposure.

While on the topic of orientation, remember that light from a blue sky is polarized most strongly from that portion of the sky 90 degrees from the position of the sun. If the sun is due south, the eastern and western skies will be most strongly polarized. The southern and northern sky will not be polarized to any noticeable extent.

Colored filters.

These are made of solid glass or a sheet of colored material which is then sandwiched between two sheets of glass. The filters most often used by amateurs are round and metal-rimmed. The rim is usually threaded on both sides so that the filters can be screwed to the camera lens and a lens hood or second filter can be attached to the filter. The more expensive filters are also coated to improve light transmission.

How colored filters work is relatively easy to understand if you remember the sequence of 'colors' of light in a rainbow or of white light 'split' by a prism. This 'rainbow' of colors runs in a sequence of red, orange, yellow, green, blue and violet. A colored filter lets light of its own color pass through easily but 'filters out' or reduces the amount of light of other colors. The effect of a specific color of filter on the other colors will be strongest on those colors furthest from the filter's color in the rainbow sequence.

As an example, let's consider a red filter. It will let red light [light from red objects] pass through to the film at close to full strength. Light from orange objects will be reduced a bit, light from yellow objects will be reduced further, and so on. When we get to objects at the far end of the color sequence, blue and violet, the red filter will strongly reduce the amount of light it lets through.

So far, so good. The final part of understanding how colored filters affect the final B&W print is a wee bit tricky, so we'll take it step-by-step.

Light passing through a lens and hitting B&W film causes the film to darken when developed. More light results in darker film. Less light results in lighter film.

If all the colors of light are allowed to reach the film in equal amounts, they will all produce about the same degree of darkening.

If the light of some of the colors is 'filtered out' or weakened, it will not darken the film as much as if it was at full strength.

Light areas on B&W film will result in dark areas in the final print. Dark areas on B&W film will result in light areas in the final print.

OK. Here we go! [Drumroll, please.] When we filter out a color of light, the result will be that the color is shown as a darker than normal area in the final print.

Going back to the red filter, the light it most strongly filters out [or reduces] is blue. If we were going to take a picture of white clouds in a blue sky and wanted the blue to be darker than 'normal', we could use a red filter. The blue light from the sky would be reduced. It would register as lighter than 'normal' on the film and therefore darker than 'normal' on the final print.

Let's sum up what we've covered.

- A colored filter will darken colors different from its own color.

- The further away a color is on the color sequence from the filter's own color, the darker it will be on the print.

If you're wondering about whether filtering out some of the light in a scene has an effect on the exposure, the answer is yes. How to deal with it is the next topic.

Exposure.

Filters block out some of the light coming to the camera lens. As you might guess, the darker filters will block out more light than the lighter ones. A UV   filter  is almost completely colorless. It blocks out so little of the light that no exposure change is ever needed. On the other hand, a dark red filter blocks out lots of light. Accordingly, the exposure must be greatly increased to compensate.

Happily for the photographer, each filter comes with specific exposure   compensation  information. This is stated as a filter factor and will generally range somewhere between 1 and 8. The filter factor tells you how many times an exposure must be increased above the normal exposure. To state it another way, it tells you how many times to multiply the normal, unfiltered exposure to get the correct filtered exposure.

Warning: Do not confuse a filter factor with f stops!

F-stops, you'll remember, double the exposure for each major f number change. In order to convert filter factors into f-stops, you need a little table. Here it is:

Filter factor     f-stop change

2                   13                   1 2/34                   26                   2 2/38                   310                 3 1/316                 4

You can use 1 1/2, 2 1/2 and 3 1/2 instead of 1 2/3, 2 2/3 and 3 1/3 f-stops without a problem.

If you wish to use two filters together, you must multiply the two individual filter factors instead of adding them together. Then go to the table to find the f-stop change.

In general, you'll get more accurate exposures if you first determine the exposure for the unfiltered scene and then apply the correction. In some instances, a filter can 'fool' an exposure meter if you try to determine the exposure based on reading the filtered light.

Specific colored filters.

UV. This filter has little use in B&W photography. In a few instances, using it might reduce the effect of haze in a landscape scene, but the change is not great. The best reason to use a UV filter is to avoid having to clean the front element of the camera lens. It also serves to protect the lens from accidental scratches or fingerprints.

K2 (yellow). Modern panchromatic films do not record all the colors in the same shades of grays as the intensities, as seen by the human eye, would suggest. In particular, we tend to see blues as being a bit darker than the films record them. The K2 filter adjusts the light to better agree with what we see in terms of gray density. Some B&W photographers simply keep a K2 filter on their lens all the time unless they have reason to select some other specific filter for a particular exposure.

Orange. This filter will darken a blue sky to a greater degree than a K2. It is used in landscape   photography  to increase the drama of a scene. For portraits, an orange filter will reduce the darkness of freckles. 

25A (red). The red filter exaggerates the darkness of a blue sky. One of the side effects is that shadows, which are basically illuminated with blue light from the sky, deepen to black, with little detail. Foliage is also darkened. In portraits, a red filter lightens skin tones.

Green. This filter, by darkening non-green colors, will make foliage appear lighter than normal. This can be used to good effect in certain landscapes. Reds and blues, at the ends of the color range, will darken quite a bit. In a still life with fruit reds, oranges and violet colors are darkened.

Blue. Blue filter use is rare. Since it is at the opposite end of the color range from red, it will darken red and orange shades. This might be of importance in some still life work. It will also lighten a blue sky to the point where clouds will not be very noticeable. Haze in a landscape will be increased, adding to what painters call 'atmospheric perspective' - the reduction of the color intensity of distant objects. In portraits, a blue filter will lighten blue eyes. The effect can be quite interesting. 

Purchasing filters. 

Mounted glass filters come in a wide variety of sizes. The sizes are stated as the diameters of the mounting threads in millimeters. When purchasing a filter, you'll need to know which diameter to buy. If you have only one camera with one lens, the task is easy. The filter size is often inscribed on the lens or given in the camera owner's manual. If you have more than one camera, or if your camera has interchangeable lenses, you can keep the total cost of filters down by buying the size which will fit your largest diameter lens and then using step-up adapters [sometimes called 'rings'] between your smaller diameter lenses and the filter. By using the adapters, you'll need just one filter of each type no matter which camera or lens you select for use. [See Appendix A for older

non-standard cameras.]

Hint: Buy a lens shade of the same size as the filter. It will work on all but the more extreme wide   angle   lenses .

Filters come in a wide range of prices, depending on the manufacturer. Unless you are using photographic equipment of the finest quality and demand the very sharpest results, the mid-price range filters from one of the major manufacturers such as Tiffin or Hoya will serve nicely.

Appendix A. Non-standard cameras.

There are two camera types which require something other than a simple screw-in filter. 

The first of these are the older 35mm cameras which do not have standard screw threads inside the lens barrel. The solution is to locate a slip-on adapter which will fit the outside of the lens barrel. Information on these can be obtained at the larger camera stores.

The second type of non-standard cameras are the older twin lens reflex cameras such as Yashicas and Rolleiflexes. They use a bayonet adapter which fits into the taking lens. These come in at least three different sizes to fit different cameras. It is necessary to find out which size of bayonet adapter you'll need for your particular camera.