Understanding format sizes

Can someone help me with a bit of basic mathematics?

 

My Super Ikonta has two windows: one is labelled 2 1/4 x 3 1/4 and the other is 1 11/16 x 2 1/4.

 

Now the internet tells me that 1 inch is equivalent to 0.393701 centimetres. That being so, multiplication suggests that the formats in centimetres would be:

 

5.714996914 x 8.254995542

 

and

 

4.286247685 x 5.714996914

 

I've always understood that the metric formats are described as 6 x 9 and 6 x 4.5.

 

Ok, so the question for the forum is : Does rounding accounting for this discrepancy, or have I made some mistake?

The metric formats 6x9 and 6 x 4.5 are poor approximations to reality.

 

AFAIK, there's no 6x9 standard. nominal 6x9 roll holders' gates are all 56 - 57 mm high, lengths range from 78 mm (2x3 Graflex with pin rollers at the ends of the gate) to 84 mm (Linhof Super Rollex, Toyo).

 

Ben, I think you're mistaken about "2x3" sheet film. You may be confusing it with 6.5 x 9 sheet film. The two formats are not the same.

Calling any format 6 cm wide has always been fudging a bit. It depends on the camera, but something around 56mm is typical. 2 1/4" is really a more "correct" value.

 

Your actual numbers sound correct for the formats we call 645 and 6x9. Calling 6x9 "3 1/4" is fudging a bit more than 645 in the long dimension.

 

BTW, I print all of my medium format on a "Besseler 23" enlarger. This is an ubiquitous enlarger, and I'd print everything on it if I didn't have a nifty Leitz for 35mm. In any case, it can print 2 1/4 x 3 1/4 sheets(I need to get a carrier) which I think are an honest 9cm long. That's where the "23" in the name comes from.

Now the internet tells me that 1 inch is equivalent to 0.393701 centimetres....

 

1 Inch = 2.54 Centimeters

Now the internet tells me that 1 inch is equivalent to 0.393701 centimetres.

 

Hi, where I come from, 1 inch = 2.54 centimeters (same as Vincent Peri points out).That being said, you did do your calcs in the right direction.

 

As a note, I believe this is a perfect conversion, established by definition. The number that you mentioned is the same thing as dividing by 2.54; that is, 1/2.54 = 0.393701.

 

If one wants to memorize a conversion, it's easier to deal with 2.54 (personally I do it as 1 inch = 25.4 millimeters). Then it's just a matter of whether to multiply or divide; no need to remember that longer string of digits.

Ben, I think you're mistaken about "2x3" sheet film. You may be confusing it with 6.5 x 9 sheet film. The two formats are not the same.

 

Hi, not sure what is being said about possible mistakes, but my father used to shoot a lot on what he always called "two and a quarter by three and a quarter." This was standard sheet film used in a Graflex SLR camera.

 

I just measured an old neg; the film is roughly 2.18" by 3.18", and given that it's over sixty years old, one can imagine that the original film could well have shrunk slightly from (pretty close to) 2.25" x 3.25". Fwiw, the actual image size is about 2.06" x 3.10"

Ben, I think you're mistaken about "2x3" sheet film. You may be confusing it with 6.5 x 9 sheet film. The two formats are not the same.

 

If that's the case, Dan, what exactly is my "Crown Graphic '23'"

 

 

And also the 2 1/4 x 3 1/4" sheets that I buy to put in the film holders that came with my camera?

 

Ilford FP4+ 125 ISO 2.25x3.25/25 sheets | Freestyle Photographic Supplies

How cool, a "mini" Graflex.

I've been thinking about buying one whenever I've seen them at a camera show, but never pushed the button.

Hi, not sure what is being said about possible mistakes, but my father used to shoot a lot on what he always called "two and a quarter by three and a quarter." This was standard sheet film used in a Graflex SLR camera.

 

I just measured an old neg; the film is roughly 2.18" by 3.18", and given that it's over sixty years old, one can imagine that the original film could well have shrunk slightly from (pretty close to) 2.25" x 3.25". Fwiw, the actual image size is about 2.06" x 3.10"

I believe sheet films are cut slightly less than the nominal size by about .06 inches or so; they may not have shrunk. I suppose the theory is to have a little play to slide into a filmholder that may be exactly the nominal size.

Now the internet tells me that 1 inch is equivalent to 0.393701 centimetres. That being so, multiplication suggests that the formats in centimetres would be:

1 inch = 2.54 cm, exactly, by international convention. The number you cite is the length of 1 cm in inches (1/2.54).

 

Film sizes are nominal. The same nominal size may vary depending on the camera. My Hasselblad, nominally 6x6 cm, has an image dize of 5.6x5.6 cm. My Rolleiflex E2 has a an image size of 5.9x5.9 cm. Do you really care if 35 mm film is 23.6x35.6 mm instead of an honest 24x36? If you scan or print film, the numbers get doubly confused, Perhaps that's why some obsess about showing the borders, even sprocket holes.

The 120 film (and most other film sizes) was devised by Kodak, and so in inches. It was originally for their box cameras with an image 2.25 x 3.25 inch. Using the same film for half-frame (2¼ x 1⅝ inch) or square format came later. Two-and-a-quarter inches is 57 (and a bit) mm, and '6x6' is a perfectly reasonable quick way to name that size. '645' or 'six by four-and-a-half' is certainly easier to say than 'two and a quarter by one and five-eighths'.

3¼ inch is only about 82.6 mm, so '6x9' would be more questionable, but as Ed shows, camera makers are free to make their actual image frame match up.

How cool, a "mini" Graflex.

I've been thinking about buying one whenever I've seen them at a camera show, but never pushed the button.

Oh, dear. The common language and Graflex-speak share little.

 

In Graflex-speak, mini means Miniature Speed Graphic. This is approximately the first 2x3 Speed Graphic. In the common language, mini means any 2x3 Graphic.

 

In Graflex-speak, a Graflex camera is an SLR, a Graphic is a press camera. In the common language Graflex means any camera made by Follmer & Schwing and successors.

 

No wonder that we confuse each other.

If that's the case, Dan, what exactly is my "Crown Graphic '23'"

 

And also the 2 1/4 x 3 1/4" sheets that I buy to put in the film holders that came with my camera?

 

Ilford FP4+ 125 ISO 2.25x3.25/25 sheets | Freestyle Photographic Supplies

 

Ben, to repeat myself with a little amplification, 2x3 is an abbreviation for the more cumbersome 2 1/4 x 3 1/4.

 

2x3 sheet film's nominal size is 2 1/4" x 3 1/4". It isn't exactly that, here's a link to the ANSI standards for sheet film holders. http://home.earthlink.net/~eahoo/page8/filmhold.html large format camera film holder specifications You'll see that the exposure area (film holder's gate) is lower than 2.25" and longer than 3 1/4". The film has to be a little larger.

 

2x3 is also a roll film format. 120, 220 and 620 roll films are 60 mm high. As I've said, 2x3 roll holders' gates' sizes vary a little. 6x9 is a poor metric approximation to 2x3. The formats are identical.

 

6.5x9 is a European sheet film format. Nominal 6.5x9 sheets are larger than nominal 2x3 sheets.

 

Your 2x3 Crown Graphic is, like mine, a camera whose back accepts 2x3 sheet film holders and insertion type 2x3 roll holders. AFAIK, there are two such for 2x3 cameras, the Adapt-A-Roll 620 and a Busch holder whose name I've forgotten. It takes 120 film. If, like mine, it has a Graflok back it will accept clip-on roll holders with nominal 2 1/4 x 2 1/4, 2 1/4 x 2 3/4, and 2 1/4 x 3 1/4 gates.

Edited February 19, 2018 by dan_fromm|2

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Thanks, Dan, for the explanation.

 

The camera I showed above was an impulse buy and was my first sheet film camera of any sort. I've enjoyed it, and it fortunately came with a half dozen film holders. It let me get my feet wet in sheet film before I finally jumped all the way in a little over a year ago with a 4x5 Pacemaker Speed and then the B&J View in my avatar. It's mostly sat idle, though-I bought a box of Efke 50 when I first got it(it was in date, which gives some idea of how long I've had the camera) and haven't shot it up. I've shot a LOT more 4x5.

 

In any case, mine has a plain spring back. My local shop has them come and go some and they are cheap-I've been tempted to pick up one with a Graflok back, but there again just have had other things I'd rather buy. It mostly just looks good on the shelf sitting on top of the box :)

 

I'm pretty well equipped in the RB67 system, and of course there's a lot of crossover there since it also uses a Graflok back. I wouldn't mind just the Graflok sheet film holder to shoot cut film in my RB67, but then that's kind of a waste considering that 6x7 makes a nice, big negative on easy to handle roll film.

 

BTW, I've also tried to be VERY conscious of my terminology since I've learned a bit more history and have learned about the Graflex SLR.

 

I'm adamant about referring to the 4x5 press camera I use as a Speed Graphic(or a Speed for short) but to many camera guys all press cameras made by that chain of companies are a "Graflex." It doesn't help, either, that my Pacemaker says "Graflex" all over it.

Edited February 19, 2018 by ben_hutcherson

"Now the internet tells me that 1 inch is equivalent to 0.393701 centimetres."

 

- I certainly hope not! One inch is internationally standardised at 2.54 centimetres, and has been since the 1930s.

 

Before that, the imperial inch was a fraction of a thou larger. (This I discovered when I came across my father's old dog-eared book of conversion tables.)

 

The two-and-a-quarter inch (= 57.15mm exactly) or 6 x 6cm film size is an approximation. Most camera gates have a width closer to between 54 and 56mm The so-called 6x6cm square format is about 5.5 x 5.5 cm in actuality. While 6 x 4.5 is 56 x 42mm to keep the 4:3 aspect ratio.

 

6x7, 6x8 and 6x9 are usually even further from their nominal sizes when in the form of rollfilm backs. Cut film holders are closer to their stated size, but take no account of the margin used to grip the film.

 

Anyway, the camera gate size is of little consequence, since enlarger masks and slide frames nearly always crop the image further.

Anyway, the camera gate size is of little consequence, since enlarger masks and slide frames nearly always crop the image further.

 

If you read Ken Rockwell(something that should always done with a big pinch of salt) he will tell you that he prefers the less-than-100% viewfinders of cameras like the FA and F100(two of his favorite 35mm SLRs) because they're a better approximation of a mounted slide. While I still like a 100% viewfinder, I do understand his argument.

 

My Focomat can show just outside the image area of a 35mm frame if I crank the frame masks all the way out, but of course I never actually print them. Heck, I CAN'T if I want a full page or even bordered 5x7 or 8x10.

Oh, dear. The common language and Graflex-speak share little.

 

In Graflex-speak, mini means Miniature Speed Graphic. This is approximately the first 2x3 Speed Graphic. In the common language, mini means any 2x3 Graphic.

 

In Graflex-speak, a Graflex camera is an SLR, a Graphic is a press camera. In the common language Graflex means any camera made by Follmer & Schwing and successors.

 

No wonder that we confuse each other.

 

Guilty as charged.

That is a world that I have very little knowledge of.

The 4x5 Speed Graphic was the camera that I had seen most of.

The 4x5 Speed Graphic was the camera that I had seen most of.

 

Just as a word to the wise-having gone down the path...

 

Unless you are collecting or have a strong desire to use barrel lenses, save the money and weight and buy a Crown Graphic.

 

The principle difference between the two is that the Speed has a focal plane shutter, while the Crown only has the in-lens leaf shutter.

 

The Speed allows high shutter speeds(1/1000-hence the "speed graphic" name) but the focal plane shutter is BIG and unless the camera has been maintained the speed can be way off. Even worse, I've seen plenty where the speed was uneven during the course of the curtain travel-a sure recipe for uneven exposure.

 

I've used the FP shutter in mine-again mostly with barrel lenses-but I use the leaf shutter whenever possible.

 

Also, all LF cameras have plenty of opportunities to mess up and fog your film, but the Speed Graphic FP shutter just adds more. It is not a two-curtain shutter like we know and love with smaller formats. Rather, it's a continuous piece of rubberized silk with different width slits cut into it. To set the shutter speed, you select both the slit width and the tension. I think the Pacemaker simplifies this considerably from older models-I know that it directly reads the speed and only has two positions for tension.

 

In any case, when you cock the FP shutter, you use a key on the side that looks like it came right off an old wind-up alarm clock to wind the shutter up to your selected slit, and then you press the shutter button(after making sure the switch has been moved to "back") and let the shutter unwind. Keep your hands away from the key or you can change the speed!

 

In addition, bear in mind that the shutter does not self cap when it is cocked(unlike what we're used to with smaller format cameras), so you can easily fog your film if the lens shutter is open and you cock the shutter with the dark slide removed.

 

Let's say that hypothetically you want to use a shutter speed of 1/500 of a second with the FP shutter. At least on a Pacemaker, with the film holder either removed or at least with the dark slide in place, you would set the tension lever to "low" and then wind the shutter key all the way up. You would open the leaf shutter, then of course make sure the shutter selector on the body was set to "back." You insert the film holder, pull the dark slide, and then press the shutter button. For a subsequent exposure, you must then insert the dark slide and wind the shutter again to get it back to 1/500. Somewhere along the way, you would get fresh film in place-whether by flipping the film holder, inserting a fresh one, or cycling your Grafmatic. Then, pull the dark slide and release the shutter.

 

Once you're done with the FP shutter, you let the tension ALL THE WAY off of it so that it's open(you can either repeatedly press the shutter button, or there's a 3rd intermittent position on the shutter selector switch that does this), and of course close the leaf shutter.

 

Overall, I find the leaf shutter much easier to use. It essentially works like any other view camera, aside from the fact that you do have a nice release button on the body if you want to use it. If you want to do GG focusing, you just lock it open, do your focusing and composition, then shut and proceed as normal with setting the speed, cocking, putting in the film holder, pulling the dark slide, etc.

 

A Crown Graphic saves you a fair bit of weight-I think around a pound. In addition, the front and rear standards can get closer together, which means that you can use wider lenses on a Crown than on a Speed.

Thanks Ben,

A Crown Graphic it will be.

I don't need the hassles of the FP shutter.

Ben, Gary, my first Graphic was a 2x3 Pacemaker Speed. Fine camera, nowhere near as difficult to use or problematic as Ben says. It has only one shortcoming relative to the 2x3 Crown and Century. Minimum flange-to-film distance 61.9 mm. The 2x3 Crown and Century's is 34.9 mm.

 

So what? The shortest original issue lens for the 2x3 Pacemaker Speed is the 80/6.3 Wide Field Ektar. The shortest original issue lens for the 2x3 Crown and Century is the 65/6.8 Optar/Raptar, functionally equivalent to the 65/6.8 Angulon. The shortest modern lenses that cover 2x3 and will make infinity on a 2x3 Pacemaker Speed are the 58/5.6 Grandagon and 58/5.8 Konica Hexanon/Omegon (ex-Koni Omega). The shortest modern lens that covers 2x3 and makes infinity on the 2x3 Crown and Century is the 35/4.5 Apo-Grandagon. That's so what.

 

The Pacemaker Speed has more extension than the Crown/Century. And, as mentioned, with its focal plane shutter it can be used with lenses in barrel. The longest lens I'm aware of that's comfortable, as in makes infinity with the front standard inside the box, on a 2x3 Pacemaker Speed is the 12"/4 TTH telephoto originally fitted to Vinten F.95, Williamson F.134 and AGI F.139 aerial cameras.

During WWII, combat photographers often used Speed Graphic camera with a 4"x3" format. This was probably to save a little size and weight. I used on in high school, which belonged to the camera club. I still have a 4x5 pre-Pacemaker Speed Graphic, which I bought in college.