View Full Version : Very basic shutter/lens questions

David F
28-Dec-2005, 19:51
I'm completely new to view camera operations, as I came "of age" photographically using digital. I recently bought a 4x5 camera to try out, using Polaroid back and film (since I don't have a darkroom).

I just pulled out my 150mm lens, mounted on a Copal No. 0 shutter. I believe I understand the basics of operating the aperture and shutter speed levers, and the preview lever, and shutter release, and how to mouting the lens on the camera, but . . .

1) to the left of the 1 second mark on the shutter speed dial (I think that's what the 1 is for?) are the letters B and T. What are these for and how do I work with them? (I assume they are for shutter speeds of longer than 1 sec, but that's just an assumption.)

2) Right next to where you screw in the shutter release cable is a switch with the letters X (in red) and M (in yellow). What are these? and how do I work with them?

3) Finally, my camera came with two shutter release cables: one just has the button/plunger on the end, and the other has a tiny screw next to the end that you push. I think its for keeping the shutter open during really long exposures (so you don't have to keep it plunged manually), but again this is just an assumption.

Any help with these questions or other starting advice is helpful. I have looked in a couple of view camera books and extensive searches on the web, but there's not a lot about these basic operations, even in the "how to" lists. I did some basic shutter info. on this web site which got me started, but didn't get to the above questions.

David Freed
Whidbey Island, WA

David F
28-Dec-2005, 19:56
Okay, I just learned that B and T stand for Bulb and Time, but still not sure how to use them. david.

28-Dec-2005, 20:02
You cruised by the answer on your way here. :)

Go to: www.largeformatphotography.info/lenses-primer/ (http://www.largeformatphotography.info/lenses-primer/)

When you get the lens mounted, and can see the scene on the ground-glass, best check to see if your particular lens creates an upside-down image.

28-Dec-2005, 20:06
Okay. B, T are not covered. Strange, but true.

"B" (stood for "bulb") means the shutter stays open as long as you press down the shutter release.

"T" (time?) - the shutter opens when the shutter release is depressed, and stays open until it is depressed again.

David F
28-Dec-2005, 20:21
Good, good, we're getting there. Now I know about bulb and time (and I assume the one cable with the tiny screw on the side is to keep shutter open when using Bulb setting).

But what about switch with X and M designations. I looked again on the web page you directed me to (which is where I got some of my basic info -- good), but didn't see X and M discussed, though I could be missing it?


N Dhananjay
28-Dec-2005, 20:28
They are for synchronizing the shutter with flash. M is for flash bulbs, X is for flash. Flash bulbs take longer to get to peak brightness, so M trips the flash a little before the shutter opens. Cheers, DJ

Randy Becker
28-Dec-2005, 20:32
M and X are the designations for flashbulb photography and electronic flash photography respectively.

It's all about the timing. The old flash bulbs would ignite then burn a short time then peak. This delay would neccesitate a delay when the shutter would open fully. In short-hit button, flash bulb ignites, shutter then opens to catch the peak then shutter closes.

With electronic flash, the shutter opens fully, flash fires instanteously, shutter closes.

Hope this helps.

ps.. (I don't think flash bulbs are even available anymore but you are prepared if you can find some.)

28-Dec-2005, 20:34
I'm sorry, David. These are things we forgot we once didn't know. No problem. Nobody is born knowing this stuff.

M and X are different flash synchronizing settings. X is for electronic flash. It works at all speeds. You will probably use it most often. M is for flash bulbs.

You will probably want to use T for focusing, by the way.

Oh, and the following link is hugely helpful. www.largeformatphotography.info/mistakes.html (http://www.largeformatphotography.info/mistakes.html)

28-Dec-2005, 20:39
ps.. (I don't think flash bulbs are even available anymore but you are prepared if you can find some.)

Ah, but they are still being made. www.meggaflash.com/ (http://www.meggaflash.com/)

Good stuff, too.

28-Dec-2005, 20:51
B for Bulb? I always thought that was confusing, since bulb can mean more than one thing. (And like you don't use the pneumatic bulb for short exposures as well...) I always remember it as B for beliebig, german for something like 'as you like it' or 'however long you wish to expose' - it has a pleasant and polite ring to it.

Ah, and your assumption about the cable release was right: tighten down the screw for long exposures using the B setting. I've done exposures of more than 30 minutes and boy, do these things come in handy...!

Good luck with your first shots, mine were very disappointing - by way of cold comfort -


28-Dec-2005, 21:10
"Bulb Exposure (B). Another term for a brief exposure - in which the shutter remains open only so long as the shutter release is held down. The word originated with the early pneumatic shutter release." -- from the Focal Encyclopedia:

Jim Ewins
29-Dec-2005, 01:55
Invest in a copy of "Using the view camera" by Steve Simmons You'll get the whole picture, not just the bits and pieces.

steve simmons
29-Dec-2005, 05:24
I usualy suggest one or all of the following books

User's Guide to the View Camera by Jim Stone

Large Fomat Nature Photography by Jack Dykinga

Using the View Camera that i wrote.

You can try your local library, Amazon.com, etc., etc.

Also, there are several articles in the Free Articles section of


that will be helpful to you.

Good luck

steve simmons

Dan Jolicoeur
29-Dec-2005, 08:11
B or T, T in particular are also the setting you should use to store your lens when not in use. This puts less stress on the spring(s), and will let your lens speeds last longer accurately.

David F
30-Dec-2005, 13:51
Thanks all. This is exactly the info. I needed to get started. As an aside, I did look in a few view camera books, but didn't find this basic info. They often started with "mount lens on camera" but not the details of the various shutter dials and functions.


30-Dec-2005, 15:50
Yes, those books overlook some of the fundamentals.

Like, when you get the lens mounted, and can see the scene on the ground-glass, best check to see if your particular lens creates an upside-down image.

Ole Tjugen
30-Dec-2005, 16:22
B for Bulb, T for Time. Cable release with lockdown screw for shutters without the "T" setting.

Some older shutters are marked TBI and ZDM - Time, Bulb and Instant in English, and Zeit, Dauer and Moment in German. If these have flash contacts at all that's likely to be "M".

Some other shutters have not only M and X, but MXV. The "V" is for "Verdauer", time release. The shutter opens after about 10 seconds depending on general repair state and how often the "V" setting has been used in the last 50 years.

steve simmons
1-Jan-2006, 09:01
go to page 42 of Using the View Camera. This answers your questions.

steve simmons

tim o'brien
25-Nov-2011, 00:18
Yes, those books overlook some of the fundamentals.

Like, when you get the lens mounted, and can see the scene on the ground-glass, best check to see if your particular lens creates an upside-down image.

Ummm... how many times you gonna try that joke? We all know if the image is upside down, you merely put the lens in top side bottom.

tim in san jose

25-Nov-2011, 01:58
You can still get flash bulbs off ebay very cheaply, I've used them in the past with with a 120 diana clone. The amount of light given off them is very impressive, however they can shatter.

There is also the theatrical side of using flashbulbs, which never fails to impress you audience..

Out of interest, can/does anyone use the victorian 'flash bars' that you often see in films... (looks like powdered magnesium going off, if there is such a thing)?

25-Nov-2011, 02:52
B for Bulb?
The B designation goes way back to a time when flashes were not fired by the shutter at all, but by the photographer using a separate appliance.

You open the shutter on B, then fire the flash, then close the shutter.

The B setting was so convenient for modestly long exposures that it has carried forward to modern designs even though its original function is long obsolete.

- Leigh