Jump to content

Film not sensitive to flash?


iconoclastica

Recommended Posts

<p>I have been using Shanghai 4x5 film for quite some time now and, once I figured out its parameters, with predictable results. However, now I tried it in a studio with flashlight, and it failed me again. I exposed four negatives. Three of them remained completely transparent after development; the fourth one I forgot to close the shutter and it apparently picked up more or less the right amount of daylight to show a blurred picture.</p>

<p>So, the development must have been correct. I anyway used freshly mixed developer (HCH-110) and fixer (Ilford rapid).<br>

The one negative with visible image picked up little or no flashlight: The light is comming from one side, as was the guide light, whereas the flashlights stood on both sides of the face.<br>

So, what's happened? Is the film not sensitive to flashlight? Should I determine another effectife film speed? Did the shutter miss the light pulse?</p>

<p>Camera: Cambo SC2, lens Caltar S2-210, shutter Copal No. 1</p>

<p>thanks,</p>

<p>Wim</p>

<p> </p>

Link to comment
Share on other sites

<p>I'd wonder if the flash missed the shutter. Does your shutter have M-X-V on it or something similar? If so you'll want X-sync. You should connect the flash, leave the film back out, look at the ground glass and fire a few test shots. Do you see the flash? If not then you won't be getting any sync with the flash and the flash fires too soon.</p>
Link to comment
Share on other sites

<p>I'm with Dan, likely you have misplaced the flash sync lever.</p>

<p>"M" is for flashbulbs and "X" is for electronic flash. "M" fires the flash an instant before the shutter opens to allow the flashbulb to be at the best brightness. "X" sync triggers the flash the instant the shutter is completely open, since electronic flash fires instantly.</p>

Link to comment
Share on other sites

<p>Yes, it has an M-X slider. On position M, where it was sitting, I could not see the flash through the lens when holding the lens board in my hand. After shifting it into the X-position as you suggested, I was blinded by the flash light at once.<br>

Thanks, problem solved. What is the M-position for?</p>

<p>Wim</p>

Link to comment
Share on other sites

<p>Crossed posts. See above. Flashbulbs use a metal in an atmosphere of oxygen (from memory). The reaction takes its time to bulid up compared to an electronic flash so thats why the shutter opens much later for flashbulb.</p>
Link to comment
Share on other sites

<p>M flash bulbs reach their peak output approximately .020 seconds after they are fired. M sync on the shutter fires the bulb approximately .015 seconds before the shutter reaches full open. Sync speed for flash bulbs is 1/30 second or slower.<br>

Electronic flash fire instantaneously and the light output last .000001 second to .005 second. X sync setting on the shutter fires the flash at ± .0005 second of the shutter reaching full open.<br>

 

 

</p>

Link to comment
Share on other sites

<p>Just to confuse things even more, there where flash bulbs that were slow, some that were medium speed and others that were actually quite fast. The X was for the fast bulbs as some of the early shutters that have X were made before eletronic flashes became readily available. One of the amazing things about flash bulbs is that they produce more light than most electronic flashes.<br>

Here are a few sites if you want to read a little more on them.</p>

<p><a href="http://www.darklightimagery.net/flashbulbs.html">http://www.darklightimagery.net/flashbulbs.html</a></p>

<p><a href="http://www.meggaflash.com/">http://www.meggaflash.com/</a></p>

<p><a href="http://en.wikipedia.org/wiki/Flash_%28photography%29">http://en.wikipedia.org/wiki/Flash_%28photography%29</a></p>

Link to comment
Share on other sites

<blockquote>

<p>One of the amazing things about flash bulbs is that they produce more light than most electronic flashes.</p>

</blockquote>

<p>Knowing that might come handy one day. Never used bulbs since my early youth. Had fun with lycopodium powder though, but even if it doesn't leave a cloud of metal oxides (it's just burned fat), I'd rather not use it indoors.</p>

<p> </p>

<blockquote>

<p>Gaffer tape is great stuff!</p>

</blockquote>

<p>Don't know how I ever lived without it...</p>

Link to comment
Share on other sites

<blockquote>

<p>One of the amazing things about flash bulbs is that they produce more light than most electronic flashes.</p>

</blockquote>

<p>That's a bit misleading. I dug out an old pack of PF1 size flashbulbs after reading this, and the Guide Number given on the packet isn't that much different from a good hotshoe-mounted flashgun. And because the light output is spread over a few hundredths of a second, the GN varies with shutter speed, unlike electronic flash. For example the GN of these PF1s varies between 66 (metres/100ISO) at 1/30th second down to 33 at 1/250th of a second. The blue-coated PF1B bulbs have an even lower GN - about 2/3rds of the clear PF1.</p>

<p>So you'd have to find something a bit larger than the once common PF1 bulbs to get more light than you could from a decent portable strobe.</p>

Link to comment
Share on other sites

<blockquote>

<p>For it's relatively small size, the humble flashbulb carries more light output power than many other portable light source! Awesome!</p>

</blockquote>

<p><a href="http://www.meggaflash.com/">http://www.meggaflash.com/</a> Bottom of the page. <br>

Those little PF1s are so cute but I was actually thinking of the the standard Press 25. Some flashbulbs are the size of 100 watt lamps and others are even larger.<br>

Check out the size of some of them at: <a href="http://www.darklightimagery.net/flashbulbs.html">http://www.darklightimagery.net/flashbulbs.html</a><br>

The little M2 and M3 were also very popular with small format camera. They do produce a respectable amount of light though.</p>

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...