New to 4x5, fault finding help?
so, having wasted most of an afternoon, I am turning to the experts for help.
Here's the setup: Toyo 45G, Symmar 150 5.6, PA-145 back loaded with FP3000B. First time to actually shoot with it. Subject is a beer can about 28" from the film plane, and lighting is from a RayFlash attached to Sunpak 30SR. Lens to subject about 18" I guess. Shutter at 1/200th - speeds not actually formally tested but sound about right. Having focused it and got the compo about right, first shot, looking at the print, it's way over exposed, with a vague image of the can. So dropped the power on the flash, and selected smallest aperture, which is F45.
Print is still almost completely white. Then I noticed........the front panel in which the lensboard sits, was not mounted properly and had probably been leaking light. ha!
Prints 3 and 4 were also duff, in the same way. Then a brainwave struck me.....I pulled #5 from the back without exposing it in the camera. It was also almost white.
I got this batch of film from B&H, dated until December this year: although it came to me airmail and presumably got xrayed in the process. even so, I very much doubt there would be a problem with the film. 1. because film problems are quite uncommon, and 2. because the other togs who I shared the order with, also got instant film and have been using it, I would have heard about any film-related problems long before (we made our order back in Feb of this year).
So I cut my losses and binned that pack that was in the PA-145. Got a fresh pack from the fridge, loaded it, pulled the black paper, then pulled the tab on #1. This time the print was black!!!
Invigorated, I loaded the back into the camera, and made an exposure........the print was again almost white, with a faint image of the can. #3 I pulled the tab on, without loading into the camera, just to check, and sure enough the print is white again.
So, where does the fault lie? I pulled the bellows out and couldn't see any obvious damage but, what is the most effective way of checking for pinholes? The only other thing I can think of, is the instant back doesn't seem to have the right type of darkslide. I looked at another PA-145 locally, and that one has a metal darkslide where my example has a d/s that seems to be made of fibre, rather like the Polaroid 405 backs. Carefully inspected the structure of the PA-145, and could not see any damage, and the dark slide is not cracked and is nice & flat.
I don't use 4x5, so just guessing here... 1/200th of a second at f/45 will need rather a lot of light. Also, might you have to consider the bellows factor, in terms of the light you'll need to make a decent exposure.
I wonder if maybe a shot in daylight would be a good idea, at least then you can rule out any flash sync issues?
Like I say, I don't shoot 4x5, but I'm interested in trying, so your progress interests me.
Shutter speed is 1/200th. highest speed on that shutter is 1/400th. FP3000B has a nice fast dev time of 20sec for 20-23degrees, which is what it was today. But I do take on board what you're saying (which I think is, let the film warm up to room temp before shooting?)
I'm fairly sure that I did try one with ambient exposure, to no avail, but will have another go tomorrow. Light meter! stone the crows, why didn't I think of that? I do have an ancient Minolta Autometer knocking around. Facepalm!
do you have access to a darkroom?
you might consider shooting paper negatives
instead of expensive+fast fuji instant film.
photo paper is cheap and nearly as instant ...
you just need developer and fixer.
rate it at about asa 6 or 12 or 24 depending on the paper you use.
point your camera out the window, don't bother with a flash
it will complicate things ...
do sunny 16 ( umm 11 ) so your asa 12 paper will be 1/12S at f 11 if it is bright sun
( 1/10th is close enough ) ...
process your paper negative in whatever developer you have, print is ok, film is ok
even instant coffee will develop your prints, but it will take a while, so be prepared to
wait a few mins in the soup.
instant film is great if you want or need instant results, but expensive if you are starting out
especially if you don't have a fast enough shutter, too much light, or confusion about over and under exposure to achieve good results ...
good luck !
Last edited by jnanian; 09-28-2012 at 09:54 AM. Click to view previous post history.
Flash exposure will depend on the flash-to-subject distance, which you have not mentioned. With a strobe, shutter speeds will not affect the exposure you get from the flash, but will affect how much ambient light you pick up.
Originally Posted by JollyGood
Try exposing the film with ambient light only, using a meter and allowing for bellows extension.
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Seems to me that you need to go back to square-1 and verify your equipment and processes. You should have seen some sort of results on the film.
What shutter? Are you sure the X-synch is properly working? If, for some reason, your shutter has M-synch and you are set their... that could be your problem.
Are you sure you loaded the film into the back properly and the rollers are working? Did the "goo" spread across the film when pulled for processing?
How did you meter the flash? Even in "auto mode", if your strobe has one, you should have seem some image. I'd suggest using guide number calculations or a flash meter.
virtually no access to a darkroom.....though I had originally acquired the camera with a view to shooting tintypes. or making a camera adapter for a DSLR.
Originally Posted by jnanian
the reason for shooting instant is the immediate feedback, given that I am a novice. significantly shortens the learning curve, the way I look at it.
Regarding overexposure, yes that would be a possibility but, how does the fact that pulling the tab on a print in the second pack, and having it come out white, after the #1 print which was also unexposed, was developed as black, sit? Unless I somehow managed to overexpose it so much that light migrated thru the material of the #2 print and fogged #3? is that even possible? it is in my twisted mind. how about reality?
sorry, the flash to subject distance was around 18". GN30m flash at 1/16th. I tried to set the shutter at the highest speed so that only flash light made the exposure. I must admit, I did not do the maths, being excited about finally getting to do some shooting! After some quick calculations on the back of an envelope, looks like 0.5m (about 18") at F16 with 3000asa film, is equivalent to the settings I made.
Originally Posted by E. von Hoegh
The shutter is a Synchro Compur, more than that I cannot tell you. And yes, it has M sync but I did make sure it was set to x sync. What is the best way to test the x-sync? I guess I could just hold it in front of a dslr body, set to b? one that is known to work? then fire the shutter when a flash is connected? at all the speeds? sound good to you?
Originally Posted by BrianShaw
I have plenty of experience with Pola backs, and can happily confirm that the print is developed properly. But always worth asking.
The flash was just set to manual and a gut instinct for the camera settings. Though, as my quick workings above show (excluding compensation for bellows), they were about right.
To test x sync
take the back/groundglass off so you can look into the bellows (from the rear) through the lens.
Open the lens wide open (5.6?) and set the shutter to whatever speed you like but test them all when you get the chance.
Fire the shutter with camera and flash pointed at a blank wall and you should see uniform illumination through the lens with no sign of the shutter blades.
edit: I'd put the rayflash aside for now until you make sure everything is kosher.
that thing will probably rob some power so the quide # will no longer apply.
Last edited by brucemuir; 09-28-2012 at 08:06 PM. Click to view previous post history.