Using electronic flash with LF cameras

[tonyowen]

three days on and no response????????

regards

Tony

[Pere Casals]

It was not clear you were asking something.

My view is that you have solved it.

Just you need to make some bracketings to find the right ISO reference for metering.

[tonyowen]

It was not clear you were asking something. My view is that you have solved it. Just you need to make some bracketings to find the right ISO reference for metering.

Thanks Pere
My original query was the use of electronic flash with paper negatives.
From my 'test' I guess that it does not work - there 'appears' to be a loss in the subject's reflective image to fp distance. In other words paper negative exposed directly to the flash as in the last image is too great, but in-camera paper exposed to flash via the camera's optical path is not exposed enough.
With the image taken with the bulb setting I wonder how much of the recorded image is to do with the several seconds of exposure rather than the output of the flash gun.
Your comment regarding the correct ISO is I assume is to do with the daylight exposure image??

regards
Tony

[Tin Can]

To explore an answer we need to do our testing

Maybe later in the week I have time

[Pere Casals]

Your comment regarding the correct ISO is I assume is to do with the daylight exposure image??

Tony, here you have a calibration issue. You just need to know how to meter to have the result you want.

First you should be proficient in nailing flash exposures with film, if this is not the case then first master that, you can simply test with a dslr, this is calculating flash power manually and then checking the practical result to see if it is like you predicted.

From that you may rate the paper medium at several EI, say from ISO 1 to ISO 8, and see what Exposure index is good for you.

I the image #2 you could do something better, this is extracting the dark slide from the film holder only 1/2", the you fire the flash once, then you extract the dark slide 1/2" more, firing again... total 10 times. I that way with that single sheet of paper you would have 10 exposures like if it was test strip with the enlarger.

You also may try with different paper grades, with graded paper or with multigrade paper and placing filters on the lens or on the flash.

[tonyowen]

you can simply test with a dslr, this is calculating flash power manually and then checking the practical result to see if it is like you predicted.

From that you may rate the paper medium at several EI, say from ISO 1 to ISO 8, and see what Exposure index is good for you.

I the image #2 you could do something better, this is extracting the dark slide from the film holder only 1/2", the you fire the flash once, then you extract the dark slide 1/2" more, firing again... total 10 times. I that way with that single sheet of paper you would have 10 exposures like if it was test strip with the enlarger.

[You also may try with different paper grades, with graded paper or with multigrade paper and placing filters on the lens or on the flash.

Pere, Answers follow to your paragraphs

Unfortunately my Coolpix does not allow manual selection of flash and I do not want to risk using my 'old' flashguns on the digital camera in case of overloading the DSLR's circuitry/U]

Agreed that is something I should do

U]I understand what you are saying, but do not understand the logic. #2 was taken at full power of the Cobra flash, so multiple exposures will show the result of increased flash power - that I do not have with the Cobra. Unless you mean the 'correct' result would indicate the GN/flash power necessary to give that result albeit with a more powerful flash gun or by studio lighting.

usually I have a yellow filter on the camera lens

I've found the reason for the discrepancy in the meter readings. The Weston was angled downwards whereas the Coolpix was horizontal. Comparing both in similar attitudes gives almost identical results.

regards
Tony

[Pere Casals]

I do not want to risk using my 'old' flashguns on the digital camera in case of overloading the DSLR's circuitry

Use a remore trigger, this is $16, you get rid of cables and you don't risk the DSLR

GN/flash power necessary to give that result albeit with a more powerful flash gun or by studio lighting.[/U]

What you need to find is the ISO rating of paper that delivers a correct exposure by using the GN of your flash and the flash to subject distance.

You always can place the flash closer to subject if flash power is not enough, or (for still subjects) you can always fire a series of flashes.

The relevant parameter you have to find is the practical ISO of the paper, from that you always may check the right result in the dslr and then calculating the equivalent power for the view camera/paper.

In the past Polaroid instant film was used to check what was to be obtained with the view camera for important shots, today we have DSLRs, at least this would be useful to learn if you are in the good path.

usually I have a yellow filter on the camera lens

In that case you have to know that with yellow (vs no filter) will need a different exposure, if paper is multi-grade then with yellow filter you also will have a lower contrast.

[DrTang]

I would start by putting the flash - on full - right next to the subject and blasting it about 3 or 4 or 5x the suggested GN aperture...just to see if you get ANYTHING

if not..then it is a mechanical problem and not a light one


if you get something..and it is over exposed..just keep walking it back until you get what you want

[tonyowen]

Use a remore trigger, this is $16, you get rid of cables and you don't risk the DSLR
In the past Polaroid instant film was used to check what was to be obtained with the view camera for important shots, today we have DSLRs, at least this would be useful to learn if you are in the good path. In that case you have to know that with yellow (vs no filter) will need a different exposure, if paper is multi-grade then with yellow filter you also will have a lower contrast.

Pere,
My Cobra flash gun has a low trigger voltage so It can be used on my Nikon Camera.
Attached are two images with the relevant EXIF data. I set the ISO to 50 therefore the GN of the flash was 32.5
The 'image subject' was about 5m away hence f6.3
So, my flash GN appear to be okay and the resulting image from the DSLR seems okay so why the problem with paper???.
The info I have is that the apparent GN for ISO 6 paper is less than 4 which does not make sense at all.

My comment about the yellow filter was for info. No filter was used on any of the previous images. I know that the filter in question need a 1 stop correction.

regards
Tony
exif data below
Attachment 187926 Attachment 187927
Filename - DSCN0201.JPG
ImageDescription -
Make - NIKON
Model - E8800
ExposureTime - 1/60.1 seconds
FNumber - 6.00
ExposureProgram - Aperture priority
ISOSpeedRatings - 50
LightSource - Auto
Flash - Flash fired, Compulsory flash mode
FocalLength - 11.80 mm
ISO Setting - 50
Color Mode - COLOR
Flash Setting - NORMAL
Unknown - 9.04
ISO Selection – MANUAL

Filename - DSCN0202.JPG
ImageDescription -
Make - NIKON
Model - E8800
ExposureTime - 1/60.1 seconds
FNumber - 6.00
ExposureProgram - Aperture priority
ISOSpeedRatings - 50
LightSource - Auto
Flash - Flash fired, Compulsory flash mode
FocalLength - 11.80 mm
ISO Setting - 50
Color Mode - COLOR
Flash Setting - NORMAL
Unknown - 9.04
ISO Selection - MANUAL

[Pere Casals]

The info I have is that the apparent GN for ISO 6 paper is less than 4 which does not make sense at all.

Anyway you may always shot the flash a number of times, to multiply the effective power, for testing and to know what flash you need.

My comment about the yellow filter was for info. No filter was used on any of the previous images. I know that the filter in question need a 1 stop correction.

Well, in this case the factor may be greater: 1 stop is for panchromatic film, but paper is orthochromatic... Filter factors are orientative...