Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

[Tin Can]

I did this a decade ago, I will try to improve

I am old and tired so I will be slow to produce

The goal is to shoot without meter

or focus

aim shoot

NOW!!

just like WeeGee
(https://www.icp.org/browse/archive/constituents/weegee?all/all/all/all/0)

Please join in with real life current examples

I will use a Speed and a Printed P&S Modern 4X5 with studio strobe, Camera Strobe, Flash Bulbs

I hope to shoot daily and not hide failure

I always need a goal!

[Tin Can]

4X5 example from 8 years ago

Handheld, one flashbulb, sport finder, plastic camera, one shot at 3 am closed bar

https://live.staticflickr.com/65535/51246617432_8b68c24c02.jpg (https://www.flickr.com/gp/tincancollege/6q59Q9)Turbo (https://www.flickr.com/gp/tincancollege/6q59Q9) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

[Mark Sampson]

With an electronic flash, use film to figure your exposure at 10 feet (or 8, or whatever) and a given f/stop, say f/16. Then you'll know.
With fixed-output flashes, bulb or electronic, we used a concept called the "Guide Number" to determine the f/stop to use at a given distance.
A well-known practice, details should be easy to find; a Kodak Master (or Pocket) Photo Guide would be a good place to look.
That's how the press photogs did it back in the day.
Best of luck- have fun- show your work please!

[LabRat]

The press fotogs also leaned heavily on their "labrat" to develop by inspection to get a printable neg density...

We have many tools now they couldn't dream of then... You can calculate exposure like they used to, but take a lot of notes while throughly testing materials in many different situations, and then depend on your "little black book" for your B/W adventures...

Steve K

[popdoc]

Guide number + tri-x + D76/Microdol-x + Stroboflash Ii (or #5s or bigger “screw base” bulbs) all put together were as close to foolproof as you could get. Even worked with my Atoron and minoxes and AG-1s beautifully!

Still dip into my stash of bulbs on occasion. Even after more than 60 years of using them, I love that sweet smell of success every time I fire one off.

Have a blast!

Has anyone used flash powder with reasonable success? Always wondered, and wanted to give it a try…


Sent from my iPhone using Tapatalk

[Tin Can]

I have a complete Flash Powder Kit, sent to me in the MAIL with a Plate camera

Yikes!

I probably have 4000 flash bulbs but missing a 75, I have 1 50

Amazing how powerful they are and how the tinests is as powerful as some way bigger

I love using them!

I bought bags of them 8 years ago

I have all kinds of flash 'handles'

and cords which are the hardest to find in usable condition

My fav is this

https://live.staticflickr.com/65535/51653741737_37f1a95e72.jpg (https://flic.kr/p/2mGsVQ6)Flash Bulb Gear Gift (https://flic.kr/p/2mGsVQ6) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

https://live.staticflickr.com/65535/50771809657_0afdca3c7d.jpg (https://www.flickr.com/gp/tincancollege/E1v1Z0)1933 Flash Gun 12 Inch (https://www.flickr.com/gp/tincancollege/E1v1Z0) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

https://live.staticflickr.com/65535/51363107133_077f6ccb4d.jpg (https://www.flickr.com/gp/tincancollege/HQ9X40)Honeywell Flash (https://www.flickr.com/gp/tincancollege/HQ9X40) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

[Dan Fromm]

Interesting, but why handicap yourself?

[Daniel Unkefer]

Could be a bit of fun with this, Sinar Norma Handy with my old wedding flash rig. Mighty Handy Indeed!

https://live.staticflickr.com/65535/51905964280_f0c476e508_b.jpg (https://flic.kr/p/2n5KCNC)SONY DSC (https://flic.kr/p/2n5KCNC) by Nokton48 (https://www.flickr.com/photos/18134483@N04/), on Flickr

This is my old bulletproof Wedding 283 Flash with Mini Soft Box. Great for Press Photography. The Viewfinder is a Mamiya 7 43mm Optical Finder. Also would work good with the Minolta SRT Era Deluxe III Flashgun. The Minolta SRT Era Flash Meter is deadly accurate with my Broncolor stuff and matches it in terms of readings. Also it reads focal plane flashbulbs!

[Tin Can]

I get bored

Father never let me use Flashbulbs, as frivolous, so I shot outside Sunny 16 for 35 years, mostly Slides

Almost always perfect exposure, same Pentax H1, then I took 1 class with someone I think you know, I no longer speak to him

I have progressed in 14 years from 2 Tota's to 4 SB800, to 4 Einsteins with plenty of modifiers

I really like the sound, smell and slow burn, of bulbs especially with slow Packards

My nephew 'lost' the H1, but I have a nice MX and will use it for film testing different lighting

Easiest to do on 35mm that is OK with amps




Interesting, but why handicap yourself?

[Tin Can]

Found this guy testing

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube (https://youtu.be/w2Oet8HCq8Q)

[djphoto]

Found this guy testing

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube (https://youtu.be/w2Oet8HCq8Q)

That guy cracks me up with the plant growing out of his head.

His hypothesis on "quality of light" is flawed, light is light--there's no difference.

The actual difference enters in due to exposure time... a strobe exposes over 1/5000 of a second or faster, whereas a flash bulb exposes over about 1/50th of a second.

This is evident in old sports photos taken with flashbulbs, there's just enough motion blur to describe the action:

227051

compare that with a photo in the film/strobe era, which looks completely static:

227052

Of course these days modern digital can shoot high enough iso's that you can shoot 1/100th of a second indoors without using a flash, so the scenarios where flashbulbs would be warranted are slim, but in very dark situations with fast action, I can still see a use.

[Bob Salomon]

That guy cracks me up with the plant growing out of his head.

His hypothesis on "quality of light" is flawed, light is light--there's no difference.

The actual difference enters in due to exposure time... a strobe exposes over 1/5000 of a second or faster, whereas a flash bulb exposes over about 1/50th of a second.

This is evident in old sports photos taken with flashbulbs, there's just enough motion blur to describe the action:

227051

compare that with a photo in the film/strobe era, which looks completely static:

227052

Of course these days modern digital can shoot high enough iso's that you can shoot 1/100th of a second indoors without using a flash, so the scenarios where flashbulbs would be warranted are slim, but in very dark situations with fast action, I can still see a use.

Depends on the strobe. Rollei E250, E1250 and E5000 had constant flash duration of 1/250.

[Jim Noel]

Weegee, and other freelance and news photographers of his time simplified things.
The lens was set at a preferred aperture. The camera was focused at the hyperfocal distance, or a preferred shorter distance. The shutter was set at a speed which allowed it to be fully open when the flash was at it's peak,
When they went to make a photograph they estimated the distance and the aperture provided enough depth of field to provide adequate sharpness. Their development was standardized, but in unusual circumstances special well known techniques were utilized.
All exposures were made with flashbulbs, day and night and exposure was based entirely on the output of the bulb.
Weegee had several cameras in the trunk of his car ready to go. Each was set for a particular type of picture - closeup, to about 10 or 12 feet, mid-distance up to about 20 feet, etc.
It worked well. I worked closely with a freelancer who gave me my first Speed, and taught me the "tricks".
I didn't own a meter for the first 10+ years i used this camera. Never an unprintable negative as long as I followed all the rules.

[Bernice Loui]

Previous discussion about flash bulbs..
https://www.largeformatphotography.info/forum/showthread.php?136587-Weegee-fact-or-1-200-with-flashbulbs

More about the differences between small compact electronic flash units -vs- vast production flash bulbs than one being "better" than the other.

If tasked with strobe/flash lighting a room used in this example, easy initial would be to use a BIG umbrella with a strobe/flash head that has enough power to produce the needed lens aperture for the image goals (larger the sheet of film, more strobe/flash power will be needed). Know both the vast production flash bulb and compact electronic flash unit are effectively a very small light source with not a lot of light output for the image area to be covered. This will result in hard/specular/ un-even lighting of the area being imaged. Using a basic umbrella with a proper strobe/flash head will produce an effectively larger light source with better light uniformity over a larger area. Other light modifiers from BIG soft box, wide angle reflector with BIG diffusion sheet in front, BIG reflector and more. All depends on how the lighting wants to be used to achieve a specific emotional expression in this area to be illuminated.

Color rendition is a factor that can be controlled and predicted by proper testing.
Clear flash bulbs have a typical color temperature of 4000 degrees Kelvin. Blue flash bulbs have a color temperature closer to 5000 degrees Kelvin due to the blue coating which works as a color correction filter, brings up the color temperature while giving up or trading off light output from the flash bulb.


All this has been previously done decades ago, being discovered by those new to all this.
Bernice





Found this guy testing

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube

Quality of light comparison - Electronic Flash vs M3 flash bulb vs AG-1 flash cube (https://youtu.be/w2Oet8HCq8Q)

[Bernice Loui]

Flash bulbs have a "burn-up" time or time required for ignition of the steel wool inside the oxygen filled glass envelop... typical "M" bulb takes about 20milliseconds to reach peak light output. This is also why vintage shutters have a "M" sync setting, to compensate for the time required for the flash bulb to reach peak light output, about 80milliseconds overall.
https://filmphotographyproject.com/flash-bulbs-lowdown/

Electronic strobe/flash units typically use a Xeon flash tube. They also have a time required to reach peak light output, except that time is often in micro seconds or less, far faster than a flash bulb (why "X" sync on shutters, and no image recorded if electronic flash/strobe is used with the shutter set at "M" sync) and their light output duration is typically shorter than a flash bulb. The xeon flash tube light output duration varies depending on tube design, power output, power source and..

One of the more common higher power flash tube configurations is circular (S type for Elinchrom) with ends like this
227084

This flash tube has a single arc path producing light when triggered. Time required to reach peak light output and for the light form the arc to die off is related to the total length of the single arc path. If 4000watt/seconds of light output is produced by these single arc path flash tubes, the flash duration would be about 1/350 to 1/500 second. Not ideal for "stop" action images, trading off LOTs of light output.
227085

Another type of flash tube has two arc light paths. This is achieved by placing the arc electrodes 180 degree apart in a circular tube (A type for Elinchrom).
With two paths for the arc to produce light, the effective distance between electrodes is reduced resulting in less time require for the arcs to produce peak light output and less time for the arcs to die out or dissipate.
227086

If 4000watt/seconds of light output is produced by these single arc path flash tubes, the flash duration would be about 1/900 to 1/1000 second. Better for "stop action" images than the single arc light path flash tubes.


Then we get into lower power flash/strobe units that can produce shorter flash durations which is ideal for stop action images. Lowest power using an type A Elinchrom flash tube/head results in a flash duration of 1/4000 second, can work good for stop action images.
227087


This flash duration spec has become a marketing hook in the current offering of electronic flash units. Note this flash duration for the Profoto 10 (near bottom of this page), it's flash duration grows as light output power grows. There is no escape from the physics involved with Xeon flash tubes.
http://www.peterbelanger.com/blog/2017/3/aovix7efo78f9lz41i1qswq0anj89h

At 2.4watt/seconds in their "freeze mode" flash duration is 1/80000 second which is not that different than compact portable flash/strobe units with similar light output. Once up to 2400watt/seconds flash duration is 1/1000 second in "freeze mode" which is much the same as using the A type flash tube/head for Elinchrom (at 4000watt/seconds, twice or 1 f-stop more than the Profoto 10). This is the current marketing game being played out in the current electronic flash/strobe struggle to sell their wares.

Current short duration electronic flash/strobe units achieve short flash duration by a combination of shorten arc light path tubes and a high power solid state device (IGBT, thyristor, SCR or similar) to cut off the power going into the flash tube. This with a combination of altering the regulated voltage at the flash capacitors and time allowed of energy flow into the flash tube is how modern electronic flash units achieve 7 or more f-stops of light output range gaining the ability to reduce flash duration time.


Bernice







That guy cracks me up with the plant growing out of his head.

His hypothesis on "quality of light" is flawed, light is light--there's no difference.

The actual difference enters in due to exposure time... a strobe exposes over 1/5000 of a second or faster, whereas a flash bulb exposes over about 1/50th of a second.

This is evident in old sports photos taken with flashbulbs, there's just enough motion blur to describe the action:

227051

compare that with a photo in the film/strobe era, which looks completely static:

227052

Of course these days modern digital can shoot high enough iso's that you can shoot 1/100th of a second indoors without using a flash, so the scenarios where flashbulbs would be warranted are slim, but in very dark situations with fast action, I can still see a use.

[Bernice Loui]

Circa 1968 Singer Company acquired GPE/ Graflex, introduced the Strobomatic 500 portable electronic flash unit with switchable power outputs of 50/100/200 watt/seconds.
https://ghq.graflex.org/GHQ-13-4.pdf

This was revolutionary back in the days when flash bulbs were the accepted and common way of achieving this kind of light output for 4x5 press camera images to weddings. Not long after this the Norman 200B (and others) replaced the Strobomatic 500 to become one of the most common portable electronic flash units made.
http://normanlights.com/manuals/200Bmanual.pdf

https://www.largeformatphotography.info/forum/showthread.php?162285-Used-Norman-200b&highlight=norman+200b



The game with these 50/100/200 watt second portable electronic flash units was their effective guide number of 160 at ASA (ISO) 100 or f16 at 10 feet using a standard reflector on the flash head. In real world image making, set the lens at f16, estimate the camera to subject distance to be about 10 ft, then "fire" to record the image. The 10 ft subject to camera chart looked like this:

f16 at 200watt/second.

f11 at 100watt/second.

f8 at 50watt/second.

This was the basic chart. At f16 images became "zone" focused as f16 allowed estimated focusing applying "apparent" focus from the small aperture used (f16) to compensate or make up sort of for critical focusing of camera to subject.



Bernice

[Bob Salomon]

Flash bulbs have a "burn-up" time or time required for ignition of the steel wool inside the oxygen filled glass envelop... typical "M" bulb takes about 20milliseconds to reach peak light output. This is also why vintage shutters have a "M" sync setting, to compensate for the time required for the flash bulb to reach peak light output, about 80milliseconds overall.
https://filmphotographyproject.com/flash-bulbs-lowdown/

Electronic strobe/flash units typically use a Xeon flash tube. They also have a time required to reach peak light output, except that time is often in micro seconds or less, far faster than a flash bulb (why "X" sync on shutters, and no image recorded if electronic flash/strobe is used with the shutter set at "M" sync) and their light output duration is typically shorter than a flash bulb. The xeon flash tube light output duration varies depending on tube design, power output, power source and..

One of the more common higher power flash tube configurations is circular (S type for Elinchrom) with ends like this
227084

This flash tube has a single arc path producing light when triggered. Time required to reach peak light output and for the light form the arc to die off is related to the total length of the single arc path. If 4000watt/seconds of light output is produced by these single arc path flash tubes, the flash duration would be about 1/350 to 1/500 second. Not ideal for "stop" action images, trading off LOTs of light output.
227085

Another type of flash tube has two arc light paths. This is achieved by placing the arc electrodes 180 degree apart in a circular tube (A type for Elinchrom).
With two paths for the arc to produce light, the effective distance between electrodes is reduced resulting in less time require for the arcs to produce peak light output and less time for the arcs to die out or dissipate.
227086

If 4000watt/seconds of light output is produced by these single arc path flash tubes, the flash duration would be about 1/900 to 1/1000 second. Better for "stop action" images than the single arc light path flash tubes.


Then we get into lower power flash/strobe units that can produce shorter flash durations which is ideal for stop action images. Lowest power using an type A Elinchrom flash tube/head results in a flash duration of 1/4000 second, can work good for stop action images.
227087


This flash duration spec has become a marketing hook in the current offering of electronic flash units. Note this flash duration for the Profoto 10 (near bottom of this page), it's flash duration grows as light output power grows. There is no escape from the physics involved with Xeon flash tubes.
http://www.peterbelanger.com/blog/2017/3/aovix7efo78f9lz41i1qswq0anj89h

At 2.4watt/seconds in their "freeze mode" flash duration is 1/80000 second which is not that different than compact portable flash/strobe units with similar light output. Once up to 2400watt/seconds flash duration is 1/1000 second in "freeze mode" which is much the same as using the A type flash tube/head for Elinchrom (at 4000watt/seconds, twice or 1 f-stop more than the Profoto 10). This is the current marketing game being played out in the current electronic flash/strobe struggle to sell their wares.

Current short duration electronic flash/strobe units achieve short flash duration by a combination of shorten arc light path tubes and a high power solid state device (IGBT, thyristor, SCR or similar) to cut off the power going into the flash tube. This with a combination of altering the regulated voltage at the flash capacitors and time allowed of energy flow into the flash tube is how modern electronic flash units achieve 7 or more f-stops of light output range gaining the ability to reduce flash duration time.


Bernice

Bernice, isn’t it about time that you learned that watt seconds is not output, can not be converted directly to a guide number or actual output?
Watt seconds is another major “marketing ploy”!

[Tin Can]

http://www.thebroketographers.com/blog/2016/9/20/color-consistency-test-paul-c-buff-einstein-e640-profoto-b2-retest

https://www.fredmiranda.com/forum/topic/997317/0 as always nearly unreadable

https://fstoppers.com/reviews/einstein-640-plm-system-review-paul-c-buff-3189

I always have the 86" umbrella mounted

Studio Lighting Comparison Review-$200+: Paul C. Buff, Alien Bees, Elinchrom, Profoto, Flashpoint (https://youtu.be/bMFjM9dzSzQ)

[Bernice Loui]

Yes indeediee Bob, watt/seconds is a relative measure. Same game with Guide Numbers.

This is why using an accurate flash meter is absolutely essential. Once light modifiers are applied (which is nearly 100% of the time for proper strobe/flash heads) all this watt/seconds, Guide numbers babble become extremely meaningless.

Fact is, two Elinchrom 404 (4000 watt/second) power packs into a X8000 flash head (8000 watt/seconds total) will produce a LOT more light output than any battery powered compact flash unit.. or why watt/second become a relative power output metric.


Bernice



Bernice, isn’t it about time that you learned that watt seconds is not output, can not be converted directly to a guide number or actual output?
Watt seconds is another major “marketing ploy”!

[Bernice Loui]

Profoto B2 – Freeze Mode

Power 2.0 (1ws) – 8000K
Power 3.0 (2ws) – 8100K
Power 4.0 (3.9ws) – 7750K
Power 5.0 (7.8ws) – 7150K
Power 6.0 (15.6ws) – 6750K
Power 7.0 (31.25ws) – 6600K
Power 8.0 (62.5ws) – 6500K
Power 9.0 (125ws) – 6350K
Power 10.0 (250ws) – 6150K


Paul C Buff Einstein E640 – Action Mode

Power 2.0 (2.5ws) – 7250K
Power 3.0 (5ws) – 7000K
Power 4.0 (10ws) – 7050K
Power 5.0 (20ws) – 6850K
Power 6.0 (40ws) – 6700K
Power 7.0 (80ws) – 6350K
Power 8.0 (160ws) – 6050K
Power 9.0 (320ws) – 5900K
Power 10.0 (640ws) – 5600K

~Physics of how Xeon flash tubes work applies here, color temperature shift due to the method Profoto is using to gain shorter flash duration.
Shift up in color temperature increases the effective "blueish" rendering for the color recording method referenced to 5000 degrees Kelvin.

Part of why those Elinchrom strobe/flash units remain, they have good color temperature control over their light output range. This is true for Broncolor and similar often forgotten electronic strobe/flash units from the past. Back then good color temperature control over the power range was essential and mandatory as color transparency film was sensitive to shifts in lighting color temperature. It was why owning a Minolta color meter IIIF and a stack of cc filters for both lens and lighting with gray card film batch testing was essential for color control in color transparencies. Today it seems, Fotoshop and similar color adjuster sliders have become the solution to this problem.. which is not quite the same as getting the color proper, accurate-precise on film from the get go.


Bernice




http://www.thebroketographers.com/blog/2016/9/20/color-consistency-test-paul-c-buff-einstein-e640-profoto-b2-retest

https://www.fredmiranda.com/forum/topic/997317/0 as always nearly unreadable

https://fstoppers.com/reviews/einstein-640-plm-system-review-paul-c-buff-3189

I always have the 86" umbrella mounted

Studio Lighting Comparison Review-$200+: Paul C. Buff, Alien Bees, Elinchrom, Profoto, Flashpoint (https://youtu.be/bMFjM9dzSzQ)

[Bob Salomon]

Yes indeediee Bob, watt/seconds is a relative measure. Same game with Guide Numbers.

This is why using an accurate flash meter is absolutely essential. Once light modifiers are applied (which is nearly 100% of the time for proper strobe/flash heads) all this watt/seconds, Guide numbers babble become extremely meaningless.

Fact is, two Elinchrom 404 (4000 watt/second) power packs into a X8000 flash head (8000 watt/seconds total) will produce a LOT more light output than any battery powered compact flash unit.. or why watt/second become a relative power output metric.


Bernice

No, that output will depend on the angle of coverage on that flash head.

[maltfalc]

Bernice, isn’t it about time that you learned that watt seconds is not output, can not be converted directly to a guide number or actual output?
Watt seconds is another major “marketing ploy”!

watt-seconds isn't any more of a marketing ploy than the wattage listed on an incandescent bulb. it's just a measure of power input to give you a rough idea of the flash's output. guide numbers are way more questionable.

[Tin Can]

I use a Sekonic L758 meter constantly

I buy what I can afford as hobbyist

Bob is a salesman

I was also selling very expensive tools and I advised all beginners to buy what they could afford

Then when they became better paid I gladly sold Pro stuff

[Bob Salomon]

watt-seconds isn't any more of a marketing ploy than the wattage listed on an incandescent bulb. it's just a measure of power input to give you a rough idea of the flash's output. guide numbers are way more questionable.

Do some study watt seconds are the storage capacity of the capacitors in a flash. An extremely efficient flash will not output more then 80% of that storage capacity. The actual output will depend on the diameter of the wires between the capacitors and the flash tube, the number of connectors between them, the design of the tube, the coverage of the reflector, etc.
Assume that you have a 200ws flash. You take one shot without a reflector and another with a 50° coverage reflector. Both are 200ws. But their outputs are not nearly the same.
Without knowing the loading capacity of the capacitors + the coverage of the reflector it is impossible to determine the gn. GN divided by the distance results in the exposure.
Learn BCPS of your system and you can determine output. Learning the WS is like guessing output.

[wclark5179]

I studied lighting patterns and various camera positions with the body and lighting set up to make flattering photographs of people. Those are two important ingredients when making photographs of people. There are others, like the environment, props, skin color, make up and clothing. I would work at a situation and I would determine, do I want the photograph to look like this?

How I achieved proper exposure was by reviewing the first of a series of photographs using the historgram on the camera as a guide.

When I was film based, I would use a polaroid back to check things out, then the film back was put on. Photography was much more limited back then.

Here is an interesting and educational site on lighting and other ingredients:

https://strobist.blogspot.com/

[maltfalc]

Do some study watt seconds are the storage capacity of the capacitors in a flash. An extremely efficient flash will not output more then 80% of that storage capacity. The actual output will depend on the diameter of the wires between the capacitors and the flash tube, the number of connectors between them, the design of the tube, the coverage of the reflector, etc.
Assume that you have a 200ws flash. You take one shot without a reflector and another with a 50° coverage reflector. Both are 200ws. But their outputs are not nearly the same.
Without knowing the loading capacity of the capacitors + the coverage of the reflector it is impossible to determine the gn. GN divided by the distance results in the exposure.
Learn BCPS of your system and you can determine output. Learning the WS is like guessing output.

you're not telling me anything i haven't known for decades, or disagreeing with anything i actually said, so why did you bother with that long-winded, condescending comment?

[Bob Salomon]

you're not telling me anything i haven't known for decades, or disagreeing with anything i actually said, so why did you bother with that long-winded, condescending comment?

Because your flash statements are incorrect and misleading.

[maltfalc]

Because your flash statements are incorrect and misleading.work on your reading comprehension, because you didn't address my points directly or disagree with anything i said.

[Bernice Loui]

Applies here...
227274


BCPS = Beam Candle Power Seconds (BCPS) Rating...
https://www.angelfire.com/electronic2/flashdoctor/bcps.html

Is of nil-usefulness for ANY electronic flash/strobe once a light modifier (umbrella, soft-box, beauty dish, parabolic reflector with the strobe/flash head reverse mounted and many others) has been applied to the flash/strobe head due to the how the light from the strobe/flash head is distributed within the light modifier.

Only situation where BCPS might be a meaningful metric applies to those portable electronic strobe/flash units with a fixed reflector used as designed/delivered. Like those used by "run & gun" still image recorders folks.

It is beyond unlikely any battery powered portable hand held "potato masher" style strobe/flash could ever hope to produce f90 at 10ft out of a BIG soft box light modifier.. To achieve that demand a truly powerful power mains strobe/flash unit..


~This is why a good flash meter, polaroid test or instant preview via digital is required to produce accurate exposures on digital or film. Any decent strobe/flash unit that is designed to be used with light modifiers will have the ability to adjust their light output by 1/10f-stop... which is variable BCPS..


Bernice



Originally Posted by Bob Salomon
Because your flash statements are incorrect and misleading.




work on your reading comprehension, because you didn't address my points directly or disagree with anything i said.

[Bob Salomon]

Applies here...
227274


BCPS = Beam Candle Power Seconds (BCPS) Rating...
https://www.angelfire.com/electronic2/flashdoctor/bcps.html

Is of nil-usefulness for ANY electronic flash/strobe once a light modifier (umbrella, soft-box, beauty dish, parabolic reflector with the strobe/flash head reverse mounted and many others) has been applied to the flash/strobe head due to the how the light from the strobe/flash head is distributed within the light modifier.

Only situation where BCPS might be a meaningful metric applies to those portable electronic strobe/flash units with a fixed reflector used as designed/delivered. Like those used by "run & gun" still image recorders folks.

It is beyond unlikely any battery powered portable hand held "potato masher" style strobe/flash could ever hope to produce f90 at 10ft out of a BIG soft box light modifier.. To achieve that demand a truly powerful power mains strobe/flash unit..


~This is why a good flash meter, polaroid test or instant preview via digital is required to produce accurate exposures on digital or film. Any decent strobe/flash unit that is designed to be used with light modifiers will have the ability to adjust their light output by 1/10f-stop... which is variable BCPS..


Bernice

Nonsense, the output is over the angle of coverage, be it a soft dish, umbrella, soft box, back light reflector, hair light, spot light, fresnel spot, etc. it is what that head outputs over the angle covered by whatever light modifier is used, even if it’s bare bulb.