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AnselAvedon
24-Jan-2018, 20:53
I am shooting an Egg on an 8x10.
I am looking to rent a light but am not sure what light to use. I do know it will need to be powerful.


My film stock is iso 50.
I want to shoot at 125th of a second.
At aperture F 32

I also know I need a bellows draw compensation of 5 stops


Is there math to figure out how much light I will need?

AnselAvedon
24-Jan-2018, 20:58
The bellows calculation comes from shooting on a 240mm lens with 1222mm of bellows

cowanw
24-Jan-2018, 22:23
Hmmm white or brown egg?

Doremus Scudder
25-Jan-2018, 02:47
How much light depends upon exposure time. I've made LF close-up shots with ambient window light where I opened the shutter, left for work, and come back 6-8 hours later and closed the shutter. If you're using hot lights or ambient light and long exposures, you just need to get a handle on the reciprocity corrections for such long exposure times (of course, I'm assuming B&W film; with color you'll want to aim for shorter exposures to avoid color shift).

If you are looking at flash, remember that, when shooting a still life (which stays still...), you can use multiple pops of the flash to arrive at your needed exposure.

If you have access to the light (flash unit) you want to rent, take your (flash) meter with you and measure. Maybe someone will come up with a formula for determining how many lumens or candles per square foot you need, but I imagine it will be rather complicated. Measuring the actual light source is likely faster and easier.

Edit: I've just seen in another thread that you're likely shooting an "action" shot, i.e., not a still life. So, long exposures won't work in this case. So, just go in to your lighting rental place with your meter and do some measuring of light intensity. Keep in mind that the distance from the light to the subject is critical (inverse square law and all that), so measure with an incident meter at the working distance or take a reading from a lit object at the working distance (or adjust the light-to-subject distance to get the intensity you need).

Best,

Doremus

Pere Casals
25-Jan-2018, 04:10
Is there math to figure out how much light I will need?

Here you have a table, use the studio reference entry at 1000 lux, this for 1/50 exposure, ISO 100, f/2.8, so you just need multiply/divide the 1000 Lux properly for your shutter speed, aperture, ISO, and bellows compensation.

https://wolfcrow.com/wp-content/uploads/2013/04/QuantityLightChart.jpg


You can also use math:

Know how many lux x second you want on film, from exposure you know how many lux you want on film, from f stop, bellows compensation, and subject reflectiveness you know howm many lux should receive you subject, and from the area you light source illuminates and the power to light convension efficiency you know the watts of your light. It would be nice if somebody can show the exact formula...

For exact exposures, a good choice for precision is using "the view's camera TTL metering feature": place a DLSR or SLR (Nikon F65...) in the back of the view camera (need a DIY attachment, made with a macro extension ring), focus to the same point you are to focus and measure... with shift/rise you can explore all the framing, or you can use camera orientation for it if fall off is not a concern.

Nodda Duma
25-Jan-2018, 06:33
To get your answer requires a radiometric calculation. Actually, it requires a series of calculations and assumptions. Very heavy stuff. I've been doing radiometry for work for years and I still have to pull out notes I wrote for myself in the past.

Easier to set up a test.. *much easier*.

Meter off the egg with an available light set at your desired distance from the egg. Determine how many stops down you are. Doubling the light output adds a stop.

When you get your actual light in, you can fine tune with lighting distance. Halving the distance adds roughly 1-2 stops depending on the characteristics of your source (baffling vs bare bulb, etc).

Tin Can
25-Jan-2018, 08:01
I think your initial requirements are impossible.

50 ISO and 1/125 shutter at f32 is a problem. As it seems you want to use hot lights. Strobes will get you there and not melt everything, but shutter speed then is irrelevant. Your shutter speed will become strobe speed. Very fast.

This is a scan from 11X14" X-Ray ISO 80. The ashtray is about 4" in diameter. I didn't keep all records. I think I shot with a 300mm Sironar stopped down to f22. We can prpbably calculate my distance to object and bellows extension. Object to lens maybe 1 foot. I bet Dan could figure the details.

I use 3 Einstein strobes full blast at very close range, fitting them around the Deardorf S11 was tight. Multiple pops of all 3 strobes. I used a flash meter and got a good exposure in a couple shots. I developed each film then adjusted from examination.

Just an exercise/experiment. I got what I wanted to know.

I do know magnification was about 2.5. The 11X14 neg doesn't fit on my V700 so the image here is cropped.

https://farm5.staticflickr.com/4762/39892851641_f778141d0b_b.jpg (https://flic.kr/p/23MchWV)Watergate 2.5-1 Macro (https://flic.kr/p/23MchWV) by moe.randy (https://www.flickr.com/photos/tincancollege/), on Flickr

DrTang
25-Jan-2018, 10:11
you will need a whole lot of light to shoot at 1/125

maybe get an arri 500 right up close to the egg... like within a foot... maybe use some frosted glass between to even the light out?

but with f32... and then tossing 5 stops on top of that..... at 1/125?

oy

Dan Fromm
25-Jan-2018, 11:33
Why use continuous light? Flash will do it. The trick is to use a short flash-to-subject distance. At close distances a flash acts like a large light source, not like a point source. No kidding.

OP, its time for you to learn how to use flash guide numbers.

Pere Casals
25-Jan-2018, 12:01
Why use continuous light? Flash will do it. The trick is to use a short flash-to-subject distance. At close distances a flash acts like a large light source, not like a point source. No kidding.

OP, its time for you to learn how to use flash guide numbers.


If subject is static, continous light is convenient, it has the advantage that we can see/control the illumination effects. We can meter easily key vs fill...

With flash we should use the modeling light, meter the continous light and adjust strobes with flashmeters to get the right balance.

But today we have DSLRs to preview the illumination effects, it is really useful to preview the effect of the modifiers, the light nature, the light fall... a bit like when in the past instant film was used to preview a result for the LF negative.

I found that a DSLR is a very good tool to adjust illumination for LF in studio conditions.

Jim Noel
25-Jan-2018, 12:18
I am shooting an Egg on an 8x10.
I am looking to rent a light but am not sure what light to use. I do know it will need to be powerful.


My film stock is iso 50.
I want to shoot at 125th of a second.
At aperture F 32

I also know I need a bellows draw compensation of 5 stops


Is there math to figure out how much light I will need?

Why 1/125 second? The egg isn't going anywhere.

Jac@stafford.net
25-Jan-2018, 12:42
1/125th of a second is a challenge.
I'm a flash bulb kinda guy.

I would need a couple Guinness then set up some super flashbulbs with a *flash meter, but man the bulbs are spendy and rare. :) If Randy Moe were nearby I bet we would have put on the welding gloves and masks and had a lighting scheme tested already. It would be fun cooking eggs under flash.

If we keep to #5 or #25 clear flashbulbs I'm pretty sure ten set off at once in a tight reflector would work even on M sync @ 1/125th second. OK, maybe fifty.

I have a case of bulbs with a duration of 1.7 seconds, and a few Mazda 75 but frankly I'm too scared to fire them off.

*Yes, you can use a flash meter with bulbs IF you use a cord connection.

AnselAvedon
25-Jan-2018, 13:14
Thanks for all the insight. The 125th shutter is because I will be breaking the egg

Pfsor
25-Jan-2018, 13:18
Thanks for all the insight. The 125th shutter is because I will be breaking the egg

Just curious - how do you intend to synchronise the egg braking with your 125th shutter firing?

Bill Burk
25-Jan-2018, 13:44
I think you need somewhere between 102,400 and 205,600 candles per square inch.

I just set my Weston Master III to ASA 50 and reduced 5 stops to EI 1.5 for bellows extension

Then set the dial at 1/125 and f/32

And looked where the arrow points into 1/3 stop below the 0.4 mark on the second pass of the dial, which works out to...

Highest candles per square inch on Weston dial: 1600

1 more stop 3200

2 more stops 6400

3 more stops 12800

4 more stops 25600

5 more stops 102400

5 2/3 more stops -> The amount of light you need.
6 more stops 205600

Perhaps use a magnifying glass to focus the light on a tiny spot and shoot just a tiny part of the egg.

Please use welder's glasses or other eye protection to protect your eyes as you compose the shot.

Luis-F-S
25-Jan-2018, 15:11
How much light depends upon exposure time.

And depending on whether you just want to photograph them or also cook them with hot lights! I think there are enough responses above to elaborate any more.

Jim Galli
25-Jan-2018, 15:11
Edgerton would have used electronic flash to accomplish this with some kind of trap to trip the flash at the precise moment. My method would be simpler. Put the egg on a flatbed scanner in a dark room and when the traveling band of light gets to the egg, push down on the lid. A borrowed scanner of course. I'd do it at Dan Fromm's house with his scanner.

Anyways, sounds like you're having fun and that's the main thing. Good luck. Share some results.

Dan Fromm
25-Jan-2018, 15:18
Jimbo, how did you know that my scanner also cooks? Scanner, printer, copier, rice steamer and electric fry pan.

Tin Can
25-Jan-2018, 15:30
I agree this is hopefully fun.

Many years ago I found a lot of CRT TV's in an alley. I wanted to video a large rock coming out of the front of a TV.

A variety of schemes were tried, mirror, ladders, strong men. I videotaped all the failures, and it was fun just doing it.

Before the Internet, we had to do something...

Jac@stafford.net
25-Jan-2018, 16:18
Disregard the 8x10 format because it cannot be justified, a medium format and a .22 CB cap to impact the egg would suffice with a sound trigger. It is a shame that today's persons have no idea.

Jim Galli
25-Jan-2018, 16:41
Jimbo, how did you know that my scanner also cooks? Scanner, printer, copier, rice steamer and electric fry pan.

All the new imported models can barbecue too. Maybe time for an upgrade?

Dan Fromm
25-Jan-2018, 19:48
All the new imported models can barbecue too. Maybe time for an upgrade?

I dunno, Jim. I usually do ribs in the oven. My Texan son-in-law is appalled but mine are more consistent than his 'cos my oven is more consistent than he is. And then there are stove top ribs and barbacoa. The electric fry pan comes in handy for stove top ribs. Barbacoa -- with cheek meat, naturally -- needs a stove, a skillet won't do for it.

Greg Davis
25-Jan-2018, 22:06
I do shots like this with splashing water. The 1/125 of a second won’t do the job. The shutter speed actually doesn’t matter. What matters is the flash duration. Either use a good quality speedlight, I use a Minolta 5400 HS, set on 1/32 power for the shortest possible flash, or use a Profoto D2 monolight. They have a flash duration of 1/63,000 of a second, or something in that area.

You will also need a trigger. Most use a digital shutter signal, so you may need to use a slow shutter speed and connect the trigger to the light rather than the shutter. I use a Miops brand trigger, but Pluto and Vello are cheaper. They can be set to fire from a loud sharp sound or by breaking a laser beam from a laser pointer. You dial in the amount of delay from trigger to flash to get the desired photo.

174052

Greg Davis
26-Jan-2018, 13:53
BTW, here is how I have this set up. The black card is blocking the view to the Minolta 5400 flash I have on a light stand. Excuse the mess.

John Olsen
26-Jan-2018, 17:57
No problem with flash. Just use the Guide Number for your flash and place on the flash head being close to the egg. For example, with one #102 head on a 2400 Ws Black Line Speedotron the Guide number is 540. That's in feet and for 100 ISO. Place the head at 1 foot distance and you can shoot at f540 on 100 ISO film. For 50 ISO, you open up one stop to f385. For 5 stops of bellows extension you open further to f68. Plenty of light to spare, you can probably dial down to half power or less for f32 at 125th.

After a couple of pops, it should be ready to eat.