Long exposure bulb settings: How does one select parameters for long exposure using the bulb setting? Is there some calculator or cheat sheet for selecting time of exposure?

IzzyKap Loc: Rockville, MD

How does one select parameters for long exposure using the bulb setting? Is there some calculator or cheat sheet for selecting time of exposure?

sarge69 Loc: Ft Myers, FL

IzzyKap wrote:

How does one select parameters for long exposure using the bulb setting? Is there some calculator or cheat sheet for selecting time of exposure?

When I had a film camera and now with digital I selected an ISO of 100 to 200 (Then ASA)

I selected 'bulb' as a shutter speed (always open)

I had a shutter cable to the shutter button (now a vello remote)

I clicked the shutter cable and counted 2 seconds, then 4 seconds then 6 seconds and went home to develop the film

Now I click the vello button and do the same. Then look at the digital photo and decide on more time or less time.

I use the vello because I can set delays in taking the photo with the mirror up (camera setting) and out of the way 2 seconds before the shutter opens.

Viewing results are instant without developer, stop and rinse for the film.

Sarge69

IzzyKap Loc: Rockville, MD

Thanks but I was thinking more of conditions requiring several minutes exposures. Depending on environmental conditions, there may only be few opportunities for trial and error approach. Is there some formula to estimate the shutter exposure requiring several minutes?

sarge69 wrote:

When I had a film camera and now with digital I se... (show quote)

jerryc41 Loc: Catskill Mts of NY

IzzyKap wrote:

How does one select parameters for long exposure using the bulb setting? Is there some calculator or cheat sheet for selecting time of exposure?

There are calculators and tables for long exposures, like for nighttime or stars. Did you have anything in particular in mind?

IzzyKap Loc: Rockville, MD

Landscape with 10 ND filter to get smooth, silky water and clouds.

jerryc41 wrote:

There are calculators and tables for long exposures, like for nighttime or stars. Did you have anything in particular in mind?

jerryc41 Loc: Catskill Mts of NY

IzzyKap wrote:

Landscape with 10 ND filter to get smooth, silky water and clouds.

Here are some good references.

http://www.redbubble.com/people/peterh111/journal/4421304-the-ultimate-easy-guide-to-neutral-density-filters?SSAID=314743

http://digital-photography-school.com/how-to-use-a-10-stop-nd-filter-to-take-long-exposure-sunset-images

http://www.cambridgeincolour.com/tutorials/neutral-density-filters.htm

http://www.lightstalking.com/strong-nd-filters

IzzyKap Loc: Rockville, MD

Thank you very much. These should be very helpful.

jerryc41 wrote:

Here are some good references.

http://www.redbubble.com/people/peterh111/journal/4421304-the-ultimate-easy-guide-to-neutral-density-filters?SSAID=314743

http://digital-photography-school.com/how-to-use-a-10-stop-nd-filter-to-take-long-exposure-sunset-images

http://www.cambridgeincolour.com/tutorials/neutral-density-filters.htm

http://www.lightstalking.com/strong-nd-filters

jimmya Loc: Phoenix

IzzyKap wrote:

How does one select parameters for long exposure using the bulb setting? Is there some calculator or cheat sheet for selecting time of exposure?

You have to consider this. All the time your shutter is open, say several minutes, your sensor is working. While it's working millions of electrons are passing through it and it can easily over heat... which would destroy the sensor and thereby your camera.

So, all cameras have a built in threshold temperature at which the camera will shut down because of heat. Forcing the shutter to stay open on the bulb setting more than say
30-seconds or a minute is considered a bad idea.

IzzyKap Loc: Rockville, MD

For some projects it's necessary, like star trails, moonlight only illumination, etc.

jimmya wrote:

You have to consider this. All the time your shutter is open, say several minutes, your sensor is working. While it's working millions of electrons are passing through it and it can easily over heat... which would destroy the sensor and thereby your camera.

So, all cameras have a built in threshold temperature at which the camera will shut down because of heat. Forcing the shutter to stay open on the bulb setting more than say
30-seconds or a minute is considered a bad idea.

IzzyKap Loc: Rockville, MD

While looking at these and doing further searches, I came across this helpful free Long Exposure Quick Calculator Chart by Doug Chinnery
http://www.s375595000.websitehome.co.uk/wp-content/uploads/2011/08/Long-Exposure-Quick-Calculator.pdf

Also, there is a very nice Exposure Calculator free app on Android.

These are the exact things that I was seeking.

jerryc41 wrote:

Here are some good references.

http://www.redbubble.com/people/peterh111/journal/4421304-the-ultimate-easy-guide-to-neutral-density-filters?SSAID=314743

http://digital-photography-school.com/how-to-use-a-10-stop-nd-filter-to-take-long-exposure-sunset-images

http://www.cambridgeincolour.com/tutorials/neutral-density-filters.htm

http://www.lightstalking.com/strong-nd-filters

SharpShooter Loc: NorCal

jimmya wrote:

You have to consider this. All the time your shutter is open, say several minutes, your sensor is working. While it's working millions of electrons are passing through it and it can easily over heat... which would destroy the sensor and thereby your camera.

So, all cameras have a built in threshold temperature at which the camera will shut down because of heat. Forcing the shutter to stay open on the bulb setting more than say
30-seconds or a minute is considered a bad idea.

Jim, I think you are partly correct. Yes the shutter is open, but he is ND'ing it to the point of shooting on a dark night. Izzy is really just doing an exposure of 1/100, but taking several minutes to do it. He is filtering the majority of the photons. Kinda with you wearing a welding helmet and looking at the sun. It won't fry your eyes. The camera will shut down, but that's usually on a bright day and using live view, unfiltered. SS

St3v3M Loc: 35,000 feet

IzzyKap wrote:

While looking at these and doing further searches, I came across this helpful free Long Exposure Quick Calculator Chart by Doug Chinnery
http://www.s375595000.websitehome.co.uk/wp-content/uploads/2011/08/Long-Exposure-Quick-Calculator.pdf

Also, there is a very nice Exposure Calculator free app on Android.

These are the exact things that I was seeking.

Thank you

Photographer Jim Loc: Rio Vista, CA

You can, of course, do some math in your head and get the exposure that way. With your camera set to AV, the ISO , and the f-stop you wish to use for the shot, take a reading without the filter. Then double the shutter duration ten times. Example: you get a reading of 1/125 without the filter. Doubled is 1/60. Doubled is 1/30. Doubled ... 1/15, 1/8, 1/4, 1/2, 1st, 2s, 4s, and finally 8s. That will be the equivalent exposure for when the 10 stop filter is in place. Mount your filter, set to Bulb, and shoot away.

Now, if you are like me, and have reached the age where your brain has gone just a tad fuzzy, making use of a smart phone app to do the calculation is a nice solution. There are a few free (or inexpensive) apps available that make the task quite easy. I use one called Longtime Exposure Calculator for my iPhone. Quick and easy. I also have a countdown timer app (Easy Timer) right next to it so I can dial in the timer to give me an audible cue to close the shutter.

SharpShooter Loc: NorCal

Photographer Jim wrote:

You can, of course, do some math in your head and ... (show quote)

Yes, but Jim, to use your method, does one need to be a MENSA card carrying member? I've misplaced my card, and if I were any smarter, I'd remember where I left it!!
Thanks for the app info. SS

jimmya Loc: Phoenix

SharpShooter wrote:

Yes, but Jim, to use your method, does one need to be a MENSA card carrying member? I've misplaced my card, and if I were any smarter, I'd remember where I left it!!
Thanks for the app info. SS

Could be but I've gotten a heat worning after about 11 minutes and the camera shut down at about 12:30... just a thought.