Page 1 of 6 123 ... LastLast
Results 1 to 10 of 59

Thread: Long Exposure - Very Different Results Between Digital and 4x5 Film

  1. #1

    Join Date
    Jun 2015
    Location
    Wherever My Laptop Is (Usually Australia)
    Posts
    32

    Long Exposure - Very Different Results Between Digital and 4x5 Film

    Hi All - Newbie here.

    I have a question I thought some of you might be able to help me with.

    I am trying to do some still life shots in very low directional light. In other words lighting the subject only, say an apple or a shell or something.

    I did some test shots on my Nikon digital camera at f 29 @ 120 seconds @ 100 ISO. Shots came out well lit, could see what the object was and even the background was well lit and clear.

    I then tried to translate those settings to my new Toyo 45A which I currently have loaded with Fomapan 100. After reading about Fomapan 100 I am using it as ISO 80.

    So my translated settings (using my handy android ev pairs app) for f 32 came to:

    f 32 @ 3.2 minutes = 3.12 minutes @ ISO 80

    After developing the shot, for example of the shell, the film was almost totally clear. I could just see a few details from the lines of the shell. In other words very very underexposed.

    So the question is why is there so much difference between the digital and film results?

    And how can I accurately determine long exposure shots when using my Toyo / Fomapan 100 if I cannot simply translate the settings from my digital camera meter?

    I guess its worth pointing out that on faster shots in well lit situations the results are fine and I can meter with my digital without the vast difference in results.

    Thanks

  2. #2

    Join Date
    Oct 2012
    Location
    Connecticut, USA
    Posts
    5,308

    Long Exposure - Very Different Results Between Digital and 4x5 Film

    Sounds like you're not accounting for "reciprocity failure" which of all films fomapan is the WORST, if you want a good film, Fuji Acros100 has the best reciprocity for long exposures, no adjustments need to be made up to 2 minutes.

    In contrast Foma needs adjustment after 1/2 second.

    This will be abstract until you read up on reciprocity failure with film. Google and read and you'll hopefully have your answer. Welcome to the fold and don't give up!

  3. #3

    Join Date
    Jun 2015
    Location
    Wherever My Laptop Is (Usually Australia)
    Posts
    32

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Quote Originally Posted by StoneNYC View Post
    This will be abstract until you read up on reciprocity failure with film. Google and read and you'll hopefully have your answer. Welcome to the fold and don't give up!
    Thanks, reading up now.

  4. #4

    Join Date
    Jun 2015
    Location
    Wherever My Laptop Is (Usually Australia)
    Posts
    32

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Okay I understand now..

    Schwarzschild effect - reciproke failure (non-linearity of exposure)
    Exposure (seconds) 1/1000–1/2 1 10 100
    Lengthening of exposure 1x 2x 8x 16x
    Correction of aperture number 0 -1 -3 -4
    So will try:

    f 25 @ ISO 80 = 100 seconds x 16 = 1600 seconds = 26.6 minutes

    Fair bit longer than the 3.2 minutes I tried first..

    Thanks again

  5. #5
    ghostcount's Avatar
    Join Date
    Mar 2009
    Location
    Condado de la Naranja, CA
    Posts
    669

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Reciprocity failure. Foma is awful for this. Their data sheet only states compensation for up to 100 seconds - I'm sure you can extrapolate for 3.12 minutes but it could be tedious.

    Don't forget about bellows factor - you didn't mention that.
    "Sex is like maths, add the bed, subtract the clothes, divide the whoo hoo and hope you don't multiply." - Leather jacket guy

  6. #6
    DannL's Avatar
    Join Date
    Mar 2013
    Location
    OK, USA
    Posts
    283

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Is there a particular reason why you can not increase the available light, in order to reduce your exposure time? Just curious.
    "Photography is a marvelous discovery, a science that has attracted the greatest intellects, an art that excites the most astute minds — and one that can be practiced by any imbecile." – Nadar, 1856

  7. #7

    Join Date
    Oct 2012
    Location
    Connecticut, USA
    Posts
    5,308

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Quote Originally Posted by secondhandrobot View Post
    Okay I understand now..



    So will try:

    f 25 @ ISO 80 = 100 seconds x 16 = 1600 seconds = 26.6 minutes

    Fair bit longer than the 3.2 minutes I tried first..

    Thanks again
    Each film has its own characteristics so check foma's chart on this. It isn't the same for all films.

    BUT you've got the idea now

    Many people also suggest that you shoot one stop longer then suggested and then develop 10% less time, in order to reduce the contrast of the image, as long exposures can be high in contrast.

    There are many techniques and you have to find your own way, definitely takes more time than digital, but also very rewarding.

  8. #8

    Join Date
    Jun 2015
    Location
    Wherever My Laptop Is (Usually Australia)
    Posts
    32

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Quote Originally Posted by ghostcount View Post
    Reciprocity failure. Foma is awful for this. Their data sheet only states compensation for up to 100 seconds - I'm sure you can extrapolate for 3.12 minutes but it could be tedious.

    Don't forget about bellows factor - you didn't mention that.
    Yes, the datasheet does not give a simple formula to apply to times over 100 seconds, thats why I calculated the original conversion back down to 100 seconds.

    Haven't heard of 'bellows factor', back to Google I guess.

  9. #9

    Join Date
    Jun 2015
    Location
    Wherever My Laptop Is (Usually Australia)
    Posts
    32

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Quote Originally Posted by DannL View Post
    Is there a particular reason why you can not increase the available light, in order to reduce your exposure time? Just curious.
    One reason is I only have limited lighting to choose from, ie. household lamps etc.

    Second reason is I was playing with using low light to keep the background illumination low - or ultimately black. Kind of worked on my digital tests. One step at a time though at this stage.

  10. #10

    Join Date
    Oct 2012
    Location
    Connecticut, USA
    Posts
    5,308

    Re: Long Exposure - Very Different Results Between Digital and 4x5 Film

    Quote Originally Posted by secondhandrobot View Post
    Yes, the datasheet does not give a simple formula to apply to times over 100 seconds, thats why I calculated the original conversion back down to 100 seconds.

    Haven't heard of 'bellows factor', back to Google I guess.
    Good job searching, you'll do well here, glad to see you soaking it all in

    There's an app I use on my iPhone to get all the calculations without error so I can focus on taking the image, SOME people call it being lazy I just view it as being efficient with my time.

    The app is appropriately named the "Reciprocity Timer" app, the creator is a member, it's not cheap (and the upgrade isn't necessary just the base app will do fine) but totally worth it. A version 3.0 is due out soon, but the 2.0 version is excellent and has many films listed.

    Hope that helps.

    PS it looks like this in the App Store

    Click image for larger version. 

Name:	ImageUploadedByTapatalk1434732717.340397.jpg 
Views:	50 
Size:	107.6 KB 
ID:	135693

    Unfortunately if you're not an iPhone user, you're out of luck. :/

Similar Threads

  1. How Do You Set Long Exposure?
    By RedSun in forum Cameras & Camera Accessories
    Replies: 30
    Last Post: 8-Jun-2014, 09:07
  2. Tried my First Long Exposure
    By Pfiltz in forum Darkroom: Film, Processing & Printing
    Replies: 19
    Last Post: 14-Jul-2013, 17:27
  3. Long Exposure
    By David Solow in forum Style & Technique
    Replies: 10
    Last Post: 8-Apr-2011, 02:56
  4. long exposure and 10/8
    By Mr. Doyle in forum Style & Technique
    Replies: 3
    Last Post: 4-Jul-2007, 10:15
  5. Use of NPS as a long exposure film
    By claudiocambon in forum Darkroom: Film, Processing & Printing
    Replies: 4
    Last Post: 28-Dec-2006, 07:41

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •