matt_torti Posted February 5, 2008 Share Posted February 5, 2008 I am going to be shooting some night portraits, where there is a significant amount of light on the subject, a backlight and nothing else. My question is, if the light pointed on the subject is equal to the amount of light from a projector, how long should I keep the shutter open on a roll of 120 at 400 speed? I'll be experimenting with a holga soon, but I'd like to pose this question before burning too much film. Process and contacts are 12.00 at the cheapest in NY (although the quality is great!) so any advice before my trial run is appreciated! I'm new to photo.net forums, welcome me with some handy answers :) (or demand more information from me if you need it!) Link to comment Share on other sites More sharing options...
justinblake Posted February 5, 2008 Share Posted February 5, 2008 That is a very hard question to answer for two reasons. Firstly we do not know how bright the subject is going to be. Projectors vary very much in power and the distance from the projector to the subject is going to impact the amount of light as well. The other problem is that we do not know what type of film you are using. Different brands will have different reciprocity characteristics. My best advice, assuming that you don't have a light meter, would be to read Fred Parkers guide to estimating exposure http://www.fredparker.com/ultexp1.htm then hit google looking for a reciprocity chart for the film you are planning on using. Good luck. Link to comment Share on other sites More sharing options...
matt_torti Posted February 6, 2008 Author Share Posted February 6, 2008 Thanks for the response. I have a few ideas that I would like some input on. Say I set up a regular 35mm camera next to my Holga (yes yes, I realize the Holga is but a toy, but I desire its effects and unpredictably in the end result). I set the 35mm on the film speed which is loaded in the Holga. If I set up the shot similarly in both cameras, will the 35mm light meter give me enough insight on an estimate exposure time for the 120 film? You're right in assuming that I don't have a light meter - its not that I don't take photography seriously, just that money is pretty tight right now, and only going to get worse...which is why I want as much insight on this as possible before shooting blind, basically. The film I'll use is Kodak Portra-400NC 120 Professional Color. I'd say the projector is close to Model 2100-R Gaf, if that helps any. Link to comment Share on other sites More sharing options...
steve_parrott Posted February 6, 2008 Share Posted February 6, 2008 Hello Matt, welcome to the insane world of Holga! Sure, you can use your 35mm camera as a light meter, the only problem is you cannot set the exact same settings on the Holga that you can on the 35mm. In other words, if the meter on the 35mm reads, 1/50 at f2.8, there is no way to set that on the Holga. I assume you have googled all the Holga sites on line, there are a bunch of them. The Holga has 2 aperture settings supposedly, but in reality it does not. It has a little Sunny / Cloudy switch that really serves no function. Just leave it on Cloudy, which is something in the area of f11 I think. The one and only shutter speed is about 1/125. So as you can see, you cannot really set the Holga to a specific light meter reading. Be sure and get a Holga FN model. It has a BULB switch so you can hold the shutter open as long as you want. This is going to sound crazy, but then when using a Holga, anything goes. Use your 35mm with the aperture set to f11 to take a light readiing. If it gives a shutter reading of 5 seconds, then hold down the Holga shutter on Bulb, and count to five! It is really your only option. Here are some of my Holga shots if you would like to take a look: http://www.pbase.com/s_parrott/holga&page=all I would suggest you use Ilford black and white 400 ISO film rather than the Kodak color. The Ilford is a favorite choice of Holga users, and black and white suits the style of photo taken by the Holga much better than color, at least in my opinion. Have fun, and just be prepared to get some really cool shots, but with maybe 3 or 4 throwaways for each "keeper". Just the nature of working with a Holga. Steve Link to comment Share on other sites More sharing options...
matt_torti Posted February 6, 2008 Author Share Posted February 6, 2008 Thanks Steve. I appreciate your suggestions on the b+w film, and that may enhance my desired outcome, so thank-you. The f11 info is of great help, and that is what I will set my 35mm to when using it as a make-shift light meter. I was planning on using the bulb function on the cam. I'm experienced in shooting Holga, but since this project deals with low-light, I wanted to get more insight on many seconds to count and the best way to estimate a proper exposure time. That f11 comment is priceless and I anticipate it'll save me a few rolls of tests, thanks again! Link to comment Share on other sites More sharing options...
evan_goulet Posted February 6, 2008 Share Posted February 6, 2008 Matt, I think you are on the right path towards getting what you need. Just be sure to factor in any reciprocity failure for a long exposure on whatever particular film you are using. According to Kodak's <a href="http://kodak.com/global/en/professional/support/techPubs/e4040/e4040.pdf">Tech Pub E4040</a>, there is no exposure compensation required for exposures less than 1 sec. If you find you need to keep it open longer than one second, you might want to multiply the exposure by 1.5 seconds to be on the safe side. <P>Now comes the tricky part, what if your meter tells you that you need an exposure of less than 1 second? That will be quite difficult to do with a bulb setting. You might want to keep a roll of 100 speed film just in case that is the situation. Although film latitude should give a safety buffer. Link to comment Share on other sites More sharing options...
matt_torti Posted February 8, 2008 Author Share Posted February 8, 2008 Good point - I have 200 speed, and maybe that'd be better to use to get bolder color and keep the shutter slow. Thanks Evan, project is taking place over President's weekend, so many thanks to you guys for getting me prepped and suggesting options. Link to comment Share on other sites More sharing options...
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