I keep hearing "experts" on the forums telling other photographers to ALWAYS use their camera's "native" lowest I.S.O.--usually somewhere around ISO 100. Bad advice! If you have a late model DSLR with an APS-C size sensor or ANY full-frame sensor you will be giving up HUGE creative potential if you slavishly follow that advice. I very rarely go down below 400 ISO when I'm outside and my starting ISO in the studio is 200. Why you ask, am I up at 200 ISO in MY studio? simple, now that I'm not tied to any particular film's ISO I'm FREE to use ISO as a tool to get me to the f-stop/shutter speed combination I need for a given subject or creative idea.
So, here's my rule for picking ISO in the studio: THE F-STOP YOU REQUIRE FROM YOUR WEAKEST LIGHT DETERMINES YOUR ISO IN THE STUDIO--PERIOD.
In my studio the ceiling mounted "hair-light", which shares my Norman pack, with two other heads that are lighting my background, is my weakest light. To get f11.0 from that light at full power requires ISO 200. It's that simple; my starting studio ISO is 200.
As an example of creative use of ISO in the studio I decided to do something different with an image of one of my older cameras I had up for sale. I placed the camera in front of one of the art prints that had been done with that camera. I loved the wild red sunset as the camera's background.
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| f22.0 @ 1/5th second ISO 800 - Lens at 82mm |
I used standard product lighting; a strip soft box (Larson 9"x24") overhead skimming the top of the camera (aimed towards me) and a kicker light (with a grid) on the right. In addition I had a reflector in front of me to bounce light back into the front of the camera--standard set-up; Boring… Hey, I though, what would it take to make it look like that red from the background was being projected through the camera's viewfinder and out the lens? The "quick and easy" answer was my red LED,flash light of course! The first thing to go was the front reflector, since it put too much light on the front of the camera and the lens. My flash light has one red LED surrounded by 5 white LED's. I knew I'd have to "drag my shutter" (go to a long shutter-speed) for this wimpy light to show-up on this mixed studio lighting scenario. So, finally with my flash light, as close as I could get it, shining onto the front of the camera's lens--the red in the lens got really good when I upped my ISO to 800 with my shutter speed at 1/5th of a second. With my ISO upped to 800 I had to stop my lens down to f22.0 because the overhead studio flash was already at it lowest power setting.
The basic rule here is that the shutter speed exposes for the continuous light (the flashlight) and the f-stop exposes for the flash; simple. Anyway, I did sell the camera! And I ended up with this nice image to illustrate high ISO and mixed lighting in the studio.
As always, should you have questions please don't hesitate to drop me a note.
Author: Jerry W. Venz, Master Photographer, Certified
Training site web address: http://www.LightAtTheEdge.com
