This begins a series on the 3 Manual controls we have as photographers that can make it possible (provided you have the vision) to elevate photography to the level of ART. So, I’ll start with the one control that has changed the most (none of the others have changed at all) and has in fact simplified our lives as photographers…
The biggest change here is that the sensitivity of your digital camera’s sensor is FIXED—you have NO control of this part of your camera. Because of this fact those old ISO steps no longer represent anything in todays digital cameras, they’re just numbers.
In our film days those ISO numbers, of course, were a vital part of correct exposure, because each film stock in fact had a real and different sensitivity, RMS number, emulsion character, and grain structure. In addition we had to match our lighting’s (when doing color) temperature to each film’s color temp sensitivity as well. And apart from color temp each film rendered color differently due to each film’s unique color palette—e.g. the color rendering of Kodacolor negative films versus Kodachrome or Ektachrome slide films not to mention the hundreds of other films we had from Ilford, Fuji, etc.
In the film era we had to learn how to use each new film we decided to try. We even had to store professional films differently that the amateur films. The regular amateur films were delivered to retailer “green”, so those films could age as they were displayed at room-temperature. But, the professional films were delivered “ripe” to retailers so they were refrigerated to hold them in their ripe state. Since we bought our pro-films in bulk that meant we also had to refrigerate all our pro-films as well. Then, we had to acclimate (bring to room temp) any of our pro-films before we could load them into our cameras; so that took planning! So, you can see how getting rid of film has really simplified photography and in fact has freed us to be more spontaneous.
Back to your digital camera’s sensor…
What happens when you raise the ISO number on your digital camera is the camera merely under exposes the image (massively when you bump it to 1600, 3200, etc.!) then post-exposure the image processor applies GAIN to the signal from the sensor proportionate to how many stops you have under-exposed the image. Unfortunately the gain applied to boost the signal also boosts noise especially in the darkest (most under-exposed) regions. That’s why it’s better to slightly over-expose a Low Light-High ISO image than to under-expose it. And because noise is not pretty (unlike film grain) and if you want to do any photography in low light….
Buy the best DSLR you can afford…
Buying a professional DSLR, with its superior image processor, is like loading a high RMS value film (like Kodachrome 25) in a film camera instead of some cheap drugstore stuff like GAF 500! OK, if you can’t relate to that analogy, how about a Canon 5D MK IV versus a cheaper smart phone. In addition because I use top quality professional DSLR’s (and the best lenses) I’m not hog-tied to the so called “native” camera ISO (usually around 100 ISO) that many photographers suggest on the internet. Nope, I’ve always regarded ISO 100 pretty much useless—I don’t even use it in the studio!
How I approach ISO use today…
ISO is merely a tool to get me to the aperture/shutter speed combination I require to create the image I have in my head. So, most of the time my starting ISO is 400 for outdoor portraits, weddings, or fine Art.
For example, in my outdoor, natural light, portrait sessions my STARTING ISO is 400 (nothing new here my starting films in portraits and weddings were ASA 400 or 800).
|f4.5 @ 1/320 sec., ISO 400; Lens @ 280mm|
ISO 400 got my other variables where they needed to be. Since I had my 1.4x extender on my 70-200 f2.8 lens (for better Bokeh) my new maximum aperture became f4.0 and I stopped down to f4.5 for better D.O.F. that gave me a metered shutter speed a hand-holdable 1/320 sec., which is fine for moving children!
What ISO to use in the studio…
Again, if you’re using a professional grade DSLR you can use any ISO you want, but there are practical limitations such as the power output of your rights. It’s definitely not practical to be using your camera’s low “native” ISO in most studio sessions. So, what ISO do I use in the studio? I use the lowest ISO necessary to get to my usual working aperture (f11.0) from my WEAKEST light. In my studio my hair light is on a lighting pack split three ways: two are on the background and one is my hair light. So, to get to f11.0 on my hair aight I needed to use ISO 200 with that bank on maximum power.
A basic studio portrait using this set-up…
|f11.0 @ 1/200 sec., ISO 200|
Low Light action images - High ISO
I love doing challenging low light photography. And bringing Action into the equation only makes it more fun for me! Forty years ago when I wanted to do low light work on film I had to find an independent lab that would push-process my Ektachrome slide films to 1000 ASA—Kodak wouldn’t do it! Our options were pretty limited in the 1970’s. Now I just dial in the ISO…
f5.0 @ 1/100 sec., ISO 3200; Lens at 24mm
Again, I pick my variables and use my ISO to get me there. With my lens at 24mm I picked f5.0 for good depth-of-field. I picked 1/100 sec., (with some testing) because that shutter speed would stop the spinning ride’s red wheel, but let the people’s motion blur a little.
This is why I don’t miss film—I’m free from film’s shackles that limited my creative spontaneity!
Now, it’s your turn, go challenge YOUR creativity with some low light photography of a challenging subject and have fun!
Next, in Part 3, I’ll go into Aperture Choice (one of the most important parts of the so-called “exposure triangle”) and why manual control of this variable is so critical in artistic photography.
Until then…have questions? Don’t hesitate to ask…
Author: Jerry W. Venz, PPA Master Photographer, Craftsman
Training site: http://www.LightAtTheEdge.com
Client site: http://www.TheStorytellersUsa.com