East of Toronto

Good news for those of you east of Toronto: The Durham Region gets its own specials in Whitby.


They are:

  • April 11: Camera Skills for the Emerging Pro”, Half Day Special
  • April 12: The Efficient Photography Business (Intermediate)
  • April 18: ”Introduction To Flash” All Day Special
  • April 19: ”Flash In Practice”, All Day Special

These four courses are for committed amateurs or emerging pros. And they come with special prices for the books, also. See learning.photography/collections/training-misc for details and booking.

Book now: each course will go ahead if we get enough people, and there is strictly limited seating.

 

Expose

A student told me today that she had issues with shooting in manual mode. Especially, she says, in difficult circumstances.


Well, here is my answer. Yes, it is tough. “Less than ideal circumstances” is as much of a problem for me and everyone else as it is for my student. That is why we buy expensive lenses (low F-numbers let in more light; expensive cameras allow very high ISO values, and so on). Perhaps my student found it tough because it is impossible with her equipment.

But the principle of exposing right in manual mode is still simple. If it is too dark in your photo, you can do exactly three things (apart, of course, from turning on more lights). Same for my student as it is for you and for me.

1. Increase the ISO
Drawback: more grainy pictures
Limit: your camera only goes so high
What the pros do: buy an expensive camera that works well at high values

2. Lower the F-number
Drawback: you get less depth of field, which sometimes you want.
Limit: your lens only goes so low.
What the pros do: spend lots of lenses with low f-numbers

3. Slow down the shutter
Drawback: you get motion blur in your photos.
Limit: anything slower than, say, 1/60 sec will give you motion blur.
What the pros do: not go too slow. Or use a tripod..

So if your picture is too dark, you just have not gone high enough (iso) or you just have not gone low enough (f-number) or you just have not gone slow enough (shutter). Not difficult.
And you can use a trick! Let’s start with that trick.

  1. Go to PROGRAM Mode (P)
  2. Press the shutter slightly so you see the chosen aperture, shutter speed, and ISO
  3. Write those down.
  4. Go to MANUAL mode (M)
  5. Enter those values for ISO, aperture, and shutter.
  6. Now start varying from there. See what happens when you vary each of the parameters.

It really is as simple as that to get a good starting point. And you can also get good starting points for the variables. Like ISO: 200 outdoors, 400 indoors, 800 in tough light. Or shutter: keep above 1/60. Or aperture: open up indoors (low “F”), and stop down outdoors (high “F”).

 

The inverse square law

As you all know, the inverse square law states that light gets weaker in proportion to the square of the distance.

So at twice the distance I get one fourth of the light. At three times the distance, one ninth of the light. And so on.

Good. So if I aim a flash at an object at one metre and get good exposure at f/5.6, then at two metres distance I expect two stops less light, i.e. f/2.8, two stops more open (i.e. 4x more light).

Let’s see. First, let’s use an LED flash light. At f/5.6:

Now when I move from 1m to 2m and make the aperture f/2.8, it should be equally bright:

What gives? It’s brighter! Only by reducing the exposure 0.5 stops do I get to the same brightness (as verified with the histogram, and looking only at the lit part):

So it seems that the inverse square law does not hold!

Here’s another example. I will shoot at 1m, 1.4m, and 2m. If the first shot is at f/8, the second one should be at f/5.6 (half the light, because 1.4 squared is 2), and the third f/4 (a quarter of the light, because 2 squared is 4). When I do that, I get:

Hard to see here, but they get brighter each time, while theory says they should stay the same.

Only by reducing the second picture by 0.25 stops, and the third picture by 0.5 stops, do I get the same exposure. So my flash apparently needs to be corrected by -0.25 stops per stop.

Wait. Is this crazy Mr Willems saying the Inverse Square Law is incorrect?

Yes. Yes, he is. I am. I am saying exactly that. The Inverse Square Law does not apply. Not to concentrated beams. The Inverse Square Law applies only to point sources of light that radiate that light evenly in all directions. When we move the light away from the subject, the angle loses us photons, but the moment we “catch” some of these lost photons and send them to the object we are lighting anyway—and that is exactly what we are doing with a concentrated beam—that moment, the law no longer holds. Yes, the light gets weaker, but by a smaller amount. That smaller amount, the “escaping photon recapture rate”, or “EPR rate” if you like silly acronyms, is +0.25 stop per stop lost, in the case of my Canon flash.

So what would affect the numbers?

Clearly, at the extreme end, with a laser beam, the correction is virtually +1 stop per stop lost (think about it: how else could we do moonbounce, where we bounce a laser off the surface of the moon). Meaning, the light does not go down at all with distance.  With a flash light, it is, as you see, a little less extreme: there is dropoff; just a little less than you would expect. With a large softbox that radiates in all directions, you will get something closer to the inverse Square Law. With an umbrella, you get closer to it still.

But this is not a theoretical discussion, of interest only to geeks. This is important in practice to us photographers. If I move a snooted hair light twice as far away from the subjects it is lighting I should get two stops less light (2 squared = 4). But the light reduces less than that. So instead of going, say, from f/8 to f/4, I might need to go from f/8 to, say, f/5.

My advice: Learn how the light sources you use (straight flash, bounced flash, umbrella, softbox, etc) behave when you double the distance. Do this in the dark, so ambient light plays no role. Easy enough, and then you have an idea that will be valuable in real-life practice.


Check out my e-books on http://learning.photography/collections/books and learn everything I know. Taught in a logical fashion, these extensive e-books (PDFs with 100-200 pages each) will help you get up to scratch quickly with all the latest techniques. And when combined with a few hours’ private coaching, in person or via Google Hangouts, you have no idea of the places you’ll go. You’ll be a pro!

Stop!

Today, a word about stops.

First of all, they are called “stops” because the rotating wheels, like the one for aperture, used to click at certain settings (in the case of aperture, settings like 2.8, 4.0, 5.6, 8, etc).

These “stops” are chosen so that in all quantities, a stop is half, or double, the light. Here’s the options:

  • ISO: 100, 200, 400, 800, 1600, 3200, 6400  –> brighter as you increase
  • Aperture: f/1.4, 2.0, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 45   —> darker as you increase
  • Shutter speed: 1 sec, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000   –> darker as you go faster (to the right).

To keep a picture at the same brightness, you need to increase and decrease by equal amounts. The three are related, in other words, like this:

So these would all be the same brightness:

  • 400 ISO, f/4, 1/125
  • 800 ISO, f/5.6, 1/125
  • 200 ISO, f/8, 1/15
  • 100 ISO, f/1.4, 1/250
  • 1600 ISO, f/16, 1/30
  • 100 ISO, f/1.4, 1/250
  • 1600 ISO, f/5.6, 1/250
  • 100 ISO, f/5.6, 1/15

So as you see, there is not “one setting” that suits a situation.

Look at the last three. The first one is what I can do in the room I am sitting in right now, with my fast prime 85mm lens. Now if you have an f/5.6 consumer lens, you need to either go to 1600 ISO (grain!), or to 1/15 sec (motion blur!). Just saying.

If you want to be a pro, you need to get a feel for this and for the numbers. So today, set your camera to manual and go take pictures. get a feel for “normal settings”. You should know, without trying, that a dark room at night will not work at 100 ISO, 1/500 sec and f/11. Or that a sunny day will look all white at f/1.4, 400 ISO, 1/40 sec.

And it’s cool to know this stuff!

 

Yes, you can.

I teach Lightroom, among other favourite things I teach. And that means I see many students’ computers.

And often, I see less than I expect. Often, options, important options, are missing.

Like the toolbar.

What toolbar?

No toolbar there.

I mean the toolbar that appears when you turn it on by pressing the letter “T” (it toggles, so if it is already there, it will be removed), or by using the menu function VIEW–TOOLBAR. This toolbar, in other words:

See it there, between the grid and the negative strip?

Now, within that toolbar, see the last option, that pulldown arrow? Click on it and you see a bunch of options. You may want to turn those on:

Now your toolbar will have all the tools. Check them out, then disable the  ones you are sure you will not use.

Another option that is often missing is also a very handy one: the filter bar. At the top. You toggle that one by first being in the LIBRARY module (press “G” to go directly to the Grid view, for instance), and then pressing “\” (the backslash key).

(NOTE: In the DEVELOP module, the backslash key \ has a different, but also very useful function: it shows you the “before” view of a picture. In other words, the picture as it was when you imported it, or when you made the virtual copy. The image at the start of its edit history, in other words).

There are many, many other cool little tools in Lightroom. You do not need to use all of them, but I recommend that you use the ones you like; the ones that are good for your way of working. And there is one simple way to learn them: just check out all the menus and try every function. Learn them. Yes, you can!

 


End notes:

First, I teach Lightroom, and I will help you set up your Lightroom installation: file structure, import methods, backups, disks, and more. Worth every moment of the session I assure you.

Second, Lightroom only takes a few days to learn and is 100% worth your time and effort. Learn it. And as a supplement to my teaching and consulting, also watch my tips videos: see www.youtube.com/user/cameratraining/videos.

Third: just saying: if the subjects interest you, then my e-books (see http://learning.photography) are worth your money also. As is my teaching (see the same site).