Stars and stripes

A technical post today—after all, this is a technical learning blog.

When you see a picture with details like this (from my Mac’s background picture)…
screen-shot-2016-12-27-at-10-10-24-pm
…then you know that a small aperture was used for this photo.

The only way to get the sharp star shape you see here, you see, is to use a small lens opening. Meaning a small aperture (“aperture” means “opening”). Meaning a high “f-number”. In this case, I used an aperture of f/22. The reflection is from my flash, which was aimed straight at the car.

I have other clues. Other detail in the picture includes:
screen-shot-2016-12-27-at-10-10-10-pm
That is at least proof that the lens was not wide open. If it had been, the polygon at the top would have been not a polygon, but a circle.

Other notable facts: the lines (there’s your stripes) all converge where the sun is. And finally, the lens is probably an expensive one: the polygon has seven sides. Most have five or six sides. The more sides, the more the lens approaches the ideal, a circle. That ideal gives you great bokeh.

Bokeh

THE TERM BOKEH, by the way, when used correctly, is used to describe the quality of the fuzzy background. “I want bokeh” is not a correct term: when people say this, they usually just mean “I want a blurry background”.

Correct usage: A lens that has great, beautiful bokeh is a lens whose blurry background is wonderfully smooth and evenly creamy. A cheap lens, on the other hand, has bokeh (especially “fully open” bokeh) that is more like clotted cream: much less smooth, more uneven. I can tell a cheap lens from an expensive one immediately, and I bet you can, too, when you see them side by side.

And that concludes today’s lesson. For more, attend one of my many upcoming workshops: scroll down to read more.

 

Fast lenses, and why again?

I regularly mention that the lens is the most important part of your equipment. Great lenses especially add to your photo-taking capabilities. Now let’s look at one aspect of that greatness again: the “speed” of a lens.

Speed is of course a misnomer. When we say “a fast lens” we simply mean “a lens with a large aperture (low “f-number”). This large aperture lets in a lot of light, which makes it possible to shoot at faster shutter speeds at the same ISO, hence the word “fast”. So a low f-number means you can obtain faster shutter speeds under the same conditions.

Like the 50mm f/1.2 lens I am selling (sadly; but I bought the 85 f/1.2 and I cannot financially justify keeping both these lenses; and for wedding portraits, the 85 will be more useful).

Here’s student Becky with the 50 f/1.2L mounted on her Canon 6D last night:

I was able, by using the large aperture of my own f/1.2 lens, to take that picture at a fast shutter speed, handheld. And I get a blurry foreground and background at the same time,  which helps me to emphasize the subject.

How fast? Let’s look at a real example from last night.

A shot of a glass of wine. That is what I focused on, so that is, of course, sharp:

I shot that at f/4.5, which is typical of the kind of lowest “f-number” that a kit lens would allow you to use. At 1600 ISO, that necessitated a shutter speed of 1/30th second. That is at the limit of what I can hope to do handheld; in fact it is beyond that “rule of thumb” limit, with an 85mm lens. So I am lucky that the shot is sharp. Also, I am lucky that nothing in the photo moved, because pretty much any motion would show, at that slow a shutter speed. And yes, the background and foreground are blurry – but they could be blurrier.

Now the f/1.2 lens, this time wide open at f/1.2:

The “f/1.2” means that:

  1. At the same ISO value, I now needed only 1/320th second shutter speed. I.e. a much faster shutter speed (i.e. less time; shorter time period; all these mean the same thing).  That means I can easily hand-hold, and also I need not be afraid of motion.
  2. The lower f-number also allows me to through both Becky and the chips in the foreground way out of focus. The glass is still sharp (I am, after all, focusing on it!), but the depth of field at this low f-number is extremely shallow; meaning that foreground and background are very blurry indeed.

Now, I do not of course always want shallow depth of field; but the point is, that with a fast lens, I can. And that expands my picture abilities; in a dark evening setting I can shoot handheld without flash, and if I want, I can get extremely blurry backgrounds. And that is one of the reasons that I use an SLR in the first place. And any SLR would do this – it’s the lens, not the camera, that determines these things.

Which is why I am happy to spend on lenses. What’s not to love?

And a good lens lasts decades, both in technical terms and in value. So if you are going to spend, and why not; then spend mainly on lenses.

 

A specialty lens worth playing with

A repeat for those new to this blog: one of the coolest lenses you can try is the tilt-shift lens. It basically turns your camera into a view camera, where the lens element can tilt and shift with respect to the film, or in our case, sensor.

This picture, at f/3.5, shows only the back of the print in focus:

To get the entire picture into focus I guess I could stop down the lens, or move back. But with a tilt-shift I can avoid this: I can just tilt (=angle) the lens down, and I get:

Now the front of the print is sharp, but so are the drawers and fridge in the background; while the curtain is still blurred. I tilted the focal plane to where I wanted it; not just perpendicular to the lens direction (and parallel to the sensor).

Shifting (up-down) allows me to correct for perspective. When I shoot this, aiming the camera up, I get things converging at the top:

Keep the camera parallel to the ground, and shift the lens up, and I get this, straight out of camera, no Lightrooming needed):

(Those were done with the Canon 24mm TS-E f/3.5L lens I have for a few days from GTAlensrentals.com. I own the 45mm TS-E f/2.8 lens, but the wider one is nice for architecture).

Of course you need to expose manually and focus manually with a tilt-shift lens. But that is easy, and a small price to pay, so I have a tilt-shift on my camera rather often. Like the other day in Toronto’s historic Distillery District, above. Here’s Gregory Talas, owner of The Kodiak Gallery in The Distillery, which held several of my exhibits, and still has a few of my pieces on display.

There’s a lot of specialty lenses, like Macro lenses, fish-eyes, and so on, but the tilt-shift is a special specialty lens worth playing with, especially if you have never operated a tilt-shift camera.

 

Learn Focal Lengths

One thing that good photographers know is  “what focal lengths do”. There is such as thing as “the right focal length for a picture”, or perhaps better, “the right types of picture for a given focal length”. And a good photographer knows these. The pictures tend to then fall into place.

We all know – I hope – that you do not do a headshot with a 16mm lens. And we all know that landscapes and travel do like that focal length.

But in general, what is appropriate?

It depends. On you and your taste. But there’s often a good range. Look at the following examples – and keep in mind, the lengths I mention are for a full frame camera. If you have a crop camera, divide by 1.5/1.6. So a 35mm lens in my examples would need you to use a 24mm lens on a crop camera.

With that in mind, let’s look at some portraits.

35mm:

50mm:

65mm:

85mm:

200mm:

Are you beginning to see patterns? Develop your own preferences and “usual lenses” – they probably will not vary much from mine – and you will be much quicker deciding how to shoot what. A prime lens is a great way to learn, by the way. It’s why we love primes.

 

Prime primer

I teach “Lenses” this afternoon (Saturday) at Vistek in Mississauga before leaving for the Sunday workshop in Timmins, Ont.

So while I am on it, let me see if I can give you some input as to why you might want a prime lens. I have explained before of course (consistency, sharpness, size, wider aperture..) but a picture, well, a picture tells 1,000 words.

Here’s my kitchen island:

Now let’s look at 1:1 pixels. Straight out of camera, and pixel for pixel; 1/80-th second at 800 ISO.

First, the 24-70 f/2.8 zoom at f/2.8, set to 50mm:

And the 50mm f/1.2 lens, also set to f/2.8:

Both are good. But when you look closely, really closely, especially at the cloth material, you see that the 50 is much sharper.

No surprise, it is stopped down while the 24-70 is wide open. But that is the point, isn’t it? In real life use the prime often gives me sharper pictures.

This fact, and a million others, in the “Lenses” course at Vistek Mississauga (after “Flash”, also a great course, if I say so). See you there perhaps!