Have you ever use your camera in “B” mode?

Many years ago I learned that using the B setting on my camera would allow me to capture images that looked very different than using a “normal shutter speed”. Nowadays, many students will never use it because the camera is of no help here. To use this setting, it is very important to know photography very well, or at the very least you need to memorize the information that I am giving you here. There are different techniques that if you know them, they will help you solve some of the problems that you encounter in photography. This is one of the reasons why photographers that learned using film and then adapted to digital, can do anything with their digital camera. One of my students asked me why that is and this was my response; In the past, when a photographer was locked to a single roll of 100 or 200 ASA film in the camera, he did not just change the ASA to capture the image you wanted; he had to figure out how to do it right with the film he had in the camera. In other words, he relied on his knowledge of photography and not on his camera.

And speaking of that, please, never ask a photographer what camera he uses as a true photographer can take excellent pictures with any camera! Why? Because it is not the camera that makes the photo; it is the photographer’s knowledge of photography that allows him to create pictures with any camera. Unfortunately, many people always look for a good camera, one that “takes great pictures”.  They never say to themselves – “I should learn photography first so I can use any camera.”   For some reason, these people think that photography is easy as long as they get a good camera. But photography is just like any other career, it’s just as long and expensive to truly learn photography. This is way places like Colombia College in Chicago offers a BA or Master degree in photography.

The other group of people that are completely wrong are people that think that photography has changed. Photography has not changed in the last 200 years.  What HAS changed are the cameras that we use. Instead of a mechanical camera that can work forever, we now have disposable digital cameras that after 100 or 200k photographs and then the shutter stops working and it’s almost cheaper to buy a new camera than repair it. Yes, all digital cameras, amateur and professional, are disposable cameras.

Some of my former students also think that photography has changed.   Not too long ago I had a student who quit after the second week.   Since I always like to know if I can help a student, I called him after the second week that he missed class. I ask him why he quit, and his answer made me hang up the phone without saying anything.  His response “because you teach photography the old fashioned way.   I don’t need to know about shutter speeds, aperture of the lens, depth of field and whatever else you talked about.  My friend is a photographer and he tells me that I don’t need to know that.  That is what was taught for people with film cameras.”  I just hang up and never bothered with him again.  I am sorry, I am rambling now. Let’s just talk about the topic at hand, the “B” setting on your camera.

So, what is the B setting and how do you use it? Well if you want to know, I will be happy to tell you.

The B setting on the shutter speed dial stands for “Bulb”. This setting allows the photographer to use a much longer time than the 30 seconds that most cameras have as the maximum amount of time controlled by the camera. When you use the B setting you better know what you are doing so you can get total control of the exposure in your photographs. Since the camera no longer controls the time automatically, you have to follow the time on your watch or cell phone.  Your question though is for how long? This is the part that most photographers don’t know, so sit down, get comfy and open your mind to what I am writing here.

Okay, let get to it. One thing that I love to do in 90% of my photos is to use a low ISO. A low ISO number in your camera will provide the best possible images without you having to use Digital Ninja or any other program that gets rid of the digital noise.  Regardless of whether you use a film or a digital camera, you can do this.  Since film encounters something called “reciprocity failure” when you expose the film for longer than ½ second, the exposure is very different for film photography.  I will cover reciprocity failure in a future post.

To do an extremely long exposure let’s start at night, maybe by the lake or someplace where there is very little light. Now set the ISO in your camera to 100 ISO put the camera in manual mode and have the lens fully open. When you point the camera to any subject, read the light meter and you will probably get something like this in figure 1.

First reading camera was set at 100 ISO, f/2.8 4 seconds exposure.

By the way, to capture the images in this post, I used 50, 100 and 200 ISO; again, never higher to avoid digital noise. I started with the ISO at 100 but one of my students wanted to know what would happen if I raised the ISO to 200, (the image received 50% more light using the same shutter speed.) The lens that I was using was a 28mm f/2.8 when I took my first reading at 100 ISO and the lens at f/2.8 the correct exposure was 4 seconds, but I did not want to use the lens fully open as I wanted everything to be sharp and for that I need it to close the lens, but not too much. So I decided to close the lens one stop to f/4 and that gave me 8 seconds, f/5.6 at 16 seconds and f/8 for 32 seconds. Since the longest time that I can do automatically is 30 seconds, I change the 32 to 30 and took a picture. So I took the picture and it turned out correctly exposed. I know you are thinking, you give the image two seconds less! Right? You forget that 2 seconds is a very small portion of the 32 seconds, for an image to be affected drastically you need to under or over expose at least 50%, 2 seconds less, is not 50% less. The only thing that is affected a bit are the highlights. So, I did not need it to use the B setting, but for the second image, I did.

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The second image was shot by the chess pavilion on North Avenue beach.   I set my camera on a tripod and for this image, I used ISO 50.  I pointed my camera to the city skyline and took a meter reading. The reading was f/2.8 at 8 seconds. But again I did not want a big aperture of the lens, I wanted a small aperture so I can use my B setting. So at f/4 the correct aperture was 15 seconds; at f/5.6 30 seconds; f/8 60 seconds; f/11 120 seconds and finally f/16 at 240 seconds. I end up with 242 seconds but when the exposure is so long 2 additional seconds is not going to affect the exposure at all. Since I have a lot of equipment, I used my cable release which is electric for the Canon 5D Mark III.  I locked the mirror up in the camera to prevent camera shake and to obtain the sharpest possible images. Of course, to get to the 242 seconds, I set the dial on my camera from M to B, clicked the shutter with the cable and then paid attention to the time on my watch. This is what you need to do to use your B setting.   I have another trick that I use when I am in extremely dark areas, places where you can barely see your hand in front of your face. To get the correct exposure in these places using a low ISO, I first start with a high ISO. Look at the chart below.


Exposure chart to use low ISO in very dark places
ISO Aperture of the lens Shutter speed
25600 f/2.8 1/15 of a second
But this is not the ISO I want to use, so I start cutting the ISO in half and extending the shutter speed to double the time.
12800 f/2.8 1/8 of a second
6400 f/2.8 ¼ of a second
3200 f/2.8 ½ second
1600 f/2.8 1 second
800 f/2.8 2 seconds
400 f/2.8 4 seconds
200 f/2.8 8 seconds
100 f/2.8 16 seconds
50 f/2.8 32 seconds
If I am using an aperture of f/2.8 this will be correct on a digital camera, but that is not what I do. I like to use small apertures! So after reaching the correct ISO that I want to use I start closing the lens and doubling the speed.
ISO Aperture of the lens Shutter speed
50 f/4 64 seconds
50 f/5.6 128 seconds
50 f/8 256 seconds
50 f/11 512 seconds
50 f/16 1024 seconds
50 f/22 2048 seconds


And there you have it, a way to use your B setting on the camera and to get some very cool photos using extremely long exposures. Are you up for the challenge? Can you go out somewhere very dark and do this? And when I say very dark, I mean the Sahara desert in the middle of the night dark!   Ha, ha, ha –  not really, you can just turn off all the lights in your house in the middle of the night, as long as you don’t live in Chicago where there is a hush amount of light from outside coming through your windows. I live in Evanston and there, with all the light off, I can barely see my hands in front of me. Of course for exposures longer than 1/30 of a second, you need a tripod for your camera.


As I mentioned at the beginning of this article, it is never the camera; it is always how much the photographer knows about photography that makes a big difference. I hope you liked this article and if you do, please remember where you learned this. I want all of you to know that you can learn this and much more in my classes at Truman College. Hopefully, you find this interesting and helpful enough that you just have to learn more. Sign up for the next session of photography, Darkroom or Photoshop classes.


Ignacio Alvarez

Copyright 2017