Talking about light, Luminous Flux, Luminous Intensity, Illuminance, Luminance, Brightness, Exposure, Exposure Value, and Light Stops – Photography Word of the Week 2

This week, we discus various words used to describe and measure light in photography and videography.

Graphic of luminance, illuminance, luminous intensity, and luminous flux

luminance illuminance luminous intensity luminous flux

Luminous Flux is how much light a light source emits, measured in lumens (lm). This could be the sun, a light bulb, a flash, etc.

Luminous Intensity is how much light travels in a certain direction, measured in candelas (cd). For example, the sun sends out light all over the galaxy, but chances are we are only interested in the light hitting around us.

Illuminance is how much of that light is hitting an object, measured in lux.

Luminance is how much light is reflected or emitted by an object or scene, measured in candela per square meter (cd/m²). Luminance can either be measured for the object or scene being photographed, or for the final print photo.

Brightness, on the other hand, is a judgement call made by a subject looking at an object or scene, which can be biased. This is usually made by comparing two objects to determine which is brighter and which is darker.

To better understand the difference, lets look at a cell phone or tablet screen. Ever noticed how bright your cell phone looks inside, but when you take it outside in the sun, you can barely see the screen? A very popular model of cell phones was measured at 536 cd/m². Inside the house, the screen looks very bright. But if you bring it outside on a sunny day at noon time, the sun’s 1.6×10^9 cd/m² luminance will make that same cell phone screen look dark.

Exposure is a measure of how much of that light reaches the camera per area, which is affected by the aperture, the shutter speed, and the luminance of the scene or object. A scene or object can be considered underexposed, if it is too dark, correctly exposed, or over-exposed, if it is too bright.

Exposure Value represents the aperture and shutter speed settings of a camera, and is measured in EV. An EV of 0 represents an aperture of 1 and a shutter speed of 1 second, where 1 EV represents a 1 stop of light difference.

Interestingly, Exposure Value does not mention the ISO light sensitivity of the film or sensor, so it is very typical to describe an Exposure value as 15 EV at ISO 100, which would give a correct exposure for a sunny scene based on the Sunny f/16 rule where in a sunny scene, a correct exposure can be obtained with an aperture of f/16 with the ISO and Shutter speed being equal (f/16, 1/100 secs, ISO 100 would work, as well as f/16, 1/2000 sec, ISO 2000).

Light Stops are used to compare Exposure and Exposure Value, where each stop of light represents double the intensity of light. Stops can be used to describe the aperture, shutter speed, and ISO settings used to take a photo, and are usually used in full stops, half stops, or third stops.

Come back next week for our next Photography Word of the Week!

Camera Calculators Android app version 1.1.0


I am very excited to announce that the Camera Calculators app 1.1.0 for Android is now released on the Google Play ™ store and the Amazon Appstore for Android!

This version includes the following new features:

•  Print Size calculator – Helps you determine how large you can print an image.
•  Minimum Pixels calculator – Helps you determine how many pixels you need for a chosen print size.

For more information and for links to download it, see the Camera Calculators App page on this site:

Camera Calculators App

Android app on Google Play Amazon App Store Badge

Photography – Photography Word of the Week 1

Welcome to this new series which I will simply call Photography Word of the Week. Each week I will take a common photography term and explain it’s meaning and why they are important. The goal of this? To enrich our vocabulary, and perhaps learn a thing or two about photography. I believe that the word worthy of the first Word of the Week should be Photography.

From the Ancient Greek words φωτός (phōtos – genitive of the word “light”) and γραφή (graphé – drawing, painting, writing, in this case drawing is the one which interests us), photography is the art of drawing light. While we may think it is a modern art, philosophers Mozi and Aristotle, as well as mathematician Euclid all described pinhole cameras back in the 5th and 4th centuries BCE, but it was only over 1500 years later that the first camera obscuras and pinhole cameras were constructed, and by the 15th century they were used by artists such as Leonardo DaVinci to project an image on a canvas, where the artist would manually draw the image. Over the years, that manual process was replaced by film, and most recently by digital sensors.

The technology might evolve at an exponential rate, but the idea remains the same: light goes through a hole (or lens) and gets focused on something (canvas, film, digital sensor), which allows to immortalize the events, both joyful and sad, for millenniums to come.

Join us next week for the next Photography Word of the Week!

Camera Calculators Android app now available!


I am very excited to announce that the Camera Calculators app 1.0.0 for Android is now released on the Google Play ™ store!

For more information and for links to download it, see the Camera Calculators App page on this site:

Camera Calculators App


Android app on Google Play

Camera Calculators app main menu

Using your camera’s Scene Modes – Photo Tutorial 101 Take Control of your Camera – Episode 11

In this video, I show how to use the Scene Modes on your camera for the times when the automatic mode doesn’t give you the results you are looking for.

Canon Extender 2x III teleconverter review

In this review, I do a review of the Canon Extender 2x III teleconverter. I rented this from Lensrentalscanada.com along with a Canon EF 400mm f/5.6L lens and the 1.4x III teleconverter hoping to get some amazing bird photos. After over 1000 shots with the lens alone, the 1.4x and the 2x teleconverters, my sad conclusion is that the lens alone probably gave me the best results.

Sure the 1.4x and 2x teleconverters do zoom in the image by 1.4x and 2x respectively, but they also deteriorate the image quality by a good amount, so taking a photo without the teleconverter and cropping it down usually gave very similar results without many of the inconveniences that comes from using a teleconverter (lost of 1-2 stops of light which sometimes disables autofocus on some lens/camera combinations).

All photos in this video are as-is .jpgs coming right out of the camera with no post-processing. Definitely some post-processing would improve some of these, but I want to show the files as they come, not after spending hours refining a RAW file. I first show the full image, then I zoom in 1:1.

Canon Extender 1.4x III teleconverter review

In this review, I do a review of the Canon Extender 1.4x III teleconverter. I rented this from Lensrentalscanada.com along with a Canon EF 400mm f/5.6L lens and the 2x III teleconverter hoping to get some amazing bird photos. After over 1000 shots with the lens alone, the 1.4x and the 2x teleconverters, my sad conclusion is that the lens alone probably gave me the best results.

Sure the 1.4x and 2x teleconverters do zoom in the image by 1.4x and 2x respectively, but they also deteriorate the image quality by a good amount, so taking a photo without the teleconverter and cropping it down usually gave very similar results without many of the inconveniences that comes from using a teleconverter (lost of 1-2 stops of light which sometimes disables autofocus on some lens/camera combinations).

All photos in this video are as-is .jpgs coming right out of the camera with no post-processing. Definitely some post-processing would improve some of these, but I want to show the files as they come, not after spending hours refining a RAW file. I first show the full image, then I zoom in 1:1.

Canon EF 400mm f/5.6L lens review a great super telephoto lens for bird photography

Support these reviews by finding out more about this lens at one of our affiliates:
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In this video, I do a review of the Canon EF 400mm f/5.6L lens. This is a great super telephoto lens for bird photography. The image quality on this lens is superb, and the build quality is even more impressive. Made from solid metal, I’d feel safe carrying this in the woods in case I need to knock out a bear or two.

The major downsides are the aperture and lack of image stabilization (IS), which may or may not be deal breakers depending what you take photos of. Using a 400mm lens, the depth of field is really small, so I realistically probably wouldn’t use a lens at f/2.8 or even f/4 too often, unless the subject was far enough away. With aperture of f/5.6 at a distance of 6 feet on a full frame camera such as the Canon 6D, you get a depth of field of 0.2 inches. In metric, at 2 meters, you get a depth of field of 0.65 cm. An aperture of f/2.8 would half those depths of field, which would make it unusable for most situations.

As for lack of IS, if you’re doing bird photography at 1/2000 or faster shutter speeds, the images should be sharp with or without IS. If you plan on using this lens indoors in bad lighting conditions, though, prepare to use ISOs in the 12’800 to 102’400 and wishing your camera could go in the millions of ISO.

The lack of IS is much more an issue for video work, where I’ve had some success handholding it and applying the warp stabilizer in Adobe Premiere Pro. It doesn’t turn it into tripod-steady footage, but closer to steadycam footage, which is usually quite acceptable.

Using a teleconverter, though, the image quality dropped quite a bit, and the aperture of f/8 (1.4x) and f/11 (2x) disabled the autofocus on my Canon 6D camera, which made this lens quite harder to use. But used without any converters, the autofocus was fast and accurate.

Overall I quite enjoyed renting this lens, and I’m looking forward to comparing it to other similar lenses such as the Canon 100-400mm L and the Tamron 150-600mm lens. My guess is the zoom versions would be more versatile in parts because of the zoom, but also because of the image stabilization, but for image quality, I believe the 400mm f/5.6L would come out on top by a large margin.

Lens Rentals Canada review

In this video I do a review of the Lens Rentals Canada camera and lens rental service: www.lensrentalscanada.com

I wanted to test out the Canon 400mm f/5.6L with 1.4x and 2x teleconverters for some wildlife photography. I’m still not decided which lens I would like to purchase, if any, so renting seemed like the most logical choice.

For a very affordable price, I was able to rent the lens and teleconverters for 10 days, which gave me plenty of time to test things out and take some great wildlife photos.

I received the lens the same week I put in the order, and it came in pristine quality. The lens and teleconverters were perfectly clean, and everything was in like-new condition.

I picked up the lens at my local Canada Post office on the expected delivery date, and on the last day of the rental I dropped it off to the local Canada Post office. It came with all the pre-paid paperwork, and the local Canada Post office helped me removing the old data and putting the new one in.

For a very small amount, you can add a damage waiver where if the lens accidently gets damaged, you only have a 10% deductible to pay and they take care of repairing or replacing the lens. The few dollars extra this costs is definitely worth it to give the peace of mind in case the worst happens. Thankfully everything went well and I returned the lens in the same condition I got it (except probably not as clean), so I thankfully can’t comment on this add-on service, but online reviews I read seem to be favourable even in those cases. :)

So if you live in Canada and want to rent out a lens for a special project / vacation, or want to rent backup gear for a wedding or other event, I definitely recommend checking them out.

My biggest disappointment is their third-party selection is quite small. There are a couple of Tamron lens I’d love to test which they don’t yet have in stock, but I noticed they did add some other third party lenses in the last 6 months, so there’s still hope for the future.

ThorFire Model C1 E27 12W Daywhite CREE COB Chip LED SMD Light Bulb Review

Support this channel by checking out this product on BangGood:
http://www.banggood.com/Thorfire-Model-C1-E27-12W-White-CREE-COB-Chip-LED-SMD-Spotlight-Bulb-p-919737.html?p=HF1522249090201308Q@

My good friend Sami from BangGood sent me this light bulb to review. Cree LEDs such as this ThorFire C1 E27 12W are really amazing. In this case, it offers about 75W equivalent power at only 12W. This is a 5000K white balance bulb which is very similar to daylight.

I would not necessarily use this for my photography and videography, but I would certainly use it to light up the studio to save on electricity costs, provide nice lighting, and not have to climb up ladders to change lights every couple of months.

For those more concerned about the environment, these bulbs do not contain Lead nor mercury, and do not produce any UV or IR radiation which is great for everyone and for the environment.