After teaching over 1000 people photography over the years two of the top points of confusion when it comes to camera terminology is “Understanding what Aperture is” and how it works and “What is a Stop”. Understanding these camera terms and how they play an integral role in your development as a photographer is critical as with knowledge will come confidence in your shooting and understanding the photo you have taken.
So What is a Stop ?
A “Stop” is the term given for a full 100% adjustment plus or minus in either your camera’s ISO, Aperture or Shutter Speed settings.
For ISO a 100% stop adjustment from 400 ISO would be 200 ISO or 800 ISO.
For Shutter Speed a 100% stop adjustment from 1/125th of a second would be 1/60th or 1/250th of a second.
For Aperture a 100% stop adjustment from F8 would be F5.6 or F11.
Now see how with ISO and Shutter speed the change makes sense mathematically. But the Aperture change doesnt… best thing to do is just accept that and move on. As with camera familarity, you will get to know your Apertures and know what a 100% stop adjustment plus or minus will be. But fear not as I will soon explain how you can work it out anyway.
Stops are referred to as “1/3rd of a Stop” “Half a Stop” and a “Stop” or “Full Stop” your camera can only be set at these settings of adjustment so someone might say looks like that’s out by a “1/4 of a Stop” but the in camera adjustment is not possible. This would be more of an exposure and blending thing.
What's this F-Stop I Hear About ?
Don’t get these confused, an f-stop is a reference used to state the Aperture an image was shot at. Like F2.8, F8, F16 etc. So forget this term when we are talking about “What is a “Stop”.
How are Stop's Used in Real World Photography ?
I remember when I was shooting film and the best thing was picking your film up from the lab and looking at it on their light table. The first time I heard about “Stops” in a practical sense was here. When looking at my film I noticed that my ground looked perfect but the sky looked “Thin” ie overly bright. The lab guy came over and said “Looks like your skies out by at least a stop. The look on my face must have prompted him to explain further.
Your sky is over exposed and you should have compensated / controlled for it further with your ND Filters (Neutral Density Filters). I didn’t know what these were at the time either. I’ll get to filter’s in another post soon.
So what was he basically telling me. Let’s say I shot my image at F11, 100 ISO for 1 second. My foreground is perfect but my sky is bright. The term your sky is out by a “Stop” will be used. What this means is to have your sky correctly exposed these things should or could have been done. Remember it’s out by one stop, so a 100% change needs to be compensated for.
- ISO Adjustment – The adjustment could be made in camera for exposure blending. So a shot at F11, 50 ISO for 1 sec. Though this change is not likely, it isn’t the best choice.
- Shutter Speed Adjustment. – F11, 100 ISO for 1/2 sec.
- Use a Neutral Density Filter to compensate the brightness in the sky. A 1 Stop filter would be used and pulled down accordingly.
Option 2 and 3 are what you would do. Option 2 is more for people who are competent Photoshop users as the image will require blending. Option three is for people who like to get the shot in camera and then use Photoshop to complement the image, not create it.
Stop Adjustments in Camera ?
Located within your camera menu is a setting that will allow you to set your camera up in “Stop” increments. Usually, a factory default setting of 1/2 stop adjustments is set. This means that when you click the wheels on your camera once it will make a 1/2 stop adjustment to your image. So this means 2 clicks for a full stop (100% change).
Setting your camera to 1/3rd stop adjustments is ideal, it really lets you have that refinement to your image capture. Especially in terms of shutter speed for water movement.
Three Clicks is a Stop - Aperture
Now remember before when I was explaining what a stop was and how the Shutter Speed and ISO showed a mathematical pattern for the stop changes but Aperture didn’t. Well now that your camera is set up correctly you know what “Three Clicks of your Wheel” will now equal a Stop. So if someone says change your aperture by a Stop to get that in your depth of field and your aperture was at F11 then click your wheel three times and Presto 100% change and you will know and come to remember a stop up from F11 is ?? …….. F16.
Getting the Stop Change Wrong ?
The beauty about digital cameras is the rear screen giving you instant feedback. So photographers can be vague when telling you what’s wrong with your shot or you might just make a total mistake. So if you were told “Hey your sky is out by two stops” and lets say your sky is too bright. Your camera settings are F11, 100 ISO, 1 second.
You correct the change to F11, 100 ISO and 4 sec. When you take the shot your image is Super Bright. Instantly you know you made the adjustment the wrong way. So you go F11, 100 ISO and 1/4 sec and you sky now looks perfect. Or you can change you ND filter to a 2 stop adjustment.
Wrapping it Up
From this article, you should now know and have the following done.
- Know what a Stop is and what it mean’s when it’s used in terms of your image.
- Have your camera set up in 1/3rd increments. Remember “Three Clicks is a Stop”
- Know that the term f-stop refers only to Aperture and has nothing to do with these “Stops”.
As always the best way to learn is trial and error and to take note of the changes in your camera. As I explain to students knowing the Stop changes in aperture especially off the top of your head means nothing. As long as you can get there with counting the clicks on your wheel then you will be fine. Rattling them off in 1/3rd stop increments will come in time, but really who cares.