Flash Limits and Back Button Focus - Ask Andy #2

Episode 161 - What to do when flash doesn't work and the benefits of back button focus.

Simon d'Entremont's YouTube Channel

The Transcript page - https://photographysidehustle.com/161

ConvertKit - Set up a free account with a list of up to 1,000 emails.

Photoshop for Photographers course:  https://photographysidehustle.com/photoshop-for-photographers-course/

Cloud Backup - Back Blaze

Please leave a voice message for Andy at SpeakPipe.com   Ask a question and get on the podcast, you know it makes sense.

Join the Facebook Group and ask as many questions as you like.

Visit PhotographySideHustle.com, and you get access to all the downloads, including the Pricing Calculator, mini-courses, and videos of how I process my RAW images.

Transcript

Hey, how’s it going? I’m Andy Jones, and this is episode 161 of the Photography Side Hustle podcast. 

This week, I have two questions to answer. One is about flash, and the other is about back button focus.

So, let’s get on with it.

This one came from Calvin Richardson, from Hull in the UK. His problem is this … 

“The main issue I find is that the church is so tall and wide that I struggle to bounce the flash off the walls/ ceiling.”
Flash Limits
Okay, so when you use flash on your camera, you want to avoid aiming it directly at the subject. To do this, you aim the flash at a wall or the ceiling. This is what Calvin has been doing, and finding it difficult.

When you are in a room with a ceiling 8 to 12 feet high, you can easily bounce light off it and fill the scene with soft light. Or if you are, say, five feet from a wall, you can do the same thing.

If the ceiling is higher than 12 feet, or you or the subject is a long way from a wall, the light won’t bounce the way you want it to. In fact, the light will fade away before it hits the vaulted ceiling of a church.

So you have two options.
Option 1
You could turn up at the church with a bag full of flashes and position them around the church. This might give you some well-lit photos, but it will annoy the heck out of everyone there. Remember, it’s a church ceremony, not a movie set.

This is just a quick tip: If you bounce flash off walls and ceilings that are painted in strong colors, you can get a color cast on your subjects. If that happens, you can use …

Option 2 
… option 2, that is, don’t use a flash at all. Calvin uses a 24-70 and a 70-200, and both lenses have a maximum aperture of f/2.8. So he can forget about using a flash and take full advantage of his lenses.

You set the aperture to f/2.8, the shutter speed to 1/125, and ISO to 100.

Now, you might think the depth of field is too small using f/2.8. But you are going to be taking photos from a distance of at least 10 feet, and even if you are using an APS-C (crop) sensor body and zoomed in at 70mm, the total depth of field will be fine at approximately 8 inches.

Anyway, so you set the aperture to f/2.8, the shutter speed to 1/125, and ISO to 100.

If the light meter is on the minus (-) side, you need more light because it is under-exposed. So, all you need to do is turn the ISO up until the meter is balanced. You could lower the shutter speed, but you risk getting blurry images if it’s too slow. 

Setting the ISO to Auto will allow you to forget about this adjustment. 

If the light meter is on the over-exposed plus (+) side, you need to reduce the amount of light coming in by turning the shutter speed up to a higher number until the meter is balanced. 

So that is what you do when the ceiling height doesn’t allow you to bounce flash off it. 

Thanks for that one Calvin.

Okay, the next one comes from Facebook group member number one, Paul Paldus.

Back Button Focus


Hi Andy, it's Paul Paldus from St. Catharines, Ontario. Hope that you're keeping well. Keep up the good work. My question, I know you're looking for questions this week, is what is back button focus? Now, this is something that I use all the time. I know what it is, but it's something that I haven't really heard you mention, during any of the episodes.

Maybe you have, and I missed it, but, uh, for the, for the good listenership out there, what is back button focus, and how is it best served?  Okay. Talk to you soon. Thanks. Keep up the good work. Bye.

I think Paul is right, and I haven’t covered back button focus before.

Right, so the shutter button, when depressed halfway, focuses on the subject, and when depressed all the way, it takes the photo.

So, all you are doing is removing the focusing from the shutter button and giving that job to a button on the back of the camera body.

The way you transfer that job is different for all makes and models. So do a search on Google or YouTube for “Setting up back button focus on the (your camera make and model).” It should be in your user manual for your camera if you have one. You can download a copy through the website at photographysidehustle.com.

Okay, so now the focusing job is done by depressing a rear button. On my Canon cameras, I use the AF-ON button.

So set your camera to Continuous mode. On Canon cameras, this is called AI Servo, and on Nikon and Sony cameras, it's AFC.

So why use Back Button focus?

I’ll give you an example. Let’s say there is a bird on a fence. You want to take the photo with the bird off to the side of the frame and not in the center.

Using back button focus, you press the back button to get the bird in focus, then release the button. You can now re-compose the photo with the bird on the left of the screen. Then you press the shutter button and take the photo.

When you release the back button, the camera keeps the bird in focus, allowing you to change its position in the frame. If you or the bird move, you will have to re-focus with the back button.

With the regular setup, using just the shutter button to focus and take the photo, you would need to change the in-camera autofocus point. By default, it will be the center autofocus point, and to take a photo with the bird on the left of the frame, it would need to be changed to an AF point that corresponds to the bird.

By the time you change the autofocus point, the bird is gone. 

If you stuck with the center autofocus point, the camera would refocus on the background when you removed the point from the bird.

Let’s say you are taking pics of your kids running around. To focus on the subject, you depress th
e back button and keep the AF point on them. The camera will keep them focused as long as the AF point is on them. All the time you are taking photos using the shutter button.

Another way to use back button focus is for pre-focusing. I saw this on Simon D’Entrements’s YouTube channel. He was capturing photos of a swallow flying in and out of its nest box.

This will only work if the subject is at a constant distance from the camera. In this case, he was taking photos from the side of the nest box. When the bird stuck its head out of the nest box, he used the back button to focus on it. Then he released the button, setting the focal distance to the area the bird was going to be traveling.

Then, as the bird flew in and out, he just used the shutter button to take photos.

A Modern Alternative
Now, if you own a newer camera body with eye detection, you might not need back button focus. 

If you shoot wildlife, sports, or anything fast-moving, you will find back button focus really useful. But, if you shoot portraits or weddings, using the eye detection modes will be more than good enough to capture great photos.

My Canon R6 mk2 will focus on an eye anywhere in the frame, so you can compose the image and take the photo simultaneously. The subject will be in sharp focus wherever it is in the frame.

I talked with a wedding photographer last week, and he said it has made his life much easier. 

When shooting a photo, he would focus on the subject's eye, release the back button, then compose the image, and click.

Now, it is just compose the image and click.

Okay, thanks for that question, Paul. I should have done back button focus much sooner.

If you have a question that needs answering, go for it and ask away. I’ll put all the links in the show notes and over at photographysidehustle.com/161.

Right then, have a great week, and I’ll talk to you soon. Bye.