The Kit Lens Is Fine, Learn on What You Have
Okay. I want to sidebar for a lesson before we go further into aperture, because I keep seeing the same thing happen in this class and I saw it again last week.
Somebody's struggling to get their aperture priority mode to do what they want, and instead of working the problem, they start thinking about buying a new lens. A fast one. f/1.8, maybe f/1.4 if they've been reading forums. They figure that's what's missing.
I'll be honest with you, it's not what's missing. Not yet.
The kit lens does everything you need right now
Whatever came in the box with your camera, the 18-55 or the 18-105 or whatever your body shipped with, that lens can teach you everything in this module. It can do shallow depth of field. It can do deep depth of field. It has an aperture range wide enough to show you the whole idea we've been working on, from the fence post picture on forward.
Here's the thing. A $900 lens does not fix a problem you don't understand yet. If you don't know why your background is soft or sharp, a better lens just gives you a more expensive version of the same confusion. Learn the concept on the glass you already own. Upgrade later, when you actually know what you're upgrading for and why.
I've had students buy fast primes in week three of a class like this and then come back frustrated because the picture still didn't look like the ones online. It was never the lens. It was that they hadn't put in the reps yet.
What to actually do with the lens you have
Zoom all the way out, then all the way in, and shoot the same object both ways at the same aperture. Notice how the zoom itself changes your depth of field, seperate from the f-number. That's a real variable and people forget about it because we've been talking about aperture in isolation.
Get close to something. Kit lenses have a minimum focus distance, closer than people think. Find it. Shoot a leaf or a doorknob as close as the lens will let you focus and watch what falls out of focus behind it.
Walk your own kit lens through its full aperture range on one subject, same as we did with the fence post. f/3.5, f/8, f/16, whatever your particular lens tops out at on the wide end and the narrow end. Write down what changed in your notebook. Not what you think should have changed. What actually did.
A caution here, since we're on the topic of gear
If you do decide later you want a different lens, don't buy used off someone you don't know without asking a lot of questions first. Ask about the mount, ask if it's ever been dropped, ask why they're selling it. I bought my whole camera that way, from a neighbor, and I asked him something like forty questions before I handed over money. Felt annoying at the time. Still worth it.
The neighborhood cleanup
Last spring our neighborhood association did a cleanup day, and somehow I ended up being the guy taking before-and-after photos for the newsletter. I didn't have anything special with me. Same kit lens I've used for years, on the same body.
People kept coming up to me afterward saying the photos turned out great, thank you so much, and I kept saying it was nothing, genuinely wishing they'd drop it. But here's what I noticed doing that day of shooting. Every photo that worked, worked because of light and timing and standing in the right spot, not because of what lens was mounted. A guy hauling a wheelbarrow of yard waste with the morning sun coming in low behind him looked like something out of a magazine, and that was an 18-55 kit lens doing normal kit lens things. The equipment wasn't the story. It never really is, this early on.
Where people go wrong
They start comparing their photos to photos taken by people with different gear, different light, years more practice, and they assume the gap is the camera. Usually it's not. Usually it's reps. Shutter priority, aperture priority, understanding what your own lens does at its own limits. That stuff transfers to any lens you ever own. A new lens doesn't transfer anything back to you.
Your problem is not your equipment yet. It might be someday. Not yet.
Before next time
Take your kit lens through its full range on three different subjects around your house or yard, something small and close, something at mid distance, something far off. Same aperture chart as before, and write down what you actually saw, not what you expected to see.