I’ve been shooting portraits on budget glass long enough to have opinions about almost every sub-$300 lens on the market. I’ve got the spreadsheet to prove it. But I kept running into the same problem during outdoor shoots: two lenses, same aperture, same light source, wildly different results. One image had this soft, dimensional quality. The other looked flat. I kept blaming the light. Turns out I was blaming the wrong thing.

In this Joel Grimes tutorial, he cuts straight to something that doesn’t get talked about enough in beginner and intermediate photography circles: your lens choice directly changes how light behaves on your subject’s face. Not just the compression, not just the background blur. The actual quality and dimensionality of the light. That reframe hit me harder than I expected.

Focal Length Changes How Light Wraps

Here’s the core of what Grimes is teaching. When you shoot at a wider focal length, say 35mm, and you’re standing close to your subject to fill the frame, the light source appears large relative to the subject. Large light sources are soft. The light wraps around the face, fills in shadows, and produces that flattering, dimensional look.

Now back up and shoot the same subject at 85mm or 135mm. You’re farther away. From that distance, the same light source appears smaller relative to the subject. Smaller light sources are harder. More contrast, more defined shadows, a more dramatic and sometimes harsher result.

The light didn’t change. The subject didn’t change. The relative size of the light to subject changed because your position changed, and your position changed because your lens changed. That’s the mechanism.

The Same Sun, Two Different Looks

Grimes uses natural light in the video to demonstrate this, which I appreciate because it removes all the gear variables. He’s not talking about a modifier or a specific strobe. He’s talking about the sun, which everyone has access to.

Shooting wide and close, the sun acts almost like a large softbox because the angular size of the light relative to your subject is bigger from a close shooting distance. The shadows on the face fall off gently. Skin texture is visible but not punishing.

At a longer focal length with the shooter backed way up, that same sun becomes a smaller, more point-like source in relation to the subject. Shadows get sharper edges. The look gets more contrasty. Neither is wrong, but they’re genuinely different tools, and choosing between them starts before you ever touch your light.

How I Tested This with Budget Glass

After watching this, I went back to two lenses I had already compared for a review: a 35mm f/1.8 and a 85mm f/1.8, both in the under-$300 range. Same subject, same overcast afternoon window light, same aperture. I shot close with the 35mm and backed up to frame the same shot with the 85mm.

The 35mm window-light shots had softer shadows and a slightly more flattering, approachable look. The 85mm frames had more defined shadows under the cheekbones and a stronger sense of shape. If I were shooting a product portrait for a tech brand, I’d reach for the 85mm. If I were shooting a lifestyle headshot for a friendly local business, the 35mm close-up wins.

This is useful information that has nothing to do with the price of the lens. A $150 35mm and a $200 85mm are giving you fundamentally different light behavior, and now you can choose between them intentionally rather than just swapping focal lengths and hoping.

Where This Breaks Down (or Gets Complicated)

I want to add one honest caveat here. In controlled studio work, or any situation where you’re moving your light source rather than yourself, this relationship gets more complicated. If you back up to shoot at 135mm but you also move your strobe closer to maintain the light-to-subject ratio, you can largely neutralize the effect Grimes is describing. The principle still holds, but experienced shooters can compensate for it.

For anyone shooting run-and-gun portraits, events, or outdoor work where you can’t reposition your light, this is exactly as important as Grimes says it is. Your lens is making a lighting decision whether you realize it or not. Knowing that means you can make it on purpose.

Pick Your Focal Length Like You Pick Your Modifier

The most useful shift in thinking here is treating focal length as part of your lighting toolkit, not just your framing toolkit. Before I watched this, I was choosing lenses based on the crop I wanted. Now I’m thinking about what quality of light I want first, and then deciding whether I need to compensate with a different position or a different focal length altogether.

If you want soft, wrapping light and you’re working outdoors with no modifiers, shoot wider and get closer. If you want drama and definition, back up and reach for the longer lens. Simple rules that cost you nothing to apply.

Watch the full video from Joel Grimes to see this demonstrated visually on an actual subject. Grimes is one of those photographers who explains the “why” behind technique, and seeing the light difference play out in real time makes the concept stick in a way that reading about it can’t fully replicate.