Photography Experiments: Aperture, Focal Length, and Sensor Size

Just a quick photography experiment to demonstrate the effects that aperture, focal length, and sensor size can have on depth of field (i.e., how much you can blur the background of a photo.)

It snowed here recently, so I took a photo of a branch with some snow on it, which came out decently enough, but it prompted me to think: what would this look like at different apertures – or even different sensor sizes? So I decided to perform a little photography experiment to find out, and these were the results.

snow on pine tree branch - f5.6First is the original photo – taken at f/5.6, at max zoom (200mm, equivalent to 400mm on a full-frame camera) using my Lumix G2 camera. Even on my smaller micro four-thirds sensor, you can see that the background is completely blurred out – even more so than I could’ve gotten with my f/1.7 lens!

The depth of field in this photo is very shallow – if you look closely at the bottom right of the photo, you can see the bottom part of the branch is slightly out of focus (because it was angled slightly towards me). This gives you an idea of how thin a “slice” of the scene was in focus.

snow on pine tree branch - f22Next, I changed the aperture to f/22, but kept everything else the same. As you can see above, the background is still blurred out, but not as much. It is still blurred somewhat because I was focusing on a branch just a few feet in front of me, while the background is easily another hundred feet beyond that.

Compared to the first photo, you can see that the bottom bit of the branch is in focus – meaning the depth of field was greater, and a thicker “slice” of the scene was in focus.

snow on pine tree branch - f5.9 (compact camera)Finally, for this last picture I switched to a different camera – a compact Canon PowerShot ELPH 320. The aperture here is f/5.9, nearly the same as my very first shot, but as you can see the background is hardly blurred at all! The depth of field here is very deep – a very large portion of the scene is in focus.

Unfortunately, the little compact camera I was using couldn’t zoom to the same focal length – so this photo is at the equivalent of 255mm, instead of 400mm, and that contributes to the greater depth of field as well.

However, the smaller sensor size also has a significant impact – because the sensor is so small, there’s less room for the light to be “smeared out” (as it were), and so less of the background can be blurred.

So, what did we learn from all this? All else being equal:

  • A larger aperture (a smaller f-number) provides less depth of field and allows for a more blurred background.
  • A longer focal length (zoomed in more) provides less depth of field and allows for a more blurred background.
  • A larger sensor allows for less depth of field, which allows for a more blurred background.

This is why compact & cell phone cameras – which usually don’t have large apertures, don’t have long focal lengths, and have small sensors – are at a serious disadvantage when it comes to getting shallow depth of field & that nice blurred-out background look.

Nothing here is terribly ground-breaking in itself, and all of this should be basic “photography 101” stuff, but I still think that actually performing photography experiments like this can be incredibly useful, in the same way that performing physics or chemistry experiments can be useful even if you already know the theory behind it.

As for myself, experiments like this help me develop an intuitive “feel” for how all the different settings and elements work together, so that I can just take the photos I want to take, without having to spend too much time thinking about which setting affects which aspect of the photo.

Perhaps this experiment will help you in the same way, or perhaps it will inspire you to perform your own photography experiments. Either way, I hope it’s been helpful, or at least enjoyable!

Keith’s Winter Driving Tips

Some common-sense tips for driving in the snow and ice of winter.

With all the snow & ice hitting us up here in the northeast US, I figured it was time to try and educate people about how to drive in the snow… because, seriously, a lot of people seem to have a real problem with it. So here goes.

Slow down

If you do just one thing while driving in the snow, it should be to slow down. Pretend that everything is happening in slow motion. In the snow, or really any time the roads are very slippery, everything you try to do takes longer to happen. This means you need to do things more slowly/gradually: accelerate slower, brake slower, and turn slower.

Check your tires

It doesn’t matter if you’ve got AWD, 4WD, traction control, anti-lock brakes, etc., unless your tires can get some grip. If you’ve got summer tires, or worn down “all-season” tires, this more than outweighs any advantage from those sorts of systems.

This is especially true if you’ve got low-profile, high-performance sport tires – if you have these sorts of tires on your (sports) car, you should really just stay home and keep off the roads. (And that goes double for people driving luxury SUVs which often come with “sporty” tires which are absolute rubbish in the snow.)

Acronyms don’t make you invincible

This is something that really needs to be drilled into people’s minds. Yes, 4-wheel drive (4WD) or all-wheel drive (AWD) is great, and yes, it gives you extra traction… for getting moving. But keep in mind that when it comes time to turn, or to stop, you still have the same number of wheels (and brakes) as everyone else on the road.

4WD/AWD will help keep you from getting stuck in the snow, but that’s about it.

Clear all the snow from your car

Yes, I know it’s annoying to have to clear all that snow off your car, and it can be tempting to just clear the windows and go… but there are a lot of good reasons to take the extra time and effort to clear the rest of the snow off your car.

If you have a tall vehicle (say, an SUV, which is probably why you don’t want to make the effort to get the snow off in the first place since it’s harder to get at) then all that snow is adding weight to your car, and adding it up high like that makes you rather top heavy – or to put it simply, you’re more likely to flip over.

And let’s also not forget that eventually that snow is going to come flying off your car – and then just think about the poor person behind you.

Turn on your lights

I’m seriously amazed at how many people I see driving in the snow without their headlights on. Many of them are driving white or silver cars, which makes it even worse.

Many states (something like 20 the last time I checked, including New York and New Jersey) have a “wipers on, lights on” rule, and for a very good reason – when visibility is reduced due to rain, fog, or snow, turning on your headlights makes it easier for other people to see (and, critically, avoid) you.


I hope that some of these tips have helped someone out there – driving in the snow really is not that complicated, you just need to keep your wits about you and make sure you have the right equipment.

If you have any winter driving tips of your own to share, feel free to share them in the comments!

Desktop Madness Vol. 19

So, it’s November 13th and it’s raining out. Again. Why can’t it be more like this picture?

So, it’s November 13th and it’s raining out. Again. Why can’t it be more like this picture?

Shack in the snow

*sigh* If only…