I’m not thinking about what I could be capturing with a different focal length. I’m concentrating on what I can shoot and not worrying about what I can’t.

I’m happy to hear you’re taking a photography class. I took some a few years ago and they’re the best money I ever spent on photography. Far more so than any gear. I hope you get a lot out of your classes too. 🙂

FOV tofocal length

So whilst out with whatever lens you might have, you should be adapting your mind to suit what you see through the viewfinder, adapting your ideas, adapting your subjects, adapting your composition, and taking your photos accordingly.

It was the Dutch Antony Van Leeuwenhoek who used the microscope to start making discoveries, not just bigger pictures of things. The tradesman turned to crafting his own lenses, which had up to 300X magnification, a huge jump in power from most previous devices, the best of which were in the 20-30 x life-size range. His curiosity was large, too. He is credited with discovering bacteria, protists, nematodes, and spermatozoa, among other things. He examined and drew the “animalcules” (from the Latin for “little animals”) of his own semen after sex. (Mrs. van Leeuwenhoek’s opinion that famous event does not seem to have been reported.)

For me, focal length is something you should probably know about as a photographer. And know about it well enough to explain it to someone else.

Focal lengthcamera

Understand a bit about focal length will help you choose the best lens for getting the best results you can. That’s important.

Biologist Clara Sue Ball examines why “the early history of the compound microscope reveals a curious lack of interest among scientists in the possibilities of the new instrument.”

I said earlier that I don’t believe focal length is something to worry about once you’re out shooting, and this is where I can explain that further.

If you have a zoom lens, say an 18-55mm, you can use it any focal length between 18 and 55mm. Prime lenses are fixed at one value.

Focaldistance vsfocal length

About the plaque on his teeth, van Leeuwenhoek noted that the bacteria was “very prettily a-moving” in the spittle, one type going “like a pike does through the water.”

The first, which is perhaps the single most noticeable, is how close to the camera your subjects appear. It’s the basic action of zooming in and out.

I adapt to what I have and if this is a prime lens then we’re essentially trying to make the best of the restrictions we have given ourselves.

If it looks bad, I highly doubt thinking about the focal length would have been the best way for the photographer to make it a better picture.

And if you think others will get something from this focal length explanation too, help them find it by sharing or pinning.  😀

As we saw above, shorter, wider angle lenses will add depth. Longer, narrower lenses will flatten the image. So what lens do we use for portraits?

The first picture, shot at 18mm, appears to show a greater distance between the objects while the one shot at 55mm is somewhat flatter, with the images appearing closer together.

Depending on what you shoot – landscape, portrait, street, travel, anything else – understanding the best focal length for the photographs you’re going to want to get is important.

When the microscope was first invented, it was a novelty item. Early examples were called flea or fly glasses, since they magnified those small insects to what seemed a great size at the time. But scientists didn’t readily take to the new technology.

Photography should be fun. Forget the numbers once you’re out there. Go enjoy it, and don’t come back without some great photos – whatever focal length it is you’re using. 😀

focallength是什么

The first compound microscopes date to 1590. These devices use more than one lens, a step above most single magnifying lenses or glasses. The actual inventor is contested because there were several people at work on them, but father and son team Hans and Zacharias Jensen are usually credited.

While that mini shoot was fun to do, we’ll always learn more from real world examples, such as these shots from the park.

For example, a 35mm lens on a DX or APS-C sensor will give something close enough to 50mm when x1.5, and a 50mm lens will give something close to 85mm, which is handily a great length for portraits.

So to repeat that earlier statement, on a full frame or FX camera, a 50mm lens will give you photos that look pretty much as the human eye sees the world.

Crop factor can be an annoyance when it negates truly wide angle lenses on non-full frame cameras, but it can usually be worked around for more common focal lengths.

Personally, I take pictures to suit the focal length I have at my disposal, without even having the words ‘focal length’ enter my head.

What is focal lengthof lens

If you have a DSLR and aren’t sure, it will probably be DX. These are the more common type, and if you never asked when you were buying it, you probably got a DX.

Focal lengthformula

With the help of some Branston Pickle, Aesop’s Fables, and two men punching each other in the face, I’ll give you another visual.

Crop factor relates directly to the type of sensor you have in your camera, and will alter the effective focal length of the lens you’re shooting with.

If a wider lens will make their features more prominent, longer lenses can, and often are, used to make them look more petite.

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Had I been in the same park to take actual photos with a 55mm lens, and not just getting shots to demonstrate focal length, I wouldn’t have taken that third shot. I would have found other things to take pictures of. Things more suited to the focal length available to me.

So some seventy years separated the invention of the microscope and “any systematic work of great and lasting scientific value.” Ball attributes this to the primitiveness of the early microscopes, which were very hard to use. Perhaps more importantly, she argues that the developing biological sciences, especially botany and anatomy—which would later benefit so much from magnification—were not advanced enough to realize “the significance of the observations made.”

Use it to pick the right lens for what you’re going to shoot, then concentrate fully on the creative side of things. Not the maths.

If you found this post on understanding focal length useful and want more practical photography guides, here are three more that can help you:

The main options for cameras with interchangeable lenses are FX and DX in DSLRs, APS-C in Sony (and other) mirrorless, and micro four thirds or m43 in Olympus (and other) mirrorless.

Not when you can always find a different angle or composition or, if it’s really not working, to just forget it and find a different subject.

When taking these pictures, the three objects did not move. I did have to move the camera further away from the pickle as I zoomed in to the higher focal lengths, to have the bottle the same size in each picture, but that was the only change I made.

As well as allowing for a shallower depth of field to blur the backgrounds, which is a whole other article, longer lenses can help make people look better.

I’ve already chosen my lens, which is always a fixed length, and am far more concerned with what I can capture with it, and how, than I am with why.

The word “microscope” first appeared in print in 1625. And yet, as Ball writes, no “truly scientific use was made of the microscope” until 1661, when Marcello Malpighi discovered capillaries in the dried lung of a frog. His work would have been impossible without a microscope. Robert Hooke’s famous book Micrographia of 1665, with its sumptuous illustrations of tiny things, confirmed the importance of the new technology for observation.

In short, the 50mm lens you buy might not be giving you a 50mm focal length. The 35mm lens you buy might not be giving you a 35mm focal length either.

However, there are further, less conspicuous ways in which focal length changes how your images look. While they may not be quite so obvious to the beginner, they can be just as important depending on what you’re shooting.

When I’m out shooting on the street, I can adapt my images to suit the focal length. However, if you’re shooting something that needs a particular look, such as portraits choosing the right focal length is vital.

Human eyesfocal length

Had people been ready, would the technology have been pushed harder?  It’s notable that van Leeuwenhoek was utterly unknown: he had no training in natural philosophy/natural history, as the sciences were then called. The “father of microbiology” was completely self-taught. In the context of a rich Dutch glass-making tradition, he perfected his own lenses, grinding and polishing them himself. His microscopes weren’t even the compound type used by others; they were single lens devices, basically extraordinary magnifying glasses. He never published a book; the record of his work is in his correspondence with the Royal Society.

One reason the focal length doesn’t matter when shooting street is that nobody knows, or cares, how near or far things really are in your images, so long as they look good.

Subjects appearing closer and fields of view becoming narrower are both rather obvious effects of different focal lengths.

Because when you’re getting started in photography, all those numbers and terms can be pretty intimidating. They lead to a lot of questions for beginners around the subject of focal length.

Put simply, focal length as denoted by the numbers on your lens (35mm, 50mm etc.) is the distance between your sensor or film and your camera lens when it’s focused to infinity.

I’m taking a photography class at a local School of Photography and always refer to your articles to flesh out my understanding of what I’m learning. You have such a gift at simplifying what can be a confusing subject. I just wish I had a book to write in a tag! For a visual learner especially, I can see the illustrations in my mind’s eye and they stay with me! Consider a book! Thanks 🙂

The pictures taken at 33mm and 55mm were taken from this position only to show you the lessening distance between the lamppost and the tree.

The first step to understanding this is to ask, what kind of camera do you have? And more importantly, what size sensor does it have?

Even though everyone is different, we do have an idea of the boundaries of normality when it comes to the human form. And no model wants to have their nose or chin enlarged by the camera.

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Compound microscopes eventually surpassed van Leeuwenhoek’s devices. And by the 1850s, they were both standard scientific equipment in labs and a pedagogical-entertainment standby in middle class Victorian homes, where the animalcules took on a life of their own.

Notice the distance from the lamppost to the tree, and the bin, and also how the blue cafe sign comes closer as the focal length increases.

You might think the images in that post are rubbish, or you might think they aren’t bad. I would be surprised to hear you thought they’re rubbish because of the focal length though.

This all means if you want to know you’re shooting the focal length as stated on your lens, you’re going to need a full frame or FX camera.

focallength中文

And that leads us down the next rabbit hole. Because if you’re going to understand exactly how the focal length of your lenses will make your images look, you’re going to need to learn a bit about crop factor.

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The first compound microscopes date to 1590, but it was the Dutch Antony Van Leeuwenhoek in the mid-seventeenth century who first used them to make discoveries.

For these three pictures, I had to stand further away from the lamppost to make it appear the same size in each picture as my focal length increased (as I zoomed in).