Hi, and welcome to Episode 55 of the photography explained podcast. I’m your host, Rick, and in each episode, I will explain one photographic thing in plain English in less than 10 minutes (ish) without the irrelevant details.
What I tell you is based on my lifetime of photographic experience, not Google, well there were things that I had to look up, but mainly this is the stuff that I know.
Yeah, well, let’s just get into it. Let’s see where it takes us.
So what does DSLR mean?
I’ve been looking forward to this one, which is driven by the need for me to explain this before I can possibly explain what a mirrorless camera is. Just think about the name mirrorless camera. I never said that the camera should have a mirror – so why are you telling me it hasn’t got one?
Well, let’s get into this. And we will find out (next episode) what a mirrorless camera is by finding out what a camera with a mirror is.
Here is the answery bit.
A DSLR is a digital single-lens reflex camera. Digital refers to the sensor in the camera, which takes digital images, not film. Single-lens is the (single) camera lens that you look through when you are taking a photo. Reflex is the pentaprism and mirror arrangement built into the camera, enabling you to look through the camera lens rather than a separate viewfinder.
So I guess this makes sense.
You can listen to the episode here
Or keep on reading. Or do both. Entirely up to you!
Even if it feels like an odd term for a camera, I mean DSLR, there must be other terms that we could use. But there is a logic. And yes we’ll get onto that in the episode.
So evolution.
Before DSLRs, you had things called SLRs. Back in the day, everyone used them, these were film cameras, single-lens reflex cameras, with film in them.
And that’s what I started with.
I mean, there were other cameras around, but you didn’t have the range of cameras you have now. You had other formats, but if you were a hobbyist/ advanced amateur/ professional (photographer), you probably used an SLR or a medium format (camera).
Now I explained medium format in the last episode, so I don’t need to go into that.
So DSLR is an SLR with a D in front of it. D for digital.
I guess that they should have been called FSLRs! But when they came up with SLR, they didn’t know that film was going to change to digital. It’s that long ago that SLR was around before we knew what digital was.
So we need to remember the history and the evolution. And I need to give more respect to some of these things that have evolved over the years because there are logical explanations.
So then, in simple crude terms. You have a film, you wind the film on and you take a photo. Take the film chamber off the back, chuck a sensor in, put a new back on it, and you have a DSLR.
Film cameras were predominantly 35mm, which evolved into full-frame cameras (the sensor on a full-frame camera is the same size as a 35mm film).
Now I’m not going to go back through full-frame and all that other good stuff because that was covered in previous episodes. But that’s the basic evolution – SLR evolved over the years into the digital version, and things have moved on from there.
So what I’m going to focus on here, I’m going to ignore all the other bits of the camera, and I’m going to stick to the DSLR bit because it’s relevant to the mirrorless bit. And that’s where I want to get with this. The rest is all stuff for the future.
How does a DSLR work?
With a DSLR you look through the optical viewfinder at the back of the camera, and you’re looking through the camera lens. If we look at it the other way round now, from the outside, the light comes in through the camera lens, where it meets a mirror, which sends the light up and into the pentaprism (and then out through the viewfinder).
Pentaprisms
The pentaprism is the thing that takes the light from the mirror and through clever stuff sends it to the viewfinder, and this is the light that you’re looking at.
This is where I get technical.
What is a pentaprism?
It’s the sticky out bit on the top of the camera on a DSLR and SLR – there’s a bit sticking out, sticking up at the front. That’s what the pentaprism is.
And what is the pentaprism?
It’s something complicated and technical and clever, that basically takes the light and directs it into the viewfinder.
And that is enough for me.
What I haven’t written in the notes here, which would have been quite helpful, where’s the mirror? Now on a camera film, the mirror is (immediately) in front of the (shutter) camera film.
Old school SLR – when you press the shutter button, the mirror flips up and the shutter opens, exposing the film to light.
Go to digital, same thing, you have still got the mirror. On a mirrorless camera, you haven’t got the mirror.
Why? Well, when these things were invented, we did not have these things called EVFs, or Electronic Viewfinders – one for another episode. You had a separate viewfinder that was fixed.
The clever thing about the SLR, the ground-breaking bit (for me) was that it changed from looking through a viewfinder which was pointing in the same direction as what your camera’s pointing at to looking through the actual lens.
WYSIWYG (What you see is what you get)
Now if you think about this when you zoom in or out, you’re seeing exactly what is happening. Now there were viewfinders on cameras that could replicate this, but not this precise.
And there’s another thing which I haven’t mentioned yet. If you stop down the aperture, you can actually see the effects of stopping down the aperture by pressing what is called the depth of field preview button.
You’re seeing what is happening in your camera. So what you see is pretty much what you are photographing. I think in modern terms, we call that WYSIWYG. But this is from a day when we didn’t have such nonsense.
Evolution
DSLR is a logical evolution from the 1930s to the late 1980s and early 1990s when DSLRs came in. Whilst it might seem an odd term, hopefully, it makes sense.
Now, I feel a bit happier having done a bit more research into this one because this is one of those things I’ve lived with all my life, well not the concerns or anything, it’s just that I’ve experienced SLR, DSLR and mirrorless cameras.
I’ve been there for a big part of this process. I like to add that if you think about this when this happened, SLRs and DSLRs are not strange things, but are miracles created by genius people that should be celebrated. I touched on this before.
The more I look into these things, the more I am understanding the history and the evolution of strange terms in photography, and how we’ve ended up with these often baffling terms and things. And quite often in fact, probably in most cases, there will be a logical explanation for the term.
Forget ISO – that’s just out there.
So yes, I want to be amusing, interesting and entertaining. But I think I also want to treat some of these terms with respect because SLR is a genius bit of precise engineering. DSLR is an even more complicated adaptation of all that amazing engineering.
My one-line explanation
DSLR is a digital single-lens reflex camera, with one lens and an optical arrangement which lets you look through the actual camera lens when you are composing a photo. And I’ve been using DSLRs for years and before that SLRs.
Next episode
So next episode 56 – what is a mirrorless camera? Yeah, I’ll say it again.
The mirror on a DSLR is what the image is bounced up off into the viewfinder. So you take the mirror out of the way and the sensor is there without a mirror in the way.
I will take the DSLR explanation. I’ll explain why a mirrorless camera doesn’t have a mirror and why it’s called a mirrorless camera.
The things you can do to help me.
Well if you enjoyed this episode, and you want to help me, please leave a nice review and rating wherever you get your podcasts from, and subscribe so you don’t miss an episode. And share my podcast with anyone you think might enjoy it.
Thank you.
Thank you for listening to my small but perfectly formed podcast.
My Websites
Check out Rick McEvoy Photography to find out about me and my photography blog, and also the Photography Explained Podcast website, where you can find out all about this podcast what I’m going to answer and you can ask me a question of your own.
This episode was brought to you very much by the power of caffeine and a chocolate digestive.
I’ve been Rick McEvoy. Thanks again very much for listening to me and for giving me just over 11 minutes of your valuable time.
And I will see you in the next episode.
Cheers from me Rick.
OK – that was the podcast episode.
Want to know more?
Head over to the Start page on the Photography Explained Podcast website to find out more.
And here is the list of episodes published to date – you can listen to any episode straight from this page which is nice.
Let me know if there is a photography thing that you want me to explain and I will add it to my list. Just head over to the This is my list of things to explain page of this website to see what is on there already.
Let me send you stuff
I send out a weekly email to my subscribers. It is my take on one photography thing, plus what I have been writing and talking about. Just fill in the box and you can get my weekly photographic musings straight to your inbox. Which is nice.
And finally a little bit about me
Finally, yes this paragraph is all about me – check out my Rick McEvoy Photography website to find out more about me and my architectural, construction, real estate and travel photography work. I also write about general photography stuff, all in plain English without the irrelevant detail.
Thank you
Thanks for listening to my podcast (if you did) and reading this blog post (which I assume you have done as you are reading this).
Cheers from me Rick
