I feel you. I just got my first camera, an A7 IV, no experience whatsoever. But I’ll watch the same video over and over, take notes and review them. Before you know it, it starts to make sense and you start applying it to the point it becomes second nature.
I just watched a video from a guy with 900k subscribers. He scribbled on an electronic drawing screen to explain these concepts but his explanation couldn't have been more confusing! Then I come here and watch an extremely SIMPLE to understand explanation with VERY good diagrams. Your video was ten times as good as his! Thank you! Liked and Subscribed!!!
Thanks so much, I really appreciate that! I try to be as simple and straightforward as possible so I don't waste anyone's time and so only the necessary information is communicated.
in case anyone got confused about the wording of "where light converges" to image sensor (like me), so I looked up the physics. Where the light converges should be the focal point, which is on the image sensor to form a clear image. focal length should be defined as the distance between the optical center to focal point instead, optical center being the place where ray light passes without any deflection
Unless I'm mistaken, at 0:28, the illustration is incorrect. It depicts focal length as the distance between the point at which light rays converge and the sensor, but it depicts the sensor as being out in the camera lens itself, instead of at the back of the camera body, where the sensor actually sits.
You are correct, technically. This is something I looked over in the illustration phase of making this video and I just noticed it now with your comment. Thanks for pointing this out.
Apalapse, I would like to thank you for this video of yours. I love the section about your explanation of the APS-C and the Full-frame camera. Now I know how to calculate the focal length of my lens when I mount them on my APS-C camera.
I'm glad you liked it! The only thing I should say is that when you switch from full frame to APS-C, the focal length itself does not change, it's only the field of view. This is just a semantics issue mostly but it's important to remember since a lot of people think that when they switch bodies the focal length of the lens also changes, making it a different lens... When you multiply the focal length by the crop factor you are just saying that on the smaller-sensor camera the lens has a new field of view of ____, since focal length is the distance from nodal point to the sensor it will never change regardless of the camera you attach it to. I just wanted to articulate this in case it helps you or anyone else. Thanks for commenting and take care!
Haha! Thanks for the kind words. My goal is always to try and break complicated concepts down into easy-to-understand tidbits. I'm glad you found that in this video, thanks for watching, friend! Take care and live HEPPily.
@@Apalapse you're right, it makes sense to use your own one. That's why I learn how to make it more professional. One day you won't hear a difference anymore))
I need some clarification on the focal length / field of view figure. On a full frame camera (36mm) , shouldn't the field of view for a focal length of 18mm be 90°? The image states 100° ... FOV=2×arctan(36/(2*18))=90°
Phenomenal. That bit (0:21) where you describe what focal length actually is, and the image of light being focused that many mm in front of the sensor was an epiphany for me. Being a dullard I never imagined or understood that the image would be focused anywhere but on the film/sensor. Because of this inability to grasp the concepts I have bought a Dwarflab 2 to introduce me to something I’ve always wanted to do and this seems an affordable starting point and not too expensive to fail. Any comments (about the Dwarflab not my denseness) anybody who might have got this far?
At 0:51 your example is slightly incorrect, the moon should be smaller in the shorter focal length because the foreground is closer than the moon. Compression would make the moon much larger in the second image.
The example at 0:51 shows the moon exactly as how you said it should be. The left image shows the moon in center frame behind the skyline while the right image shows a crop on one of the taller left buildings, and a resulting larger moon. If you're referring to the size of the moon in the left frame in relation to the design of the wide angle lens pictured, there's no way to guess the focal length of the lens to the left and the argument is arbitrary.
Apalapse what im saying is that changing focal lengths isn’t the same as cropping. The moon in a cropped wide angle image will be smaller in relation to the buildings and the moon in the image on the right. Your right though you cannot know how much this factor would be because neither picture really exists.
Now I understand. I could have made the image in accordance with the compression that would result from switching to a lens with a longer focal length. My mistake.
I have a camcorder with three 1/2.8-inch sensor it. it's a 20x zoom going from equivalent to f=28.8 - 576mm on 35 mm lens(16:9) . So I have an APS-C camera with a full frame nikon 80-200mm lens on it is almost the same view when fully zoomed in? So how do have to understand this? I thought the 576mm would be much further zoomed in than the 200mm full frame lens on a aps-c body?
Sir... I teach by writing on the White board with enough lighting. I have Canon M50. But when I shoot with this camera, I & words written on the whiteboard don't look bright, sharp & crispy. If I want me & my to good with proper light, words written on the whiteboard don look sharp & crispy. Please tell me which lens should I purchase for white board teaching for best quality ? Sir plz help me....
I never saw any photography video on RU-vid could explain so much information in such simple clear efficient way with such fantastic stunning animation! Thank you!
@@ApalapseI’m very grateful as well. The information is delivered so efficiently I had to pause several times and go back. There’s no fluff, I love it!
Continuing what I've said in the Aperture video... DUDE: on 0:34 can you please explain how is that nobody use such clear and obvious image to explain the angle of view? You just rock, man.
Your animation art is absolutely beautiful, coupling that with the detailed yet understandable explanations and your videos are amazing. Thank you for your hard work!
i guess im randomly asking but does anybody know a trick to log back into an instagram account? I was dumb forgot the login password. I would love any tips you can give me!
In the past I contracted my voiceover work but going forward I am using my own voice. To be completely honest with you my voice was still changing when I was creating this videos so I felt a little insecure about it but I'm narrating my own stuff now so that inconsistency should be removed.
@@snehalgaikwad4812 Thank you. I'll be producing more soon, I am just setting up a studio currently, and it's more expensive than I thought originally.
I've looked all over for this answer. Every video promises to "explain" camera lenses, but NONE of them explain exactly what the numbers mean - except this one. I'm not one of those people who takes words on faith - I want to KNOW what things mean so that I know how they work. Thanks for giving me that info.
Thanks, John. What you said sums up exactly what I thought when I started out in photography; everyone was telling me to believe this or that, but I wanted to know the hard science and truth behind things; that's what led me to create this channel. Thanks for the feedback and I'm glad I am delivering on my promise to provide straightforward and factual content. Take care.
Having the same effective focal length and actual focal length does not mean the focal lengths are equal, only that the image they produce has similar dimensions. Having 50mm lens on a cropped sensor still obeys the lens equation physics of 50mm lens, it just gets cropped down.
Your animation art is absolutely beautiful, coupling that with the detailed yet understandable explanations and your videos are amazing. Thank you for your hard work!
New to Photography and just found your channel. The graphics and animation is amazing along with the demystifying explanation. Absolutely well done. That Focal Length and Field Of View animation at 0:36 and its explanation has hands down got to be the most concise explanation I’ve ever seem represented. So good I decided to subscribe.
That's awesome to hear, man. I really appreciate the kind words and feedback. Happy to have you on board and stay tuned for more coming soon.
6 лет назад
35mm is not the lenght of diagonal (obvisously cannot be, because the diagonal must be longer than any other side, so it should be bigger than 36mm). It is a naming from film era. It comes from fact, that the film with the holes was 35mm wide. en.wikipedia.org/wiki/135_film
Thanks for the clarification. A lot of graphics on google were wrong about this and after I did some research I realized that I made an error in the video.
Nice video!! just a point, the distortion or compression is not created by te lens itself, they are created by the physical distance between the camera and the subject.
Totally agreed with this video... I learned most of basic and advance information's... I can't get it clearly from my friends.. But with your help.. I get more n more.. Thanks!
This animation is so helpful I cannot express that enough. I always come back to this video when I get confused about focal lengths. 0:38 is by far the best graphic for describing this!
Crop factor is one of those snob terms, that does more to confuse than to educate... especially given the broad differences in sensor technology over a very short period of time. My 50mm may not be your 50mm, but how many photographers do you see running around with 1 lens and 5 different camera bodies? This full frame, crop, and effective terminology needs to go away. Implying that a 50mm lens on one camera will be the same as a 75mm lens on a different camera, due to so-called "crop factor" is absolute rubbish. Never mind, that most of the time... the given factors are usually rounded, not even close, broken rules of thumbs.
I agree with this but half the problem is being able to effectively teach the concept that field of view depends on not only the lens but also the sensor the lens is placed on. The term "crop factor" is inherently easy to understand; a lens you place onto a full frame will have a different crop than one placed on an APS-C body. There is nothing objectively wrong with this thought process; a lens' image circle will be cropped differently based on the camera sensor it is placed above. What I think you were trying to articulate is that often in education, especially in photography education, certain concepts are misconstrued, and focal length and crop factor is one that is especially notorious for being misunderstood. The common misconception is that the focal length of the lens physically changes as the camera body is altered. This is untrue, since a 50mm lens on a Canon APS-C or on a Sony full frame will output the exact same amount and intensity of light; nothing changes but the crop. This misconception is one I avoided in my video, and it's important when explaining concepts to use clear and precise semantics. Full frame and crop are meant to educate, but effective is where intentions get ambiguous. My job is to teach and teach accurately. While full frame and crop might annoy some people the bottom line is is that when used correctly it can effective explain difficult-to-understand concepts. Sorry for taking so long to respond to your comment; I was busy with college and research. I appreciate your feedback and hope this helps you understand where I stand on this "issue."
I do my own narrations now, and yes, the videos are scripted. They are scripted because the point of the video is to provide information clearly and concisely without mistake. A "robotic" voice doesn't distract the viewer from the content of the video and reading from a script makes sure the right information is being said. My new videos are less robotic, though, since I am using my own voice.
@@Apalapse "it's a calculation of the distance from "where ALL light rays converge into the lens to the image sensor."" "so a lens with a focal length of 24 mm would have light R___ coverage 24 mm ABOVE the image sensor" what? I don't understand. you have a good sounding voice though and great looking graphics. I'm just having an issue understanding i guess. Ok watched the whole thing, i pretty much knew everything after the 38 second mark, I really just came here to understand the first 30 seconds, i will continue my search but likely watch some more of your videos in the near future. They are pretty well done. *UPDATE* Figured out what i was curious about. Not your fault, i just had a mental block going on. I think if your graphic just had 2 illustrated beams of light crossing more in the middle of the lens at the start you could have helped me get over my confusion. You should have more subscribers for the quality of your content. Keep it up
Yeah, the vast majority of people will just buy a phone and it does do a great job capturing most photos EXCEPT telephoto past 100mm / 4x but the Apple Pro Max has a whopping 125mm/5x😂😂
Was this voiced by computer? The pronunciation and pacing of the read is unnatural and distracting. Honestly, in the future it would be MUCH BETTER if you simply hired an of the THOUSANDS of voiceover artists looking for work. Your video would be much easier to follow.
Slight error. That 35 mm is not a diagonal measurement, it is the total width of the film, including the edges that have holes for manipulating the film's position. 35 mm camera film is exposed over an area that is 36 mm x 24 mm. There are also a number of APS-C lenses that will go down to 11 or 12mm without fish-eye distortion.
0:35 cool diagram! Does an APS-C lens called an 85mm and a fullframe 85mm lens both have the same 28-30 degree angle of view? This came out around 2017 and you're talking about Canon and Nikon? Nikon is still on life support from those days, relying on their medical and hunting revenue for the camera division to stay afloat.
Great video However there is a mistake about focal length. Focal length is the distance a single lens element would have to be to focus at infinity and give the same image as the lens. e.g. an 8mm Lens gives the same Image (Angle ov view) as a Lens Element that focuses infinity at 8mm away from the Sensor. en.wikipedia.org/wiki/Focal_length
Personally I think we should get rid of length and use angle of view which is the farrrrr more important measurement number. Infact length really means nothing as this changes without affecting perspective by using different sensor sizes.
Sorry for the late reply. I agree completely. Focal length readings on lenses are confusing when soe are designed for full frame, others or medium format, and even others for M4/3. I have had many photography friends send me 10mm f2 lenses or 8mm f2.8 lenses and ask which one would be better on their full frmae camera only for me to tell them that these lenses are designed for smaller sensor cameras. Unfortunately like many concepts in photography the days of film have ingrained certain standards and conventions that don't apply well to the digital world of photography.
This is an excellent video and your graphics are extremely helpful. However, your explanation of how focal length is measured is incorrect. The measurement of focal length in photographic optics is from the rear nodal point to the focal plane when the system is focused at an object at infinity. It's not the point where the light rays converge to the image sensor although I see this described on a few websites incorrectly and google puts these websites at the top of the search. If you look at the ray trace of a common lens (google image something like 50mm ray trace) you'll see that the rays converge at the focal plane. The nodal points are defined as points in the optical system where an incoming ray aimed at the front nodal point appears to exit the lens from the rear nodal point at the same angle.
Thanks for the clarification. This is the correct definition but in the video I oversimplified the concept so that beginner photographers would not be confused. I appreciate the feedback a lot and thank you for the correction.
i sitll don't undestand focal length. is it a waste to use a smaller sensor? most of the image is cropped? do they make smaller lenses that don't crop on smaller sensors?
Hi, Jeff. Focal length is simply a lens characteristic that references the field of view of the lens. Higher focal length lenses correspond with narrower field of views and lower focal lengths correspond with wider field of views. Lenses on crop sensor cameras simply obey the crop factor, meaning that some of the image circle projected by the lens gets cropped out. This isn't a big deal for most people since manufacturers will make lower focal length lenses specially designed for APS-C and M4/3 camera sensors so that users can still shoot wide angle. On the telephoto side, having a smaller sensor is sometimes an advantage because it can give moderately long focal length lenses more "reach," allowing you to gather more magnified images.
Ignore the term "crop factor" The focal length of a lens does not ever change. It still stays the same whether you use it on a 35mm or APS-C camera. A 50mm lens is a 50mm lens. Ignore phrases that state that a 50mm lens suddenly becomes a 75mm just because you are using it on an APS-C camera. Lenses that have been specifically designed for APS=C cameras have a smaller imaging circle so there is no "crop". So what about large and medium format cameras ?
Crop factor is a term that is helpful for beginning photographers to understand. To some people it may be misleading but when explained correctly it is simply he amount of crop that occurs when a certain focal length lens is attached to any type of image sensor other than full frame. Large and medium format cameras have a crop factor of less than one (
@@Apalapse I disagree with everything you have just said. Why reference a camera / lens system that a beginner to photography may have never seen or used ? An APS-C lens doesn't "crop" anything. APS-C lenses have an imaging circle that matches the size of an APS-C sized sensor. Similarly, 35mm sized film/digital cameras use lenses that match the larger size of the frame. No-one ever talked about "crop factor" when comparing 35mm and medium format cameras, it wasn't required, so why should we use it now ?
@@alanelesstravelled8218 Whether or not APS-C is a term a beginner will know is not something you nor I can comment on. I like to think that APS-C and full frame are both terms that will ring a bell to most photographers, even if they are a total beginner, so I feel comfortable using them in my camera basics videos. While you're right in that an APS-C lens will produce an image circle large enough to cover an APS-C sensor camera, the focal length measurement is still in reference to a 35mm sensor format. Why is crop factor such a bad term? When I put a full frame lens on my full frame camera, the field of view equates to what is written on the lens body, but when I put it on my APS-C camera, the field of view is NOT the same in the files, it is increased by a factor known as the crop factor. I never said the lens itself crops anything, that's obvious; glass is glass and the physicality of the lens does not alter based on the camera it is attached to. Just because it is a new term doesn't mean it can be used effectively.
at 1:18 : the 35mm film does not have a 35mm diagonal. It has a 35mm height, the actual image size is 24x36mm (the height is not 35 because you need spece for the holes allowing the film to move) same goes for a full frame sensor that has the same size as 35mm film : it has a 24x36mm size, therefore it isn't its diagonal that is 35mm also for crop factor, the APS-C sensors used by Sony, Nikon, Fujifilm etc actually have a crop factor of about 1.52, but people just use 1.5 and 1.6 for canon as it is easier. If you use "1.50" you actually use a wrong number
Wow. What an incredibly misleading video. Focal length of a lens DOES NOT CHANGE if the size of the sensor changes!! Mount a 35mm lens onto a cropped frame digital camera and it DOES NOT become a 50mm lens. It will not have the focal compression of a 50mm lens, nor will it have the depth of field of a 50mm lens, nor will it inherit the perspective of a 50mm lens and as aperture is a ratio between focul length and the diameter of the glass, the f-stop will not change to that of a 50mm lens. The only thing that happens is that the image gets cropped by the smaller form factor of the sensor and so "digital zoom" gives the reach equivalent to a 50mm lens.
Make a Patreon web page please! thank you very much, i wish to drop a few bucks for such a quality video, i hope others feel the same! together we can motivate your team to keep doing such wonderful videos!
I'm thinking of making a patreon page. It's just one person though. I do all the animations, scripting, and illustrations and have someone else do the voiceover, although I will start doing my own soon.
well i hope you keep up with it sir!, there is lots of information, but the way you digest it and feed it back to in this illustrated mode you have chosen is superb, i mean you can have an edge here, because every other tutorial youtuber wants a ´´persona´´ driven channel. Having you chosen this illustrated right-to-the-point form, made it so much easier for me to understand some holes with Focal lengths. Please do so, there there will be a time you might regret not doing the patreon page form start =) . i have good faith this channel might go viral.
If you have a fixed lens no zoom like a prime lens when you shoot wide the image will be wide since no zoom the image won't be so big. Dx 35mm have crop factor fx have no crop factor
This was the only video I could find on RU-vid that actually explained how lenses and their numbers work technically. One nitpick: in the list of drawbacks of zoom lenses it didn't mention that zoom lenses lose aperture stops with increased zoom.
If focal lgt varies with lens crop magnifier minutes is shirt length. If 1.5lens changes length of frame mm swap and factor is 100 mm how is ficus mag in optra
I still don't understand focal length, I have a 70-300mm lens and even when fully extended the distance from the sensor to the front element is less than 300mm, so it doesn't fit your definition
It is a telephoto lens. That by definition means that its optical length is longer than its physical lens. The optical center of the lens is in fact outside the lens in front of the lens. What the lens does it first bends the light much inwards, then it again spreads it somewhat so that it looks like the front element was further forward than it actually is. Wide angle lenses do the opposite and the optical center is actually well inside the camera body. Look this: upload.wikimedia.org/wikipedia/commons/thumb/5/55/Lens_telephoto_1.svg/1920px-Lens_telephoto_1.svg.png Optically it seems like the front element was much further in front of of the actual front element. This covers only light that hits at the very center of the sensor. If one views other parts it becomes somewhat more complex-
I'm glad it was helpful! I try and make the videos striaght to the point with simple terms so that everyone can understand. Thanks for the feedback and good luck with your photography.
