One of the most important and basic parameters of any photographic equipment is value of the photosensitive camera sensor. And this is not about about megapixels, but about the real physical area of the photosensitive element.
Previously, most photographers shot on film cameras that used the so-called 35mm film (film standard from the distant 1930s). Those were quite old times, and somewhere since 2000, digital-SLR cameras (DSC) became very popular, the principle of operation of which remained the same as in film cameras, but instead of the DSC film, they began to use an electronic photosensitive matrix, which forms the image ...
That's just the price of making such a matrix hundreds of times more expensive than ordinary film. Due to the huge price of manufacturing an analogue of 35mm film and the general complexity of manufacturing a huge matrix with millions of transistors, a number of manufacturers began to produce sprinkled cameras... Concept 'cropped matrix 'meansthat we are talking about a smaller matrix for a standard size of 35mm film.
Crop factor (Crop - from English "cut") Is an indicator for cropped matrices, it measures the ratio of the diagonal of a standard 35mm film frame to the diagonal of the cropped matrix. The most popular crop factors among CPCs are K = 1.3, 1.5, 1.6, 2.0. For example, K = 1.6 means that the diagonal of the camera sensor is 1.6 times smaller for the diagonal of a full-frame sensor or for a 35mm film diagonal.
In fact, not all central control centers are equipped with a cropped matrix, now there are a lot of cameras in which the matrix size is equal to the size of a 35 mm film, and K = 1.0. Cameras in which there is a matrix the size of a classic 35mm film, are called full-frame digital SLR cameras.
Cropped cameras are usually APS-C cameras with K = 1.5-1.6, or APS-H cameras with K = 1.3. Full-frame cameras are commonly called Full Frame. For example, Nikon's cropped APS-C cameras are called Nikon DX, while full-frame cameras are called Nikon FX.
DX (cropped camera, APS-C type, K = 1.5) has a matrix with dimensions of approximately 23.6 to 15.8 mm, the area of such a matrix is equal to 372,88 sq. Mm.
FX (full-frame camera, K = 1.0) has a matrix with dimensions of approximately 36 to 23.9 mm, the area of such a matrix is equal to 860,4 sq. Mm
Now we divide the area of the matrices and we find that the DX matrix is smaller than the full-frame matrix in 2,25 times. To quickly calculate the real difference in the physical dimensions of a full-frame and a cropped camera, it is enough to square the crop factor. So, DX cameras use crop factor K = 1.5, we get that the areas of DX and FX cameras differ by 1.5 * 1.5 = 2.25 times.
If we install a standard (for example) lens with a focal length of 50mm per cropped camera and look into the viewfinder, we will see that the viewing angle is narrower than with the same lens on a full-frame camera. Do not worry, everything is in order with the lens, simply because the matrix of the cropped camera is smaller, it “cuts out” only the central region of the frame, as shown in the example below.
At the same time, many people have the opinion that the focal length of the lens is changing - but this is just an illusion. In fact, the angle of view that a person observes in the viewfinder is changing, the focal length of the lens does not change. Focal length is the physical size of the lens and will remain the same on any camera. But because of this illusion, it is convenient to say that on a cropped camera, the visible picture is similar to a 75mm lens (50mm * 1,5 = 75mm) when used on a full-frame sensor. That is, if we take two tripods and two cameras - one full-frame, the other cropped and screw a lens with a focal length of 75mm on a full-frame one, and on a cropped one with a focal length of 50mm - then in the end we will see an identical picture, since they have will be the same.
The recalculated focal length is called Equivalent Focal Lengthabbreviated EGF. EGF recalculated even for cropped lenses like Nikon DX and canon Ef-s.
And an example of the same picture taken from the same distance, without changing the settings, but only in cropped mode:
In fact, when using lenses from Full frame cameras on cropped cameras, we get some significant advantages:
- Reduced viewing anglemaking a telephoto from a standard lens, and a super telephoto from a telephoto. So using a 300mm telephoto, we get a viewing angle the same as in a 450mm lens on a 35mm film. This is a pretty great opportunity to buy a cheap zoom telephoto for less money and due to the crop factor, get a large EGF.
- Due to the fact that full-frame lenses work only in the central area on cropped cameras, you can get rid of such image defects like vignetting, a drop in resolution at the edges of the frame, part of the distortion. Usually in the central region of the frame, image quality is maximum.
Also, using lenses from cropped matrices, we get lenses cheaper. Although there are downsides. Lenses from cropped cameras need to cover a smaller area of the photosensitive element, which means you can use less expensive glass, make less weight, etc. At the same time, when buying lenses for cropped matrices and with the subsequent transition to full frame, you will have to additionally buy new lenses for a full frame. I advise you to read the related article - Nikon lens differences, and - Features of cropped cameras and lenses
Conclusions:
Cropped cameras (cropped matrices) are simply smaller matrices, and in order to understand the amount of matrix reduction, the concept of crop factor is used. The crop factor is convenient to use to obtain EGF lenses when using them on cropped cameras. To obtain EGF of any lens, when using it on a cropped camera, it is enough to multiply the value of the focal length of this lens by the crop factor of the camera.
More information in the sections
Material prepared Arkady Shapoval.
here it is, what's the matter ... ... thank you very much for the clarification.
Hello Arkady! I read your answers to various questions in the field of photography with great interest. In my introduction I want to say that I am a beginner photographer and I really like this lesson. From the instrument I have a Nikon d5100 with a whale kit nikkor 18x55 lens. This lens is not bad in quality in close shooting. But at the moment I was on fire to purchase a telephoto for long-distance shooting. the choice was between AF NIKKOR 70-300mm 1: 4-5.6 D and Nikkor 55-300mm televisions. Please give me your professional advice whether it makes sense to overpay for the first lens model. As far as I know that the 55x300 lens is for cropped matrices, but it’s slow to focus outrageously and when hunting for the same birds or other moving objects, you can click through everything. The first lens is more frisky, but here it is for full-frame DSLRs, whether it will somehow negatively affect the pictures. If I understand correctly, then he simply will not reveal his potential on my Nikon. The lens was about to be acquired on the secondary, your advice is worth it. Maybe there’s some other worthy TV set for my Nikon advise. For earlier I am grateful to you for advice and help.
My advice is that a person reveals his potential. I would save on Nikon 70-300 VR, otherwise I would take 55-300, it is optically better than old AF telephoto lenses, and you can get used to the speed. And yes, AF NIKKOR 70-300mm 1: 4-5.6 D on d5100 will not focus automatically.
Thank you for your prompt response.
Hello, Arkady. Please explain this question ... I am a Family Photographer. Today I have a Canon 5D Mark 2 + 135mm. There is a question about changing the technique. I planned to change it to Mark 3. But then I got rainbow reviews about the Canon 1D Mark IV. Please tell us everything + and - of this camera. Thanks.
I did not shoot on Mark 4, because it will be difficult for me to tell all its pros and cons.
Before someone sends this camera to Arkady and he prepares an overview on it (if this happens at all), isn’t it easier for you to read what is already on the network, for example here https://ru.wikipedia.org/wiki/Canon_EOS-1D_Mark_IV
I read it all on the net ... I wanted to hear some kind of summary.
The Chinese resume made: https://www.youtube.com/watch?v=DevbqSJhmfE
There 3 and 4 nickels are compared, not 1
and I didn't see 1D - I was thinking about the fourth penny :) Or Arkady's answer confused me or a bunch of marks from Canon :)
Good day! I don’t understand how the depth of field and crop are related? Judging from the article, the depth of field should increase when cropping a frame? But on soapboxes, as I understand it, there are wide-angle lenses that give more depth of field than televisions, only they are very cropped by a very small matrix. Thanks for the site and for the article makes me think! :)
Hello .. I have a question ... I have a nex5 camera and CANON EF + MARK III lenses FIRST I thought about buying another "carcass" because it is not very convenient / practical to constantly change lenses, especially when I am in a hurry there is a risk of dropping or getting dust ... But then I heard about adapter with which you can attach Canon ef lenses k nex e mount ... Tell me please, will it work or not?!?! Thank you in advance!!!
I read your articles long enough. And then the question has ripened. The d700 camera and now the d500 legend has come out if you buy it for shooting video and what lenses to buy as an additional camera? Hire weddings and genre. Since I live in Italy, there is often a landscape and architect
17-55 / 2.8 + 70-200 / 2.8 + Tokina 11-20 / 2.8.
GOOD AFTERNOON! THERE IS A PENTAX K-5 AND ZENITAR 50 \ 1.7 THE BLACK HOUSING, WITH M42 THREAD FITTING, WITH A JUMPER AND SWITCH A / M (WHITE WITH RED DOT) ... THE BULGAR IS LARGE BULGARIDE ... IS LARGE BULGARIDE ... ON KIEV-6 AND I DRINK AROUND THE PIN OF THE JUMPER ... THE JUMPER DOES NOT WORK ... THE POLARIZATION FILTER IS NOT REMOVABLE ... THEREFORE, THE LENSES ARE NOT SEEN ... All the rest is OK ... THERE IS WITHOUT REMAINED - LENS? PURCHASED TOGETHER WITH KIEV-42 AT THE “FIELD OF MIRACLES” IN MINSK ... THE PROFILE KIEV-19 DOESN'T REMOVE IT WELL ... AND THERE WITH THE APPEARANCE OF K-5, THE PROBLEM WITH THE ADAPTER TO K-19 \ M10 HAS BEEN DISPPOINTED? ... MAYBE WHO WILL GIVE A DRAWING OF AN ADAPTER WITH SIZES OR A LINK TO SUCH A MOUNTING MOUNT slavsovst@mail.ru... THERE IS A GREAT TURNER ... I WILL BE EXTREMELY ACKNOWLEDGE and grateful for the HELP. ONLY OFFERING CHINESE ADAPTERS ...
Alas, Arkady, you are deeply mistaken. A TV set on a crop does not bring objects closer at all than on a full frame. It gives exactly the same image, only cropped at the edges. However, such a delusion is characteristic of a huge number of amateur photographers, and not only amateurs ... Therefore, a 300mm lens will not become almost 500mm cropped, no matter how much we want it.
By itself. Most likely you misunderstood. Fixed
Try to master here is this material on the topic.
Yes Yes. The last b / w image specifically shows who is wrong.
No, Arkady, I understood correctly. But the main thing is that you also understood your error. Indeed, this morning, when I accidentally got to this site and left my comment here, wishing to put both you and your readers on the path of truth, you wrote at the beginning of this article: “In fact, when using lenses from full-frame cameras on cropped cameras we get some significant advantages: the viewing angle is reduced, making a telephoto lens from a standard lens, and a super telephoto lens from a telephoto lens. ... This is a pretty great opportunity to buy a cheap zoom telephoto for little money and, due to the crop factor, get a strong approximation. " And now this statement is no longer there. And it's done right!
You recommend that I try to overpower your other article. Thank you, I hope I succeed. Nevertheless, it seems to me that I understand something in photography. After all, I have hundreds of prestigious exhibitions all over the planet together with the leading masters of world art photography. As well as gold medals received not only in New York, London and Paris, and much, much more. ...
I wrote 'Fixed' to you in the previous comment, although the previous version of the statement was normal, because it spoke specifically about the viewing angle, and sticking to the word "approximation" is your business. Experts with valor and medals are a dime a dozen, I can praise myself too.
What a bad luck! And this time you, Arkady, are mistaken. There are not many experts with valor and medals. But a dime a dozen of those who, having learned in which direction the diaphragm and shutter speed are turning, having memorized the rule of thirds and somehow mastering the golden ratio, are already striving to write "educational" articles about what they themselves are poorly versed in. Moreover, in the space of the Internet, where even the most useless amateur photographer “knows a lot about all sciences”, it is completely useless to make such, if I may say so, to the guru, even from the best intentions. Because they don't need the truth. For them, the main thing is that everything they say is considered the truth, even if they carry sheer nonsense, which is enough in their opuses. They believed in their infallibility and stubbornly refuse to admit that someone can be more successful than them, know more and better than them.
Such fingeriness is more dangerous than a monkey with a grenade, which can explode only once. And who counts how many novice photographers their ridiculous arguments circulated on the network will create a distorted idea of how to shoot, who to shoot, what to shoot and why to shoot? However, history is as old as the world. Confucius also said that the less a person knows, the more confident his judgment.
Fig you balobol)))
If I am wrong somewhere, I will gladly correct the inaccuracies. I always do this if the reader finds an error or inaccuracy, as you have already seen. So far, I quote: "finger-like" is observed only from your side.
I disagree with you. Everyone has mistakes. But personally, I did not notice any moralizing tonality in Arkady's articles, he does not try to "put anyone on the right path", does not try to show his superiority, is always polite and tactful ... In general, he is a pure and bright person. Maybe you can someday be the same
GOD, INERT GAS! As the classic said - Art is threatened by two monsters: an artist who is not a master, and a master who is not an artist. It seems that you “specifically swim” in technical things, but you do not want to admit it to yourself. I wish you success at the “numerous international exhibitions”!
There is no boat in the world that deserves you, Captain!
Quote: The crop factor is conveniently used to recalculate the effective focal length of full-frame lenses when used on cropped cameras. To recalculate the focal length of the lens on a cropped camera, just multiply it by the crop factor.
STORE !!! )))))
Thanks. Fixed
That is the question. If we take a 200mm lens and put it on a crop, we won’t get 300. That is, in addition to the viewing angle, there is also an approximation. 50 mm is considered normal does not zoom in does not delete. 100 approximates approximately 2 times 200 to 4. If you put 200 on the crop, it will still be 4 and not 6. That is, they say the crop is closer in comparison with F.F., but if you take 24 megapixels the full frame and 6 megapixel crop making from one point the frame will receive on the crop part of the frame F.F. smaller by permission. And if you take the same cameras in resolution, then the actual image size will be larger due to the higher resolution of the matrix, and it seems to be closer, but here we should talk about the electronic approximation and not the optical one. Or am I mistaken?
“And if you take the same cameras in terms of resolution, the actual size of the image will be larger due to the higher resolution of the matrix…” - Sorry, here it is completely incomprehensible.
When viewing the actual size of the frame (that is, when opening the frame with the left mouse button - view the actual size) on a 24 megapixel crop, this will be 24 megapixels on a f.f. 24MP part of the frame is cropped, it will be about 10MP. small details are better viewed at XNUMX% magnification.
It became even more incomprehensible ...
You have mixed the concepts of physical matrix size (in mm) and matrix resolution (or image size) in megapixels. If we compare 12MP-FF and 24MP-crop, the proportions of images at the same focal length and distance to the object will be the same 1,5 times along the diagonal of the frame. And the pixels are different in size, the old ones are large, modern. - small. In addition, science does not know whether it brings 50mm closer or less (on the crop? On the FF?).
I do not know who is talking about whether a crop zooms in or removes a full frame. They say that the viewing angle is changing. You can spray in the camera (for example, DX mode in the D700 / D800), in the camera (using a DX camera instead of an FX) or on a computer. The image that you get as a result of cropping will occupy the full area of the screen or printed image. And this go-kart after sprinkling will look like a picture taken with a lens with a different angle of view. In order not to bother with recalculating angles, we are talking about an equivalent focal length, which is considered quite simple, and an experienced photographer can easily imagine what kind of view will be at one or another focal length. Nobody proves that a 50mm lens becomes a 75mm lens on a crop - just on a crop, the angle of view of a 50mm lens is approximately equal to the angle of view of a 75mm lens on a full frame.
I'm not talking about that. here it is written “The angle of view is reduced, making a telephoto from a standard lens, and a super telephoto from a telephoto lens. So using a 300mm telephoto lens we get the same angle of view as a 450mm lens on 35mm film. This is a pretty great opportunity to buy a cheap telephoto zoom for not a lot of money and, due to the crop factor, get a large EGF. ” Long-focal lenses are obviously bought not because of the viewing angle, but in order to shoot from a distance, that is, to zoom in like binoculars. Well, the lenses zoom in and if you shoot on f.f. 300 mm will approximate approximately 6 times, then on the crop it will approximate 6 times only the frame will not be all. We will get a smaller viewing angle (so who is interested in the viewing angle, everyone is interested in what kind of approximation will be), but it will be the same to zoom in. I do not accuse you of anything, but it is not correct to write like this for me - because we will not get a telephoto from a standard lens. Or I am mistaken.
Physically, the lens is the same, in this sense you are not mistaken. But no one else asserted. Simply due to the crop factor, a matrix with a 50 mm lens captures such a piece of the projected image that would correspond to the angle of view of a 75 mm lens in a full frame. Now you are looking at your screen (or a 15x20 photo), which is completely filled with an image from a full frame (wide angle of view) and is completely filled with an image to the cropped matrix (narrow angle of view). Visually, you will see that the subject of the cropped matrix is larger. The lens, as you write, zoomed in in both cases the same, and you see the object as if you were shooting with lenses with different focal lengths. I say it again - this applies to any sprinkling, even with cameras, even on a computer. You can sprinkle until the resolution and quality of the footage allows.
Wide-angle, standard, telephoto - depends on the ratio of the FR to the diagonal of the frame. Therefore, technically, we can say that a standard lens on a crop will be a telephoto lens, since the diagonal of the frame on which it operates changes. But to be guided purely by the EGF for dividing lenses into classes is sometimes much more convenient.
Just everything is relative. The whole point in the adopted frame of reference and terminology.
Victor, did you finally figure out the physical size of images with different matrices and different pixels? I cannot find an intelligible answer anywhere either. Probably, the question will be correctly formulated here: we have a monitor with a resolution of 160000 * 90000 (let's take it with a margin))) which image will take more than the area of this monitor d610 or d7100? And d5100 with 18MP or d700 with 12MP?
who has more resolution will take up more space. do not confuse image output and recording device
Thank you.
So I don’t get it? Is there a difference between a 50mm 1.8G DX lens and a 50mm 1 / 8D lens on my D90?
What is it that turns out to get a shot like on the D700 I need to shoot a portrait at 28mm?
A 50mm 1.8G DX lens does not exist. The question is difficult to quickly understand, there are many nuances described here и here.
ZoomZoom: No, at 35mm (50: 1,5), 35 / 1,8 DX will do, - the same standard on the crop as the fifty on the FF.
Moreover, to get the same depth of field on crop as from 50 / 1,8 on FF, you need a class 35 f / 1,2 lens.
Question: Take Nikon's APS-C cropped cameras (DX with K = 1.5)
If the lens was designed for a cropped camera, has the focal length specified in the instructions been recalculated for cropping, or is it still necessary to recalculate the EGF? Those. - is it always necessary to recalculate the focal length for the owner of a cropped camera, or are there exceptions?
For portraits they recommend 50 mm, so the owner of the crop needs to buy ...?
Did I understand correctly that the owner of the crop can take FF lenses for growth? Everything is clear here, here it is necessary to recalculate the focus clearly, because the lens was designed for a different frame size. With lenses originally designed for crop, the question arises.
I apologize if the questions are stupid ... I am only planning to buy the first cropped DSLR, and I would like to understand this issue.
Thank you.
Always recalculate, no exceptions. The focal length is indicated the same, regardless of whether the lens is intended for a crop or for a full frame. 50 mm for FF - 75 mm for crop. And yes, lenses released for FF are great for crop DSLRs.
“If we attach a standard (for example) 50mm lens to a cropped camera and look through the viewfinder, we see that the angle of view is narrower than with the same lens on a full frame camera. Don't worry, the lens is fine, just because the sensor of the crop camera is smaller, it only cuts out the central area of the frame, as shown in the example below. ”
Will the cropped camera cut out the center of the frame from the cropped lens image? Those. despite the fact that this cropped lens was developed for this cropped camera, will the camera take not the whole picture, but only its central part? This is somehow strange) Are cropped lenses developed with a certain margin?
If you put the cropped lens to the full frame, and then again to the crop, then yes, the same feeling will develop that the cropped camera just cuts out. As such, there is no stock, or the stock is small or is very rare, like this.
How much the matrix needs, so much will take.
You will be surprised that the lens is round and the matrix is rectangular ... Manufacturers are clearly hiding something from us.)
You will be surprised, but the matrix is rectangular and fits into the circle of the lens.
Therefore, even if the mount is suitable, this does not mean that the calculated surface of the lens will cover the entire matrix with a given resolution, if the lens for crop and the matrix ff.
Therefore, when installing for example a crop of 1.5 lenses on ff, there will be a huge vignette on the open.
This is the most-most-most common misconception that is most often discussed.
The rule is very simple: on ANY cropped camera, EGF is ALWAYS recounted for ANY lens. Without any exceptions.
It is recounted not focal, but equivalent focal, EGF. Made just for convenience. For example, whale 18-55 gives EGF 28-80. And everyone understands that this is a station wagon.
For growth or not - everyone decides for himself.
Arkady, you need to put it in faq in the first place and ban everyone who will ask about it again.
And then now the trolls will jump up and begin a holivar on a new one.
Thank you all for your answers. Everything seems to be clear, but it doesn’t fit in my head that it is necessary to recount what was indicated by the manufacturer.
It's like buying shoes on aliexpress ... size 40 is indicated, but in fact, you need to make an amendment)
As for the FAQ, the thought is good.
Recalculated for ease of comparison only. You can just forget this and remember that on the crop there is a standard 35 mm, less - shirik, more - telephoto. Manufacturers are not to blame - the focal length is an optical parameter and has nothing to do with the size of the matrix. But the resulting viewing angle already depends on the size of the matrix. EGF is what focal point a lens must have when set to full frame in order to have the same angle of view as your crop.
Vitaly N, thanks. Before that, I dealt (very long time ago) only with small-format film cameras, which are now considered FF. Apparently from there the habit of counting 50 mm as a standard lens.
Since this format is dark for years and it is the most popular, it is compared with it. 35 * 1.5 = 52.5. And it will also be more convenient for you out of habit to compare with it.
Leonid, you can take fixes for growth, especially high-aperture ones - 35, 50, even 85, 100 and 135, 200, if you shoot on the street or there is a mackerel. Zooms are just something like 70-200, 100-400, 150-600 (there are no native analogues of the latter for a crop). Standard zooms such as 24-105, 24-70 are very undesirable at the crop, they turn, rather, into portrait lenses. Widths like 16-35 and 17-40 are generally meaningless, because they are large and heavy, and they won't give a wide angle even in comparison with a whale. The only exception here, perhaps, is the fish-8-15, which behaves well on crop and gives an interesting picture due to distortions that can be varied.
Arkady, good afternoon. There is a question regarding crop:
I shoot with a Nikon D3300 camera (crop, respectively), bought a Jupiter-21m (200/4) lens - and expected that the crop factor would work, and the picture from Jupiter would be about 300 mm. However, when comparing with my old zoom 55-200 (DX version), I saw that the difference was almost invisible to the eye, and after taking test shots, I calculated the difference - the frame from Jupiter is only 1,15 times larger than Nikkor, and not 1,5. XNUMX, which is what the crop factor of the camera implies.
Regarding the viewing angle of the lenses - Nikkor (would have been) 12 degrees, Jupiter - 8, which in turn also hints that there should be a "gain".
What and where am I mistaken in my calculations and expectations?
I am also waiting for the arrival of the Tair-3s lens, how will the camera crop affect it?
PS
I like the picture from Jupiter-21m more than from my own Nikkor 55-200 DX VR. It is sharper, well, noticeably lighter.
It should be so. Any lens on which 200 mm will be written will give the same viewing angle at infinity.
The fact that 55-200 is for crop only says that he will give a vignette for crop and in full frame. But he has an honest 55-200 mm.
The rule is very simple: on ANY cropped camera, EGF is ALWAYS recounted for ANY lens. Without any exceptions.
Not focal, but equivalent focal, EGF is recounted. Made just for convenience.
"At infinity, the viewing angle is the same" ...
hmm ... there is something to think about. ))
I, too, first of all remembered the corner, and here's what I found:
Jupiter - viewing angle = 12 degrees
Nikkor - viewing angle = 8 degrees at the far end.
What already differs as if by one and a half times.
And if you turn to the review of this telezoom here on Radozhiv -
https://radojuva.com/2011/03/obzor-nikon-55-200-dx-vr-otzuvu/
then there is a paragraph in the text:
“The zoom is 3.6X, which is normal for these optics. The larger the zoom, the more complex the optical design and the more difficult it is to get good image quality. Also, keep in mind that an angle of view from 55 to 200 mm on DX cameras is equivalent to an angle of view of an 82.5-300 mm lens for full-frame cameras ”
So what do we end up with? Does the crop factor work or is everything wrong?
Then, it is possible that the 12 degrees of Jupiter on the crop turn into 8 (!!) and then we really have one angle and one scale.
Damn, I figured it out myself)
Well then, the question is removed))))
I'll add 3 kopecks - I also bought Tair-3, and his angle of view = 8 degrees. Most likely, the crop will affect it.
Crop affects any lens. On any.
Again.
The rule is very simple: on ANY cropped camera, EGF is ALWAYS recounted for ANY lens. Without any exceptions.
That is, put 55-200 on the cropped camera, you get 1.5 * EFR (55-200). Put Jupiter-21, get EGF 1.5 * 200. Put Tair-3, get EGF 1.5 * 300. Put 18-55, you get EGF 1.5 * (18-55).
The angle at Jupiter-21 is indicated for the full frame. Angle 55-200 is indicated for Nikon DX. Put Jupiter on the DX get the same angle.
There are no other options and cannot be, even if somewhere it is written differently or if you really really want to think so.
This does not contradict each other. This is the most common question for beginners. Use the rule that I described above.
Good afternoon, Arkady! Don't you think that you shouldn't have touched this topic in vain? How many people "fought" ... there are few experts in physics ...
I've already posted this picture a zillion times))
Lord, it seems that 90% of people did not go to school at all. A few pages to discuss the elementary, and also to argue.
This is how I understood the article. To shoot a frame the size of a FF on a cropped lens, you need a greater distance to the object. For example, to shoot an object with a height of 1800mm on a FF with a 50mm FF you need approximately 2,5 meters, and for a crop you need almost 4 meters (i.e. crop size x1.5), which is the focal length for a full frame of 75mm, but the photo will still be made at 50mm, not 75mm. It's like looking through binoculars while moving them away from your eyes.
Terrific!