Are Camera Manufacturers Misleading Us by Not Calculating Sensor Size Into Specs?

Tony Northrup, an award-winning author and well-known reviewer of camera gear, recently put out a video that takes an interesting, in-depth look at how mirrorless camera companies might be fudging the specifications of mirrorless cameras to make them seem better than they are.

The video (which is basically an expansion on this shorter, very controversial demonstration) is an extremely long watch, coming in at almost 40 minutes, but it goes into great detail regarding how Northrup believes camera manufacturers are cheating and misleading us. He claims the stats like ISO, focal length and aperture are untrue as presented due to variations in hardware — specifically the sensor size.


I won’t go into the nitty-gritty details, as that’s what the video is for, but it’s well worth noting that he specifically calls out Panasonic, Sony, Olympus and Fuji as the main perpetrators, while giving a bit of praise to Canon, Nikon and Sigma for being the honest “Good Guys.”

However, as Mirrorless Rumors admin Ale explained in an update to their original coverage of the video, Northrup may have made a few logical errors in his calculations, rendering the insights irrelevant.

According to MR (and the laws of physics), the aperture of lenses remains constant throughout sensor sizes, not relative, as Northrup asserts. Specifically, they point to this article from Admiring Light, which does a great job of explaining why this is.


This has been a heavily debated topic, especially in the mirrorless game where users were initially concerned they weren’t getting what they were promised, but things seemed to have sorted themselves out at least a little bit.

Feel free to give us your input, however, and let us know what you think of the numbers Northrup has come up with.

(via Mirrorless Rumors)

Update: Mr. Northrup was kind enough to reply to some of the more common comments in the comments section, but since his reply has gotten buried among the almost 100 comments this post has as of this update, we’re reprinting it here in full.

The guy in the video here, let me address some common comments:

* I know it’s long, but please do watch the entire video before accusing me of being wrong.

* With that said, I do have a few minor corrections that I made with YouTube annotations (which might not be displayed on all clients): 18mm should have been 16mm on one of the slides (and there was another typo that I forget), and Canon, Nikon, & Fuji have also abused crop factor… but not quite as blatantly. Oh, I use ‘bokeh’ very casually, and I’m aware of the technical definition, but you know what I meant, and that’s what counts. To the best of my knowledge, those are my only mistakes, and I’ve done my best to verify hundreds of comments.

* If you read the Admiring Light article, and watch my entire video, you’ll see that we totally agree with each other… to such an extent that I feel like I have to say I didn’t see the Admiring Light article before making my video. I did my own primary research and came to the same conclusions. Note that the article goes into detail about how sensor technologies differ, and my video is a bit more theoretical, but I specifically say, “given similar sensor technology” to address the concern. If you think this article disagrees with my video in a fundamental way, than you probably misunderstood one of us.

* The Mirrorless Rumors guy says that if you get the same brightness photo using the same settings on two cameras with different sized sensors, than it proves I’m wrong. I think this just proves that he didn’t watch my video, because I actually show the results of that exact test multiple times (and of course the brightness is the same). The fact that those settings produce images with the same brightness is the basis for my entire argument.

* I’m not discussing per-pixel noise, I’m discussing per-image noise. An A7R and A7S both have the same per-image noise, as will film or your eye. Different pixel densities will yield different per-pixel noise, yes, but that’s simply not the topic of the video. At several people’s request, I am planning a video to discuss the merits of pixel density. It’s an interesting subject; it’s just a different subject.

* The “35mm camera makers are cheating us because of something with medium format” argument: Nobody labels non-medium format lenses with medium-format equivalents. My math holds true for medium format systems, which have a crop factor < 1.

I'll check back and I'm happy to answer any questions! Thanks for watching!

  • MIchael Casimir

    What captures more rain? A bucket 5 inches or 20 inches in diameter? The larger the sensor the more light hits the sensor. Two sensors at 18 megapixels, one FF and one cropped, they both have the same number of pixels but the FF has larger pixels where each pixel gets more light therefore each pixel can be less sensitive to capture the same amount of light. Have you actually watched the entire video?

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  • Leif Sikorski

    In practice they often don’t have the same amount of pixels and what he’s also missing are the sensor technologies. If this number game would be right all FF sensors would have about the same quality at same pixel density which is just untrue. Just compare Canon and Nikon/Sony Fullframe sensors for example and you’ll see a huge difference. In practice it’s way more than just the size that matters.

  • kpoz

    The British pronunciation predates the American pronunciation, and so it is we (as Americans) who pronounce the word “Jaguar” incorrectly.

    Also, ISO is properly pronounced “eye-so,” and not “I-S-O.”

  • Another Cynical Bloke

    Just pretend the f is a t like all photographers do! Whilst it not exact it’s good enough without over complicating things with BS that no one but geeks care about.

  • Another Cynical Bloke

    What Tony doesn’t get as he isn’t a photographer is that we essentially use the f stop as a t stop so we don’t care if it isn’t a scientifically accurate number based in the lens diameter blah blah. There really is better things to make a video about. It’s not a lie they are just keeping it simple and sticking to what people know. Who here would want a lens labelled f16 to f128

  • imajez

    What a silly thing to say. You should save being offended for say people being raped and tortured, not for some normal everyday linguistic borrowing. English is a Germanic language full of French words thanks to the Normans and with a large amount of other language’s words too from when we went around the world subjugating other countries. e.g bungalow from India
    Try not using a foreign word in English and you won’t get very far as English itself is actually a foreign language in Britain, not being Brittonic/Brythonic.

    Or should we ask the Japanese back for the words they borrow too?

  • imajez

    So how should Jaguar be pronounced then?
    Jag-war, jag-wer, jag-u-er, jag-u-wer, jag-u-are?
    All are regional accent variations of the word.

  • Lukas Prochazka

    just dont used that example thats a bad example… I think…the thing that “catches” the light is pixels not senzor itself…its more light as a quantitum not as brightness…more light come bot there is that more area to cover…I dont know…

  • imajez

    “You get the same brightness from an f2.8 lens no matter what the format in a given area. ”

    Not actually true in one sense because f stops are theoretical, not actual values. If you want consistency you need to use t-stops, as in ‘t’ for actual transmission.
    If I use f2.8 on my Canon 16-25 f2.8L lens then it’s a markedly different exposure to a prime with fewer elements at f2.8. Which can be a complete nightmare when shooting video and why cine lenses have t-stops

    And this is where ALL manufacturers tell tall tales because they use f-stops not t-stops.

  • imajez

    You’ll have to spell it wrong then. ;-)

  • mongo

    Imagine you have 2 cameras with the same sensor technology and pixel density but with different sensor sizes, let’s say full frame and aps-c. And than you take a 50mm lens and take a picture at the same aperture. You will get the same picture except for one difference. Field of view! If you take the picture taken with the full frame camera and crop it to the same field of view there won’t be ANY difference. That’s it.

    So in order to get a picture with the same FOV with the crop camera you need a wider lens. A wider lens has more depth of field though… So in order to compensate for that (to get a more shallow DOF) you would need a larger aperture. Most of the small sensor cameras don’t have larger apertures than full frame cameras. That’s where the myth “smaller sensors have more DOF” comes from. So yes, manufactorers are wrong when they claim 12-35mm f2,8 lens is an equivalent to a 24-70mm f2,8 lens because they will produce different results. But would also be wrong to say it is a 24-70mm f5,6 (or whatever) equivalent because the aperture does not refer to the DOF a lens produces but to light gathering abilities. (i know he discussed this also but it’s just not true when you compare sensors with the same pixel density)

  • mongo

    Imagine you have 2 cameras with the same sensor technology and pixel density but with different sensor sizes, let’s say full frame and aps-c. And than you take a 50mm lens and take a picture at the same aperture. You will get the same picture except for one difference. Field of view! If you take the picture taken with the full frame camera and crop it to the same field of view there won’t be ANY difference. That’s it.

    So in order to get a picture with the same FOV with the crop camera you need a wider lens. A wider lens has more depth of field though… So in order to compensate for that (to get a more shallow DOF) you would need a larger aperture. Most of the small sensor cameras don’t have larger apertures than full frame cameras. That’s where the myth “smaller sensors have more DOF” comes from. So yes, manufactorers are wrong when they claim 12-35mm f2,8 lens is an equivalent to a 24-70mm f2,8 lens because they will produce different results. But would also be wrong to say it is a 24-70mm f5,6 (or whatever) equivalent because the aperture does not refer to the DOF a lens produces but to light gathering abilities.

  • Adam Klíma

    Thank you Tony you did a great explanation of how do the things work. But based on the discussion physics and math should be taught more at schools, because people don’t believe they work. ;-)

  • Phil Angers

    He should`ve stated that pixel size was out of the question, but really guys? He`s trying to make people understand the theory of it, and when some people seem to think they know it all, this presentation is just refreshing you on very basic simple theories. I really liked his analogy, about the bucket of water catching rain. though he should of mentioned that the circumference of the bucket is what makes the difference here… The circumference of a bucket catching rain will affect how much water it will have in the end. Small circumference buckets will catch less water as the rain falling is fairly evenly dispersed… The more light you have for your image the cleaner it will be (If someone argues this, i wouldn`t even know what to say, that`s the basics) , with a larger bucket you will obviously be able to capture more water. he`s going down to the theory of it, not the technology of the sensor. the technology comes after you know the theory. We should be smarter than to argue this fact, we are all very knowledgeable, but some are replacing basic theories with advancements in technology and comparing sensors… which i agree is a valid argument, BUT its not what he is trying to say. I think if he mentioned that the size of the photosites are out the question for the theory he was explaining, everybody probably would have said nothing. but my overall reaction to his presentation was ‘uh ok, yes that’s how a camera works.’ And it seems like his presentation is in our subconscious OR some of us have forgotten physics and math they learnt in high school. our angry human like reaction is to say ‘NO TAKE THIS COOL TECHNOLOGY INTO CONSIDERATION!’

  • MIchael Casimir

    Your point was clearly stated in the video. The author asked to dismiss the differences in sensor technologies. If all sensors were made equal, a larger sensor would gather more light than a smaller sensor. If both sensors receive the same amount of light, the images should be identical..

  • GeniusUnleashed

    I’ve been a working photographer for 20 years and worked with hundreds of others on set and have no idea what you’re talking about. Good luck with your career.

  • MIchael Casimir

    Its actually the sensor size, take a 10 square inch container (represents a 10 square inch sensor with one pixel) vs a 20 square inch container with 18 small containers fitted inside (represents a 20 square inch sensor with 18 pixels). and place them outside to collect rain. Which container would gather more rainfall? The larger container / sensor will always gather more.

  • Phil Angers

    I read this over and yeah, I see where everyone is coming from. The pixel size really has to be taken into consideration. The pixel alone is the bucket of water analogy he uses. I had to step away from it all and look back to it.

    After watching this over, Tony really took the long way around of explaining that a 2.8 lens ACTS like a 5.6 in DOF but not in capturing light. As the singular size of the photosites are responsible capturing the light, not the size of all the photosites put together.


  • Lukas Prochazka

    I mean I get it….I imagine it as a pixel is one bucket so 18 million buckets gather more than 16 million buckets but when you compare it…each of the bucket has same amout of water but at total has more water….lol this is like some Platon’s theory about cave idols :D ….I give up on this and I will read some books about it

  • Allen

    Tony, I got around to watching your video, but I can’t get past one particular point. You say that smaller sensors gather less light. At 9:38 – “The bigger sensor gets a cleaner image because it’s able to gather more light.” This is just blatantly not true. It’s not how optical physics works.

    I can easily prove this to you with film. All Kodak, Fuji, Ilford, etc have the same emulsion for 35mm cameras as they do for MF and Large format cameras. A 400 ISO film is the exact same chemical construction for each format. If you were right, you would have to compensate for larger negative size when you meter, but you don’t.

    The reason you’re getting more noise on smaller sensors is because there are more pixels per square inch on smaller chips than on larger chips (being that each sensor has the same number of pixels), making each pixel smaller. Larger pixels = better signal to noise ratio.

    You try to hide behind saying that “this is a point of confusion.” It’s not. larger pixels gather more light, not larger sensors.

  • Allen

    “A full frame sensor collects about 4x more light at f/2 than a m4/3 sensor does.”

    Only if both sensors have the same total number of pixels. If they have the same pixel size, then the light per pixel, thus total signal/noise ratio, would be the same.

    It’s about pixel size, not sensor size.

  • Gery

    Mr. Northrup,
    You said that the manufacturers are misleading with aperture value. That is correct in the terms of Depth of Field. But you saw it yourself when you compared the 100 mm between FF vs MFT. If I follow your theory, when you balance the aperture, you balance the incoming light. So if on a MFT Sensor you open for 2.8 aperture, you just need a 5.6 opening on a FF sensor to get the same amount of light, which you did. If the equation is already balanced, you don’t have to change the ISO then, since you already have the same amount of light. But the fact is you need to crank up the ISO on the FF to increase the FF sensor’s light sensitivity.
    So even if you have a different DOF with different sensor size on the same noted aperture, light received per area exposed is still the same.

    In another way around, if all the manufacturer change the noted aperture, say a 1.8 on MFT becomes 3.6, there will be a new confusion on light sensitivity. As far as I know, people are more interested in light sensitivity then bokeh.

    Also, I might be mistaken so correct me if I’m wrong, but Canikon have been making crop factor APS-C bodies for a long time, and I think the stated aperture on the lenses are actually crop factor aperture.

    However, I should thank you for your crop factor – aperture – ISO chart, that is something I’ve been looking for. Thank you.

  • Gery

    That is quite an interesting subject of discussion. In terms of well capacity you are right. But do search for Eric Fossum, dpreview using your google search. Mr. Fossum is the inventor of the beloved CMOS sensor, and in there you will find a discussion when someone asks him that question, and you will be surprised by his answer.

  • Allen

    I read through the dpreview thread you mentioned but I couldn’t find the specific question that we’re asking.

    It’s my understanding that sensors have a fixed sensitivity, like ISO 200 (a guess of course. Every camera is different), and you have to amplify the signal via software to get other ISOs.

    It’s possible that MFT and other cropped camera manufacturers are amplifying their smaller sensored cameras more than large ones, but it’s not because larger sensors collect more light.

  • Gery

    I should state here that I get Mr. Northrup’s idea; if a manufacturer states the equivalent in one thing, they should do it with other variables also.

    I noticed that a lot of people commenting are not talking the same language as Mr. Northrup. And I think that is because he might got into a slight confusion in his calculations. When he gave the equation of focal length to aperture, he uses the EQUIVALENT focal length, not the ACTUAL. The bottom part of the equation, however, (I forgot, is it filter size, or iris?) he used the ACTUAL size, not the EQUIVALENT. There is a confusion there.

  • Scott M.

    Excellent video!
    Thank you for making sense on those tiny lenses that seem to be as good as the FF size but have vastly different depth of field. Depth of field matters. I understand better than before. Next video should be on pixel pitch and how that affects diffraction. :)

  • MIchael Casimir

    lol… Just get out there and keep shooting…

  • Woody ONeal

    Well said. You have it correct. Which is why the whole “multiple your ISO times the crop factor squared” math is just nonsense. I find it a bit reckless to put out information that will only confuse, not educate.

  • J. Dennis Thomas

    “A wider lens has more depth of field”.

    Completely untrue.

    Although focal length seems to be a factor in depth of field, technically
    speaking, it is not a factor. Telephoto lenses appear to have a shallower depth of field due to a higher magnification factor, but if the subject stays the same size in the frame, the depth of field is consistent at any given aperture, regardless of the focal length.

    What does change is the distribution of the zone of acceptable sharpness. At shorter focal lengths, most of the zone is behind the focal point or subject. At longer focal lengths, the zone of acceptable sharpness falls more in front of the focal point. This means that, although mathematically the depth of field is consistent at all focal lengths, the distribution of the zone of sharpness is different.

    Wide-angle lenses have a more gradual fall-off of sharpness, which makes the depth of field appear deeper. Telephoto lenses appear to have a shallower depth of field because the zone of sharpness falls off more quickly behind the focal point.

  • Joey Miller

    So are you saying if I shoot an image on a D800 set to use the full frame, then crop it to DX in post, it’ll be better than cropping to DX in camera?

  • Joey Miller

    Ok, let me see if I can sum this up. Basically this whole 40min video and ensuing discussion is all meant to say something we all already basically knew, or at least I hope we all knew (obviously some people didn’t know this): smaller sensors are noisier by design. In a similar way, I suppose, smaller film formats are grainier, by design (please correct me if I’m wrong). There’s not really any way around it, because physics. You’ve just gone out of your way to quantify it for everyone and point the finger and manufacturers when really, they could care less. I guess my only quibble is that your video isn’t very clear to a lot of people, and that can be a big problem. The whole equivalency thing is what seems to be riling people up, myself included at first. The video is also a little smug and a tiny bit incendiary, which certainly drives page views, if nothing else. It was a mole hill, now it’s a mountain. Good job marketing. Rather genius, actually.

  • Joey Miller

    I think different people are assuming different things about choosing equivalent focal lengths. You’re not recalculating the focal length. That remains the same. That’s absolute. A 35mm lens is a 35mm lens, no matter what sensor size you have behind it. 99 times out of a 100 what you’re wanting to calculate is field of view equivalence. Lens manufacturers have apparently decided this is the main determining factor when making a lens selection, which for the most part is true and has been well established. Panasonic’s 12-35mm f/2.8 is just that. But it gives a somewhat equivalent field of view as a 24-70 f/2.8 on a 5D3. Depth of field will be completely different, and noise level will be completely different, but those considerations are part of choosing a specific sensor size, not necessarily a focal length.

    If you want an across the board equivalence, then yes, you have to recalculate every aspect of the lens. I’m always very careful to tell people crop sensor cameras don’t make their lenses longer, they just narrow the field of view. It’s a difficult concept to grasp because, well, semantics. I usually try to point out depth of field for a given aperture will also be different, but at that point their eyes glaze over and they zone out.

  • GeniusUnleashed

    “If you want an across the board equivalence, then yes, you have to recalculate every aspect of the lens.” That’s all he’s saying. He just did a poor job of it, which would make this statement of yours wrong, because you forgot to recalculate the f-stop to 5.6.

    “Panasonic’s 12-35mm f/2.8 is just that. But it gives a somewhat equivalent field of view as a 24-70 f/2.8 on a 5D3.”

  • Joey Miller

    My statement isn’t wrong. Aperture has nothing to do with field of view. I clearly stated “equivalent field of view”. Perhaps you would prefer I call it angle of view?

  • GeniusUnleashed

    You kind of half to since bokeh is one of the most important things to take into effect as a professional photographer/cinematographer.

  • GeniusUnleashed

    He’s not saying they change, he’s saying the effects change and he wants manufacturers to pass that information along to the customer. You’ll no longer have the same bokeh effect when downsizing the sensor and that’s why most people purchase fast lenses.

  • Jonathan Kim

    Could not understand the video at first but after looking at the comments I finally get it. Tony you da man!

  • Tiktian C

    This video is long, it’s like an infomercial, drilling it into your head. (stopped watching at 15minutes, got tired of it)

    don’t see what’s wrong with older standards, if what your doing is measuring exposure I don’t see the difference between film and digital. if you compare the same speed emulsion between various size film (or the aperture or focal length) you get more or less similar effects. If you use the same speed film on smaller formats it has more apparent grain than and equivalent speed emulsion on a larger format, same with ‘crop factor’ and depth of field.

    @SAR_Admin:disqus I think it is more he doesn’t get how light works rather than optics

    also Bou-quet is killing me.

    I would love it (probably not because it would make it super confusing) if they started engraving 48mm f/0.7 on my large format aerial lenses :)

    If you had individual values for total light captures, light per unit area (iso), focal length to iris size (aperture), depth of field measure of some sort?, field of view (this is would be useful, but as a addition not replacement) , I think it would be somewhat useful for direct comparison, but then again… meh.

    -I’ve watched a bit more (let it play in the background) and it’s true no one shoots wildlife at 600mm f/16 because of not enough light, but your conversion factor only applies to depth of field, the point is that the light gathering ability is the same, so it’s like 600mm field of view with f/whatever the lense was, and a depth of field of a 600mm f/16.

    iso,aperture,exposure time are for consistent exposure calculation, some values correlate to some things like dof and noise/grain, but they were not designed for equal comparison of those, they were designed for equal comparison of exposure.

  • Gery

    Ok, Mr. Northrup, you should explain your statement regarding Panasonic FZ200 and Olympus Stylus 1. You mentioned that since ther aperture is not really 2.8 but significantly smaller, you can’t use these camera for sports, wildlife etc. If you are talking about light received, you are really wrong and misguiding people in your guide, and for your own good you need to change that statement. Unless of course, you only care about bokeh.

    Even a 1/2.3″ sensor superzoom camera can still produce decent pictures on their longest end. And really, you should admit you were confused between equivalent and actual focal length in calculating the aperture.

  • Gery

    He is asserting that superzoom prosumer are not worthy for him, so he never bother to handle it. I’m still waiting for him to man up and swallow his pride and admits his fault tho. With a bit more correction, it would be good for people to have a comprehensive (but not faulty) buying guide. But now, he is showing to the world how to write a book without proper research and study.

  • Tiktian C

    Technical nitpick,

    Smaller film formats result in grainier prints because you need to enlarge (magnify) them for for the same print size as a larger film format. The grain is technically exactly the same, it’s a piece of plastic (or paper) with the same coating cut into different sizes.

    so it would more accurately be smaller film formats appear more grainy by design.

  • Tiktian C

    Consistency. The point his video is about, is missing in his video.

  • Albert

    I think Tony Northrup is RIGHT and that Crop factor is applied to PRICES!

    Take for example the Olympus 75 mm f/1.8 it costs twice (or more) than an 85 mm f/1.8 from Canon/Nikon.


    Because Olympus is taking in consideration Crop factor, so they are selling is as 150 mm (equivalent) lens. NO, this is a 75 mm and should be priced for what it is!

    They are CHEATING, like Tony says!

    Field of view equivalence does not increase production costs. MFT lenses even uses less glass (smaller sensor = smaller lens = less glass) so less raw materials needed.

    So WHY the 75 mm is so expensive?

    Roger Cicala of LensRentals told us that is well built (

    Ok but I think he was misled by Crop factor too. In fact he compared the 75 mm to Canon 135 L, Nikon 135 DC, Sony 135 f/1.8.

    Roger, you are an experienced guy, this is not physically a 135 mm (or 150mm), this is a 75 mm and should be priced for what it is. It is well built, ok let’s price it 100$ more than other than 85 mm lenses available from Canon/Nikon etc.

    Am I WRONG?

  • Aaron W

    Except the only way to get the same picture is to use the same lens on the same sensor. An MFT sensor with a 25mm f/2 lens will NOT produce the same picture as a full-frame sensor with a 50mm f/2 lens. Your foreground elements might be equal in size, but your background elements will be markedly different. The only way to get the same picture would be to put the 25mm lens on the FF camera, then crop it down by 50%.

  • Oskarkar

    You are perfectly right. That’s the point of that guy too.

  • Lukas Prochazka

    true…but I love photography and knowing more and more about photography gives me not just better understaning of photos and how better shoot but also it’s fun and I enjoy it even if I can’t use it in practice :)

  • Gary

    I’ve read this entire thread and it seems that no one has mentioned the reason tony is EXACTLY CORRECT re: DoF and f-stop. He clearly shows right at the beginning of the video that in order to get a visually equivalent frame on a sensor that is smaller than FF, you will need to STEP BACK…..i.e. lengthen your focusing distance. Doing so INCREASES your DoF!! That is precisely why f/2 on a MFT sized sensor will NOT yield as shallow a DoF as on a FF sensor when you are trying to get the SAME COMPOSITION! That really is the ENTIRE point of the video re: DoF and f-stop. C’mon folks, this isn’t all that difficult. :)