...
Why can’t the cropped sensor and equivalent focal length discussion just go away.
...

It's because of the deceptive and misleading advertising by manufacturers who suggest that there would be a magnifying effect when there is none on account of the fact that you can blow up an APS-C image to the same width and height as a full-frame image; and what they don't tell you is that it's going to be at lower resolution. What they don't mention is that at equal resolution (which is dots-per-unit of horizontal measurement, not total number of dots), the APS-C image is going to be smaller in width and height than that of a full-frame image, in proportion to the relative sizes of the sensors. It's a marketing trick designed and intended to confuse and mislead, and so it does, as we have seen here.

Here's an analogy: they advertise memory cards in terms of megabytes and multiples of megabytes. But "megabyte" is a computer term and represents a binary number (2 to the 100'th power). In order to misrepresent the capacity of the cards, they talk of "megabytes" or "gigabytes" (one byte being two to the fourth power, one kilobyte being 1024 or two to the tenth, etc.) but what they're really selling is defined by decimal numbers - and they round UP to the nearest power of two to suggest that there are more bytes on the card than there really are. Marketing tricks and deceptive advertising.

No surprise that it fools people. But it doesn't make sense to me - do they really think that people won't buy the products unless they be lied to about what they're getting?

[pepperberry farm]

If you have a K3 and do not own a K1, "equivalence" is not actually going to help you. Any 200 mm lens will have the same magnification and FOV on your K3, irrespective of the format it was specifically designed for.

^^^ this^^^

Warning. THIS IS A RANT

Why can’t the cropped sensor and equivalent focal length discussion just go away.

We have been at this for years and years now, and the discussion just does not die.

To be very clear, there are really only 3 properties of a lens that matter, focal length, which defines the magnification ratio of the lens, aperture which determines how big the lens is in diameter, and the image circle that defines how big in diameter the projected image is on the focal plane.

The only difference between any format of lens is the image circle. APSC lenses have an image circle that covers the 16 x 24 mm sensor full frame lenses have an image circle that covers 24 x 36mm sensor medium format lenses have even bigger image circles.

So when you have an APSC lens the only thing that is different than full frame is the absolute dimensions of the image before vignetting takes place

^^^ and this^^^


there is no equivalence - if you have a 300mm lens, that's it; if you want a longer focal length, you'll have to buy a longer focal length...

[Sandy Hancock]

there is no equivalence - if you have a 300mm lens, that's it; if you want a longer focal length, you'll have to buy a longer focal length...

....if you only shoot one format.

Adapt a K-mount lens onto a Q system body and suddenly equivalence (angle of view, not focal length) becomes interesting.

But I understand what you mean

[pepperberry farm]

....if you only shoot one format.

Adapt a K-mount lens onto a Q system body and suddenly equivalence (angle of view, not focal length) becomes interesting.

But I understand what you mean

EXACTLY!!!


and once you have the APS-C and FF both in hand, put the same lens on both frames... you'll see that the term 'equivalence' is soooo much marketing bs.....

[ehrwien]

If you have a K3 and do not own a K1, "equivalence" is not actually going to help you.

Except when reading guides on this or that field of photography when there are recommendations for focal lengths, say 50mm being called a "normal" lens, 85 or 105 being called portrait focal lengths, everything under 24mm "ultra-wide" or the like... those names have been established in the analog age of photography and refer to the field of view you get when using lenses of those focal lengths on a full frame camera. So when you do not use a full frame camera, you have to convert those numbers with your crop factor to get the desired properties. Of course the main property that changes when using the same lens on two cameras with differently sized sensors is the distance to the subject if you want the same framing without cropping digitally, and with it the perspective.

Imho the main issue responsible for the arising confusion is the use of focal length instead of field of view, but you can't use field of view to differentiate lenses of different focal lengths because you can use the same lens on cameras with different sensor sizes...
And that we view images with image viewers that fit the image to the screen, regardless of pixel size of the image (which is, most of the time, greater for full frame cameras than crop cameras of the same generation), without much consideration for the resulting zoom factor so that the image fits the screen.

So I guess we should accept that this is a concept that can be very confusing for people new to photography and just spread the knowledge amongst each others.

[pschlute]

Except when reading guides on this or that field of photography when there are recommendations for focal lengths, say 50mm being called a "normal" lens, 85 or 105 being called portrait focal lengths, everything under 24mm "ultra-wide" or the like... those names have been established in the analog age of photography and refer to the field of view you get when using lenses of those focal lengths on a full frame camera. So when you do not use a full frame camera, you have to convert those numbers with your crop factor to get the desired properties. Of course the main property that changes when using the same lens on two cameras with differently sized sensors is the distance to the subject if you want the same framing without cropping digitally, and with it the perspective.

A valid point. Although i suspect for the vast majority, the terms "ultra-wide" "normal" or "portrait" mean nothing until you have looked through a viewfinder with said lens fixed to the camera.

[clickclick]

Of course the main property that changes when using the same lens on two cameras with differently sized sensors is the distance to the subject if you want the same framing without cropping digitally, and with it the perspective.

And varying this distance as you try to keep the same field of view gets into that whole depth of field thing, which drives me nuts. I hate seeing claims like DOF is thinner on full frame. DOF for a given focal length at a given aperture at a given distance to the subject is going to be the same regardless of the size of the image circle you are grabbing - crop vs. full frame. It's when you start moving the camera to keep the FOV equivalent that will change this perception, so I think statements like this (full frame thinner DOF) are highly misleading and cause confusion.

[DWS1]

One of the reasons this discussion won't go away is there are new, budding photographers entering the market everyday looking for an upgrade from their phone or old fixed lens camera. They have never shot with a 35mm film ICL camera, and have no understanding of the relationship of FOV to focal length to sensor/film size. The 35mm equivalent focal length of lens on any particular camera (an entry in the EXIF data of each image) provides a standardized frame of reference for comparing different camera/lens systems and combinations. Also, the advertising and marketing has falsely implied one will increase the focal length lens when using it on a crop sensor camera. That is an easier concept to explain and grasp than explaining one's FOV will be as if one cropped the center half out of a 35mm image.

[Kunzite]

Sigh... this, again?
No, "equivalence" is not easier: it makes things more complicated because it's an invalid abstraction. Thus, people wondering if the same focal length, on the same camera (no crop) would have different angles of view. This is made worse because "equivalence" is forced on those "new, budding photographers" who have no 35mm experience and can't relate to it at all.

[UncleVanya]

Sigh... this, again?
No, "equivalence" is not easier: it makes things more complicated because it's an invalid abstraction. Thus, people wondering if the same focal length, on the same camera (no crop) would have different angles of view. This is made worse because "equivalence" is forced on those "new, budding photographers" who have no 35mm experience and can't relate to it at all.

I strongly disagree. I shoot a lot of formats and it helps me get close to what I need when planning. I think the main issue is that apsc and full frame often share the same mount and the crop factor is fairly modest. Shoot with a Q or any small sensor and then medium format or large format the same day. It gets a little confusing to recall all the various needs of each platform without a little heuristic to keep yourself on track. For tge record new photographers get confused but so do old ones. My dad with 30+ YEARS in the industry still gets confused by it. It clicks and helps some. It confuses others.

[Kunzite]

I strongly disagree.

That's fine, but I'm right.
Confusion? It's what "equivalence" does. It doesn't have any purpose, other than to confuse people into one company or another's marketing ploy

[monochrome]

Except when reading guides on this or that field of photography when there are recommendations for focal lengths, say 50mm being called a "normal" lens, 85 or 105 being called portrait focal lengths, everything under 24mm "ultra-wide" or the like... those names have been established in the analog age of photography and refer to the field of view you get when using lenses of those focal lengths on a full frame camera. So when you do not use a full frame camera, you have to convert those numbers with your crop factor to get the desired properties. Of course the main property that changes when using the same lens on two cameras with differently sized sensors is the distance to the subject if you want the same framing without cropping digitally, and with it the perspective.

Imho the main issue responsible for the arising confusion is the use of focal length instead of field of view, but you can't use field of view to differentiate lenses of different focal lengths because you can use the same lens on cameras with different sensor sizes...
And that we view images with image viewers that fit the image to the screen, regardless of pixel size of the image (which is, most of the time, greater for full frame cameras than crop cameras of the same generation), without much consideration for the resulting zoom factor so that the image fits the screen.

So I guess we should accept that this is a concept that can be very confusing for people new to photography and just spread the knowledge amongst each others.

Building an entire cultural paradigm around the Kodak-centric 24x36 sensor lacks diversity of approach to capturing images. We should stop referring to 50mm as a ‘normal’ lens. Every time we say ‘Normal’ anything oriented toward, designed for or derived from something alternative to 24x36 points out the difference of its Otherness. When we blithely do that we are making a micro-aggression against all different sized sensors, especially when we use the term Full Frame! Is every alternative frame something other than Full? Pictures are pictures; Frame size is a continuum and all pictures have characteristics of many Frames sizes in them.

From the outside, cameras may look similar, but that doesn’t mean they’re all the same on the inside - we shouldn’t assume!! Assuming is just evidence of our historical prejudice against and habitual, subtle disparagement of alternative sensor sizes. 24x36 must not be assumed superior. There are beautiful pictures inside APSc and M43 and even MF and LF cameras. We need more diversity View in our image culture.

Ban The Normal!! Refer to every lens by its Focal Length. Understand and accept that different sensors have different views from the inside when seeing what is Objectively on the outside. There is no Objective reality. Your Objective may be constant for you, but another camera’s view through that Objective is just as valid to him as yours is to you.

When you think about it, in the modern world 24x36 isn’t even a majority of the sensors inside cameras. Why should 50mm FF be the Normal against which everything else is, Objectively, not a normal?

[luftfluss]

Building an entire cultural paradigm around the Kodak-centric 24x36 sensor lacks diversity of approach to capturing images. We should stop referring to 50mm as a ‘normal’ lens. Every time we say ‘Normal’ anything oriented toward, designed for or derived from something alternative to 24x36 points out the difference of its Otherness. When we blithely do that we are making a micro-aggression against all different sized sensors, especially when we use the term Full Frame! Is every alternative frame something other than Full? Pictures are pictures; Frame size is a continuum and all pictures have characteristics of many Frames sizes in them.

From the outside, cameras may look similar, but that doesn’t mean they’re all the same on the inside - we shouldn’t assume!! Assuming is just evidence of our historical prejudice against and habitual, subtle disparagement of alternative sensor sizes. 24x36 must not be assumed superior. There are beautiful pictures inside APSc and M43 and even MF and LF cameras. We need more diversity View in our image culture.

Ban The Normal!! Refer to every lens by its Focal Length. Understand and accept that different sensors have different views from the inside when seeing what is Objectively on the outside. There is no Objective reality. Your Objective may be constant for you, but another camera’s view through that Objective is just as valid to him as yours is to you.

When you think about it, in the modern world 24x36 isn’t even a majority of the sensors inside cameras. Why should 50mm FF be the Normal against which everything else is, Objectively, not a normal?

This is quite brilliant on several levels. Both my idealistic and cynical aspects appreciate this post. You win the Internet for the day.

[swanlefitte]

....if you only shoot one format.

Adapt a K-mount lens onto a Q system body and suddenly equivalence (angle of view, not focal length) becomes interesting.

But I understand what you mean

Still if you use the lens on a Q and K3 the traditional 35mm film equivalence is cumbersome at best.
The sensor to lens ratio works regardless. A 200mm on apsc's roughly 35mm sensor is about 5.7x telephoto. On a Q's roughly 7.7mm sensor It's about a 26x telephoto. Doesn't matter what a 5.7x or 26x is on full frame. It's much more intuitive.

[swanlefitte]

It's because of the deceptive and misleading advertising by manufacturers Marketing tricks and deceptive advertising.

Case in point with the sony rx100vi
Published as "ZEISS® Vario-Sonnar T* 24–200 mm2 F2.8–4.5 high-resolution zoom lens"
Yet the full frame equivalent is around f8-f16 (not doing the math) it's a half truth conflating the ff equivalence they want without adjustments to the f stop they don't want to make you think you get something you don't.
Scroll past the marketing and you get full specs and it is called as is printed on the lens, 9-72mm. And says it's 8x zoom.
RX100 VI Premium Compact Camera | Super-Fast AF, 4K HLG Video | Sony US