I recently read a question asking if a 35mm DX lens on a APS-C body would produce a 35mm picture. There was a good bit of discussion / corrections regarding the crop factor vs field of view terminology being used.

Maybe a revised question that many of us may wonder is if we're trying to buy a DX lens for a DX camera body then why doesn't Nikon artificially alter the field of view so it matches the field of view on a full frame camera / lens combo? So maybe its actually a 22mm DX lens on a DX body but says 35mm on the lens to accurately describe the field of view?

That way consumers could buy the lens they really want without worrying about the math and not confuse people. You have to keep in mind that most of the people buying camera combos are not pros and do photography for a living.

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    \$\begingroup\$ Voting to close as opinion-based: we can't tell you why Nikon label lenses the way they do. The fundamental point is that it is a 22mm lens. \$\endgroup\$
    – Philip Kendall
    Commented Sep 14, 2016 at 12:26
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    \$\begingroup\$ Would you suggest that medium and large format lenses also be re-labelled? What system would be used when a different aspect ratio is used? For example, the Fujifilm GF670. It can switch between 6x6 and 6x7 format. Which format should be used to determine the equivalent focal length? \$\endgroup\$
    – osullic
    Commented Sep 14, 2016 at 13:46
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    \$\begingroup\$ What about lenses that can be used with multiple format sensors? For which format should they be labeled? \$\endgroup\$
    – Michael C
    Commented Sep 14, 2016 at 15:17
  • \$\begingroup\$ Why should NIKON name its lenses the way YOU want ? What about the rest of us real photographers ? \$\endgroup\$
    – Janardan S
    Commented Sep 15, 2016 at 14:57

2 Answers 2


A mm unit does NOT describes the field of view. A mm unit on a lens is a focal leingth. It does not matter if you project it on a "full frame" camera, dx sensor or a sheet of paper.

But field of view is an angular dimension which needs to take into account other factors like size of the sensor, shape of the sensor, distance to the sensor, plus some internals of the lens, like quality of the image arround the borders for example.

The problem is not the names used. They are right. The problem is what new photographers expect from a camera.

I understand that some photographers that used a 35 mm film camera all their lives need to understand the crop factor to preview the results compared to the other format.

For a photographer that was used to handle a medium format camera all his life, the 50mm lens as a "normal" lens, has no sense. It is arround 80mm.

So new photographers need to know its own equipment. A "normal" focal lens on some cameras is arround 30-35mm. Period. The user needs to get used to his own camera characteristics.

On pocket cameras yes, probably a manufacturer can fake the focal length equivalent, because nobody cares of the sensor size on a fixed lens on a pocket camera, on an mobil phone.

But if you have any kind of interchangable lenses, you need to know your camera and stop comparing it to a "full frame".


Probably what photographers need to stop doing is calling a 35 mm sensor, "full frame".

All cameras are full frame. All cameras make use of its own full frame.

A medium format digital camera is not called by any means humongus frame. It is a bigger frame than others.

We should stop calling a sensor "crop sensor" it is a sensor of diferent size.

A special case

On 35mm frame and reduced size frames o cameras like Nikon, Canon, Sony, there is a special case because you can interchange lenses between them. But a 50 mm lens is a 50mm lens. If you change lenses you should know what to expect. If you exchange bodies you should know what to expect.


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