camerapapi Loc: Miami, Fl.

As far as I am concerned there is no 50mm DX lens. Yes the field of view on a DX body is 75mm because of the so called "digital factor." It is not labeled 75mm simply because it is not. 75mm is only the view it offers with a DX body.
As I just said, there is no such a thing as a 50mm DX lens. If you use a 35mm lens with the DX body then your field of view will be 52mm.

Skiextreme2 Loc: Northwest MA

May not make any difference but when crop sensor cameras were introduced, one of the big "new" things also introduced, was the wide screen TV. In Nikons case (and most other 35mm camera manufacturers), they already had the FX version, so they only had to R&D only the DX version. You may also notice that TVs and monitors are getting wider and wider but not taller (ultrawide). It's probably just a matter of giving people what they want. Full frame will be around for a while at least at the pro and semi-pro camera levels.

I prefer full frame images and I preferred full frame TV but even if I had a "full frame" TV, most all newer TV shows and movies are wide and ultrawide screen, so I'm out of luck as far as TV and monitors go.

BebuLamar

I didn't say that the DX cameras don't take good pictures. I don't use them just to avoid the crop factor. When I bought my lenses for my 35mm cameras each lens has its own purpose and when mounting on a DX camera it no longer work for the same purpose. Also I use film along side with digital I don't want the camera changes my FOV when I switch camera. Also I don't want the transition from DX to FX. Staying with FX make it simple and save the money.

dcampbell52 Loc: Clearwater Fl

I have 2 DX cameras and an FX. I love the DX for long to Telephoto shots and the FX for wide to normal. Also, the FX seems to have better depth of field (to me). My DX cameras are very good (D7000 and D7100) and my FX is a D610. When I'm out shooting, I carry the D610 with a 50mm or wider and have my 80-400mm Nikkor on the D7100.

Silverman Loc: Michigan

With any Nikon DX Camera & DX lens you must consider the "Crop-Factor" of 1.5, so, your Nikon DX 50mm lens on a DX Camera will have a actual "Field of View" of a 75mm lens.
Although I am not sure exactly, if any, the effect a FX 50mm lens on a "Crop Sensor" Camera will present.
Really, I think it is the Camera's "Sensor Size" which will determine the "Crop-Sensor" effect. So, I am guessing, but your 50mm FX lens might have the same "Crop-sensor" effect on any "Crop-sensor" DX Camera.
Do research, ask Nikon.

You will have other more knowledgeable Photographers here at UHH provide you a more accurate answer.

BebuLamar

I must point out that there is no such thing as a 75mm field of view. You can say the field of view of a 75mm on an FX camera but without mentioning the sensor size the 75mm lens doesn't have a field of view attached to it. There is though an angle of coverage for the lens. Hypothetically you can say the FX 50mm lens as a 50mm lens with the angle of coverage of about 43 degrees and the 50mm DX lens as a 50mm lens with an angle of coverage of about 30 degrees.

flferg Loc: Driftwood, TX

You can go to the following link and find most anything you want to know about the technical reasons for sensor sizes and what each yields for different lenses. I worked in the semiconductor industry from 1965-2003 as a design/production engineer and I can tell you with certainty that sensor size is driven by the manufacturing capabilities (read cost), the type camera being designed and the cost of all the other components. The manufacturing costs of the electronics in a camera (sensor, processor, etc.) are driven by two main factors - complexity and volume. The more units produced the lower the manufacturing cost. This may not result in a lower end product cost but usually results in more complex/capable products, i.e. cameras, cell phones, flat screen tv's, etc.

www.google.com/search?q=diagram+showing+ff+and+dx+sensors&safe=active&rlz=1C2CHBD_enUS718US718&tbm=isch&source=iu&ictx=1&fir=w9WmbOWy_1B-WM%253A%252ChDKxtfbhqy9pSM%252C_&usg=__A_YeO6w3kGhPzBzdFZlzXggjXtw%3D&sa=X&ved=0ahUKEwjG3o6-sY_bAhWCj1QKHUl8BUIQ9QEIUDAG#imgrc=w9WmbOWy_1B-WM:

If you don't want this much info you can open the attached pdf file which shows a simple diagram of the object, lens and sensor and shows how the sensor size affects the photo.

Attached file:
(Download)

Tom K 66

Thanks for the information.

ecurb1105

Lenses are designed for specific focal length as measured from the plane of focus (ie, film plane or sensor) to the front nodal point of the lens. Focal length has on bearing on the field of view of the lens, that is determined by the size of the film/sensor used in the camer. The smaller the film/sensor the smaller the field of view.

PHRubin Loc: Nashville TN USA

The confusion comes from the terminology. The ANGLE OF VIEW is not expressed in MILLIMETERS but in DEGREES. A 50 mm lens gives the angle of view on a DX body the same as a 75mm would on a FF body. BUT! the depth of field of the 50 mm on any body is the same, that of a 50mm lens.

I'm not aware of a 50mm DX lens. All Nikon 50mm lenses I know of are FX format but any FX format lens can be used on DX bodies as well.

Flickwet Loc: NEOhio

Focal lengths are virtual (retro focus) or actual depending upon the design. Theoretically 50mm is the distance from the rear element to the “film or sensor” plane. For instance, if you cut out a rectangle of the DX and FX sensor and held them each at 50mm from your eye you would see the apparent field of view. If you took the same cutouts and held them 200mm from your eye you would find the same relative view. So focal length is a constant, sensor size will vary. This is also why view camera lenses are so relatively long, and why wide angle lenses for DSLRs and SLRs are retro focus which allows them to compensate because a true wide angle will interfere with the mirror box.

rehess Loc: South Bend, Indiana, USA

Apparently you operate differently than I do. I decide what perspective I want, what framing I want of that perspective, and then I zoom my lens to get that framing at that perspective; that is the only "job" each lens has for me {I don't even look at the focal length most of the time}.

Cheese

The label indicates the focal length of the lens, not the field of view. The focal length of the lens is the distance between the lens and the image sensor. That is why zoom lenses generally have 2 focal lengths, indicating focal length at max and min zoom.

To my knowledge, no manufacturer puts the field of view on any lense.

BebuLamar

For example my 24-85mm is fine for me on an FX camera as I rarely need above 85mm. When I do it's much more like at least 200 and more not a little bit more. So on a DX camera the 85mm is long but I don't need but when in the wide angle side 24mm is barely qualify as wide angle while on the FX it's considered a very wide angle lens. When I need very wide angle the 20mm on the FX is considered ultra wide angle but on the DX it's only a wide angle. Same thing the 50mm is a normal lens if I put it on the DX it's no longer a normal lens.

amfoto1 Loc: San Jose, Calif. USA

First of all, I am not aware of any 50mm DX lenses from Nikon or anyone else. AFAIK, all 50mm are FX (except for one "CX"... see below).

But that's really beside the point, since a 50mm FX lens designed for use on your Nikon F-mount camera will serve exactly the same purpose.

A 50mm lens is a 50mm lens, period. Focal length remains the same. It doesn't change regardless of format it's used upon. 50mm is still 50mm if it's FX or DX (or any other format, for that matter). The only difference with a DX design lens is that it may be smaller, lighter and less expensive. Thanks to the smaller size of the sensor that DX cameras use, the lens doesn't need to produce as large diameter an image. This might allows lens elements to be smaller, and the rest of the lens may be smaller too... and less expensive. However, 50mm in particular there wouldn't be much difference, so not much reason to make one that's DX only.

How any given focal length "behaves" changes depending upon the format of the camera it's used upon. Any 50mm lens.... be it DX or FX... that you put on your camera with its DX format sensor (approx. 15x23mm) will "act as" a short telephoto lens, "equivalent to a 75mm lens on a full frame/FX camera" and a nice choice for portraiture, among other things.

If instead used on an FX camera with it's larger 24x36mm sensor, a 50mm lens is a "normal" or "standard" lens, i.e. it's not wide nor telephoto.

Your camera can use either DX or FX lenses equally well. OTOH, for all practical purposes an FX camera requires FX lenses. (Note: All or most Nikon FX cameras can use DX lenses, but they will self-crop the images and in many cases that ends up lower resolution than your D7200 offers. So using a DX lens on an FX camera largely defeats the whole purpose of buying an FX camera.)

BTW, Nikon happens to make a 50mm CX lens for their Nikon 1 mirrorless cameras.... which use a 1" format sensor (8.8x13.2mm) that's even smaller than your camera's. As a result, on that camera the same focal length acts as an even more powerful telephoto (135mm equivalent on an FX/full frame camera). BTW, this lens won't work on your camera, since it produces an even smaller diameter image circle than required by your camera's DX format sensor (it also has a shorter lens register... the distance between the flange of the lens and the sensor plane of the camera is much shorter, so the lens wouldn't focus properly on your camera, even if it were possible to mount it).

Some digital cameras use very small sensors... such as so-called 1/2.5" (4.29x5.76mm). On a camera with that tiny sensor, the same 50mm would act as a fairly powerful telephoto (equiv. to 300mm on full frame/FX).

Conversely, "medium format" digital cameras use larger sensors (approx. 40x54mm is common). On those, the same 50mm will act as a moderately wide lens (equiv. to about 32mm on full frame/FX).

Focal lengths behaving differently on different format cameras is nothing new. The same thing occurred with the many different film formats. There were small 110 and 126 format films.... on those a 50mm focal length lens would act wide. And there were 35mm film cameras that mostly use what we call "full frame" today (some 35mm film cameras were "half frame" though), where 50mm is a "normal" lens. Plus there were several different medium formats that all used 70mm film.... on a 6x7 camera, for example (60x70mm image size), 50mm will act quite wide. And on "large format" cameras that used sheet film (such as 4x5, with images close to 100x125mm), the same 50mm focal length would act as an ultrawide.

Different angles of view, but the same 50mm focal length (other design factors would need to be different, to produce the correct diameter image to cover the film or sensor and to insure light focused properly on the film/sensor plane).

We really only refer to "full frame equivalents" to have means of comparing how a given focal length can be expected to work on different format cameras.... such as if we were switching from one to another. Early on with digital, this was important because most people were accustomed to cameras using 35mm film and how the lenses for those behaved. Early on, there were almost no full frame digital cameras, so those of us coming from film cameras had to rethink our lens selections.

More and more now, though, there are people who have never used a film camera and have no reference to "35mm film/full frame". To them it doesn't really matter. All you or they really need to know to choose lenses for your or their DX format cameras is that:

10 to 15mm is ultrawide
16 to around 21mm is wide
22 to approx. 29mm is moderately wide
30 to 35mm is normal or standard
40 to 60mm is short telephoto
70 to 150mm it moderate telephoto
180 to 300mm it powerful telephoto
longer than 300mm might be considered super telephoto