NikonD7100 lens factor of 1.5: If I put one of my lenses,say a50mmf1.4full frame lens on a D7100, It then becomes a 75mm lens, but what happens to the max. Apature Of 1.4? Does that...

Rexw

If I put one of my lenses,say a50mmf1.4full frame lens on a D7100,
It then becomes a 75mm lens, but what happens to the max. Apature
Of 1.4? Does that also change? Or do I now have a 75mmf1.4lens??

mwsilvers Loc: Central New Jersey

Rexw wrote:

If I put one of my lenses,say a50mmf1.4full frame lens on a D7100,
It then becomes a 75mm lens, but what happens to the max. Apature
Of 1.4? Does that also change? Or do I now have a 75mmf1.4lens??

You still have a 50mm f/1.4. 50mm is always 50mm regardless of the crop factor. What the crop factor gives you is a 35mm angle of view similar to a 75mm lens on a full frame body, but it doesn't change the focal length. This is due to the smaller sensor on a crop body. And f/1.4 aperture remains f/1.4.

To expand the concept a bit, when you see a 30x superzoom P&S cameras that claim for example a 1100mm zoom, they are actually also referring to a 35mm, or full frame, equivalent angle of view. The crop factor on those cameras' very small sensors is around 6 or so. The actual focal length of those lenses is less than 200mm.

Nikonian72 Loc: Chico CA

mwsilvers wrote:

You still have a 50mm f/1.4. 50mm is always 50mm regardless of the crop factor. What the crop factor gives you is a 35mm angle of view similar to a 75mm lens on a full frame body, but it doesn't change the focal length. And f/1.4 aperture remain f/1.4.

'Xactly!

jlrivera Loc: Round Lake, Illinois

You still have a 50mm f/1.4. 50mm is always 50mm regardless of the crop factor. What the crop factor gives you is a 35mm angle of view similar to a 75mm lens on a full frame body, but it doesn't change the focal length. This is due to the smaller sensor on a crop body. And f/1.4 aperture remains f/1.4.
This is true but; when you look in the view finder the image looks like it was taken with a 75mm lens, even it is cropped. I like when I take a picture with my 300mm with my Nikon D90...........it looks like it was taken with a 450mm :mrgreen:

mwsilvers Loc: Central New Jersey

jlrivera wrote:

You still have a 50mm f/1.4. 50mm is always 50mm r... (show quote)

That's not the point. The OP said "It then becomes a 75mm lens" which is simply not true. This subject causes a lot of confusion and its important to get the facts straight. Regardless of what you see through the viewfinder and regardless of the effect of the crop factor on the resulting image, the focal length of the lens does not change to 75mm. What changed was the smaller sensor generating a smaller image circle.

jlrivera Loc: Round Lake, Illinois

mwsilvers wrote:

That's not the point. The OP said "It then becomes a 75mm lens" which is simply not true. This subject causes a lot of confusion and its important to get the facts straight. Regardless of what you see through the viewfinder and regardless of the effect of the crop factor on the resulting image, the focal length of the lens does not change to 75mm. What changed was the smaller sensor generating a smaller image circle.

I didn't said that the 50mm focal length becomes a 75mm, it is a 50mm. I said that it looks like a 75mm, just looks like. And I still like my 300mm looking like a 450mm......just looking, is not a 450mm focal length !!!!!
:thumbup:

amehta Loc: Boston

jlrivera wrote:

I didn't said that the 50mm focal length becomes a 75mm, it is a 50mm. I said that it looks like a 75mm, just looks like. And I still like my 300mm looking like a 450mm......just looking, is not a 450mm focal length !!!!!
:thumbup:

It "looks like a 75mm", which means it has the same angle of view of a 75mm, which is exactly what mwsilvers first wrote.

You guys are in violent agreement. :-)

jlrivera Loc: Round Lake, Illinois

amehta wrote:

It "looks like a 75mm", which means it has the same angle of view of a 75mm, which is exactly what mwsilvers first wrote.

You guys are in violent agreement. :-)

Yes, we are in violent agreement. We are going to have a duel. Each one is going to shot the other. Which weapon do you recommend: Nikon, Canon, Sony, Pentax, Minolta, Kodak, Leica, Hasselblad, Mamiya, Konica etc etc.....
:mrgreen: :lol: :mrgreen:

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Rexw wrote:

If I put one of my lenses,say a50mmf1.4full frame lens on a D7100,
It then becomes a 75mm lens, but what happens to the max. Apature
Of 1.4? Does that also change? Or do I now have a 75mmf1.4lens??

Nothing happens. Nor does it become a 75mm lens. Everything remains the same - depth of field, sharpness, maximum aperture, image magnification on the sensor etc. What you are doing is cropping the image projected by the exit pupil of the lens. In theory, a lens with strong center performance and weaker corner sharpness when mounted on a full frame camera will provide better results when only the center section of the image is used.

The only thing that changes when you put a 50 mm lens on a crop camera is that the field of view will change, to be equivalent to a 75mm lens on a full frame camera. For the same image size (not magnification, but percentage of sensor used), you will have to take a few steps back, which changes the perspective, and so on.

mwsilvers Loc: Central New Jersey

jlrivera wrote:

I didn't said that the 50mm focal length becomes a 75mm, it is a 50mm. I said that it looks like a 75mm, just looks like. And I still like my 300mm looking like a 450mm......just looking, is not a 450mm focal length !!!!!
:thumbup:

I know you didn't say that, the OP did. :-) He made an uniformed statement and then wanted us to expand on it with regard to aperture. Any response required providing him with a clarification of his original assertion.

mwsilvers Loc: Central New Jersey

jlrivera wrote:

Yes, we are in violent agreement. We are going to have a duel. Each one is going to shot the other. Which weapon do you recommend: Nikon, Canon, Sony, Pentax, Minolta, Kodak, Leica, Hasselblad, Mamiya, Konica etc etc.....
:mrgreen: :lol: :mrgreen:

70-200mm at 50 paces. WIDE OPEN! :)

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

jlrivera wrote:

Yes, we are in violent agreement. We are going to have a duel. Each one is going to shot the other. Which weapon do you recommend: Nikon, Canon, Sony, Pentax, Minolta, Kodak, Leica, Hasselblad, Mamiya, Konica etc etc.....
:mrgreen: :lol: :mrgreen:

Forgot a few. Rolliflex, polaroid.voitlander,amsco,speed grafic,linhof, can't remember any others

Michael66 Loc: Queens, New York

Rexw wrote:

If I put one of my lenses,say a50mmf1.4full frame lens on a D7100,
It then becomes a 75mm lens, but what happens to the max. Apature
Of 1.4? Does that also change? Or do I now have a 75mmf1.4lens??

What is happening is that you are getting the full FX image coming through the lens; depth of field, angle of view, f/stop, plane of focus, resolution and depth of field. On a DX body, you are keeping only the central 2/3 of the image, hence the term, 'cropped'.

If you could look at the image projected on the rectangular sensor, you would see a circular image overlaid on the sensor. On an FX camera, the corners of the image would be close to the edge of the circle. Imagine cutting a rectangle out of the center of that circle that is ~35mm wide and ~24mm high. Then cut a smaller rectangle from the center of that image that is ~24mm by ~16mm. That is your DX image. The DX image only 'looks' like you were using a 75mm lens.

skiman Loc: Ventura, CA

mwsilvers wrote:

70-200mm at 50 paces. WIDE OPEN! :)

FX or DX :)

mwsilvers Loc: Central New Jersey

skiman wrote:

FX or DX :)

I'm a Canon man. But mine would be on a crop body.