lens varying- digi vs 35mm

[george_miraba_]

Hello,

I've been told that a 85 on a digital camera will act like 50 on a 35mm, and a 50 like a 28...like on a medium format

camera.

Is this true?

Thanks.

George

[starvy]

yes.

 

how does it affect you?

 

what appears to be the problem?

[Spearhead]

Lenses don't "act." What you are mis-interpreting is that field of view is different from one format to another. Other things stay the same.

[Spearhead]

I would stress is that this is specific to format - a lens on a Canon 5D has the same field of view as the same lens on a 35mm camera.

[vincent_peri]

"Hello, I've been told that a 85 on a digital camera will act like 50 on a 35mm, and a 50 like a 28"

 

It depends on the camera sensor's crop factor (let's use Nikon's 1.5 crop factor). A 50mm lens on such a digital camera will appear to be a 75mm lens (50mm x 1.5 = 75mm). If you put a 28mm lens on the same camera, it will appear to be a 42mm lens (28mm x 1.5 = 42mm). If you put a 200mm lens on, it will appear to be a 300mm lens (200mm x 1.5 = 300mm) and so on.

 

Nikon also makes cameras (D3 and D700) with no crop factor, called FX (full frame) cameras. A 28mm lens on these cameras is 28mm, the same as a 35mm film camera, and an 85mm lens is 85mm, and so on.

 

Is it a little clearer now?

[Craig_Cooper11664875449]

I think I'm going to have to start calling my Mamiya 7II 43mm lens a 21mm lens from now on... or at least tell it to start acting like one ;)

[pankaj purohit]

I think a 50mm lens standard Fall of Fiev is 39 digree, this is not on a perticullar camera ( If I am not correct please

correct me for the standard value)

 

And the 50mm field of view on a 35mm SLR is 46 digree.

 

And the 50mm field of view on a crop sensor DSLR is about 85 digree ( If I correctly remember)

 

You can see the difference, actually tFOV depends on destination size where the light will be stored after passing

through the lens

[matt_needham]

"I've been told that a 85 on a digital camera will act like 50 on a 35mm, and a 50 like a 28...like on a medium format camera. Is this true?"

 

No. Format change only effects angle of view. Even though photographers have been using multiple formats since the very beginning, for some reason with the introduction of digital APS format cameras the camera manufacturers decided the concept of multiple formats was too complex, so they introduced the term "crop factor", and made everything ten times more confusing.

[kelly_flanigan1]

In cine work one rises above this confusion and deals with angular coverage. Thus in the 1950's a chap might place a Exakta 35mm slr lens such as a 5cm F2.8 Tessar on his Bolex 16mm cine camera as a super telephoto; using a Exakta to C mount adapter; or on his Bolex 8mm cine camera by adding a D to C adapter. The average person understod this; cine viewfinders had gizmos that selected the focal length for a format; and one saw the angular coverage. One can go back 1/2 century ago and folks shot with manual exposure guides; calculated Guide numbers for flashes; they got off their bums to select the TV channel by turning a knob; folks used slide rules; some did square roots long hand. Using a crop factor term today is good marketing; folks are dummer about math and the basic sciences; using a dummed down analogy works for most. Folks who shot with 1/2 frame 35mm still cameras in the 1960's knew a 50mm lens covered less angle than a full frame 35mm camera. They also knew a softball was smaller than a basketball too :) Maybe the term "crop factor" could be introduced to sports; thus a golfball would be some crop factor; or maybe the term yardline could be removed from football; and the ball's position a crop factor?:) In all fairness the early times had folks expermenting more; using war surplus lenses; all drinking out of garden hoses en-grained the concept of angular coverage.:)

[kelly_flanigan1]

Some of us shot with 2x3 formats on 620 roll film long ago; here the normal lens was often 100 to 105mm. With a 35mm still camera; the active area is about 1/4; ie the sides are about 1 x 1.5 inches to slide rule accuracy; the films sides are 1/2 the size of the 620's vigilant. Thus ones 50mm lens on an Argus A2 35mm camera had the same angular coverage as a 105mm lens on a Vigilant 620 Kodak folder. Here I have a 178mm F2.5 Kodak Aero Ektar with a 35mm Exakta slr mount; and on a 4x5" speed graphic mount. If somebody used the term "crop factor" 35 years ago about my two 178mm settups; I really would not know what the heck you meant!