35mm f2 - I thought this got me a 50mm?

hi there

after some research and after some weeks of new d70 ownership, I went and got a new lens, the 35mm f2.

My previous experience with SLRs, is my trusty Canon A1 with a 50/1.4 which produces a wonderfully understandable and predictable view from the viewfinder.

I was hoping for the 35mm f2 to act a like the 50mm since the 'cropping factor' of the d70 makes for 1.5x magnification...

Basically I bought a 35mm lens, and I think I'm getting 35mm images. Which in of itself isn't a problem, since it's a very usable lens, but I was somewhat under the impression that I'd get 50mm like images...

I just wonder where I got confused? Can someone explain what's going on? I don't get 'it'.

thanks

g

Effective fov is 52.5mm. So it should look like a 50mm on FF 35mm. No getting around the math.

In a way your thought process was correct. The 35mm lens on you D70 gives you the FIELD OF VIEW of a 50mm lens, however all aspects of the wide angle lens that you have stand true, including perspective, distortion, depth of field, etc. If you took a picture with your Canon and a 35mm lens, cropped the center portion of your print/slide you would see a very similar crop to what you are seeing with your D70/35mm lens. If you liked the general effect of the 50mm lens you can shoot with a 50mm on the D70, however your field of view would be that of a 75mm lens.

--
--
Jeff
http://www.cheap-fineart-printing.com
http://www.digitalprecisionimaging.com

Well, this is the thing, since I don't really understand the 'field of view' part. Where does it come in, when the image from the 35mm lens looks wide in comparison to a 50mm.

Maybe I'd understand it more, if I can a 50mm AF D to stick on my d70 to compare it with...

Whether I understand the relatively simple physics of this or not, I'm trying to effectively make it such that what I see I with my eyes, I reproduce it when I bring the viewfinder to my face... kinda like what happens with my canon with the 50/1.4

Will a 50 give me that effect? I should go back to Calumet and try them both out...

g

Jeffrey Lazo said:

In a way your thought process was correct. The 35mm lens on you
D70 gives you the FIELD OF VIEW of a 50mm lens, however all aspects
of the wide angle lens that you have stand true, including
perspective, distortion, depth of field, etc. If you took a
picture with your Canon and a 35mm lens, cropped the center portion
of your print/slide you would see a very similar crop to what you
are seeing with your D70/35mm lens. If you liked the general
effect of the 50mm lens you can shoot with a 50mm on the D70,
however your field of view would be that of a 75mm lens.

--
--
Jeff
http://www.cheap-fineart-printing.com
http://www.digitalprecisionimaging.com

Click to expand...

georgeaye said:

Well, this is the thing, since I don't really understand the 'field
of view' part. Where does it come in, when the image from the 35mm
lens looks wide in comparison to a 50mm.

Maybe I'd understand it more, if I can a 50mm AF D to stick on my
d70 to compare it with...

Whether I understand the relatively simple physics of this or not,
I'm trying to effectively make it such that what I see I with my
eyes, I reproduce it when I bring the viewfinder to my face...
kinda like what happens with my canon with the 50/1.4

Will a 50 give me that effect? I should go back to Calumet and try
them both out...

g

Click to expand...

Hopefully, this will help:

(From the glossary on dpreview.com)

Focal Length Multiplier:
http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_Multiplier_01.htm

It should behave just like a 50 mm lens with regard to perspective and field of view. Make a 5 x 7 print of the full frame using a 35mm camera with a 50mm lens. Make a 5 x 7 print of the full image captured by a D70 using a 35mm lens. Aside from depth of field, the images should look identical! I'm ignoring rounding errors and slight differences in aspect ratio, of course.

Again, the subject on the print should be the same size and foreground/background perspective should be identical whether you use a 50mm on a 35mm body or a 35mm on a D70.

Depth of field will be greater for the 35mm on the D70 than for the 50mm on the full-frame camera at a given f/stop.

Distortion should be virtually zero in either lens, so that should not be a concern.

The D70 viewfinder image will look comparatively small since Nikon did not increase viewfinder magnification to account for the cropping. I expect this was just to save money. That accounts for the "tunnel vision" you get with many digital camera viewfinders. Is this where the problem is? The image you see in the viewfinder using a 35mm lens on a D70 will have approximately the same magnificatin as that same 35mm lens on a full-frame body. The image will appear SMALLER in the VIEWFINDER than you would expect from the 1.5x "magnification" factor.

• Jared

georgeaye said:

hi there

after some research and after some weeks of new d70 ownership, I
went and got a new lens, the 35mm f2.

My previous experience with SLRs, is my trusty Canon A1 with a
50/1.4 which produces a wonderfully understandable and predictable
view from the viewfinder.

I was hoping for the 35mm f2 to act a like the 50mm since the
'cropping factor' of the d70 makes for 1.5x magnification...

Basically I bought a 35mm lens, and I think I'm getting 35mm
images. Which in of itself isn't a problem, since it's a very
usable lens, but I was somewhat under the impression that I'd get
50mm like images...

I just wonder where I got confused? Can someone explain what's
going on? I don't get 'it'.

thanks

g

Click to expand...

--

• Jared Willson

http://resolutionphotography.com

The crop factor for the D70 is approx 1.53 which means that the 35 mm act similar to a 53 mm lens on film. This is true for everything, except for the depth of field will be larger, not as much as the depth of field for a 35 mm on film, because you loose some of it in the magnification factor 1.53, but still larger than what you get from the 50 mm on film. This must be the difference you notice.

What you can do, is to use a bigger f-stop on the 35 mm if possible, to get the more shallow field of view. You can adjust the ISO down or even use ND filter in order to achieve this. But still, using f/2 will be the most you can get. You can not get the same as the 50 mm at f/1.4.

georgeaye said:

hi there

after some research and after some weeks of new d70 ownership, I
went and got a new lens, the 35mm f2.

My previous experience with SLRs, is my trusty Canon A1 with a
50/1.4 which produces a wonderfully understandable and predictable
view from the viewfinder.

I was hoping for the 35mm f2 to act a like the 50mm since the
'cropping factor' of the d70 makes for 1.5x magnification...

Basically I bought a 35mm lens, and I think I'm getting 35mm
images. Which in of itself isn't a problem, since it's a very
usable lens, but I was somewhat under the impression that I'd get
50mm like images...

I just wonder where I got confused? Can someone explain what's
going on? I don't get 'it'.

thanks

g

Click to expand...

You could tell the difference right away with a telephoto lens that has these two zoom ranges. All you have is the 35?

Hal

georgeaye said:

Maybe I'd understand it more, if I can a 50mm AF D to stick on my
d70 to compare it with...

Whether I understand the relatively simple physics of this or not,
I'm trying to effectively make it such that what I see I with my
eyes, I reproduce it when I bring the viewfinder to my face...
kinda like what happens with my canon with the 50/1.4

Will a 50 give me that effect? I should go back to Calumet and try
them both out...

g

Jeffrey Lazo said:

In a way your thought process was correct. The 35mm lens on you
D70 gives you the FIELD OF VIEW of a 50mm lens, however all aspects
of the wide angle lens that you have stand true, including
perspective, distortion, depth of field, etc. If you took a
picture with your Canon and a 35mm lens, cropped the center portion
of your print/slide you would see a very similar crop to what you
are seeing with your D70/35mm lens. If you liked the general
effect of the 50mm lens you can shoot with a 50mm on the D70,
however your field of view would be that of a 75mm lens.

--
--
Jeff
http://www.cheap-fineart-printing.com
http://www.digitalprecisionimaging.com

Click to expand...

Click to expand...

Judging from his description (and comparison to his Canon film body), that sounds like it. The viewfinder on the D70 is indeed quite small. It's quite noticeably smaller than that on the D-Rebel/10D for instance.

But yeah, the final result should be about the same for D70 + 35mm lens vs FF body + 50mm lens (DoF notwithstanding).

Man

Jared_Willson said:

Again, the subject on the print should be the same size and
foreground/background perspective should be identical whether you
use a 50mm on a 35mm body or a 35mm on a D70.

Depth of field will be greater for the 35mm on the D70 than for the
50mm on the full-frame camera at a given f/stop.

Distortion should be virtually zero in either lens, so that should
not be a concern.

The D70 viewfinder image will look comparatively small since Nikon
did not increase viewfinder magnification to account for the
cropping. I expect this was just to save money. That accounts for
the "tunnel vision" you get with many digital camera viewfinders.
Is this where the problem is? The image you see in the viewfinder
using a 35mm lens on a D70 will have approximately the same
magnificatin as that same 35mm lens on a full-frame body. The
image will appear SMALLER in the VIEWFINDER than you would expect
from the 1.5x "magnification" factor.

• Jared

georgeaye said:

hi there

after some research and after some weeks of new d70 ownership, I
went and got a new lens, the 35mm f2.

My previous experience with SLRs, is my trusty Canon A1 with a
50/1.4 which produces a wonderfully understandable and predictable
view from the viewfinder.

I was hoping for the 35mm f2 to act a like the 50mm since the
'cropping factor' of the d70 makes for 1.5x magnification...

Basically I bought a 35mm lens, and I think I'm getting 35mm
images. Which in of itself isn't a problem, since it's a very
usable lens, but I was somewhat under the impression that I'd get
50mm like images...

I just wonder where I got confused? Can someone explain what's
going on? I don't get 'it'.

thanks

g

Click to expand...

--

• Jared Willson

http://resolutionphotography.com

Click to expand...

--



Just another amateur learning to paint w/ 'the light of the world.' (John 8:12)
Motto for the season: 'Cameras are for making photos, not war...'
See my profile for more + some basic photog resources.
As usual, YMMV + caveat emptor.
Contact me at [email protected]
Indulge my fancies at http://www.pbase.com/mandnwong

Thank you all so much for your informed responses. I think that some of it is the smaller viewfinder on d70 than the canon, and some of it is that I don't have a 50mm to actively compare it against.

I'm just not a fan of zooms. Make me lazy, as I don't move around enough I think.

But I'm going to go back to Calumet and just test them out and I'll let peeps know what happened. It's not that complicated an issue, I just want to understand this phenomena more.

thanks again!

g

Bob GB said:

The crop factor for the D70 is approx 1.53 which means that the 35
mm act similar to a 53 mm lens on film. This is true for
everything, except for the depth of field will be larger,

Click to expand...

I strongly disagree. I think Jeffrey said it best in his post above.

The 35 will NOT act like a 50 (or 53)... it will act exactly like a 35. The image will be the equivalent of a cropped segment of a normal film camera's image with the 35mm lens.

Think about it... the digital sensor doesn't have any effect on the lens' optics. It just records a smaller portion of the projected image.

This is important to realize when using wide angle lenses onb the D70. As an example, an image from my D70 using my 18-35 f/3.5-4.5 at 18mm does not look at all similar to a image shot with a 28mm lens on my F4 film body. It definitely has the "look" of an image shot with an 18mm lens. You just don't see as much of the image as you would if the lens was used on a film camera.

Good shooting,
Bob Scott

Well, if you think about it, a 50 mm view is just a cropped part of the 35 mm view, except for the depth of field. Geometrically, it is precisely the same. Unfortunately, Jefrey is mistaken. There is no difference in perspective and distortion, and the depth of field is somewhere between the 35 and the 50 mm on film.

The depth of field is the only difference beween these two cases. But the larger depth of field is very significant, when you look at the image. However, as stated, the depth of field for the 35 mm on the D70 is less than on film, because of the additional 1.5 magnification.

-regards-

desmobob said:

I strongly disagree. I think Jeffrey said it best in his post above.

The 35 will NOT act like a 50 (or 53)... it will act exactly like a
35. The image will be the equivalent of a cropped segment of a
normal film camera's image with the 35mm lens.

Think about it... the digital sensor doesn't have any effect on the
lens' optics. It just records a smaller portion of the projected
image.

This is important to realize when using wide angle lenses onb the
D70. As an example, an image from my D70 using my 18-35 f/3.5-4.5
at 18mm does not look at all similar to a image shot with a 28mm
lens on my F4 film body. It definitely has the "look" of an image
shot with an 18mm lens. You just don't see as much of the image as
you would if the lens was used on a film camera.

Good shooting,
Bob Scott

Click to expand...

Try shooting 2 images, of the same setup and subject, with both of your cameras. Either that or just hold them up to your eye. What you will see is that the 35mm lens on the D70 is a near match for the Field of View you get using a 50mm lens on the 35mm camera. Try and ignore the fact that the D70 has a tiny viewfinder image compared to your film camera. Just look at the area that is taken in by both cameras and you will see that they are about the same. That is what the "crop factor" is all about, it allows you determine the Field of View using a standard that you are familiar with.

There will be a difference in the Depth of Field that you observe, that is a product of the shorter focal length and the 1 stop loss in speed. The DX format "gains" a bit in the DOF that you get, compared to 35mm film. It's a consequence of the smaller format and there isn't a lot we can do about it. I have done a little "fast math" and, in order to match the 35mm cameras DOF, you need to open the lens on a DX format camera by about one stop. That means, an exact match for your 50mm f1.4 would require a 35mm f1.0 lens. It's a lens to dream for but I don't think it will happen, everyone is buying zooms today. Since your using a 35mm f2 lens, you have "gained" about 2 stops worth of DOF compared to your 50mm f1.4. It really does make that "dream" 35mm f1.0 lens something to lust after.

Bob GB said:

Well, if you think about it, a 50 mm view is just a cropped part of
the 35 mm view, except for the depth of field. Geometrically, it is
precisely the same.

Click to expand...

In a theoretical sense, sure. In real life, it's not; especially when you get into the wide angle lenses. Try it yourself and see... shoot the same exact scene at 18mm with your D70 and with a 28 on your 35mm film body. (these lenses should be within a mm or so due to the crop factor.) I bet you'll be able to easily pick the 18mm shot.

I'll try and remember to do this the next time I shoot some film. I'll post the shots.

Good shooting,
Bob Scott

the whole crop factor thing is this...the lenses were created to project a certain size image onto the film...the film is a certain size...the CCD on the D70 is smaller, so it "sees" only part of what the film would see. if you took a pic with a 35mm lens on a 35mm film camera, and then cropped around the outside of the picture, that is effectively what you would see with the lens on your D70. The depth of field is somewhat greater I believe, but don't bet the farm on that part. Hope this helps.

georgeaye said:

hi there

after some research and after some weeks of new d70 ownership, I
went and got a new lens, the 35mm f2.

My previous experience with SLRs, is my trusty Canon A1 with a
50/1.4 which produces a wonderfully understandable and predictable
view from the viewfinder.

I was hoping for the 35mm f2 to act a like the 50mm since the
'cropping factor' of the d70 makes for 1.5x magnification...

Basically I bought a 35mm lens, and I think I'm getting 35mm
images. Which in of itself isn't a problem, since it's a very
usable lens, but I was somewhat under the impression that I'd get
50mm like images...

I just wonder where I got confused? Can someone explain what's
going on? I don't get 'it'.

thanks

g

Click to expand...

--
D70 and photo discussion
D70 custom tone curves @ http://forum.mastersphoto.net

In real life, the difference is the depth of field, nothing more. But it is a significant difference.

desmobob said:

Bob GB said:

Well, if you think about it, a 50 mm view is just a cropped part of
the 35 mm view, except for the depth of field. Geometrically, it is
precisely the same.

Click to expand...

In a theoretical sense, sure. In real life, it's not; especially
when you get into the wide angle lenses. Try it yourself and
see... shoot the same exact scene at 18mm with your D70 and with a
28 on your 35mm film body. (these lenses should be within a mm or
so due to the crop factor.) I bet you'll be able to easily pick
the 18mm shot.

I'll try and remember to do this the next time I shoot some film.
I'll post the shots.

Good shooting,
Bob Scott

Click to expand...

Hi George,

Here is an example I shot very quickly to illustrate. Notice that as long as you don't change your position, the perspective remains the same. I used 24mm & 50mm on the D70 to exaggerate the principal.

Hope this helps.

-john

desmobob is right here. I have an N80 film camera and a D70 and I know that when I mount my 28-75 on both cameras and look through the VF at 28mm the only difference is that I can see more on the edges of the frames. The wide ange look remains the same, you get the same field of view with digital, just cropped out of the center. I don't know what you mean by "in real life" Bob GB but in my reality I can easily tell that the field of view is the same...

Bob GB said:

desmobob said:

Bob GB said:

Well, if you think about it, a 50 mm view is just a cropped part of
the 35 mm view, except for the depth of field. Geometrically, it is
precisely the same.

Click to expand...

In a theoretical sense, sure. In real life, it's not; especially
when you get into the wide angle lenses. Try it yourself and
see... shoot the same exact scene at 18mm with your D70 and with a
28 on your 35mm film body. (these lenses should be within a mm or
so due to the crop factor.) I bet you'll be able to easily pick
the 18mm shot.

I'll try and remember to do this the next time I shoot some film.
I'll post the shots.

Good shooting,
Bob Scott

Click to expand...

Click to expand...

I think John Adler's example illustrates what I try to explain.
I also believe, georgeaye has got a fair explanation about the fenomenon.

I am sure, if you care to test it out, shooting with both cameras on the same object and with the coresponding focal lengths, you will see the same thing as John Adler has shown us.

I think Jared_Willson and in particular monte12345 has added valuable explanation to the matter.

However, I fully admit that the depth of focus plays a major role here. In addition, the different shape of the circle of confusion (bokeh), will also add to the photographic difference.

I wish everybody a Happy Holiday.

-best regards-

Brad Berry said:

desmobob is right here. I have an N80 film camera and a D70 and I
know that when I mount my 28-75 on both cameras and look through
the VF at 28mm the only difference is that I can see more on the
edges of the frames. The wide ange look remains the same, you get
the same field of view with digital, just cropped out of the
center. I don't know what you mean by "in real life" Bob GB but in
my reality I can easily tell that the field of view is the same...

Click to expand...

... about comparing results between a film body and digital that has not been mentioned. Not sure if this has contributed to anyone's confusion, but it's apparently quite common practice for cheap photolabs (eg. the drugstore variety) to arbitrarily crop your prints by a significant margin, which often also comes close to the amount of cropping in viewfinders on consumer cameras. So you cannot really make a good comparison using film prints from such photolabs against what you see on screen from the D70 (or your own at-home prints). If you compare, make sure you're comparing w/ prints from good photolabs that don't arbitrarily crop you images.

See the "Dirty Little Secrets" section of this article to see what I mean:

http://www.luminous-landscape.com/tutorials/understanding-series/viewfinders.shtml

In a way, the whole consumer film industry has added their own "crop factor" to the 35mm film format w/out most people realizing it.

BTW, that's an excellent article for learning more about viewfinders too -- at least for us laymen who are not about to design our own DIY viewfinder.

Man

Brad Berry said:

Bob GB said:

desmobob said:

Bob GB said:

Well, if you think about it, a 50 mm view is just a cropped part of
the 35 mm view, except for the depth of field. Geometrically, it is
precisely the same.

Click to expand...

In a theoretical sense, sure. In real life, it's not; especially
when you get into the wide angle lenses. Try it yourself and
see... shoot the same exact scene at 18mm with your D70 and with a
28 on your 35mm film body. (these lenses should be within a mm or
so due to the crop factor.) I bet you'll be able to easily pick
the 18mm shot.

I'll try and remember to do this the next time I shoot some film.
I'll post the shots.

Good shooting,
Bob Scott

Click to expand...

Click to expand...

Click to expand...

--



Just another amateur learning to paint w/ 'the light of the world.' (John 8:12)
Motto for the season: 'Cameras are for making photos, not war...'
See my profile for more + some basic photog resources.
As usual, YMMV + caveat emptor.
Contact me at [email protected]
Indulge my fancies at http://www.pbase.com/mandnwong