35mm SLR lenses on digital

On 2007-04-18 07:59:14 -0700, Oscar <a_h_1969.TakeThisOut@hotmail.com> said:

> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.
>
> Please don't turn this message in to a debate over which camera is the
> best as there are loads of these around, I know the pitfalls of the
> D40 models over the D80.
>
> Thanks
>
> Oscar

An 35-70mm lens is a 35-70mm lens, no matter what camera it is on.

What they are saying is that since the sensor in a digital camera is
smaller than a frame of 35mm film, then the part of the image circle
that actually gets recorded is smaller. It is like taking a 35mm slide
and just keeping the middle part of it.

The multiplier is appoximately 1.5, which makes it easy. 28mm now
records the same size image as a 42mm lens did. It isn't any sharper;
it is just as if you cropped the middle out of all your 35mm pictures.

Your old lenses will work just as they always did, only now your wide
angle lenses will not seem as wide as they once were, and your
telephoto lenses will seem more powerful. They aren't, but you just
don't get to see the entire image they are capable of producing.

This has its good and bad points. The bad is that you are now forced to
use an APS size film format, complete with all of its limitations in
resolution. The good is that the center part of the image on your old
lenses was the sharpest part anyway. So you have lost the fuzzy edges,
the vignetting, and all the other problems you remember from film days.
The manufacturers don't want you to miss out on those, though, so Nikon
makes "DX" lenses that bring back the vignetting, if not the less sharp
edges. I say you don't need 'em. Use your old lenses.
--
Waddling Eagle
World Famous Flight Instructor
 >> Stay informed about: 35mm SLR lenses on digital 

On Apr 18, 7:59 am, Oscar <a_h_1....DeleteThis@hotmail.com> wrote:
> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.
>
> Please don't turn this message in to a debate over which camera is the
> best as there are loads of these around, I know the pitfalls of the
> D40 models over the D80.
>
> Thanks
>
> Oscar

The way I remember this is to imagine the size of the sensor against
the size of the film frame. As the sensor is only 2/3 the size of the
35mm film frame, it only "sees" the center 2/3 of the image that is
thrown onto the "backplane" of the camera. i.e. Imagine that the outer
1/3 of the image falls beyond the outside edges of the digital sensor.
So the effect is the same as if you had zoomed in on the center 2/3 of
a 35mm film frame. (much like "digital zoom" works on P&S digital
cameras). So the effect is the same as if you had zoomed 1.5 times
with a 35mm camera.

HTH.

/M
 >> Stay informed about: 35mm SLR lenses on digital 

On 18 Apr 2007 07:59:14 -0700, Oscar <a_h_1969.DeleteThis@hotmail.com> wrote:
> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.

Multiplied by 1.5, so 52.5-105mm.

-dms
 >> Stay informed about: 35mm SLR lenses on digital 

Oscar wrote:
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.

For me the easiest way is to remember that what is stamped on the barrel is
standardized for 35mm film. That means, if you are using that D80 kit lens
(18-70mm) on a 35mm film camera than you will get an 18-70mm zoom lens.

Now, compared to 35mm film the D80 has a conversion factor of 1.5. That
means that because of the smaller sensor compared to film this lens when
used on a D80 has a zoom range of 18x1.5-70x1.5 which equals 27-105mm.
Same with your old lenses. 35-70 on 35mm film times 1.5 on the D80 equals
52-105mm.

Unfortunately this conversion is necessary because different cameras have
different sensors dimensions and therefore different conversion factors,
e.g. if you were to use this D80 kit lens on some other camera you probably
end up with slightly different numbers. The one thing to remember is that
what is stamped on the lens is always for 35mm film.

jue
 >> Stay informed about: 35mm SLR lenses on digital 

In article <JDqVh.5522$F32.1633@trndny02>, Jürgen Exner
<jurgenex DeleteThis @hotmail.com> wrote:

> Unfortunately this conversion is necessary because different cameras have
> different sensors dimensions and therefore different conversion factors,
> e.g. if you were to use this D80 kit lens on some other camera you probably
> end up with slightly different numbers. The one thing to remember is that
> what is stamped on the lens is always for 35mm film.

Or, more accurately, what is stamped on the lens is always WHAT THE
FOCAL LENGTH ACTUALLY IS.

The field of view that focal length gives (compared to 35 mm) is what
the magnification factor tells you. As in, your 50 mm lens will give
the field of view which habit makes you expect from a 75 mm. But the
focal length, which is an inherent characteristic of the lens. doesn't
change.
 >> Stay informed about: 35mm SLR lenses on digital 

On Wed, 18 Apr 2007 15:16:57 GMT, "Jürgen Exner"
<jurgenex DeleteThis @hotmail.com> wrote:

>Oscar wrote:
>> What I don't understand is the way the lenses are now described
>>
>> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
>> film days, understand.
>>
>> All new lenses now seem to be marketed this way, but what if you
>> already have lenses which are from the 35mm film days. Does it mean
>> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
>> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
>> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
>> somebody please help.
>
>For me the easiest way is to remember that what is stamped on the barrel is
>standardized for 35mm film. That means, if you are using that D80 kit lens
>(18-70mm) on a 35mm film camera than you will get an 18-70mm zoom lens.
>
>Now, compared to 35mm film the D80 has a conversion factor of 1.5. That
>means that because of the smaller sensor compared to film this lens when
>used on a D80 has a zoom range of 18x1.5-70x1.5 which equals 27-105mm.
>Same with your old lenses. 35-70 on 35mm film times 1.5 on the D80 equals
>52-105mm.
>
>Unfortunately this conversion is necessary because different cameras have
>different sensors dimensions and therefore different conversion factors,
>e.g. if you were to use this D80 kit lens on some other camera you probably
>end up with slightly different numbers. The one thing to remember is that
>what is stamped on the lens is always for 35mm film.

Focal length is a property of the lens and does not change, no matter
what system you mount it on. But because the image circle is cropped
more in small sensor systems, the FIELD OF VIEW changes, AS THOUGH the
focal length changed, compared to 35mm.

What is stamped on the lens is a property of the lens and does not
change.

It's like taking a medium format lens (for instance a Hasselblad 80mm
lens) and putting it on a 35mm camera. On the 35mm, it behaves like an
80mm lens! But its field of view is different than when it was on the
'Blad.

KS
 >> Stay informed about: 35mm SLR lenses on digital 

"Oscar" <a_h_1969.RemoveThis@hotmail.com> wrote in message
news:1176908354.940308.110210@o5g2000hsb.googlegroups.com...
> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.

The 1.5 is a multiplier. Some have objected to the term "multiplier" on the
grounds that the actual focal length is not changed; your lens is still
35-70mm as it always was. Nevertheless, the 1.5x lens factor does mean that
in most respects your 35-70 becomes *equivalent* to a 52.5-105mm lens on a
35. The only reason it's commonly expressed this way is that most of us are
familiar with focal lengths on a 35mm camera. It is useful to have some
standard for visualizing the effects of different focal lengths on angle of
view, and 35mm is that standard because it's been around so long.


>
> Please don't turn this message in to a debate over which camera is the
> best as there are loads of these around, I know the pitfalls of the
> D40 models over the D80.

Not much to debate anyway, since you already know about the autofocus issues
with older lenses on the D40 models.. The D40, D40x and D80 are all top
choices in their respective classes.

Neil
 >> Stay informed about: 35mm SLR lenses on digital 

"Oscar" <a_h_1969 RemoveThis @hotmail.com> wrote in message
news:1176908354.940308.110210@o5g2000hsb.googlegroups.com...
> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.
>
> Please don't turn this message in to a debate over which camera is the
> best as there are loads of these around, I know the pitfalls of the
> D40 models over the D80.
>
> Thanks
>
> Oscar
>
It is the angle of view that changes. So, a 105mm lens on my D70 has the
same angle of view as a 150mm lens on my F3.
Jim
 >> Stay informed about: 35mm SLR lenses on digital 

This message is not archived
 >> Stay informed about: 35mm SLR lenses on digital 

Hi Oscar,

The cropping/magnification issues have been well enough dealth with, but the other thing you might need to think about is the effect
on DoF.

Since you'll be enlarging from a smaller 'film', a print of a given size will have greater DoF. As an example, to get the same DoF
from a 50mm lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR) you'll need to open the aperture up by two stops.

Cheers
--
cmyk
"Oscar" <a_h_1969.TakeThisOut@hotmail.com> wrote in message news:1176908354.940308.110210@o5g2000hsb.googlegroups.com...
> Hi,
>
> I've owned a Nikon F401s for many years and always enjoyed using it,
> but with the onset of digital cameras my SLR was assigned to the
> cupboard in favour of a couple of super zoom digital cameras. Anyway
> I now feel the need to change away from these back to a proper SLR and
> have been looking at the Nikon D40, D40x and D80.
>
> I already own three lenses form my SLR days and I know if I brought
> either of the D40 models these lenses will not auto focus.
>
> What I don't understand is the way the lenses are now described
>
> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
> film days, understand.
>
> All new lenses now seem to be marketed this way, but what if you
> already have lenses which are from the 35mm film days. Does it mean
> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
> somebody please help.
>
> Please don't turn this message in to a debate over which camera is the
> best as there are loads of these around, I know the pitfalls of the
> D40 models over the D80.
>
> Thanks
>
> Oscar
>
 >> Stay informed about: 35mm SLR lenses on digital 

cmyk wrote:
> Hi Oscar,
>
> The cropping/magnification issues have been well enough dealth with, but
> the other thing you might need to think about is the effect on DoF.
>
> Since you'll be enlarging from a smaller 'film', a print of a given size
> will have greater DoF.

Only if using a "35mm equivalent" focal length on a crop-format DSLR
camera, eg: a 3.5cm lens on a DSLR to get the same angle of view as a
5cm lens on a 35mm film SLR (or FF DSLR) camera.
This is a function of the actual focal length used to achieve the same
angle of view.

> As an example, to get the same DoF from a 50mm
> lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR)
> you'll need to open the aperture up by two stops.

It would show greater DoF than a 75mm lens on a FF sensor (or 35mm film)
DSLR camera, but less DoF than if the same 50m (5cm) lens when it's used
on a FF DSLR (or film) camera.
This is also a function of the actual focal length used to achieve the
same angle of view.

If you tested by printing both at the same size, you would discover that
the 1.5x crop DSLR has 2/3 (two thirds) the DoF of the same lens used on
a FF DSLR (or 35mm film) camera, if images are taken with the actual
same lens on both a 1.5x crop DSLR and a FF DSLR (or 35mm film) camera.
This is caused by the 30% extra enlargement required from the 1.5x crop
sensor image to be printed at the same size as an image from a FF sensor
camera.
 >> Stay informed about: 35mm SLR lenses on digital 

If you read the OP's posts you'll see he's talking about a Nikon DSLR. Nikon doesn't make full frame sensors. My comments were for
the DSLRs Nikon does make, not some hypothetical camera they don't. Nikon's DSLRs all have a 1.5 FoV crop factor. Do the math and
you'll find I got it right.

--
cmyk


"dj_nme" <dj_nme DeleteThis @hotmail.com> wrote in message news:4628d06f$0$25447$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> cmyk wrote:
>> Hi Oscar,
>>
>> The cropping/magnification issues have been well enough dealth with, but the other thing you might need to think about is the
>> effect on DoF.
>>
>> Since you'll be enlarging from a smaller 'film', a print of a given size will have greater DoF.
>
> Only if using a "35mm equivalent" focal length on a crop-format DSLR camera, eg: a 3.5cm lens on a DSLR to get the same angle of
> view as a 5cm lens on a 35mm film SLR (or FF DSLR) camera.
> This is a function of the actual focal length used to achieve the same angle of view.
>
>> As an example, to get the same DoF from a 50mm lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR) you'll need
>> to open the aperture up by two stops.
>
> It would show greater DoF than a 75mm lens on a FF sensor (or 35mm film) DSLR camera, but less DoF than if the same 50m (5cm) lens
> when it's used on a FF DSLR (or film) camera.
> This is also a function of the actual focal length used to achieve the same angle of view.
>
> If you tested by printing both at the same size, you would discover that the 1.5x crop DSLR has 2/3 (two thirds) the DoF of the
> same lens used on a FF DSLR (or 35mm film) camera, if images are taken with the actual same lens on both a 1.5x crop DSLR and a FF
> DSLR (or 35mm film) camera.
> This is caused by the 30% extra enlargement required from the 1.5x crop sensor image to be printed at the same size as an image
> from a FF sensor camera.
 >> Stay informed about: 35mm SLR lenses on digital 

cmyk wrote:
> If you read the OP's posts you'll see he's talking about a Nikon DSLR.
> Nikon doesn't make full frame sensors. My comments were for the DSLRs
> Nikon does make, not some hypothetical camera they don't. Nikon's DSLRs
> all have a 1.5 FoV crop factor. Do the math and you'll find I got it right.
>

Do the experiment and you will find that I'm correct.
Using a shorter lens to make up for the crop factor means that you will
have more DoF.
Using the same lens (ie: the same 50mm lens on both your film and your
Digital Nikon SLR camera) as on a 35mm film Nikon will result in images
with 2/3 (two thirds) the DoF, due to the extra enlargement required to
print at the same size.
It is the exactly the same as using a 80mm lens on a 6x6 120 film camera
compared to an 80mm lens (or the same medium format lens with an
adaptor) on a 35mm film camera, the prints made from the 6x6 negs will
have more aparrent DoF than the prints made from the 35mm negs.
If you could go the other way (and somehow fit a 35mm lens on a medium
format body, also making it cover the full 6x6 frame), then you'd find
the same thing and the MF prints will seem to have more DoF due to less
enlargement for the same print size.
 >> Stay informed about: 35mm SLR lenses on digital