SLR lens on DSLR's

"Zeno" wrote in message

> Hi
>
> I'm sortof new to this I currently use a Nikon F80 and I have a range
> on lens ie. 80-200mm F2.8.
>
> If I buy something like the DSLR F70, I know the focal length will be
> multipled by the a factor of the DSLRs sensor. But does the Aperture
> F2.8 also change as well or does that stay constant.
>
> Cheers.......
>
 >> Stay informed about: SLR lens on DSLR's 

On 15 Oct 2005 09:40:44 -0700, "Zeno" wrote:

>Hi
>
>I'm sortof new to this I currently use a Nikon F80 and I have a range
>on lens ie. 80-200mm F2.8.
>
>If I buy something like the DSLR F70, I know the focal length will be
>multipled by the a factor of the DSLRs sensor. But does the Aperture
>F2.8 also change as well or does that stay constant.
>
>Cheers.......

SLR lens on DSLR can mean....CA, spherical aberration, etc.
Why? Because old SLR lenses do not control aberrations well enough
to allow digital sensors to function as well as they can. To do this,
you need ED glass and aspherical elements, something rare on old SLR
lenses, even L-series lenses.
As time goes on, even hold outs like Canon will start dedicating lens
design to digital and pros and amateurs will slowly get rid of their
ancient FILM lenses.
-Rich
 >> Stay informed about: SLR lens on DSLR's 

This message is not archived
 >> Stay informed about: SLR lens on DSLR's 

In article ,
Zeno wrote:
>If I buy something like the DSLR F70, I know the focal length will be
>multipled by the a factor of the DSLRs sensor. But does the Aperture
>F2.8 also change as well or does that stay constant.

As a result of the crop, you get a field of view from a particular focal
length that is the same as the field of view you get on a full frame
camera with a lens that has a focal length that is 1.5 times longer.
(focal lengths always stay the same, it the field of view that changes
with the imaging format).

The effect on an f-stop number also changes. If you select lenses that
provide a corresponding fields of view on a 1.5x crop DLSR and on full frame,
then at the same f-stop number, the DLSR will have more DoF. So you have
to select a one stop wider aperture on the DLSR to get the same DoF as you
have on the full frame camera.

For exposure calculations nothing changes.


--
That was it. Done. The faulty Monk was turned out into the desert where it
could believe what it liked, including the idea that it had been hard done
by. It was allowed to keep its horse, since horses were so cheap to make.
-- Douglas Adams in Dirk Gently's Holistic Detective Agency
 >> Stay informed about: SLR lens on DSLR's 

On Sat, 15 Oct 2005 22:31:10 -0400, Bill wrote:

>Rich wrote:
>
>>On 15 Oct 2005 09:40:44 -0700, "Zeno" wrote:
>>
>>>Hi
>>>
>>>I'm sortof new to this I currently use a Nikon F80 and I have a range
>>>on lens ie. 80-200mm F2.8.
>>>
>>>If I buy something like the DSLR F70, I know the focal length will be
>>>multipled by the a factor of the DSLRs sensor. But does the Aperture
>>>F2.8 also change as well or does that stay constant.
>>>
>>>Cheers.......
>>
>>SLR lens on DSLR can mean....CA, spherical aberration, etc.
>>Why? Because old SLR lenses do not control aberrations well enough
>>to allow digital sensors to function as well as they can. To do this,
>>you need ED glass and aspherical elements, something rare on old SLR
>>lenses, even L-series lenses.
>>As time goes on, even hold outs like Canon will start dedicating lens
>>design to digital and pros and amateurs will slowly get rid of their
>>ancient FILM lenses.
>>-Rich
>
>WOW part II...
>
>You're not making it hard to keep me from dumping your comments into the
>good old twit filter...at this rate, you're gonna make it there before I
>finish reading this group.
>
>Are you sure you're not on drugs...?
>
>Or perhaps you're simply looking for bait with which to troll...?
>
>You don't actually believe this stuff...do you?

Fine, ignore it. And ask yourself WHY Canon would post
samples images from the 5D that exhibited some of the problems
people have mentioned. Reason? They had no choice because they
didn't have a suitable (in that case) wide angle lens to use with the
camera. There are some lenses in their vast stable of lenses that
work reasonably well. Perhaps their new 60mm macro.
But now you've got the owners of 5Ds (see the Fred Miranda site)
modifying their Canons to take Leica glass. Ask yourself why.
Those big FF sensors simply do not tolerate or hide aberrations
in the lenses that film would.
-Rich
 >> Stay informed about: SLR lens on DSLR's 

Everything stays the same except the image coverage is smaller due to the
photo sensor size is smaller than the 35mm film size. Imagine a 80mm lens is
normal lens to 6 x 6cm format but when use on 35mm format become a telephoto
lens. Same logic. Your lens becomes 120 to 300mm on D70 virtually.

"Zeno" wrote in message

> Hi
>
> I'm sortof new to this I currently use a Nikon F80 and I have a range
> on lens ie. 80-200mm F2.8.
>
> If I buy something like the DSLR F70, I know the focal length will be
> multipled by the a factor of the DSLRs sensor. But does the Aperture
> F2.8 also change as well or does that stay constant.
>
> Cheers.......
>
 >> Stay informed about: SLR lens on DSLR's 

kctan wrote:
>Your lens becomes 120 to
> 300mm on D70 virtually.

The focal length doesn't change in any way.
Only the field of view is different--which is cropped.

>
> "Zeno" wrote in message
>
>> Hi
>>
>> I'm sortof new to this I currently use a Nikon F80 and I have a range
>> on lens ie. 80-200mm F2.8.
>>
>> If I buy something like the DSLR F70, I know the focal length will be
>> multipled by the a factor of the DSLRs sensor. But does the Aperture
>> F2.8 also change as well or does that stay constant.
>>
>> Cheers.......
 >> Stay informed about: SLR lens on DSLR's 

"Mark?" wrote:
: kctan wrote:
: >Your lens becomes 120 to
: > 300mm on D70 virtually.

: The focal length doesn't change in any way.
: Only the field of view is different--which is cropped.

In the strictest sense you are totally correct. But many of us are used to
a particular field of view being percieved as equating to a particular
lens length with a particular camera. Since DSLRs resemble a 35mm film
camera the expectation is for a similar correlation between lens length
and field of view to continue. But with the smaller sensor size the
cropping of the image will give the field of view of a lens length
different than we expect. So for the ease of conceptualizing an image from
the users point of view (for those who are coming from 35mm) a "conversion
factor" makes this easier.

So while it is true that this conversion factor has nothing to do with
changing the properties of the lens, the perception of the outcome will
differ by a predictable amount.

So to the OP, all functions of the lens (focus, aperture, etc) remain
constant for both film and digital. Only the field of view (which many
of us equate to lens length) is affected. Of course the viewfinder is
giving the view of the image that will be captured by the sensor so if you
use the finder to frame your photo, the conversion factor can be ignored.


Randy

==========
Randy Berbaum
Champaign, IL
 >> Stay informed about: SLR lens on DSLR's 

"spirit" wrote in message

> Aperture stays the same.
>
> Your lenses only seem to be all a bit longer. In confined spaces this
> can be a problem, it also makes one stand further away than normal and
> this can effect the flash, giving out more power and taking longer to
> recycle etc. .

How about AF? Will it work or do you have to switch to Manual focus?
Marcel
 >> Stay informed about: SLR lens on DSLR's 

Rich wrote in
4ax.com:

> On 15 Oct 2005 09:40:44 -0700, "Zeno" wrote:
>
>>Hi
>>
>>I'm sortof new to this I currently use a Nikon F80 and I have a range
>>on lens ie. 80-200mm F2.8.
>>
>>If I buy something like the DSLR F70, I know the focal length will be
>>multipled by the a factor of the DSLRs sensor. But does the Aperture
>>F2.8 also change as well or does that stay constant.
>>
>>Cheers.......
>
> SLR lens on DSLR can mean....CA, spherical aberration, etc.
> Why? Because old SLR lenses do not control aberrations well enough
> to allow digital sensors to function as well as they can. To do this,
> you need ED glass and aspherical elements, something rare on old SLR
> lenses, even L-series lenses.
> As time goes on, even hold outs like Canon will start dedicating lens
> design to digital and pros and amateurs will slowly get rid of their
> ancient FILM lenses.
> -Rich

You know, if you don't want people to think you are a crackpot then you
should mention that what you say only applies to wide angle lenses on FF
digital cameras. The problem is the light hitting the sensor at an angle,
long lenses don’t have this problem and smaller sensors don't use the light
on the edge of the image circle.


--
Mark Heyes (New Zealand)
See my pics at www.gigatech.co.nz (last updated 5-September-05)
"The person on the other side was a young woman. Very obviously a
young woman. There was no possible way she could have been mistaken
for a young man in any language, especially Braille."
Maskerade
 >> Stay informed about: SLR lens on DSLR's 

This message is not archived
 >> Stay informed about: SLR lens on DSLR's 

Off course it won't change physically but virtually, I repeat virtually, or
simply it behaves like a 120 to 300mm on 35mm format form factor camera. The
field of views is still the same or the angle of view doesn't change at all.

"Mark²" wrote in message

> kctan wrote:
>>Your lens becomes 120 to
>> 300mm on D70 virtually.
>
> The focal length doesn't change in any way.
> Only the field of view is different--which is cropped.
>
>>
>> "Zeno" wrote in message
>>
>>> Hi
>>>
>>> I'm sortof new to this I currently use a Nikon F80 and I have a range
>>> on lens ie. 80-200mm F2.8.
>>>
>>> If I buy something like the DSLR F70, I know the focal length will be
>>> multipled by the a factor of the DSLRs sensor. But does the Aperture
>>> F2.8 also change as well or does that stay constant.
>>>
>>> Cheers.......
>
>
 >> Stay informed about: SLR lens on DSLR's 

On Sun, 16 Oct 2005 11:02:12 GMT, MarkH wrote:

>Rich wrote in
>4ax.com:
>
>> On 15 Oct 2005 09:40:44 -0700, "Zeno" wrote:
>>
>>>Hi
>>>
>>>I'm sortof new to this I currently use a Nikon F80 and I have a range
>>>on lens ie. 80-200mm F2.8.
>>>
>>>If I buy something like the DSLR F70, I know the focal length will be
>>>multipled by the a factor of the DSLRs sensor. But does the Aperture
>>>F2.8 also change as well or does that stay constant.
>>>
>>>Cheers.......
>>
>> SLR lens on DSLR can mean....CA, spherical aberration, etc.
>> Why? Because old SLR lenses do not control aberrations well enough
>> to allow digital sensors to function as well as they can. To do this,
>> you need ED glass and aspherical elements, something rare on old SLR
>> lenses, even L-series lenses.
>> As time goes on, even hold outs like Canon will start dedicating lens
>> design to digital and pros and amateurs will slowly get rid of their
>> ancient FILM lenses.
>> -Rich
>
>You know, if you don't want people to think you are a crackpot then you
>should mention that what you say only applies to wide angle lenses on FF
>digital cameras. The problem is the light hitting the sensor at an angle,
>long lenses don’t have this problem and smaller sensors don't use the light
>on the edge of the image circle.

Well, because the 5d is much less expensive than the big flagship
Canon, we should begin to see many more examples of photography from
it. At that point you'll see overall how well it works with Canon's
legacy glass. Problem is, I don't know if Canon is even making new
lenses that specifically cater to digital sensors and their
differences from film so comparisons are a problem, unless someone
grafts (as is being done) other mfgs lenses onto the bodies.
-Rich
 >> Stay informed about: SLR lens on DSLR's