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Difference between lenses for film and lenses for digital?

 
 
One4All
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      01-07-2007
Is there a difference between lenses made for photographing with film
vs. digital photographing? I've read that there is. I ask because I
want to buy one of the new Pentax K cameras that will allow me to use
my film lenses. If there is a difference, is it so small as to make the
issue irrelevant?

 
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bluezfolk
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      01-07-2007

One4All wrote:
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?



AFAIK they are the same, but the film lenses focal lenghts are based on
the diagonal of the film size which may not be the same as the sensor
size (then again it may) so there may a discrepsancy in the focal
length. Thats why you always see digital zooms showing their 35mm
equivalant (which is what people are used to). If I were you I'd use
my film lenses on the digital.


Eric

 
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Malcolm Stewart
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      01-07-2007
"One4All" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ups.com...
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?
>


Digital sensors reflect more light than film, so "digital" lenses may have
different coatings, element shapes etc. to minimise any ghost images caused
by the light reflected off the sensor surface. It's not a new phenomenon -
I can find decades old slides where bright point images against a dark
background have their duller ghosts imaged quite clearly. Good for the
marketing types to have something "new" and attractive for us.

--
M Stewart
Milton Keynes, UK



--
Posted via a free Usenet account from http://www.teranews.com

 
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David J. Littleboy
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      01-07-2007

"One4All" <(E-Mail Removed)> wrote:
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?


For DSLRs, the basic rule is that _most_ digital lenses can't be used with
film, and that _most_ film lenses can be used with digital.

(Aside: Old Canon manual focus lenses are essentially unusable on any AF
Canon body (film or digital), and Nikon is an amazingly confusing can of
worms.)

My understanding is that Pentax is one of the better companies in terms of
supporting old film lenses. You should be able to use both your Pentax 67
and Pentax 645 lenses just fine (as I understand it: I went Mamiya and not
Pentax for my MF work, and my Mamiya 645 lenses are sort of usable on my
5D).

But you need to "read the fine print". The Dpreview Pentax discussion forum
should be able to answer specific questions.

http://forums.dpreview.com/forums/forum.asp?forum=1036

David J. Littleboy
Tokyo, Japan


 
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Stephen M. Dunn
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      01-07-2007
In article <(E-Mail Removed). com> "One4All" <(E-Mail Removed)> writes:
$Is there a difference between lenses made for photographing with film
$vs. digital photographing? I've read that there is. I ask because I
$want to buy one of the new Pentax K cameras that will allow me to use
$my film lenses. If there is a difference, is it so small as to make the
$issue irrelevant?

There are a couple of technical differences.

One of the technical differences is that most DSLRs have sensors
which are substantially smaller than the 35mm film frame. Lenses
designed for use on 35mm bodies have to project an image circle
which is large enough to cover the 35mm frame; lenses designed for
digital cameras can get away with projecting a smaller image circle,
and that can make the lens smaller and lighter than an equivalent
lens for a 35mm camera would be. (It should also be cheaper, as it
requires fewer raw materials, but the reduction in materials costs
doesn't always make it through the production, marketing, and
distribution process to the end user.)

The other is that digital sensors tend to be more reflective than
film. Lenses include anti-reflection features, but in the film days,
these were primarily to cut down on problems caused by light reflecting
off surfaces within the lens itself. On a digital body, light
reflecting off the sensor is another issue, and so digital lenses
typically take additional anti-reflection measures designed to
reduce the impact of such reflections.

That said, lots of us use "film" lenses on our DSLRs with great
results, which goes to show that a substantial part of the reason
for existence of "digital" lenses is marketing rather than technical.
--
Stephen M. Dunn <(E-Mail Removed)>
>>>----------------> http://www.stevedunn.ca/ <----------------<<<

------------------------------------------------------------------
Say hi to my cat -- http://www.stevedunn.ca/photos/toby/
 
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nick c
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      01-07-2007
One4All wrote:
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?
>


According to Canon there is a difference, how much of a difference or
does the difference matter in the real world is debatable. Canon makes
lenses they label as DO. These lenses direct light entering the sensor
differently than conventional lenses. Conventional lenses direct light
in an angular manner with is suitable for film but not as well suited
for a sensor.

Does it really matter? Will photographic differences be obvious? Not
that I can see in a finished print. At this time, in availability of
lenses and lens design, I think it's irrelevant.





 
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Chuck Dubois
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      01-07-2007
Is there an adapter that will allow the use of lenses from other brands on
a Canon 20D? Is there any place to buy quality used lenses?
 
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Ken Lucke
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      01-07-2007
In article <(E-Mail Removed)> , Chuck
Dubois <(E-Mail Removed)> wrote:

> Is there an adapter that will allow the use of lenses from other brands on
> a Canon 20D?


Yes.

> Is there any place to buy quality used lenses?


Yes.

--
You need only reflect that one of the best ways to get yourself a
reputation as a dangerous citizen these days is to go about repeating
the very phrases which our founding fathers used in the struggle for
independence.
-- Charles A. Beard
 
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One4All
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      01-07-2007

One4All wrote:
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?


Thanks to all for their very relevant information.

 
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Steve Wolfe
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      01-07-2007
> Is there a difference between lenses made for photographing with film
> vs. digital photographing? I've read that there is. I ask because I
> want to buy one of the new Pentax K cameras that will allow me to use
> my film lenses. If there is a difference, is it so small as to make the
> issue irrelevant?


According to the "Eyes of EOS" book, there is one possible difference.
Without going into technical detail, there are design characteristics of
particular individual elements within the lens which can make the lens
slightly more prone to flare *if* something is reflected back into the lens
from the film plane. Because digital sensors are more reflective than film,
Canon says that they have gone out of their way to produce lenses with more
appropriately-curved elements to reduce that phenomenon. There is also
consideration as to the coatings on individual elements, there is a pretty
wide range of combinations of which elements get coated in what ways, and
with what materials. (That can also infuence the color balance as well
resolution or flare.)

That being said, *good*, modern lenses (even those that weren't "designed
for digital") don't really seem to display more flare with digital than they
do with film, so there is evidence that if you're buying decent lenses to
begin with, there's nothing to worry about. Cheap lenses with particularly
bad design or particularly cheap coatings may show a bit more flare with
digital, but such lenses are going to be poor-performers even with film.

More than anything else, "designed for digital" seems to simply mean "This
lens has a smaller image circle, so it won't work on a film or full-frame
camera." (Perhaps unless you're buying bottom-of-the-barrel lenses anyway,
in which case, you're screwed anyway.)

steve


 
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