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Pentax question



 
 
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  #1  
Old February 6th 13, 07:46 PM posted to rec.photo.digital.slr-systems
Lyndon[_3_]
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Posts: 1
Default Pentax question

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.

Lyndon
  #2  
Old February 6th 13, 08:33 PM posted to rec.photo.digital.slr-systems
nospam
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Posts: 24,165
Default Pentax question

In article ,
Lyndon wrote:

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.


the lenses will fit but how well they work will vary. lenses from the
mx era (1980s) are not auto-focus, so you'll need to manually focus.
autofocus slrs are optimized for the camera to do the focusing (i.e.,
no split image or microprism focusing aids), but there might be an
electronic indication of focus. lenses without an 'a' setting won't be
able to fully support auto-exposure.

another issue is the crop factor of the sensor. pentax slrs have a
sensor that's smaller than a 35mm film frame with a crop factor of
1.5x, which means the effective focal length of any lens you use will
be 1.5x whatever is on the lens. thus, your 24mm will work as if it's a
36mm lens on 35mm film. to get a similar view of 24mm on 35mm film with
a pentax digital slr, you would need a 16mm lens. on the other hand,
you get a free bonus for telephoto. an 80-200mm works as a 120-300mm.
  #3  
Old February 6th 13, 08:44 PM posted to rec.photo.digital.slr-systems
[email protected]
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Posts: 1
Default Pentax question

On 2/6/2013 2:46 PM, Lyndon wrote:
I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.

Lyndon



nospam gave you a reasonably accurate answer. However, the digital world
is slightly different from film. Old lenses that were optimized for film
may or may not be OK for digital. Just because the lens mount fits,
doesn't mean the lens will function as with your old camera. You may
want to check for compatibility of features, if they are imp9ortant to
you, such as autofocus & autoexposure. When I switched to digital I
verified the functionality of the lenses I cared about and brought them
to the store so I could check for myself and see how comfortable i was.


HTH

--
PeterN
  #4  
Old February 6th 13, 09:05 PM posted to rec.photo.digital.slr-systems
me[_5_]
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Posts: 578
Default Pentax question

On Wed, 06 Feb 2013 11:46:14 -0800, Lyndon wrote:

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.


Google may be your friend. Try pentax dslr lens compatibility

First hit:
http://www.robertstech.com/compat.htm


  #5  
Old February 6th 13, 10:23 PM posted to rec.photo.digital.slr-systems
Alex Monro[_2_]
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Posts: 3
Default Pentax question

nospam wrote:

In article ,
Lyndon wrote:

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.


the lenses will fit but how well they work will vary. lenses from the
mx era (1980s) are not auto-focus, so you'll need to manually focus.
autofocus slrs are optimized for the camera to do the focusing (i.e.,
no split image or microprism focusing aids), but there might be an
electronic indication of focus. lenses without an 'a' setting won't be
able to fully support auto-exposure.

You can get split image focussing screens for Pentax and other makes
of DSLRs from various third parties, such as KatzEye:

http://www.katzeyeoptics.com

There are other less expensive suppliers, but I don't have details to
hand.

Also, the K30 has a focussing aid called focus peaking when using live
view to compose using the rear LCD screen. This in some ways makes the
area in focus even more clear than a microprism screen.

Pentax probably have the best backwards compatibility with old lenses
of any current make of DSLR cameras. Even non-A lenses can be supported
for metering via a stop down metering method. Stabilisation (Anti-Shake)
is supported if you enter the focal length manually at switch on. Even
screw-mount lenses are supported via a simple adapter.

another issue is the crop factor of the sensor. pentax slrs have a
sensor that's smaller than a 35mm film frame with a crop factor of
1.5x, which means the effective focal length of any lens you use will
be 1.5x whatever is on the lens. thus, your 24mm will work as if it's a
36mm lens on 35mm film. to get a similar view of 24mm on 35mm film with
a pentax digital slr, you would need a 16mm lens. on the other hand,
you get a free bonus for telephoto. an 80-200mm works as a 120-300mm.


Some lenses may not perform as well on digital sensors as they did on
film because a digital sensor is sensitive to the angle at which light
reaches it. This is likely to be a more frequent problem with wide
angle lenses. Vignetting and apparent chromatic aberration (actually
sensor blooming or optical crosstalk) are the main symptoms.
  #6  
Old February 6th 13, 10:34 PM posted to rec.photo.digital.slr-systems
nospam
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Posts: 24,165
Default Pentax question

In article , Alex Monro
wrote:

Some lenses may not perform as well on digital sensors as they did on
film because a digital sensor is sensitive to the angle at which light
reaches it. This is likely to be a more frequent problem with wide
angle lenses. Vignetting and apparent chromatic aberration (actually
sensor blooming or optical crosstalk) are the main symptoms.


that's a myth.

those problems existed with film, but often went unnoticed. many old
lenses just weren't that good.

the only issue that *might* be a problem is film lenses have little to
no coating on the rear elements and a digital sensor being perfectly
flat and very reflective (unlike film), can cause problems if the rear
element is also uncoated. however, it's rare.
  #7  
Old February 6th 13, 11:58 PM posted to rec.photo.digital.slr-systems
Fred McKenzie
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Posts: 214
Default Pentax question

In article ,
Lyndon wrote:

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.


Lyndon-

As others have mentioned, you will be able to use all of your old Pentax
lenses one way or another. There is a screw-mount adapter if you still
have any of these older lenses. I suggest you download the owner's
manual for the K30. It probably has a section that tells you how to use
older lenses.

I do not consider 24mm to be "very" wide, but it was great for taking
pictures when you could not back up any further! With the smaller K30
sensor, it will be more like a 35mm lens was on your MX. For the wide
angle case, go ahead and get the K30 with a kit lens. My Pentax *ist DS
DSLR came with a 18-55mm f/3.5-5.6 kit lens, equivalent to 27-82.5mm on
your MX.

I have tried using my older K-mount lenses with the *ist DS. Yes, it
can be done. However, it is not very convenient except with the "A"
lenses. In other words, you can use the old lenses but you may not like
it!

The KA lenses only need you to set the body for manual focus.
Everything else is automatic. (I can not speak for the anti-shake
feature. I do not think mine has that.)

Fred
  #8  
Old February 7th 13, 08:30 PM posted to rec.photo.digital.slr-systems
Wally
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Posts: 231
Default Pentax question

On Wed, 06 Feb 2013 15:33:39 -0500, nospam
wrote:

In article ,
Lyndon wrote:

I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.


the lenses will fit but how well they work will vary. lenses from the
mx era (1980s) are not auto-focus, so you'll need to manually focus.
autofocus slrs are optimized for the camera to do the focusing (i.e.,
no split image or microprism focusing aids), but there might be an
electronic indication of focus. lenses without an 'a' setting won't be
able to fully support auto-exposure.

another issue is the crop factor of the sensor. pentax slrs have a
sensor that's smaller than a 35mm film frame with a crop factor of
1.5x, which means the effective focal length of any lens you use will
be 1.5x whatever is on the lens. thus, your 24mm will work as if it's a
36mm lens on 35mm film. to get a similar view of 24mm on 35mm film with
a pentax digital slr, you would need a 16mm lens. on the other hand,
you get a free bonus for telephoto. an 80-200mm works as a 120-300mm.


I too was a Pentax man, and had a very nice collection of screw mount
lenses, all Super Multi Coated and in excellent condition, ranging
from 20mm to 500mm. These all metal and glass lenses were worshipped
in their day and still look and feel very impressive.

When it came time to go digital, I considered getting a system so I
could keep using these cherished lenses. (Couldn't figure out why
Pentax wouldn't release a Spotmatic with a digital back!) But after
due consideration, I opted instead for a whole new start (with Canon).
The main reason at the time was that the Canon lenses and bodies work
so well together, with features like autofocus (which I shunned
before). I was ready to embrace the new technologies. (Same reasoning
if I had chosen for Nikon.)

What I found out later was that the new Canon zoom lenses way
outperformed the old Takumar primes. See, I bought a low-cost adapter
and was able to use all those old lenses on the Canon body. And the
results were not good. The 500mm, which was VERY expensive in its day
and looks very impressive, had terrible chromatic aberration, poor
sharpness and low contrast. Even my consumer grade 70-300mm Canon zoom
with the 500D closeup attachment outperformed my 100mm Takumar Macro
prime.

I still love the Pentax Spotmatic system and will keep my core system
(body and 3 lenses), but it's because I'm a collector, and they were
fine items in their day. Everything is usable and I could go out and
shoot a roll of IR film, or shoot without a battery in sub-zero
weather no problem... but mostly it will sit on a shelf.

If good files are your goal, I suggest you select a good modern
system, whether Canon, Nikon, Sony, or other. I'm pretty sure your
photography will benefit.

W
  #9  
Old February 9th 13, 08:57 PM posted to rec.photo.digital.slr-systems
David Hare-Scott
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Posts: 89
Default Pentax question

John A. wrote:
On Thu, 7 Feb 2013 18:22:46 -0800 (PST), RichA
wrote:

On Feb 6, 2:46 pm, Lyndon wrote:
I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with
many Kmount lenses. I have noticed the K30 pentax camera and am
wondering if it will take the K mount lenses and get approx the
same results with them. For instance, I have a 24mm lens which is a
very wide angle lens. I have been told that earlier dslr cameras
could be modified to take such a lens, but it would no longer give
24mm film comparable pictures. Hope this isn't too confusing. But I
would like to keep using all my older K mount lens if possible with
similar digital result.

Lyndon


I'm frankly amazed Pentax is still in business. They have a market
share that makes Olympus's look big. I can only surmise they have
reasonable margins on what they sell.


Maybe...
http://www.petapixel.com/2012/06/30/...-satisfaction/


You will note that the ratings of the top three are very close together.
Without some assessment of the statistical spread of the ratings in the
sample saying 899 is better than 891 is better than 888 cannot be justified,
they might all be within the spread and the differences of no significance.
I couldn't see such a measure of significance in the linked full report
which doesn't even say what the sample size was, nor is the sampling
methodology explained. The footnote to the chart says "rankings were based
on numerical scores not statistical significance". A proper survey would be
the contrary.

This survey is well worth ignoring.

David

  #10  
Old February 10th 13, 04:08 AM posted to rec.photo.digital.slr-systems
John Turco
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Posts: 2,436
Default Pentax question

On 2/7/2013 8:22 PM, RichA wrote:
On Feb 6, 2:46 pm, Lyndon wrote:
I have been using Pentax film cameras for all of my photography life
(from the H-1a screw mounts). I currently have the MX camera with many
Kmount lenses. I have noticed the K30 pentax camera and am wondering if
it will take the K mount lenses and get approx the same results with
them. For instance, I have a 24mm lens which is a very wide angle
lens. I have been told that earlier dslr cameras could be modified to
take such a lens, but it would no longer give 24mm film comparable
pictures. Hope this isn't too confusing. But I would like to keep using
all my older K mount lens if possible with similar digital result.

Lyndon


I'm frankly amazed Pentax is still in business. They have a market
share that makes Olympus's look big. I can only surmise they have
reasonable margins on what they sell.



Pentax bodies boast much better build quality, than either Canon or
Nikon equipment. Even its entry-level DSLR cameras blow away the
competition, in this particular respect.

(I own a Pentax "K100D" and have always been impressed with its fine
feel and sturdiness.)

John
 




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