Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-05-2008, 10:07 AM   #76
Veteran Member




Join Date: Dec 2006
Location: Outside of Philly
Posts: 1,564
Source for this? Why would Sigma come up with an entirely different HSM implementation for the Pentax mount?

QuoteOriginally posted by falconeye Quote
Nor do the new Sigma HSM lenses for Pentax. Unfortunately. The HSM Sigmas are even slower than Pentax SDM because of requiring more steps to aquire focus. Tried them at Photokina.

I am still curious to try a ringmotor lens on a Pentax some day


11-05-2008, 10:11 AM   #77
Veteran Member
Gooshin's Avatar

Join Date: Sep 2007
Location: Toronto, the one in Canada.
Posts: 5,611
QuoteOriginally posted by egordon99 Quote
Source for this? Why would Sigma come up with an entirely different HSM implementation for the Pentax mount?
they have to do alot of things differently for the pentax mount

1. aperture lever
2. screw driver server connection

and on top of that throw in HSM, which probably required a redesign in the light of the additional parts ^^^

but thats just my guess.

Last edited by Gooshin; 11-05-2008 at 10:22 AM.
11-05-2008, 10:26 AM   #78
Veteran Member
RBellavance's Avatar

Join Date: Nov 2006
Location: Near Montréal, Canada
Photos: Gallery
Posts: 1,716
QuoteOriginally posted by Gooshin Quote
they have to do alot of things differently for the pentax mount

1. aperture lever
2. screw driver server connection
AFAIK, Nikon's F-mount uses a mechanical aperture coupling as well.

I'm not sure what you mean by your 2nd point.
11-05-2008, 10:32 AM   #79
Veteran Member




Join Date: Dec 2006
Location: Outside of Philly
Posts: 1,564
But the Sigma HSM lenses are NOT compatible with non-SDM bodies, so there is NO "screw driver server connection"

And HSM has already been "throw in" as it exists on the Canikon versions of the lens.

EVERY comment I have seen points to the Pentax Sigma HSM lenses using the same ring-HSM as Canikon.

And RBellavance covered your first point, so again, HOW/WHY would Sigma be using a completely different HSM implementation for Pentax mounts?



QuoteOriginally posted by Gooshin Quote
they have to do alot of things differently for the pentax mount

1. aperture lever
2. screw driver server connection

and on top of that throw in HSM, which probably required a redesign in the light of the additional parts ^^^

but thats just my guess.


11-05-2008, 04:42 PM   #80
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,862
QuoteOriginally posted by egordon99 Quote
Source for this? Why would Sigma come up with an entirely different HSM implementation for the Pentax mount?
Looking at the Sigma web site, I now see many HSM lenses for Pentax. My comment applies to Sigma 2.8/70-200mm EX DG Macro HSM II. I tried it myself at Photokina on a K20D and talked about it with THE Pentax Expert at Sigma Germany at their booth in Cologne. I "believe" to remember that the statement was "no ringmotor". And I know for sure that my screw drive FA*300/4.5 focusses a lot faster.
11-07-2008, 06:53 AM   #81
Veteran Member




Join Date: Jul 2008
Location: Sweden, Umea
Posts: 869
I can tell you why aps-c sensors >>> FF

Take a look at our teles: We got 300/4 and 200/2,8 (I know there are other teles out there )

With the "crop" factor they will corespond to 450/4 and 300/2,8. If I would buy those lenses for a FF camera today ie Canon or nikon. I would have to pay 5 times the money.

So for tiny amount of money, we will get those legendary focal distance and aparture

So next time some FF canon/nikon shoter complains about pentax not having any long teles, correct them.
11-07-2008, 07:15 AM   #82
Veteran Member
Gooshin's Avatar

Join Date: Sep 2007
Location: Toronto, the one in Canada.
Posts: 5,611
QuoteOriginally posted by melander Quote
I can tell you why aps-c sensors >>> FF

Take a look at our teles: We got 300/4 and 200/2,8 (I know there are other teles out there )

With the "crop" factor they will corespond to 450/4 and 300/2,8. If I would buy those lenses for a FF camera today ie Canon or nikon. I would have to pay 5 times the money.

So for tiny amount of money, we will get those legendary focal distance and aparture

So next time some FF canon/nikon shoter complains about pentax not having any long teles, correct them.
you phail

focal length is reponsible for magnification, the PHYSICAL focal length

that 300 lens will still magnify like a 300 lens, you will just have a FIELD OF VIEW that is akin to a 450 lens.

so you gain nothing in magnificaton, and lose in your field of view.

if this is better, its only better for those that cant afford a 500 or 600 fast telephoto and so they make due with less magnified but more cropped images because 6 mega pixels is all they can afford.

Last edited by Gooshin; 11-07-2008 at 07:37 AM.
11-07-2008, 07:17 AM   #83
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by melander Quote
I can tell you why aps-c sensors >>> FF

Take a look at our teles: We got 300/4 and 200/2,8 (I know there are other teles out there )

With the "crop" factor they will corespond to 450/4 and 300/2,8. If I would buy those lenses for a FF camera today ie Canon or nikon. I would have to pay 5 times the money.

So for tiny amount of money, we will get those legendary focal distance and aparture

So next time some FF canon/nikon shoter complains about pentax not having any long teles, correct them.
Long telephotos are all well and good, but with the K Mount register distance, wide angle lenses are compromised. Note that the widest rectilinear lens available from Pentax is the 12-24.
It is a pretty good lens, but not a great lens, and isn't what I would call super wide angle. My 15mm on film is a lot wider.
The 14mm is a better lens than the zoom, but is only a so-so wide angle.

If you like telephoto lenses, then the cropped sensor has some advantages but if you like wides, then full frame has advantages.
FF Nikon and Canon shooters have the best of both worlds in this case, as they can choose between cropped sensor cameras and full frame cameras.

11-07-2008, 07:19 AM   #84
Veteran Member




Join Date: Dec 2006
Location: Outside of Philly
Posts: 1,564
OK, I'm a crop-Canonite, so I'll complain about Pentax not having a 400mm f/5.6 or 100-400mm zoom

QuoteOriginally posted by melander Quote
So next time some FF canon/nikon shoter complains about pentax not having any long teles, correct them.
Gooshin - Your "phail" comment was hilarious


Oh, and melander - OK, a 300mm f/4 on a crop body will have the same FOV as a 450mm lens on a FF body, but assuming the same framing, the DOF of the 300mm f/4 (on crop) will NOT be the same as 450mm f/4 on FF. So again, PHAIL
11-07-2008, 07:22 AM   #85
Veteran Member




Join Date: Dec 2006
Location: Outside of Philly
Posts: 1,564
And if you want SUPER-FREAKIN' WIDE, stick the Sigma 12-24mm on a full-frame body.

Another (related) advantage to FF is the ability to use a 24mm f/1.4 with the FOV equivalent of 17mm on a crop (the "anti-crop factor") FAST and VERY WIDE!

(or go third party with a Sigma 20mm f/1.8 for ~12mm equivalent)

QuoteOriginally posted by Wheatfield Quote
Long telephotos are all well and good, but with the K Mount register distance, wide angle lenses are compromised. Note that the widest rectilinear lens available from Pentax is the 12-24.
It is a pretty good lens, but not a great lens, and isn't what I would call super wide angle. My 15mm on film is a lot wider.
The 14mm is a better lens than the zoom, but is only a so-so wide angle.

If you like telephoto lenses, then the cropped sensor has some advantages but if you like wides, then full frame has advantages.
FF Nikon and Canon shooters have the best of both worlds in this case, as they can choose between cropped sensor cameras and full frame cameras.
11-07-2008, 08:09 AM   #86
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by egordon99 Quote
And if you want SUPER-FREAKIN' WIDE, stick the Sigma 12-24mm on a full-frame body.

Another (related) advantage to FF is the ability to use a 24mm f/1.4 with the FOV equivalent of 17mm on a crop (the "anti-crop factor") FAST and VERY WIDE!

(or go third party with a Sigma 20mm f/1.8 for ~12mm equivalent)
Sigma? You are kidding, right?
11-07-2008, 08:22 AM   #87
Veteran Member




Join Date: Dec 2006
Location: Outside of Philly
Posts: 1,564
Kidding about what? The Sigma 12-24mm is a Full-frame lens, and AFAIK the widest rectilinear lens available for full frame.

Or the 20mm? OK, I'm sure it's not "L" quality, but I'm sure someone somewhere has been able to take a decent picture with one. And it's alot cheaper than the 24L (and wider )

Sigma | Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF | 411101

QuoteOriginally posted by Wheatfield Quote
Sigma? You are kidding, right?
11-07-2008, 10:11 AM   #88
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,225
QuoteOriginally posted by melander Quote
I can tell you why aps-c sensors >>> FF

Take a look at our teles: We got 300/4 and 200/2,8 (I know there are other teles out there )

With the "crop" factor they will corespond to 450/4 and 300/2,8. If I would buy those lenses for a FF camera today ie Canon or nikon. I would have to pay 5 times the money.

So for tiny amount of money, we will get those legendary focal distance and aparture

So next time some FF canon/nikon shoter complains about pentax not having any long teles, correct them.
There are tons of comments on this one, so I will jump in with my short bit. As Gooshin points out, the crop factor is just that. You take the center of the image and ignore the rest. It is analogous to cropping in the darkroom and enlarging the cropped image. The end result is the potential for a certain amount of image degradation relative to what you might expect from the same lens at a closer shooting distance on FF. The cropping amplifies whatever lens faults might exist. Whether there would be poorer image quality compared to a longer lens at the same shooting distance on FF depends on the lenses in question.

I am expecting some film in the mail today or tomorrow and am planning on doing a few comparison shots using the same optics with the same subjects and same composition on both film and my K10D. The film is the new, extremely fine grain Kodak Ektar 100 so the comparison should prove interesting. I plan on using my Sigma 50 Macro, Pentax-A 50/1.7, Pentax FA-35, and Jupiter-9 85/2. I might also include the Tamron 28/2.5, a lens that I know performs much better on film than on the K10D.

Steve
11-07-2008, 10:20 AM   #89
Veteran Member




Join Date: Jul 2008
Location: Sweden, Umea
Posts: 869
I do buy that you get a different DoF when the crop comes into place. BUT you will still get a sharp 15MP shot with a high resolution 300mm glass that will be > than if you crop a FF 300mm Shot. Imo
11-07-2008, 10:25 AM   #90
Veteran Member
Gooshin's Avatar

Join Date: Sep 2007
Location: Toronto, the one in Canada.
Posts: 5,611
QuoteOriginally posted by melander Quote
I do buy that you get a different DoF when the crop comes into place. BUT you will still get a sharp 15MP shot with a high resolution 300mm glass that will be > than if you crop a FF 300mm Shot. Imo
>than if you crop a 24MP FF300 Shot...hmmm
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, ff, iso, lenses, lot, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Buying locally, when you can. The advantage. Ed n Georgia General Talk 2 10-26-2010 07:55 AM
Advantage of mixed system yusuf Pentax DSLR Discussion 10 10-05-2010 07:07 AM
One EVIL/MILC/etc advantage Eruditass Non-Pentax Cameras: Canon, Nikon, etc. 21 06-07-2010 05:14 AM
advantage of SDM lenses Wulifou Pentax SLR Lens Discussion 16 10-20-2008 10:02 AM
advantage of CMOS vanguy Pentax DSLR Discussion 4 01-23-2008 10:27 PM



All times are GMT -7. The time now is 10:53 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top