Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-12-2013, 01:25 PM   #706
Veteran Member
tclausen's Avatar

Join Date: May 2012
Posts: 1,397
QuoteOriginally posted by Cynog Ap Brychan Quote
That's not a lens in that picture! That's a Saturn 5 second stage!
Close, but no cigar -- rather, this:



Saturn IB at KSC, taken with a K-01 and the 21mm ltd, stopped down to get the starburst effect (& I disagree with Cynog Ap Brychan simply because I don't have a good photo of a Saturn V)

03-12-2013, 03:28 PM   #707
Veteran Member
Cynog Ap Brychan's Avatar

Join Date: Sep 2012
Location: Gloucester
Photos: Gallery
Posts: 1,199
QuoteOriginally posted by tclausen Quote
Saturn IB at KSC, taken with a K-01 and the 21mm ltd, stopped down to get the starburst effect (& I disagree with Cynog Ap Brychan simply because I don't have a good photo of a Saturn V)
Now that's what I call a telephoto!
03-12-2013, 05:35 PM   #708
Site Supporter
Site Supporter
Digitalis's Avatar

Join Date: Mar 2009
Location: Melbourne, Victoria
Photos: Gallery
Posts: 11,694
QuoteOriginally posted by normhead Quote
And I've blown up a couple of carbon fibre tennis rackets... the plastic stuff is good while it's good, but if you ever stress it so much it lets go, there's not much left.
The resins used to bind carbon fibre composites are highly susceptible to damage from ultraviolet light - the best way to protect CF products is to have them painted over by a thick coat of paint that doesn't get scratched or damaged*. But considering how tennis players play these days I don't even think stolid tungsten alloy would survive for long.

QuoteOriginally posted by johnmflores Quote
One of the good things about metals is how they fail; they will bend before they breaks
But that usually means something will either be bent or deformed by the malfunctioning part as well - also metal gears can leave shredded parts of themselves all over the interior of a camera which is a PITA to clean out and prevent further failures.

*one of my biggest criticisms of CF tripods is the exposed composite material.
03-12-2013, 06:09 PM   #709
Site Supporter
Site Supporter
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 8,183
QuoteOriginally posted by ElJamoquio Quote
'Plastics' are called 'plastic' because they deform plastically (bending) rather than brittle-ly (breaking).

Not all plastics are like that of course, which is why many engineers prefer the term 'polymer'.

The ductility of CFRP is dictated by the carbon fiber, not the polymer.

As others have mentioned you could easily mould plastic into a shape that is much stronger than the equivalent-cost cast/stamped/machined metal. It just depends on what you want to do.

I have no doubts that the D600 is less durable than the top model (D3 or something). I also have no doubts that the D600 will not fail at the mount for me. I don't hand-hold 800mm lenses.
I don't mean to be picky (but I am) however the term "plastic" was originally used to distinguish the non-linear stress-strain curve of non-metallic materials from the linear ("elastic") characteristic of metallic materials. Metals also deform in a "plastic" manner beyond the elastic limit, ie where the deformation becomes permanent.

Incidentally, I had a tripod-mounted SP-F attached to a 300/4 SMC Takumar (all metal and glass both sides of the mount) knocked over by an errant small daughter, many years ago. All survived (even the daughter) with practically no damage. I wouldn't be over-confident about the same outcome with a non-metallic mount, but our longevity expectations are lower these days, anyway (except for daughters, naturally).

03-12-2013, 06:30 PM   #710
Banned




Join Date: Mar 2012
Location: Charleston & Pittsburgh
Photos: Albums
Posts: 1,668
QuoteOriginally posted by Sol Invictus Quote
Weakling. I regularly hand hold the Canon EF 1200mm f/5.6 L USM Lens...
http://static.bhphoto.com/images/images200x200/870227.jpg

Lens only weight; mostly air with a few very finely polished mirrors = Just shy of #200 depending upon finderscope.

Complete assembly = About six hundred pounds.

But at least it's an f8.o aperature with a focal length of over 4000mm
03-12-2013, 08:00 PM   #711
Veteran Member




Join Date: Feb 2011
Posts: 4,873
QuoteOriginally posted by RobA_Oz Quote
I don't mean to be picky (but I am) however the term "plastic" was originally used to distinguish the non-linear stress-strain curve of non-metallic materials from the linear ("elastic") characteristic of metallic materials. Metals also deform in a "plastic" manner beyond the elastic limit, ie where the deformation becomes permanent.
I'm aware.
03-12-2013, 10:36 PM   #712
Site Supporter
Site Supporter
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 8,183
QuoteOriginally posted by ElJamoquio Quote
I'm aware.
I suspected as much, but others may not have been.

03-13-2013, 05:31 PM   #713
Veteran Member
Wired's Avatar

Join Date: Aug 2009
Location: Edmonton, AB
Photos: Gallery | Albums
Posts: 2,519
QuoteOriginally posted by Sol Invictus Quote
Fair enough, I see what you mean. Although I have yet to see a rash of broken lens mounts on the D7000 and D600.
No rash of mount breaks, but I have heard of it. I'm sure its less comon than the SDM faliures. That being said, I'm scare to get the 70-200 f2.8 for my D600 and let it hang with my Black Rapid strap... more so than I am of SDM faliure which I haven't experienced.
03-13-2013, 09:02 PM   #714
Veteran Member
johnmflores's Avatar

Join Date: Apr 2009
Location: Somerville, NJ
Photos: Gallery | Albums
Posts: 5,361
QuoteOriginally posted by ElJamoquio Quote
'Plastics' are called 'plastic' because they deform plastically (bending) rather than brittle-ly (breaking).

Not all plastics are like that of course, which is why many engineers prefer the term 'polymer'.

The ductility of CFRP is dictated by the carbon fiber, not the polymer.

As others have mentioned you could easily mould plastic into a shape that is much stronger than the equivalent-cost cast/stamped/machined metal. It just depends on what you want to do.

I have no doubts that the D600 is less durable than the top model (D3 or something). I also have no doubts that the D600 will not fail at the mount for me. I don't hand-hold 800mm lenses.
Thanks for the refresher.

See dad, I would have made an awful engineer.

The D600 is likely less durable than the top model simply because it's designed to a lower price point, not due to some inherent disadvantage of the materials.
03-13-2013, 09:35 PM   #715
Forum Member




Join Date: May 2008
Location: BC
Posts: 93
re: 70-200mm

Wired:

You'd probably hang the camera off of the 70-200mm with the black rapid, at least that's how I do it anyhow. The 70-200mm weighs like 3x more than the camera, and it hangs pretty nice off the tripod mount. Doesn't work like that for the 24-70mm, but it doesn't feel like it's going to break any time soon.
03-22-2013, 06:08 PM   #716
Ash
Loyal Site Supporter
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 23,920
Getting back to topic, my chief drive for this long-awaited FF is a very selfish desire to get every fine detail I can out of the FA Limited lenses. I don't mind them on APS-C either though, so it's no big loss at all to me if it doesn't come in the next 10-20 years.
03-23-2013, 02:08 PM   #717
Ash
Loyal Site Supporter
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 23,920
Pentax's incremental upgrades are slight but deliberate and calculated. The FF model might well come out to be 24 Mp and thus have minimal benefit over the K-5 on paper, but practically, there may be more to it than meets the eye - high ISO capability, good size/weight for a FF camera, and a slick AF system.
03-23-2013, 02:27 PM - 1 Like   #718
Loyal Site Supporter
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: Working From Home
Photos: Gallery | Albums
Posts: 26,276
QuoteOriginally posted by Ash Quote
Pentax's incremental upgrades are slight but deliberate and calculated. The FF model might well come out to be 24 Mp and thus have minimal benefit over the K-5 on paper, but practically, there may be more to it than meets the eye - high ISO capability, good size/weight for a FF camera, and a slick AF system.
As I wrote on another thread, products are tactics, market segments are strategy.
03-23-2013, 06:16 PM   #719
Ash
Loyal Site Supporter
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 23,920
QuoteOriginally posted by monochrome Quote
As I wrote on another thread, products are tactics, market segments are strategy.
Nicely put.
03-24-2013, 09:17 AM   #720
Veteran Member




Join Date: Feb 2011
Posts: 4,873
QuoteOriginally posted by Ash Quote
Pentax's incremental upgrades are slight but deliberate and calculated. The FF model might well come out to be 24 Mp and thus have minimal benefit over the K-5 on paper, but practically, there may be more to it than meets the eye - high ISO capability, good size/weight for a FF camera, and a slick AF system.
A 24MP FF will have ~40-50% better resolving power on the same lens as the K-5.
The FF will have more control over DOF (unless you're shooting at F/22 on APS-C).
The noise will be better if you tolerate or want smaller DOF.
The viewfinder will almost certainly be bigger and brighter.
Tracking moving subjects will be easier while maintaining equal resolution.
The AF point will be smaller for the same AF-point-performance, meaning that AF will be more precise inherently.

Last edited by ElJamoquio; 03-24-2013 at 09:23 AM.
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!
change, cp, ff, full-frame, interview, pentax, photokina, question, time, video
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax Full Frame dand33 Welcomes and Introductions 5 10-16-2012 07:50 AM
K30, K5n, K3 and maybe full-frame at Photokina... frankfanrui Pentax News and Rumors 638 09-06-2012 07:08 AM
Pentax To Announce the K-3 Full Frame DSLR At Photokina Danny Delcambre Pentax News and Rumors 662 09-04-2012 05:05 PM
Tokina plans 16-28mm F2.8 for full-frame. Is that a singht? i83N Pentax News and Rumors 20 03-03-2010 02:19 AM
Any plans for full frame soon? FrancisK7 Photographic Technique 2 09-22-2008 07:15 PM



All times are GMT -7. The time now is 04:50 AM. | See also: NikonForums.com, CanonForums.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