Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-09-2011, 02:51 AM   #76
Pentaxian
gazonk's Avatar

Join Date: Feb 2009
Location: Oslo area, Norway
Photos: Gallery | Albums
Posts: 3,746
QuoteOriginally posted by falconeye Quote
And only about 1.8x vs. a 24MP K-5mkII or NEX7, i.e., not more than what a 1.7x TC provides.
That's assuming the TC doesn't degrade resolution, isn't it? (I.e. not quite so IRL?)

09-09-2011, 04:07 AM   #77
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by smc Quote
so if I understand your previous post, for longer lenses, we are limited to glass that is sharp wide open at F5.6?
Sharpest at f/4 would be better. But you're not limited. You just don't get the full 12MP resolution. At f/8, you still get some 3 MP (after sharpening) which mean the toy lenses (some are f/8 fixed) may still be good enough for HD video.
09-09-2011, 04:09 AM   #78
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by gazonk Quote
That's assuming the TC doesn't degrade resolution, isn't it? (I.e. not quite so IRL?)
Yes. But even using a K-5, I've seen detail with the Pentax 1.7x TC I couldn't see without. When using good lenses.

But you're right, the Q is the better TC, about 1.8x (24MP) to 2.2x (16MP). Unfortunately, w/o AF.
09-09-2011, 09:46 AM   #79
Veteran Member




Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by falconeye Quote
What has been said here about the diffraction limits is not accurate.

I tried to make a more accurate statements here:

Basically, the Q is "influenced" by diffraction between f/2 and f/4 (loosing contrast in a recoverable way using sharpening tools as MTF doesn't become zero at Nyquist) and then looses resolution when going beyond (e.g., at f/8, 100% crops look visibly soft).

Therefore, shooting a DA*300 or DA*60-250 with a Q at their sharpest aperture (about f/5.0) will still deliver plenty of detail a K-5 won't render.

But the additional reach will not be that of the crop factor. It will be only roughly be 2-2.5 vs. a K-5 (because you can crop a K-5 image more). And only about 1.8x vs. a 24MP K-5mkII or NEX7, i.e., not more than what a 1.7x TC provides. OTOH, the * lenses do resolve enough detail to exploit this ~2x factor near the center.
Hi Falk,

Thanks for doing the math! Your calculations pretty much confirm what I felt intuitively -- that my premium teles would work pretty well with the Q + adapter. The thing that I didn't factor into my considerations was the comparison with K-5 crops, so the actual advantage will not be as great as I had anticipated .

Luckily, I have some really good teles to play with -- D FA 100/2.8 Macro, Tamron SP 180/2.5, Sigma EX 180/3.5 Macro, A* 200/2.8, FA* 300/4.5, FA* 300/2.8, Sigma EX 300/2.8 APO, so it should still be fun as these all resolve pretty well wider than f5.6. . . now I need to find some tripod rings for some of these lenses. . .and a very good light tripod -- it never ends. . .

The IQ also holds up pretty well with most of these lenses with the Sigma EX 1.4x APO TC or the F 1.7x AFA, so these will also be worth a try with the faster lenses, IMO.

Scott

09-09-2011, 10:39 AM   #80
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by snostorm Quote
D FA 100/2.8 Macro
Tamron SP 180/2.5
Sigma EX 180/3.5 Macro
A* 200/2.8
FA* 300/4.5
FA* 300/2.8
Sigma EX 300/2.8 APO
Scott, the Q provides an excellent opportunity to find out what these fine lenses are really capable of. Measurements like photozone.de cannot go beyond the 4.8/6µm of sensors used.

Of course, the 300mm are the most interesting ones. Nevertheless, my own measurements tell me that the DA*60-250 at 250mm may resolve equally well in the center.
09-09-2011, 11:10 AM   #81
Veteran Member
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,806
QuoteOriginally posted by falconeye Quote
Of course, the 300mm are the most interesting ones. Nevertheless, my own measurements tell me that the DA*60-250 at 250mm may resolve equally well in the center.
What about the 200mm f2.8? That should be a great match optically.
And the D FA 100mm is so compact, it won't look out of place at all.
09-09-2011, 11:23 AM   #82
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by audiobomber Quote
What about the 200mm f2.8? That should be a great match optically.
And the D FA 100mm is so compact, it won't look out of place at all.
I would always prefer a DA*300 on a K-5 over the DFA100 on a Q ...

09-09-2011, 11:27 AM   #83
Veteran Member
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,806
QuoteOriginally posted by falconeye Quote
I would always prefer a DA*300 on a K-5 over the DFA100 on a Q ...
Oh sure, except of course for size.
09-09-2011, 11:50 AM   #84
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by audiobomber Quote
Oh sure, except of course for size.
Ok, if you prefer to keep it small ...
I'd have a serious look at the DA 70 Ltd. It seems to have the biggest resolution muscle of all longer DAs.

On the Q, use it at f/3.2 and enjoy a true 400mm lens FoV (35mm equivalent).
09-09-2011, 12:05 PM   #85
Veteran Member




Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by audiobomber Quote
What about the 200mm f2.8? That should be a great match optically.
And the D FA 100mm is so compact, it won't look out of place at all.
Hi Dan,

The possibility of using the smaller teles are one of the reasons why I initially got pumped for the Q. If I can get similar results with the little body and the D FA 100 Macro as I get with a DSLR and a 300/2.8, then the size and weight advantages will be well worth the Q's cost for me. This is the one thing that those who are comparing the size of the Q to the µ4/3 and APS-C MILCs don't seem to get. With either of the latter bodies, they'd still have to carry the 300/2.8 to get equivalent reach (FOV) and lens speed. . .not to mention the tripod needed to support it all, and this just can't come close to comparing to the convenience of a 20 oz alternative, despite some loss of ultimate IQ potential.

All of the Pentax 200/2.8s are exemplary lenses if my A*200/2.8 is any indication, and most reviewers of the FA* and DA* versions seem to confirm that if anything, the optics have just gotten better (though not really that much -- it's hard to improve much on "superb" ). Since they'd all be fully manual with the Q, the A* is looking like it's going to be a great match with the Q though it's a bit heavier than the AF versions . It's currently a bit of an orphaned child with my DSLRs since the FL is not quite long enough for my use, so it will be very happy to get the call more often. . .I can also see using the Tamron SP 80-200/2.8 Adaptall 2, even though it's something of a beast in comparison, but it's a great lens.

Scott
09-09-2011, 06:49 PM   #86
Site Supporter
Site Supporter




Join Date: Sep 2006
Location: midwest, United States
Photos: Gallery | Albums
Posts: 5,714
Can't wait to try the Q with some of my longer lenses. For Pentax: 77 ltd, DFA 100 and A*200 for macro, and DA*300 for wildlife. From Oympus: 55 1.2, 100 2, 180 2, and 350 2.8. Also have the matched 1.4 teleconverter. The Q is going to be a fun camera!
thanks
barondla
Would still love to see a field compressor.
09-12-2011, 05:35 AM   #87
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
Rayqual announced new adapters with built-in tripod mount

They also show new adapters for the Q.
http://www.rayqual.com/

09-12-2011, 06:07 AM   #88
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,871
QuoteOriginally posted by jogiba Quote
They also show new adapters for the Q.
http://www.rayqual.com/
All manual focus only.

Now, Olympus, Panasonic, Sony and Nikon mirrorless all support AF with their adapters:
So, it will become increasingly tough for Pentax to market a mirrorless system with no AF adapters available.
09-12-2011, 06:57 AM   #89
Veteran Member




Join Date: Jun 2009
Posts: 11,913
QuoteOriginally posted by falconeye Quote
All manual focus only.
...
So, it will become increasingly tough for Pentax to market a mirrorless system with no AF adapters available.
I'm not so sure. The NEX LA-EA2 AF adapter is large and clunky and costs a few hundred. Things get even more ungainly when you add a normal sized A-mount lens onto the Sony adapter.


[image from ephotozine's review of the NEX5N

The penalty of extra bulk and $ probably means these sort of add-ons aren't a must-have feature for compact mirrorless. I wouldn't be surprised if hardly anyone buys these things.
09-12-2011, 07:18 AM   #90
Veteran Member
froeschle's Avatar

Join Date: Sep 2007
Location: Germany
Photos: Gallery
Posts: 552
New Olympus Four Thirds to M43 adapter
Patent
Reply
« - | New Q in hand »

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, k-mount adapter, mirrorless, pentax q, pentax q10, pentax q7, q10, q7
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax Q to K mount adapter ? jogiba Pentax Camera and Field Accessories 23 12-08-2012 12:47 AM
Can I use PK mount M42 adapter on Pentax K-r vass Pentax K-r 6 12-28-2010 07:08 AM
For Sale - Sold: Genuine Pentax Mount Adapter K (M42 to K-mount) zx-m Sold Items 6 01-30-2009 01:22 AM
Pentax Mount Adapter K vs Chinese Mount Adapter Vylen Pentax SLR Lens Discussion 7 01-23-2009 01:03 AM
For Sale - Sold: *New* Pentax Mount Adapter-K M42 to K-Mount X Man Sold Items 4 12-31-2008 04:10 PM



All times are GMT -7. The time now is 04:58 PM. | 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