Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-26-2011, 10:04 AM   #1036
Pentaxian
johnmflores's Avatar

Join Date: Apr 2009
Location: Somerville, NJ
Photos: Gallery | Albums
Posts: 5,096
QuoteOriginally posted by ogl Quote
~ 224 mm/f16 equiv. for FF.

FA77/1.8 ~ 430 mm/f10

FA50/1.4 ~ 280 mm/f8


hard to say that such adapter has any serious sense. just for fun IMO.
Paper thin DOF is not the Holy Grail of photography.

08-26-2011, 12:27 PM   #1037
Loyal Site Supporter
eddie1960's Avatar

Join Date: Aug 2010
Location: Toronto
Photos: Gallery | Albums
Posts: 12,234
QuoteOriginally posted by johnmflores Quote
Paper thin DOF is not the Holy Grail of photography.
tell that to the people on all the Full Frame threads. it's the number one argument for FF (erroneously if you ask me; there are better reasons for FF)
08-26-2011, 01:08 PM   #1038
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,197
QuoteOriginally posted by eddie1960 Quote
tell that to the people on all the Full Frame threads. it's the number one argument for FF (erroneously if you ask me; there are better reasons for FF)
Not really. It gets kicked around. I would say one of the main arguments has more to do with the actual size of the sensor relative to the fov which favors the wide angle lenses more than aps-c does.
08-26-2011, 01:44 PM   #1039
Veteran Member
ghelary's Avatar

Join Date: Jul 2008
Location: Paris, France
Photos: Gallery
Posts: 617
QuoteOriginally posted by ogl Quote
~ 224 mm/f16 equiv. for FF.

FA77/1.8 ~ 430 mm/f10

FA50/1.4 ~ 280 mm/f8


hard to say that such adapter has any serious sense. just for fun IMO.
Nice trolling attempt. Now please learn what F-stop means.

08-26-2011, 03:56 PM   #1040
Veteran Member
devorama's Avatar

Join Date: Apr 2009
Location: Chicago, IL
Photos: Gallery | Albums
Posts: 638
Someone has some real world photos from the Q at full res. Some are ISO 1600 and 1250.

http://www.yaotomi.co.jp/blog/used/2011/08/pentax-q-2.html
08-26-2011, 06:13 PM   #1041
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
QuoteOriginally posted by devorama Quote
Someone has some real world photos from the Q at full res. Some are ISO 1600 and 1250.

http://www.yaotomi.co.jp/blog/used/2011/08/pentax-q-2.html
Wow!

Impressive!

Wonder if these images have been post-processed.

There are a few hot spots (red pixels) in the long exposures, which suggest they haven't been extensively noise reduced.

Judging by the blog entry, the poster said the images were uploaded straight after shooting, so probably not post processed. The poster also promised to take more photos in daylight.
08-26-2011, 06:23 PM   #1042
Pentaxian




Join Date: Sep 2007
Location: La Crescenta, CA
Posts: 7,452




Pentax 1000mm f/8 on the Q.
08-26-2011, 09:29 PM   #1043
ogl
Pentaxian
ogl's Avatar

Join Date: Dec 2007
Location: Siberia
Photos: Gallery | Albums
Posts: 7,114
QuoteOriginally posted by ghelary Quote
Nice trolling attempt. Now please learn what F-stop means.
Learn yourself

08-27-2011, 03:07 AM   #1044
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,863
QuoteOriginally posted by ogl Quote
~ 224 mm/f16 equiv. for FF.

FA77/1.8 ~ 430 mm/f10

FA50/1.4 ~ 280 mm/f8


hard to say that such adapter has any serious sense. just for fun IMO.
Actually, I personally consider the tele converter effect to be the most interesting option offered by the Q.

We don't need to consider the crop factor. The difference in pixel pitch is what is of concern here.

Pentax K-5: 4.75 Ám
Pentax Q: 1.55 Ám

"Pitch-Factor" Q/K-5 = 3.06 (~3)

(the difference in crop factor is a bit larger, like 3.75.)

This means that a DA*300 on the Q could resolve (in theory) like a 900mm lens on a K-5.

A DA*300 has best resolution (and it needs its absolute best to make any sense on the Q) around f/4.7. At f/4.7, the diffraction disk (Airy) radius is 3.15 Ám meaning its diffraction-limited resolution (pixel distance) would be 1.58 Ám. That would be on the edge of things and pixel contrast of a DA*300 on a Q would be small. But not zero if its optical construction permits.

In practical terms, I'd say a DA*300 may resolve like a 500-600mm lens on a Q.

Still good enough and not useless.


BTW,
it's not uncommon to mount small pixel pitch cameras onto large tele lenses. It is the standard technique when doing planet photography, where a webcam is the small pixel pitch camera and a mirror scope is the large tele lense. To improve image quality, stacking a couple hundred images is another standard technique then (as this allows to boots the contrast up to the exact diffraction limit and compensates for air turbulence and tracking issues).

Last edited by falconeye; 08-27-2011 at 03:17 AM.
08-27-2011, 03:57 AM   #1045
Pentaxian
aurele's Avatar

Join Date: Jan 2011
Location: Paris, France
Photos: Albums
Posts: 2,926
QuoteOriginally posted by deadwolfbones Quote



Pentax 1000mm f/8 on the Q.
i did'nt realize what you were showing.

A 1000mm f8 on the Q gives such a huge zoom effect

it's incredible !!

A nice body for birding and no more need for Canon ultra expensive and long lenses
08-27-2011, 05:55 AM   #1046
ogl
Pentaxian
ogl's Avatar

Join Date: Dec 2007
Location: Siberia
Photos: Gallery | Albums
Posts: 7,114
QuoteOriginally posted by falconeye Quote

This means that a DA*300 on the Q could resolve (in theory) like a 900mm lens on a K-5.

A DA*300 has best resolution (and it needs its absolute best to make any sense on the Q) around f/4.7. At f/4.7, the diffraction disk (Airy) radius is 3.15 Ám meaning its diffraction-limited resolution (pixel distance) would be 1.58 Ám. That would be on the edge of things and pixel contrast of a DA*300 on a Q would be small. But not zero if its optical construction permits.

In practical terms, I'd say a DA*300 may resolve like a 500-600mm lens on a Q.

Still good enough and not useless.
.
Like 900 mm or like 600 mm? Only at f4.5?

It's rather strange way to get picture with 600 (900) mm lens resolution:
To buy Pentax Q for USD800 + Q-K adapter for some USD (I think USD200) and then buy DA*300/4 for USD1300....
Wow...it's outstanding. To spend more than USD2000 for make some shots at 1680 mm (without AF!!!) at f4.5 in very good sunny weather at ISO125 with exposure limit 1/2000 .


Don't forget about ISO and exposure (1/2000 only), please. I doubt that It will give any good IQ at ISO above 200.

Last edited by ogl; 08-27-2011 at 06:06 AM.
08-27-2011, 06:08 AM   #1047
ogl
Pentaxian
ogl's Avatar

Join Date: Dec 2007
Location: Siberia
Photos: Gallery | Albums
Posts: 7,114
QuoteOriginally posted by deadwolfbones Quote



Pentax 1000mm f/8 on the Q.
Show me, please, the photos from this combo - 1000 mm needs 1/6000. Pentax Q can only 1/2000.
08-27-2011, 06:53 AM   #1048
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,863
QuoteOriginally posted by ogl Quote
It's rather strange way to get picture with 600 (900) mm lens resolution:
To buy Pentax Q for USD800 + Q-K adapter for some USD (I think USD200) and then buy DA*300/4 for USD1300....
Think about it again.

Many already have a DA*300, the Q will drop to $250 (at least, DxO sees them there) and the parameters you quote aren't that unrealistic.

Say, we speak about a lens which would be equivalent to an APSC lens of 600mm f/8, shot at f/9 - f/10 (it may indeed be too hard to exploit the 900mm reach). The Q has SR, so 1/500s may be fast enough (assuming the focal can be dialed in). The ISO noise is that what would result from f/10 at 1/500s on APSC. E.g., for EV 14.5, you'll only need ISO 200. Which is noiseless. On the Q, you'll actually already use base ISO then.

So, that's perfectly making sense.


I agree, a 600mm f/8 $1000 K-mount lens with ~8 elements and ED glass is the preferred option (*). It just doesn't exist. So, don't neglect an option the Q gives you.

__
(*) As I write in my blog, I actually recommend Pentax to do a 500mm f/5.6 $2000 lens ( -> Falk Lumo: A hypothetical Pentax DFA* 500mm F5.6 ED(IF) SDMii )

Last edited by falconeye; 08-27-2011 at 06:59 AM.
08-27-2011, 07:28 AM   #1049
ogl
Pentaxian
ogl's Avatar

Join Date: Dec 2007
Location: Siberia
Photos: Gallery | Albums
Posts: 7,114
QuoteOriginally posted by falconeye Quote
Think about it again.

Many already have a DA*300, the Q will drop to $250 (at least, DxO sees them there)
OK. Good joke...
08-27-2011, 09:08 AM   #1050
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,863
QuoteOriginally posted by ogl Quote
OK. Good joke...
Joke?
Then look it up here -> DxOMark - Pentax Q

Personally, I'd give it a $350,-

It either drops to this price after first enthusiasts have purchased their box, or Pentax sees it as a limited edition experiment with samples soon being sold out.

In any case, if the price doesn't drop below $400 then there is no reason to discuss the Q at all: because then there are only so few samples out there.

Therefore, if I invest my time to discuss the Q, it is only logical to assume a price which makes sense.


And if you argue the Q is allowed to be more expensive than another good 1/2.3" P&S -- just because it is a system camera with a mount -- then I'd reply that my Phillips ToUcam Pro II has a mount and wasn't more expensive than other webcams.

Last edited by falconeye; 08-27-2011 at 09:21 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!
camera, mirrorless, pentax, 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
Spotmatic motordrive...in the flesh! pickles Pentax Film SLR Discussion 8 08-09-2010 01:00 PM
Of Flesh and Clay dantuyhoa Post Your Photos! 9 11-11-2008 11:57 PM



All times are GMT -7. The time now is 05:14 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