Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-08-2016, 06:57 PM   #16
Pentaxian
johnyates's Avatar

Join Date: Aug 2011
Location: Saskatoon, SK
Posts: 1,189
QuoteOriginally posted by GregMac Quote
Both were shot in automatic mode in the 'portrait' setting – it seemed to be the best fit for shooting stationary cars, which is most of my subject matter.
Landscape mode would probably be more suitable.

09-08-2016, 08:14 PM   #17
Pentaxian




Join Date: Jun 2008
Location: Flyover America
Posts: 4,475
I agree with others - get the right mode and quit pushing the hell out of the tiny sensor (unnecessarily high ISO).

Also this is the kind of shot that benefits from some bling so don't forget what PP can do for you....

Last edited by wildman; 09-11-2016 at 02:38 AM.
09-14-2016, 12:54 AM   #18
Site Supporter




Join Date: Dec 2012
Location: Perth Western Australia
Photos: Gallery
Posts: 131
My two bits worth: Just took a photo of our cars on the Q with 01 lens which I suggest is the best lens in the Q range.
With Av mode and Iso at 125, the photo defaulted to 1/2000 with aperture wide open (F1.9). Photo is sharp. The 06 lens (15-45mm) is also sharp.
I have no experience with the 02 lens. I usually shoot Jpegs to minimize time on the computer.
09-14-2016, 08:27 AM   #19
Site Supporter
CWRailman's Avatar

Join Date: Feb 2014
Location: Scottsdale, Arizona
Photos: Albums
Posts: 503
QuoteOriginally posted by beachboy2 Quote
My two bits worth: Just took a photo of our cars on the Q with 01 lens which I suggest is the best lens in the Q range.With Av mode and Iso at 125, the photo defaulted to 1/2000 with aperture wide open (F1.9). Photo is sharp. The 06 lens (15-45mm) is also sharp.I have no experience with the 02 lens. I usually shoot Jpegs to minimize time on the computer.
Depending on the amount of available light that sounds about right for those settings.

09-14-2016, 10:38 AM   #20
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,660
QuoteOriginally posted by CWRailman Quote
Personally I believe that diffraction is an over exaggerated issue
Not according to Photozone.

MTF (resolution) Pentax-01 Standard Prime 8.5mm f/1.9

"The Pentax Q camera has a very small sensor so you can't expect the same pixel-level sharpness like in other mirrorless or DSLR systems. That said, the Pentax-01 8.5mm f/1.9 makes the most of the given potential here. It is very "sharp" across the image frame even at max. aperture. The peak performance is then reached around f/2.8. The lens is capable to keep the quality at f/4 before diffraction ends the glory at f/5.6 - this is not a problem of the lens but a limitation of the system due to the small sensor size."

Pentax-01 Standard Prime 8.5mm f/1.9 (Pentax Q) - Review / Lens Test - Analysis

MTF (resolution) Pentax-02 Standard Zoom 5-15mm f/2.8-4.5

As already mentioned in our previous Pentax Q lens test, the system suffers somewhat from its small sensor size. The pixel-level sharpness is not comparable to systems using a bigger sensor. Within its scope the Pentax Q lens does an excellent job though. It is fully usable at max. aperture already and the excellent peak is reached at f/4 (at 5mm and 7mm respectively). You can already observe that diffraction is limiting the performance at the tele end (@ f/4.5). There's a more pronounced quality penalty at f/5.6 and f/8 should be definitely avoided. This is no lens issue but simply a physical limitation (due to the small pixel size) so don't use the aperture settings that you're used to on your DSLR. Remember that f/4 is already equivalent to f/22 on a full format DSLR!

Pentax-02 Standard Zoom 5-15mm f/2.8-4.5 (Pentax Q) - Review / Lens Test - Analysis
09-14-2016, 06:12 PM   #21
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,660
QuoteOriginally posted by Professor Batty Quote
Those charts give both lenses a very good rating at f5.6 with more uniform edge to edge sharpness as well as better CA. With the increased DOF @f5.6 or F8, using the smaller stops on these lenses is definitely a big plus for table top shooters like CWRailman.
The MTF figures are not good in absolute terms. The small sensor on the Q has no resolution to spare. A DA 35mm f2.4 for example resolves almost twice as much at f5.6. http://www.photozone.de/pentax/598-pentax_35_24?start=1

The Q at f8 is equivalent to APS-C at f30. Such extreme dof is unnecessary and definitely not worth the penalty in noise and sharpness.

Stay with f4.5 or wider for better resolution, lower ISO and naturally deep DOF (f4.5 on Q = f16 on APS-C).

Last edited by audiobomber; 09-14-2016 at 06:18 PM.
09-14-2016, 06:30 PM   #22
Site Supporter




Join Date: Nov 2014
Location: South Bend, IN, USA
Photos: Gallery | Albums
Posts: 2,879
QuoteOriginally posted by audiobomber Quote
The MTF figures are not good in absolute terms. The small sensor on the Q has no resolution to spare. A DA 35mm f2.4 for example resolves almost twice as much at f5.6. Pentax SMC DA 35mm f/2.4 AL - Review / Lens Test - Analysis

The Q at f8 is equivalent to APS-C at f30. Such extreme dof is unnecessary and definitely not worth the penalty in noise and sharpness.

Stay with f4.5 or wider for better resolution, lower ISO and naturally deep DOF (f4.5 on Q = f16 on APS-C).
There is something wrong with your logic, but I don't know what that would be.
What I do know is that when I performed my backyard tests with a paper target, my Sigma 70-300mm APO mounted on my Q-7 performed "best" {was the sharpest} in the range f/8 to f/11 when at its maximum of 300mm.
09-15-2016, 04:23 AM   #23
Veteran Member
gbeaton's Avatar

Join Date: Apr 2012
Location: Montreal
Photos: Gallery
Posts: 337
QuoteOriginally posted by audiobomber Quote
Not according to Photozone.

MTF (resolution) Pentax-01 Standard Prime 8.5mm f/1.9

"The Pentax Q camera has a very small sensor so you can't expect the same pixel-level sharpness like in other mirrorless or DSLR systems. That said, the Pentax-01 8.5mm f/1.9 makes the most of the given potential here. It is very "sharp" across the image frame even at max. aperture. The peak performance is then reached around f/2.8. The lens is capable to keep the quality at f/4 before diffraction ends the glory at f/5.6 - this is not a problem of the lens but a limitation of the system due to the small sensor size."

Pentax-01 Standard Prime 8.5mm f/1.9 (Pentax Q) - Review / Lens Test - Analysis

MTF (resolution) Pentax-02 Standard Zoom 5-15mm f/2.8-4.5

As already mentioned in our previous Pentax Q lens test, the system suffers somewhat from its small sensor size. The pixel-level sharpness is not comparable to systems using a bigger sensor. Within its scope the Pentax Q lens does an excellent job though. It is fully usable at max. aperture already and the excellent peak is reached at f/4 (at 5mm and 7mm respectively). You can already observe that diffraction is limiting the performance at the tele end (@ f/4.5). There's a more pronounced quality penalty at f/5.6 and f/8 should be definitely avoided. This is no lens issue but simply a physical limitation (due to the small pixel size) so don't use the aperture settings that you're used to on your DSLR. Remember that f/4 is already equivalent to f/22 on a full format DSLR!

Pentax-02 Standard Zoom 5-15mm f/2.8-4.5 (Pentax Q) - Review / Lens Test - Analysis
Thanks for the disambiguation! Some real useful information there. I was saying that most lenses are best at f8 but of course thats a rough rule of thumb based on die hard held beliefs stemming from 35mm film days. I even know my DA17-70 works very well at f4 so I had my doubts about repeating that mis-information. So trying to keep things simple doesn't always work!

09-15-2016, 08:35 AM   #24
Site Supporter
CWRailman's Avatar

Join Date: Feb 2014
Location: Scottsdale, Arizona
Photos: Albums
Posts: 503
QuoteOriginally posted by audiobomber Quote
Not according to Photozone.

MTF (resolution) Pentax-01 Standard Prime 8.5mm f/1.9

"The Pentax Q camera has a very small sensor so you can't expect the same pixel-level sharpness like in other mirrorless or DSLR systems. That said, the Pentax-01 8.5mm f/1.9 makes the most of the given potential here. It is very "sharp" across the image frame even at max. aperture. The peak performance is then reached around f/2.8. The lens is capable to keep the quality at f/4 before diffraction ends the glory at f/5.6 - this is not a problem of the lens but a limitation of the system due to the small sensor size."

Pentax-01 Standard Prime 8.5mm f/1.9 (Pentax Q) - Review / Lens Test - Analysis

MTF (resolution) Pentax-02 Standard Zoom 5-15mm f/2.8-4.5

As already mentioned in our previous Pentax Q lens test, the system suffers somewhat from its small sensor size. The pixel-level sharpness is not comparable to systems using a bigger sensor. Within its scope the Pentax Q lens does an excellent job though. It is fully usable at max. aperture already and the excellent peak is reached at f/4 (at 5mm and 7mm respectively). You can already observe that diffraction is limiting the performance at the tele end (@ f/4.5). There's a more pronounced quality penalty at f/5.6 and f/8 should be definitely avoided. This is no lens issue but simply a physical limitation (due to the small pixel size) so don't use the aperture settings that you're used to on your DSLR. Remember that f/4 is already equivalent to f/22 on a full format DSLR!

Pentax-02 Standard Zoom 5-15mm f/2.8-4.5 (Pentax Q) - Review / Lens Test - Analysis

While the statement about where a particular lens is the sharpest, hence identifying the sweet spot of any lens is probably accurate, it always amuses me when techno geeks make statements about diffraction and attempt to "scare" a photographer away from using any aperture that is not the sweet spot. They obviously have never spent time with an optometrist nor do they understand how the human eye works or they want to completely ignore those facts. It also makes me wonder if their creative juices are paralyzed by such statement and if they ever take images of anything other than charts or flowers in vases.

During the process of my lady having meetings with eye surgeons at Barnet Dulaney Perkins eye center leading up to her eye surgery this past summer, I had the opportunity to talk with several doctors about how the human eye and brain work together to see and interpret what is seen. Both concurred with what I had known for many years. The human eye first registers color, then shape and finally detail in that order. In assessing an image, that process is more tolerant of slight blur (diffraction) then it is of complete out of focus such as caused by shallow depth of field. Shooting at f 2.8 produces a sharp rendering of everything in a rather narrow focal plane and tells the eye to only look at what is sharp and to ignore that which is not sharp. If all you want a viewer to look at falls within that narrow field of focus you are OK however shooting at smaller f stops such as f8 in the Q system enlarge the area to be considered. Next time you have your eyes checked talk to your optometrist, he or she will explain this to you.

Images tell stories. They freeze moments in time. If you always shoot at the lens sweet spot you may not be telling the story you want to tell. In the case of this image,the story being told is of an old steam locomotive sitting near it’s service facility. (For posting purposes to my WEB site these images were reduced to approximately 33% their original size.The original images are larger and sharper.) The Tonal Expansion effect was chosen for this image to give it the feeling of a oil based painting similar to those produced by Howard Fogg. Railroad historians recognize that silver car in the background not as a passenger car but as a self powered car called a RDC which in part helped to replace steam locomotives on certain routes. So we are showing the past, the steam locomotive, with that to come in the future, the RDC. If I had had used the lenses sweet spot of f2.8 or even f4.0 the entire locomotive would not have been in reasonable focus and that RDC which is off in the distance would not have any shape and would only be a blob of silver in the distance and the story would not be told.


The same image without the Tonal Expansion


For other similar shots in which I ignore the techno geeks check out the Scottsdale Model Railroad Historical Society Gallery Scottsdale Model Railroad Historical Society. Most were shot at f8 using the Q, Q10 or Q7. As I have said in the past, unless you are studying individual pixels and not the entire image, diffraction is grossly over stated and usually by those who do not understand how the human eye works. By the way, while I use other brands of cameras with larger sensors for other types of photography, I still believe that the Q7 is one of the best I have ever used for the type of photography shown above and I continue to recommend it for such. To see how I have reported on the Q series click on my name and go to my CWRailman.com WEB site.

Last edited by CWRailman; 09-15-2016 at 08:41 AM.
09-15-2016, 07:56 PM   #25
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,660
QuoteOriginally posted by audiobomber Quote
The Q at f8 is equivalent to APS-C at f30. Such extreme dof is unnecessary and definitely not worth the penalty in noise and sharpness.
QuoteOriginally posted by Professor Batty Quote
I'll be the judge of that, thank you.

> The Q at f8 is equivalent to APS-C at f30

That part is not judgement, it is a fact, and so is the loss of resolution due to diffraction. Your photo would have been sharper if you had used f5.6 and ISO 400 instead of f8 and ISO 800.

---------- Post added 2016-09-15 at 23:08 ----------

QuoteOriginally posted by CWRailman Quote

The same image without the Tonal Expansion
Both are blurry and the reason the colours needed punching up is because raising ISO reduces colour depth.

F8 on a Q has the same DOF and same diffraction as f45 on a full frame body. I don't know of any scenario where f45 is better than f32.

Last edited by audiobomber; 09-16-2016 at 05:00 AM.
09-15-2016, 08:32 PM   #26
Site Supporter




Join Date: Nov 2014
Location: South Bend, IN, USA
Photos: Gallery | Albums
Posts: 2,879
QuoteOriginally posted by audiobomber Quote
That part is not judgement, it is a fact, and so is the loss of resolution due to diffraction. Your photo would have been sharper if you had used f5.6 and ISO 400 instead of f8 and ISO 800.
Rather amazing then that my tests clearly showed f/11 being better than f/8 when using the Sigma 70-300mm lens on my Q-7.
09-15-2016, 09:33 PM   #27
Site Supporter




Join Date: Sep 2006
Location: midwest, United States
Photos: Gallery
Posts: 3,278
Not really amazing reh321. Diffraction is only one flaw we have to deal with. All this means is lens flaws improved more stopping down to f11 than diffraction degraded the image. Everything has trade offs.

Shoot what works for you and the desired image.
Thanks
barondla

Last edited by barondla; 09-16-2016 at 04:00 PM.
09-16-2016, 03:03 AM   #28
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 15,528
QuoteOriginally posted by reh321 Quote
Rather amazing then that my tests clearly showed f/11 being better than f/8 when using the Sigma 70-300mm lens on my Q-7.
Some lenses just aren't very good and the Sigma isn't one that performs well even close to wide open.
09-16-2016, 07:33 AM   #29
Site Supporter




Join Date: Nov 2014
Location: South Bend, IN, USA
Photos: Gallery | Albums
Posts: 2,879
QuoteOriginally posted by Rondec Quote
Some lenses just aren't very good and the Sigma isn't one that performs well even close to wide open.
However, on my Q-7, the Sigma 70-300 is the best I have at 300mm, better than the Super Takumar 300, the Adaptall 60-300 or the DA 55-300, at least.

More to the point, on my Q-7, this lens clearly performs better at f/11 than at f/5.6, so we have to be careful in proclaiming "never go above ..."


Last edited by reh321; 09-16-2016 at 08:56 AM. Reason: "more to the point"
09-16-2016, 09:42 AM   #30
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,660
QuoteOriginally posted by reh321 Quote
However, on my Q-7, the Sigma 70-300 is the best I have at 300mm, better than the Super Takumar 300, the Adaptall 60-300 or the DA 55-300, at least.

More to the point, on my Q-7, this lens clearly performs better at f/11 than at f/5.6, so we have to be careful in proclaiming "never go above ..."
That's an odd result, because the Sigma has a reputation for softness at the long end. According to DXOMark, the 55-300mm should be sharper at f5.8 than the Sigma at f11.
Click on Measurements, Sharpness, Field Map, focal and aperture: https://www.dxomark.com/Lenses/Compare/Side-by-side/70-300mm-f-4-5.6-APO-DG-...59_865_279_914

Not to insult you, but the IQ of that image is not within acceptable range for me, even at this small size.
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!
aps-c, camera, diffraction, dof, f30, f8, focus, image quality, mirrorless, pentax q, pentax q10, pentax q7, q-s1, q10, q7, quality, quality making camera, subject
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Choices... Pentax or Sigma Best image quality for the Money... help me Pentaxians Krusty Surfer Pentax SLR Lens Discussion 28 12-01-2014 11:18 AM
Best Compact Camera For Image Quality & Low Noise reivax Non-Pentax Cameras: Canon, Nikon, etc. 3 01-05-2014 10:03 PM
Same camera, different photographers, image quality different? Corvairfan Troubleshooting and Beginner Help 50 12-02-2010 06:29 AM
Desperately NEED HELP choosing a lens irelandswind Pentax SLR Lens Discussion 16 10-14-2010 09:37 AM
KX in camera noise reduction shut it off to improve image quality jlaubza Pentax DSLR Discussion 14 04-27-2010 01:11 PM



All times are GMT -7. The time now is 01:42 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