Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-17-2009, 08:44 AM   #1
Inactive Account




Join Date: Dec 2009
Posts: 14
Why can't the K7 render these details?

Recently purchased a K7, which I haven't begun using yet, but I just came across the Imaging Resource review of the camera. So, mostly good stuff I guess, but one thing that I worries me about about the review is the camera's inability to render the red leaf fabric details like all the other cameras can. Instead of rendering any detail whatsoever, the fabric is completely blurred. No other camera does this. What's going on?

Attached Images
View Picture EXIF
PENTAX K-7  Photo 
12-17-2009, 08:54 AM   #2
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,314
i'm not sure I can follow, I can see details in the image you posted,

what are you looking at specifically?

Also is this a question of blurring i.e. indicating poor focus on a red image or lack of resolution due to color saturation
12-17-2009, 09:05 AM   #3
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,600
Remember the IR samples are JPG's, and reflect the camera defaults for saturation, sharpness, contrast, noise reduction etc, which vary slightly from camera to camera and brand to brand. Your own results will also vary considerably from the IR samples in real life, depending on how you tell the camera to render JPG's recorded by the camera.

Your results will vary even more from the IR samples if you shoot in RAW and process your own JPG's from RAW. Which is usually the best way to go if you want excellent image quality.
12-17-2009, 09:10 AM   #4
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
I am continually astounded by people's ignorance when reading reviews. One picks a litle corner and says "see, see it can'tdo that" or "see, see camera X is better than Y" without considering for a second that processing parameters will influence different parts of theimage differently.

This is why we have RAW and we have pping software, inthis example you just decrease the red luminance a tad if you're so inclined.

Jesus.

12-17-2009, 09:13 AM   #5
Veteran Member




Join Date: May 2007
Location: Prince George, BC Canada
Photos: Gallery | Albums
Posts: 644
I don't find that to be a problem with my K-7 ...here is a shot of a very deep red bagonia and the detail shows.

PentaxForums.com - MikePerham's Album: Fayes Garden - Picture
12-17-2009, 09:19 AM   #6
Veteran Member
netuser's Avatar

Join Date: Oct 2008
Location: Azores Islands, Portugal
Photos: Gallery
Posts: 2,241
Hi sammie

All cameras/brands have their colour trouble. On Pentax it's the red one.
When I have red subjects I shoot raw becauseI know almost 100% that I will have to ajust the colour saturation, contraste etc.

Just my 2 eurocents
12-17-2009, 09:51 AM   #7
Inactive Account




Join Date: Dec 2009
Posts: 14
Original Poster
Thank you for posting the link: gorgeous picture!

And, thanks for all other thoughtful responses. Certainly, I am coming from place of naivity as my wife is the phtographer in the family. I just got her a major upgrade for this Christmas, and I do want to make sure I made the right choice...camera can still be returned. So, anyway, there's a lot I don't understand. I do appreciate your patience. Happy Holidays!
12-17-2009, 10:03 AM   #8
Pentaxian




Join Date: Mar 2009
Location: Perth Australia
Photos: Albums
Posts: 1,511
i think sammie raises a good point, but it really flags an issue with the comparometers process (not the camera) since jpg output is irrelevant when your pixel peeping like this as you'd be using raw anyway!

12-17-2009, 10:04 AM   #9
Pentaxian
MRRiley's Avatar

Join Date: Feb 2007
Location: Sterling, VA, USA
Photos: Gallery | Albums
Posts: 6,276
First, welcome to PF Sammie! Second, rest assured that you've bought your wife a very very fine camera. Pentax in general does indeed have problems with RED but no more so than other cameras have other problems. As you can see from Mike's example, red can be handled to perfection.

Mike
12-17-2009, 11:11 AM   #10
Veteran Member
Jasvox's Avatar

Join Date: Oct 2007
Location: Melbourne, Australia
Posts: 3,110
"Recently purchased a K7, which I haven't begun using yet..."

Maybe after you begin to use yours, you will be happy with it like most people are. I bet you'll find that in the real world and in real life scenarios, this camera is quite capable of rendering plenty of detail.

Jason
12-17-2009, 11:36 AM   #11
Veteran Member




Join Date: Sep 2007
Location: USA
Posts: 1,812
QuoteOriginally posted by sammie Quote
Recently purchased a K7
I just came across the Imaging Resource review of the camera. So, mostly good stuff I guess, but one thing that I worries me about about the review is the camera's inability to render the red leaf fabric details like all the other cameras can. Instead of rendering any detail whatsoever, the fabric is completely blurred. No other camera does this. What's going on?
First I think this is a really good call and observation.

JPGs have a difficult time rendering in the red - the lossy compression seems worst in red - anyone can easily see this for themselves by saving in JPG with increasing compression.

However I believe most APS-C dSLRs all have this problem to an extent.

I think the crop shown was at ISO1600 or above - this is intrinsically pretty noisy for an APS-C sensor - it is actually pretty amazing the image quality that modern dSLR are capable of extracting.

But let us see some actual examples and comparisons all crops from Imaging-Resource sample test shots -

First establish a baseline -

All crops still have their EXIF data attached

At ISO200 -

as one can see the K7 does pretty well against the 12Mp FULL-FRAME Nikon D3S at its true base ISO.

Of course the details are destroyed by ISO1600 for the K7 -
but it is not alone -
compare to the top of the line APS-C dSLRs Nikon D300s and Canon 7D -

yes, the Nikon and Canon are a bit better - but really nothing to write home about - especially if one compares these to the baseline shots at ISO200 above -
by ISO3200 both the Nikon and Canon look pretty bad too:


Actually the K7 at ISO800 is still pretty respectable for this patch -


all this means is that there is probably a "leap" in noise at and above ISO1600 -
and unfortunately Pentax strategy in its JPG appears to sacrifice more in the red area.....

However what really surprised me was this:

I think the K7 uses the same Samsung sensor as the Pentax K20D - look how much detail is retained in that same red area even at ISO3200!
The K20D ISO200 crop is included for a base reference.
12-17-2009, 01:48 PM   #12
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
But it's all pointless, all of it. Look somewhere else ont he frame and it all gets turned on it's head. not to mention if you just dial down saturation/red luminance then it's problem solved.

The comparometer is a great idea until you actually start tjhinking about it when you realise it's near useless for serious comparisons.
12-17-2009, 01:59 PM   #13
Veteran Member




Join Date: Mar 2007
Location: U.K.
Posts: 685
Every Beyer sensor digital camera I've used has problems with red detail. Probably a Foveon sensor is best but I haven't used a camera with one.

The best way to get a good detailed image with bold red textures is to slightly underexpose and use RAW, then play around with the RAW converter's exposure and saturation settings. If printing, it's good to use Qimage which can sharpen reds more than other colours at print time, which helps to overcome Beyer resolution losses in the red channel.
12-17-2009, 07:07 PM   #14
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 6,982
Here is some red, taken last week while doing focus tests with the K7.
ISO 320, f5.6, 300mm with DA*300 f4. Image already at 100%.
JP

Last edited by jpzk; 08-30-2015 at 06:47 PM.
12-17-2009, 10:53 PM   #15
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,148
QuoteOriginally posted by sammie Quote
Recently purchased a K7, which I haven't begun using yet, but I just came across the Imaging Resource review of the camera. So, mostly good stuff I guess, but one thing that I worries me about about the review is the camera's inability to render the red leaf fabric details like all the other cameras can. Instead of rendering any detail whatsoever, the fabric is completely blurred. No other camera does this. What's going on?
Make sure you have turned Noise suppression OFF, or if at high ISO, to its lowest setting. Shoot RAW and open it in whatever your PP program is. This looks like noise suppression to me.
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, fabric, k7, photography, review
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Some more details on K-r (AF etc.) Noisychip Pentax News and Rumors 9 09-11-2010 02:50 PM
Details Of Spring Nitrok Post Your Photos! 3 05-07-2009 11:36 AM
Winter Details II Nitrok Post Your Photos! 11 03-01-2009 04:45 AM
3 details from a church lukastrika Post Your Photos! 5 06-01-2007 09:00 AM
Render Delay tparker Pentax DSLR Discussion 4 01-07-2007 10:26 AM



All times are GMT -7. The time now is 08:13 PM. | 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