Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Nov 20, 2006, 12:17 AM   #21
Member
 
Join Date: Sep 2006
Posts: 49
Default

Catbells wrote:
Quote:
Quote:
chacha wrote:
The photos for the 18--200mm lens was more helpful, but the photos for the 18-55mm was less so because you scrambled the photos for the 18-55mm lens. I was not able to unscramble them to make sense. Sorry.

But what I observed in the 18-200 mm was that the Sigma was soft and really clipped it's highlights. The Tamron was too dark, but had great highlights (see the window sills above the sign.) The Pentax was so bright and vivid that it seemed like a different day.
I'm not sure what you mean by 'scrambled' There are two sets of images - 18mm & 55mm. There are two columns for each with the Pentax JPEG at the the top. On the left hand side are the JPEG images for the Sigma & Tamron & on the right hand side, the RAW converted images.

I agree that the images are probably not so good so as to allow a constructive comparison - at the original time of posting, I carried a link to the full size image which was obviously clearer. But it does sort of indicate that at these focal lengths, the Sigma & Tamron preform reasonably well against the Pentax DA 18-55mm.

The shots at a longer focal length using the Sigma & Tamron were on the same day & the results from these convinced me to go for the Pentax DA 50-200mm. Several days passed before I took delivery of the lens & I tried to choose a day that was as near to that for the Sigma/Tamron comparison - so yes, the Pentax images were taken on a different day - BUT they really did convince me that I'd made the right choice.

Have a look at these reviews and you'll see that the Sigmas has real problems at 135mm & beyond - particularly with the Canon>

http://www.photozone.de/8Reviews/len...3563/index.htm

http://www.photozone.de/8Reviews/len...3563/index.htm

Given the choice of the Sigma or Tamron, I'd go for the Tamron - at least it focuses at 200mm.
Hey Catbells, actually the pictures were great for comparison and very thoughtful. But here's what I meant by "scrambling". In the 18-55mm pictures: The first set has the Pentax 18-55 @18 listed in both rows. Then below ityou listed asigma 18-200mm @ 18mm row one and raw row two. Then the Tamaron as an 18-200mm row one jpg and row two raw. So because row one is listed as an 18-55mm pentax (both rows jpg shots) and then the next two rows are 18-200mm lens, Icould notcompare the first row shots to row two and three. Row four has the pentax 18-55 at 55mm row one jpg and row two jpg, then rows five and six have the sigma and tamaron lense properly columned (but listed as 18-200mms), at 55mm jpg row one and 55mm raw rows two. I realize now that you meant the sigma and tamarons to be listed as 18-55mms and the pentax to be shown as jpg and raw and at 18mm row one and 55mm row four. So thank you for all the work it took to get those things labeled and uploaded. The only real glitch is that the pentax pictures for the 18-55mm lense have the same jpg picture in each row, rather than a raw in rows two. So, with my gratitude for your infinite patience, here's my observation on the pentax short lense. It seems like at 55mm, it's too dark. I feel the other two lens are sharper at both ends of the short lense. Apart from the fact that the pentax 50-200 is clearly superior to the other two, which short lense do you prefer of the three? Now this raises a question, if you go to the imageresource.com web site and compare the sample still life picture of the k100 at enlarged view and the same still life sample of say the nikon d50 at enlarged view, the k100 seems soft (as in fuzzy)--see the crayons for example, while the nikon d50 is sharp.Also if you look at the enlarged view of the still life for the k100 at normal and high saturation the shoe lace color, expecially reds, are run together, so there is no detail. Is thisan issue with the lens used or is it an issue with the cameras. I plan on printing my pictures large on my epson 7800 printer, so this is an important question for me. ChaCha
chacha is offline   Reply With Quote
Old Nov 20, 2006, 5:04 AM   #22
Senior Member
 
Catbells's Avatar
 
Join Date: Nov 2004
Posts: 874
Default

chacha wrote:
Quote:
Hey Catbells, actually the pictures were great for comparison and very thoughtful. But here's what I meant by "scrambling". In the 18-55mm pictures: The first set has the Pentax 18-55 @18 listed in both rows. Then below ityou listed asigma 18-200mm @ 18mm row one and raw row two. Then the Tamaron as an 18-200mm row one jpg and row two raw. So because row one is listed as an 18-55mm pentax (both rows jpg shots) and then the next two rows are 18-200mm lens, Icould notcompare the first row shots to row two and three. Row four has the pentax 18-55 at 55mm row one jpg and row two jpg, then rows five and six have the sigma and tamaron lense properly columned (but listed as 18-200mms), at 55mm jpg row one and 55mm raw rows two. I realize now that you meant the sigma and tamarons to be listed as 18-55mms and the pentax to be shown as jpg and raw and at 18mm row one and 55mm row four. So thank you for all the work it took to get those things labeled and uploaded.
I still don't think that I've necessarily explained myself too clearly.

In the tests that I performed, I used The Pentax DA 18-55mm, Sigma 18-200mm & Tamron 18-200mm lens.

Because the Pentax is limited to 55mm, I took a set of images at 18mm with each lens followed by a set of images at 55mm, again with each lens.

I also shot RAW images with the Sigma & Tamron BUT for some strange inexplicable reason, didn't shoot any RAW images with the Pentax.

At the top of each column in each of the comparisons, is the Pentax JPEG image. On the left hand side are Sigma & Tamron JPEGs & on the right hand side, RAW converted images thus:

Row 1. Column 1, Pentax 18-55mm lens set to a focal length of 18mm - JPEG
Row 2. Column 1,Sigma 18-200mm lens set to a focal length of 18mm - JPEG
Row 3. Column 1,Tamron 18-200mm lens set to a focal length of 18mm - JPEG
Row 1. Column 2, Pentax 18-55mm lens set to a focal length of18mm - JPEG
Row 2. Column 2,Sigma 18-200mmlens set to a focal length of 18mm - RAW converted
Row 2. Column 2,Tamron 18-200mmlens set to a focal length of 18mm - RAW converted

Row 4. Column 1, Pentax 18-55mmlens set to a focal length of 55mm -JPEG
Row 5. Column 1,Sigma 18-200mmlens set to a focal length of 55mm -JPEG
Row 6. Column 1,Tamron 18-200mmlens set to a focal length of 55mm - JPEG
Row 4. Column 2, Pentax18-55mmlens set to a focal length of 55mm -JPEG
Row 5. Column 2,Sigma 18-200mmlens set to a focal length of 55mm - RAW converted
Row 6. Column 2,Tamron 18-200mmlens set to a focal length of 55mm - RAW converted

Also, be careful when comparing test results from one camera against another. I know that reviewers do try to keep their test conditions as closely matched as possible but JPEG images used in 'in camera' processing and are a quick way to produce a relatively good image. The JPEG quality depends very much upon the manufacturer and yes, there will be differences say between Canon, Nikon, Pentax etc.

In RAW, it's very much different as the basic detail is contained in each shot with the conversion being done by the user. Depending upon which RAW converter you use will also depend upon the quality of the converted image but you also have much more control over the output with such things as colour, saturation, contrast, sharpness etc.

Before I bought my *istDS, i was initially very disappointed with the shots that appeared on this review site (and others) as they appeared soft compared against other brands- these were the JPEG images & not RAW.

As I delved deeper into things & became better enlightened through this & other forums, I soon appreciated that basically, all dSRLs at similar CCD sizes will produce an image of near identical quality when taken in RAW; it's the lens that makes the difference - the better the lens, the better the image quality will be.

Major differences in camera design are more to do withergonomics, lens availability, backwards compatability for lens, what accessories are available etc. I liked the *istDS because at that time it was the most compact dSRL available (which suited my purpose for hiking) and it just felt right in my hands.
Catbells is offline   Reply With Quote
Old Nov 20, 2006, 5:20 PM   #23
Member
 
Join Date: Sep 2006
Posts: 49
Default

Catbells wrote:
Quote:
chacha wrote:
Quote:
Hey Catbells, actually the pictures were great for comparison and very thoughtful. But here's what I meant by "scrambling". In the 18-55mm pictures: The first set has the Pentax 18-55 @18 listed in both rows. Then below ityou listed asigma 18-200mm @ 18mm row one and raw row two. Then the Tamaron as an 18-200mm row one jpg and row two raw. So because row one is listed as an 18-55mm pentax (both rows jpg shots) and then the next two rows are 18-200mm lens, Icould notcompare the first row shots to row two and three. Row four has the pentax 18-55 at 55mm row one jpg and row two jpg, then rows five and six have the sigma and tamaron lense properly columned (but listed as 18-200mms), at 55mm jpg row one and 55mm raw rows two. I realize now that you meant the sigma and tamarons to be listed as 18-55mms and the pentax to be shown as jpg and raw and at 18mm row one and 55mm row four. So thank you for all the work it took to get those things labeled and uploaded.
I still don't think that I've necessarily explained myself too clearly.

In the tests that I performed, I used The Pentax DA 18-55mm, Sigma 18-200mm & Tamron 18-200mm lens.

Because the Pentax is limited to 55mm, I took a set of images at 18mm with each lens followed by a set of images at 55mm, again with each lens.

I also shot RAW images with the Sigma & Tamron BUT for some strange inexplicable reason, didn't shoot any RAW images with the Pentax.

At the top of each column in each of the comparisons, is the Pentax JPEG image. On the left hand side are Sigma & Tamron JPEGs & on the right hand side, RAW converted images thus:

Row 1. Column 1, Pentax 18-55mm lens set to a focal length of 18mm - JPEG
Row 2. Column 1,Sigma 18-200mm lens set to a focal length of 18mm - JPEG
Row 3. Column 1,Tamron 18-200mm lens set to a focal length of 18mm - JPEG
Row 1. Column 2, Pentax 18-55mm lens set to a focal length of18mm - JPEG
Row 2. Column 2,Sigma 18-200mmlens set to a focal length of 18mm - RAW converted
Row 2. Column 2,Tamron 18-200mmlens set to a focal length of 18mm - RAW converted

Row 4. Column 1, Pentax 18-55mmlens set to a focal length of 55mm -JPEG
Row 5. Column 1,Sigma 18-200mmlens set to a focal length of 55mm -JPEG
Row 6. Column 1,Tamron 18-200mmlens set to a focal length of 55mm - JPEG
Row 4. Column 2, Pentax18-55mmlens set to a focal length of 55mm -JPEG
Row 5. Column 2,Sigma 18-200mmlens set to a focal length of 55mm - RAW converted
Row 6. Column 2,Tamron 18-200mmlens set to a focal length of 55mm - RAW converted

Also, be careful when comparing test results from one camera against another. I know that reviewers do try to keep their test conditions as closely matched as possible but JPEG images used in 'in camera' processing and are a quick way to produce a relatively good image. The JPEG quality depends very much upon the manufacturer and yes, there will be differences say between Canon, Nikon, Pentax etc.

In RAW, it's very much different as the basic detail is contained in each shot with the conversion being done by the user. Depending upon which RAW converter you use will also depend upon the quality of the converted image but you also have much more control over the output with such things as colour, saturation, contrast, sharpness etc.

Before I bought my *istDS, i was initially very disappointed with the shots that appeared on this review site (and others) as they appeared soft compared against other brands- these were the JPEG images & not RAW.

As I delved deeper into things & became better enlightened through this & other forums, I soon appreciated that basically, all dSRLs at similar CCD sizes will produce an image of near identical quality when taken in RAW; it's the lens that makes the difference - the better the lens, the better the image quality will be.

Major differences in camera design are more to do withergonomics, lens availability, backwards compatability for lens, what accessories are available etc. I liked the *istDS because at that time it was the most compact dSRL available (which suited my purpose for hiking) and it just felt right in my hands.
Catbells. Wow, thank you for that very considerate and thoughtful reply. I am astounded at the patience and the good will of pentax users when it comes to forum responses. And please forgive the fact that this reply comes with my quote and your quote at length. I do not know how to extract just the relevant part of a quote to be included in my reply.

Phew, thanks to your patient "explanation" I now understand your photo arrangement and can see just how helpful they are. Still though, my study of lens output is so new, that for some reason I'm just not "yet" able to form conclusions from all the image differences of the 55mm and below length pictures. I see so many things that I don't know what to think. So I'm going to take your conclusion as right. However at 200mm the pentax is clearly superior.

Regarding your extremely valuable cautions about comparing camera image quality from review sites photos. Words cannot express how important your information is and will be. It's taking me a little longer than others to make a decision on camera choice firstly because I always take forever to understand photography technology. I'm an oil painter and I have always envied photographers who can so quickly grasp camera technique and nomenclature. They also have an advantage in understanding the use of photoshop. But I'm very stubborn and so when I commit to learning something, I eventually get there. But also I decided to hold off on buying a k100 because one forum writer advised that an important issue is upgrading. I want to see how the k10 turns out before I start making investments in pentax lens and accessories. If it bombs, I'm either going with the new nikon d40 or the canon rebel xti. Like you, I actually like the smaller dslr bodies (and the canon and k100 little grips are fine).

So while I have been waitng for the k10 reviews, I have unexpectantly fallen in love with the nikon d50 review photos that I see. The default color setting, when toned down a couple stops to protect the highlights, produces a "look" that I really like. It's color is--pardon my use of non technical words--rich, silky, creamy looking. I think the technical wording would be rich color density. So since the d40, smaller body than the d50,is producing the same "color look" of the d50 (see the imagingresource web site photos from the d40), I have put it on my maybe list, if the k10 bombs.

But with the cautions that you have included in your last forum reply, I am guessing that shooting in raw, I should be able to photoshop the same d50-d40 color density "look" from any dslr, including from the k100; especially since the default color setting of the d50 is their consumer setting and probably not naturalistic. But I'm still concerned with the k100d normal and especially high saturation color settings as portrayed in the www.imagingresource.com sample test still life photo. The red shoelace color is really bleeding in the high saturation picture and moderately bleeding in the normal. It only reads red shoe lace in the low saturation picture. When you compare it to the d40 same same still life, only the high saturation version bleeds moderately. Be honest, am I knitpicing? Shouldn't I expect sharp detail in the normal saturation picture from the k100? I realize that these are jpgs and not raws. Maybe I should check the results from the other entry dslr's?

Well, Catbells, I realize I'm taking up a lot of your time. And I am thankful that you are the one who has latched onto my thread and tried to help. I really appreciate it. Thanks. ChaCha

chacha is offline   Reply With Quote
Old Nov 21, 2006, 12:34 PM   #24
Senior Member
 
Catbells's Avatar
 
Join Date: Nov 2004
Posts: 874
Default

chacha wrote:
Quote:
Well, Catbells, I realize I'm taking up a lot of your time. And I am thankful that you are the one who has latched onto my thread and tried to help. I really appreciate it. Thanks. ChaCha
You're very much welcome.

Glad to have been of help.
Catbells is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 4:48 AM.