Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax Lenses

Reply
 
Thread Tools Search this Thread
Old Oct 9, 2007, 9:45 PM   #1
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

Well since I posted a comparison of the wide angle lens I have, I thought I would go ahead and do some other comparisons. So I have 2 lenses that are moderate telephoto zooms.
Pentax DA 50-200 mm f4 - 5.6
Pentax FA J 75-300 mm f4.5-5.8

This may be a bit of apples to oranges, since at 200mm, were at the end of one lens and about mid point of the other, but this is what I have and here was a common area. So the full frame images were taken in Raw converted to Jpg by the Pentax supplied software and then resized to 800x600 using IfanView, then saved at 95% to meet the file size limitations here.

The center of each image is the same. The focus box was centered on the small out cropping of rock just below the ridge, thus each lens (with the 75-300 set at 200mm) should have had the same focal point, where only the optical field of view would have varied in the lens design.

The detailed crops are full sized (no resizing and at 100%)

Pentax DA 50-200 mm - 200mm 1/180 f8 ISO 200
Pentax FA J 75-300 mm - 200mm 1/180 f8 ISO 200

So here is Pentax DA 50-200 mm - 200mm 1/180 f8 ISO 200


Attached Images
 
interested_observer is offline   Reply With Quote
Sponsored Links
Old Oct 9, 2007, 9:46 PM   #2
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

and here is Pentax FA J 75-300 mm - 200mm 1/180 f8 ISO 200

Attached Images
 
interested_observer is offline   Reply With Quote
Old Oct 9, 2007, 9:47 PM   #3
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

here is a full sized crop of Pentax DA 50-200 mm - 200mm 1/180 f8 ISO 200

Attached Images
 
interested_observer is offline   Reply With Quote
Old Oct 9, 2007, 9:50 PM   #4
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

and (I lied 99% to make it fit) crop of Pentax FA J 75-300 mm - 200mm 1/180 f8 ISO 200
Attached Images
 
interested_observer is offline   Reply With Quote
Old Oct 9, 2007, 9:57 PM   #5
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

While doing the croping I noticed that the 75-300 was brighter, however the 50-200 (to my eye) had more detail and deeper color. I tried to crop the same visual region, however the each of the lenses as it applies the image across the pixels of the sensor, does apparently add some distortion as it maps the image across the sensor, thus the physical size difference between the two crops. Also, each image was taken only a minute or so appart so the sun light should not have varied that much (the 50-200 image was taken first, so if anything it had better light). Also the exposure and aperature were exactly the same for each image, so this should be apples to apples.

I guess you would refer to the 50-200 lens as the telephoto kit lens, since it pretty much goes hand in hand with the actual kit (18-55) lens. Overall, paring the two, I am very happy with the pair. I'll leave it to the rest to you to make additional comparisons and comments.

Just as a point of interest, I pulled up Google Earth, and took some measurements. Its about 500 feet from where I was standing to the trees in the foreground of the crops. Also about 2,500 feet (or about a half a mile) to the face of the mountain that is the main focus point of the images. Actually, for that range, I think that the detail is great.

Actually jump on over to the last comparison on the wide end and see what the entire view looked like at 16, 17, and 18mm...

http://forums.steves-digicams.com/fo...mp;forum_id=94

... also there was a discussion on the 75-300 on another thread

http://forums.steves-digicams.com/fo...mp;forum_id=94

enjoy!!!!
interested_observer is offline   Reply With Quote
Old Oct 10, 2007, 8:07 AM   #6
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,052
Default

Looks like the 50-200 is sharper, though that's probably to be expected. You notice it more with the crops than with the resized ff versions. An interesting comparison.
mtngal 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 1:26 AM.