It was still pretty ugly outside today but I wanted to try to do some kind of comparison between all these telephoto zoom lenses I have now. Not much to look at out my back door so I just took some test shots of the radio tower with fake owl on top that is a couple city blocks away.
In my test shots, I compared :
Pentax-A 70-210mm f/4
Vivitar Series 1 70-210mm f/3.5 (v2 - Tokina)
Pentax-F 70-210mm f/4-5.6
Pentax-DA 50-200mm f/4-5.6
Pentax-DA 55-300mm f/4-5.8
Under most realistic shooting settings for this lighting, I would be shooting at f/8-f/11 so I tested each lens under these settings throughout their zoom ranges and I was not very surprised to notice that all of these lenses performed very good to excellent. Sharpness, contrast, and color were all pretty nice considering the gray skies. Only the Vivitar Series 1 lens showed significant different color rendering than the rest (much warmer - more yellow). Other than that, the sharpness and contrast on all were nice at f/8 and f/11. CA and PF was visible (but not bad) from all lenses except DA 55-300mm and F 70-210mm (where I could not spot any at all).
So most of us know that these lenses perform well under ideal situations (and if you didn't know... they do!)... but I wanted to see where the images rendered from these lenses start to fall apart. I wanted to test them to their limits. So I shot the cell tower again, this time at long focal lengths with the lens aperture wide open. My findings definitely show the limitations to some of the lenses, while others pass with flying colors.
All test shots were performed hand-held at 210mm zoom (200mm for DA 50-200) on a Pentax K-x, ISO 200, aperture f/5.6, 1/3200 shutter speed.
Here are the shots:
Pentax-A 70-210mm Vivitar Series 1 70-210mm (v2) Pentax-F 70-210mm
Pentax-DA 50-200mm
Pentax-DA 55-300mm
100% crops of each photo:
Pentax-A 70-210mm
Vivitar Series 1 70-210mm (v2) Pentax-F 70-210mm Pentax-DA 50-200mm
Pentax-DA 55-300mm
The DA 55-300mm lens outperformed all other lenses tested by a considerable margin. Sharpness, color rendering, and contrast were always spot on. I was trying to get this lens to show me some fringing or CA. This is a very nice lens (especially for the money).
After establishing the clear winner, it was harder to place an order to the rest of the lenses. I would probably rank them as follows (considering all aspects of the image quality):
1. Pentax-DA 55-300mm
2. Pentax-A 70-210mm
3. Pentax-DA 50-200mm
4. Pentax-F 70-210mm
5. Vivitar Series 1 70-210mm (v2)
Not to say that the F or Vivitar lenses are not good lenses (far from it in my opinion), I would just say that the A series and DA series lenses are more favorable overall. It was a really tough choice of which one I personally prefer to shoot with between the Pentax-A and Pentax-F. The autofocus is nice on the F but the A has a macro feature and constant f/4 aperture.... in the end I like the solid feel of the Pentax-A over the plasticky feeling Pentax-F although they both were very similar in their rendering. I am a big fan of the classic Vivitar lenses and shoot with them frequently. I also have the version 3 of the Series 1 70-210mm lens that I think will compete better against these Pentax lenses but I don't have it here today. I also have some old Kiron made Vivitar lenses in this zoom range that I think are great and take some amazing photos but the lack of the aperture contacts and the weight of these lenses is a huge disadvantage to the Pentax-A or Series 1 (v2 or V3) so I don't really see them as comparable.
What I have learned from my testing with these lenses today is the DA 55-300 is one darn nice lens, especially for what I paid for it. The other thing I discovered is how well the Pentax-A stands against the competition in this zoom range. It will give the DA 50-200mm a run for its money all day long, and with the constant f/4 aperture and macro function, I would take it over any other of these lenses tested (besides the 55-300).