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04-20-2008, 03:29 PM   #1
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New AL 2 kit vs A50 1.7 vs A50 2.0

NOTE: Currently using photobucket to host pix. I'd like higher resolutions available for posting, so if you know of a free hosting service that will allow larger file size, please PM me.

I picked up a new AL 2 kit lens to replace the glass I recently sold to fund a trip. I wasn't sure about the level of alleged lens resolution improvements that Pentax claimed were needed for the K20D, so I decided to compare it with my A 50mm f1.7 and the A 50mm f2.0 in my bag.

I was saddened by what I found on the new kit lens, but thrilled to find that my sample of the A series 50mm f2.0 lens is awesome.

Since this idea hit me at work, the first pictures taken were in the office with the flash. All lenses are sans filter. Bare glass for all photos. So, camera set to Av at f8.0 this is what I got:

The color reproduction is very good for all three lenses, but try to guess which lens is which... The 18-55 AL II lens should be obvious. It is on the right and lacks some definition and resolution.

Those of you familiar with the A 50mm f1.7 will know that the darker image is the 1.7. It generally requires an exposure compensation of .7 or so. I love this lens. It is the best glass in my bag.

Now study the A 50mm f2.0. Good color, excellent sharpness - on par with the f1.7 easily. I was expecting to see some small contrast problem or chromatic aberration because of the flash, but the f2.0 held up just fine. Except for the exposure compensation, it would be impossible to tell which photo was taken with the f1.7 lens. Excellent!

The next test would be the outdoor photos. In the sunshine, a lesser lens will display some minimal flare, or ghosting, or ... something... So here I'm expecting to separate the rams from the goats.

Again, camera set to f8, flash off, I sat about 3 or 4 feet from my subject and snapped pictures only moments apart.

Again, you can see the difference between the 50 f1.7 and 50 f2.0 is primarily the exposure compensation. Also worthy of note is the definition of the two pictures. Overall they're nearly identical - even when you pixel peep - but the A 50mm 1.7 appears to have more 3D look to it. Better depth is evident, but I wouldn't want to live on the difference.

The DA 18-55mm AL II kit lens may have improved resolution to match the K20D, but I'm having trouble finding those improvements. Just have a look at the left side of the frame. The flower near the edge of the capture area is comparatively very fuzzy. Colors are good, but the new AL II is just too soft for my liking. Get what you pay for in this case.

Perhaps it isn't fair to compare the zoom kit lens to a pair of primes, but frankly I was expecting a closer competition than this. The new kit lens falls well short of my expectations for a lens that is supposed to have been improved.

In these tests, the pleasant surprise was the A 50mm f2.0. Turns out it is a very fine lens; comparable to the faster 1.7 sibling. This is by no means a comprehensive testing, but thus far it looks like the 50mm f2.0 is the most under-appreciated lens on these boards. Even in the sunlight picture where a slight loss of 3D depth was noted, the difference could simply have been the lack of exposure compensation for the f1.7. Match the exposures & the 2.0 may indeed be the equal to the 1.7 under most conditions - which I expect is the case.

So, those of you wanting a super sharp & inexpensive lens, I would suggest you not shy away from a 50mm f2.0 - particularly the A series. Based on my own use of that lens compared to the f1.7 you will be well pleased with it.

Next I'll do some comparisons between the two A series 50mm lenses at their limits. Expect a difference, but if experience is any indication, it won't be much.

04-20-2008, 03:39 PM   #2

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I have never used the A 2.0 but I think its grand that it holds up to the 1.7 now we need a test against the 1.4. as for the kit lens... its still better than other kits. my concern about the II is with fixing the vignetting at 18mm because my 18-55 ruined a few shots at the beach a few months back... not that I'm looking to buy the II. I haven't even mine since then.
04-20-2008, 08:19 PM   #3
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TourDeForce, good test though I'm a little surprised by your comment that the A 50mm f/1.7's has a tendency to underexpose and requires a +2/3 stop compensation. Well I had both the A 50mm f/1.7 & A 50mm f/2 and I never needed to dial in any compensation for my f/1.7. I do agree that the f/2 is under-rated and actually deserves more credibility and acceptance than it usually gets. Definitely cheap and very good.
04-20-2008, 08:29 PM   #4
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good work TourDeForce
be nice to throw in a 1.4 somewhere


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