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Forum: Pentax SLR Lens Discussion
06-06-2011, 01:33 AM
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I beg to differ here.
1. How sharp is sharp? Sometimes A 50/1.2 is sharp enough wide open. And the wider the aperture the more narrow is DOF - the more critical is AF precision. If all these elements are in place, FA 50/1.4 is very sharp. Again, I am talking about my own preferences. I don't like biting sharpness. I do like smooth tonal gradations and smooth transition from IF (in-focus) to OOF. Here FA 50/1.4 is good enough for prints as large as A3.
2. FA 50/1.4 has the same SMC coatings as FA 43. There may be some difference in coatings specifics, but I've found no flare issues with either lens.
3. As for corner sharpness - again, if we're measuring against standard targets - you may have a point. But if we're talking real-life photography, corner sharpness suddenly becomes moot.
Busy rendering is rubbish in my book. If I have a shot with really busy OOF - it goes to trash bin. Again, IMO which obviously may differ from that of yours, pop has to do with the light and not with the lens. The lens may accentuate the pop, but without proper light, FA 43 won't be of any help.
I'd like to ask you what exactly do you mean by "The 43 has much better colour"?
I certainly agree. It is just that with 43, 55 seems like too close a focal length. 70/77 is more like it. To me.
I tend to disagree. I do agree that the comparison is somewhat silly. However, both lenses can be used as a standard low light short tele/portrait fast optic. I am too lazy, but I think it is entirely possible (and not too difficult) to come up with the dozen shots, where 6 will be shot with FA 50 and another 6 with FA 43 where to tell which is which is going to be nearly impossible.
It was certainly helpful to me, as it got me thinking about certain things. I think that FA 43 and FA 50 are quite close unless like I said earlier in this thread, one is really very well experienced shooter intimately familiar with one's gear. So up to a certain level it is an uneven toss where unevenness comes from the price difference between the two.
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Forum: Pentax SLR Lens Discussion
06-05-2011, 01:49 PM
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Edgar, since you are not clear about why I make certain points, I’ll try again. However, this time I’ll try a different route, so please do not take me as being curt--okay?
In a nutshell, you can not compare a wide-to-normal lens to a near-normal-to-short-telephoto lens and call that apples to apples--IT IS THAT SIMPLE!
Compromises go into wide angle design--compromises which affect performance in other areas, particularly vignetting. Let me give you a concrete example of why your illustration is not apples to apples. What are the vignetting numbers for the 28-75mm @ 17, 18, 19, 20 and so on MMs? There are none, because the 28-75mm is not apples to apples to 17-50mm--right? However, ironically for our discussion, there is a way to provide apples to apples for these 2 lenses because they each provide almost exactly the same focal range on their designed format--right? In other words, on their designed formats, each lens is a wide to normal lens--in other words, on their respective formats, the lenses are apples to apples. ta----daaaaaaaa.
Natural vignetting is unduly affected by wide angle lenses. Again, Natural vignetting is unduly affected by wide angle lenses. Conversely, Natural vignetting is not unduly affected by normal lenses. Is this helping?
If you want apples to apples, place each lens on their intended mounts and look at the vignetting numbers. The reason I did not provide vignetting numbers for the 28-75 on APS-c is because those numbers have no place in this discussion. Now, once again, the reason I got into this discussion is because you wrote something which is not accurate. Here it is again:
 Quote: Edgar in Indy: The only real optical weakness I noticed with the 17-50mm was noticeable vignetting in certain situations. But this is typical for lenses designed for APS-C, as opposed to lenses designed for full-frame (such as the 28-75mm). Am I more clear in this post? The vignette performance of the 17-50 is not a weakness; rather, it is an inherent result of designing a lens from wide to normal--. Also, and again, this is NOT, as you say, “typical for lenses designed for APS-C as opposed to lenses designed for full frame (such as the 28-75mm).” In fact, vignetting is much more typical of lenses designed for full frame. PERIOD!!!!!
Okay, sure, you have a purpose in this thread. You wish to explain the awesome nature of the 28-75. I too bought a 28-75mm Tamron, because I knew it was great value. I too wish to relay its awesome nature here in this thread--but I will not make unfounded claims for its performance---this is our point of departure. You started the thread, this does not license you to censor or dogmatize its content. Okay, I am finished--will not return to this thread now because I have done all time will allow me to do. Best of luck to you. :)
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Forum: Pentax SLR Lens Discussion
05-23-2011, 07:44 PM
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I have both so I'll see if I can take a few in the next day or so.
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