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12-29-2012, 07:51 AM   #31
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QuoteOriginally posted by oeriies Quote
phase detect
I'd be curious to know if you would get any better sharpness at f/1.4 using CDAF from live view.
My Tamron 17-50/2.8 zoom (on a K-x) is sharper fully open when focused that way.

12-29-2012, 07:48 PM - 1 Like   #32
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QuoteOriginally posted by DSims Quote

If you only have $200-300 to spend, any of the Pentax F/FA 50's can be very useful. But they (any of them) need to be thought of as simply a reasonable quality 50mm f/2 lens. Not to worry - I doubt anyone else's cheap 50 is much good below f/2 either.
Your definition of 'much good' is too narrow for my taste. I've got very pleasing results from both 1.4 and 1.7 50s wide open (and also my K 1.2 before it was nicked). If it's hard edges you're after, maybe you have a point, but even there I persist in the view that many of the cases of alleged softness of these lenses wide open can be put down to lack of contrast rather than resolution, and/or the difficulty of focusing accurately. And a dab of selective USM can often bring up the edges if that's what you want. Anyway, sometimes a slightly dreamier look is entirely appropriate.
01-02-2013, 02:55 AM - 1 Like   #33
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QuoteOriginally posted by timo Quote
Your definition of 'much good' is too narrow for my taste. I've got very pleasing results from both 1.4 and 1.7 50s wide open (and also my K 1.2 before it was nicked). If it's hard edges you're after, maybe you have a point, but even there I persist in the view that many of the cases of alleged softness of these lenses wide open can be put down to lack of contrast rather than resolution, and/or the difficulty of focusing accurately.
Cheaper lenses are cheaper for a reason. It doesn't matter whether it's contrast, resolution, or a combination of those plus other factors - if a lens can't hold its image quality as it gets close to wide open then I fail to see the point of it being that "fast" in the first place, and I'm not going to be happy with the results much of the time.

I have both the FA28 Soft and FA85 Soft. Quite frankly, I find it a big challenge to take a shot with them that achieves the look I want - and they're designed to be soft! Usually it just looks like I took a poor photo. Only occasionally have I approached the result I want.

Without a relatively prominent subject (due to sharpness, contrast, color, texture, pattern, or other reasons), even the smoothest or dreamiest background is usually a waste. While not the sharpest lens, the K50/1.2 still gives beautiful photos at or near wide open. The F/FA50/1.4 just looks like a substandard lens was used. I want the photo to look nice to me and others without having to explain what it's "supposed to" look like. So if the photo isn't striking or noticeable to me I don't care what the technical cause is. If it's simply because of the lens I chose, I'm going to choose a different one.

I have a number of quality lenses I really like. I don't view any of them as being even near perfect. But each one gives me a better than average looking image - a pleasing look that I wouldn't have gotten using an average lens with the same composition. Since my compositions are far from perfect, I like to have a lens that gives me an interesting image for those few shots which somehow manage to come close to my goal. Any time I dedicate a couple of hours or more to a shooting session, it seems that I come up with a few images I really do like, and the lens(es) used were an essential component of that result.


I think whenever we use or recommend a better quality lens (regardless of actual price) we increase the odds of producing image(s) that not only capture a viewer's attention, but actually hold it.

Last edited by DSims; 01-02-2013 at 04:01 AM.
01-03-2013, 09:51 AM   #34
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QuoteOriginally posted by oeriies Quote
I own the F 50mm 1.7 and the FA 50mm 1.4. I've tested them for sharpness under identical conditions through the aperture range from wide open to f/8.0: My testing conditions were shots of a $20 bill from about 3 feet away using a tripod-mounted K-5, setting ISO to 100, letting shutter speed vary, using autofocus, and a remote shutter release with a 3 sec delay. I cropped each image to the size of the $20 bill and pixel peeped. I found that the FA 1.4 was quite soft wide-open, sharpening up nicely by f/2.8, whereas the F 1.7 was sharp wide-open and very sharp stopped down to f/2.8, where it held a slight edge on the FA 1.4. After f/2.8 the lenses were very close but I thought the FA 1.4 had more contrast.

While I was at it I tested the zooms I own that have a 50mm focal length, including the DA* 16-50, the DA* 50-135, the F 35-70, and the A 24-50. None was as sharp at 50mm as either the F 1.7 or the FA 1.4. The DA* 50-135 was the best of the zooms, and to my surprise was followed closely by the F 35-70 and then the DA* 16-50. All were acceptably sharp whereas the A 24-50 was soft. My comparison of the zooms was only done systematically at f/5.6. Obviously these zooms might perform differently at other focal lengths and f stops and all of this pertains only to my copies of these lenses and is only about their sharpness at 50mm. As has already been commented on in this exchange, there is more to a lens that its resolution.

As to the choice between the F (or FA) 1.7 and the FA 1.4, based on my copies and tests I would prefer the 1.7 because it is sharper than the FA 1.4 at the fastest apertures, which is where I expect most people want to use a fast lens. And although it is slower than the FA 1.4, unless you want a "dreamy" rendering the 1.4 needs to be stopped down to be acceptably sharp. The 1.7 is also less expensive.

Russ
I have a few of the lenses you have compared.

I have never compared them anywhere near as closely as you have, and thanks to you, I have no need to!

Like and Thanks!

01-03-2013, 12:42 PM   #35
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I only have the FA50/1.4 of the three being considered here and just want to add that ignorance can be bliss too.. Aside from some purple fringing that adds to the post processing at times, I often get results that I am happy with at 1.4. (I always use my hood).... I am sure based on what DSims is saying that if I had some other lenses to compare with, I'd begin to notice the difference. I wouldn't really consider the manual focus lenses because if I am shooting at 1.4 I want autofocus, but I would love to have me some *55 and FA43, and the FA50/1.7... Alas I am just a low budget hobbyist and am used to just making what I have work the best for me that I can and I am happy to have the FA50/1.4...
01-05-2013, 06:33 PM   #36
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One thing that hasn't been mentioned (I don't think) is the different number of aperture blades. Several have said that the bokeh is better with the 8 bladed 50/f1.4 but I don't have a copy. The 50f1.7 meets my needs although I want to buy one of everything but that's not happening this year.
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